Merge branch 'master' into master

.github/workflows/main.yml

@@ -43,7 +43,7 @@ jobs:
 
       - name: Delete composer lock file
         id: composer-lock
-        if: ${{ matrix.php-version == '8.0' || matrix.php-version == '8.1' }}
+        if: ${{ matrix.php-version == '8.1' }}
         run: |
           rm composer.lock
           echo "::set-output name=flags::--ignore-platform-reqs"
@@ -124,6 +124,37 @@ jobs:
       - name: Code style with PHP_CodeSniffer
         run: ./vendor/bin/phpcs -q --report=checkstyle | cs2pr
 
+  phpstan:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup PHP, with composer and extensions
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+          extensions: ctype, dom, gd, iconv, fileinfo, libxml, mbstring, simplexml, xml, xmlreader, xmlwriter, zip, zlib
+          coverage: none
+          tools: cs2pr
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Static analysis with PHPStan
+        run: ./vendor/bin/phpstan analyse
+
   coverage:
     runs-on: ubuntu-latest
     steps:

.php_cs.dist

@@ -160,7 +160,7 @@ return PhpCsFixer\Config::create()
         'php_unit_test_annotation' => true,
         'php_unit_test_case_static_method_calls' => ['call_type' => 'self'],
         'php_unit_test_class_requires_covers' => false, // We don't care as much as we should about coverage
-        'phpdoc_add_missing_param_annotation' => true,
+        'phpdoc_add_missing_param_annotation' => false, // Don't add things that bring no value
         'phpdoc_align' => false, // Waste of time
         'phpdoc_annotation_without_dot' => true,
         'phpdoc_indent' => true,

CHANGELOG.md

@@ -9,6 +9,38 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Added
 
+- Implemented the CHITEST(), CHISQ.DIST() and CHISQ.INV() and equivalent Statistical functions, for both left- and right-tailed distributions.
+- Support for ActiveSheet and SelectedCells in the ODS Reader and Writer. [PR #1908](https://github.com/PHPOffice/PhpSpreadsheet/pull/1908)
+
+### Changed
+
+- Nothing.
+
+### Deprecated
+
+- Nothing.
+
+### Removed
+
+- Nothing.
+
+### Fixed
+
+- Fixed issue with quoted strings in number format mask rendered with toFormattedString() [Issue 1972#](https://github.com/PHPOffice/PhpSpreadsheet/issues/1972) [PR #1978](https://github.com/PHPOffice/PhpSpreadsheet/pull/1978)
+- Fixed issue with percentage formats in number format mask rendered with toFormattedString() [Issue 1929#](https://github.com/PHPOffice/PhpSpreadsheet/issues/1929) [PR #1928](https://github.com/PHPOffice/PhpSpreadsheet/pull/1928)
+- Fixed issue with _ spacing character in number format mask corrupting output from toFormattedString() [Issue 1924#](https://github.com/PHPOffice/PhpSpreadsheet/issues/1924) [PR #1927](https://github.com/PHPOffice/PhpSpreadsheet/pull/1927)
+- Fix for [Issue #1887](https://github.com/PHPOffice/PhpSpreadsheet/issues/1887) - Lose Track of Selected Cells After Save
+- Fixed issue with Xlsx@listWorksheetInfo not returning any data
+- Fixed invalid arguments triggering mb_substr() error in LEFT(), MID() and RIGHT() text functions. [Issue #640](https://github.com/PHPOffice/PhpSpreadsheet/issues/640)
+- Fix for [Issue #1916](https://github.com/PHPOffice/PhpSpreadsheet/issues/1916) - Invalid signature check for XML files
+
+## 1.17.1 - 2021-03-01
+
+### Added
+
+- Implementation of the Excel `AVERAGEIFS()` functions as part of a restructuring of Database functions and Conditional Statistical functions.
+- Support for date values and percentages in query parameters for Database functions, and the IF expressions in functions like COUNTIF() and AVERAGEIF(). [#1875](https://github.com/PHPOffice/PhpSpreadsheet/pull/1875)
+- Support for booleans, and for wildcard text search in query parameters for Database functions, and the IF expressions in functions like COUNTIF() and AVERAGEIF(). [#1876](https://github.com/PHPOffice/PhpSpreadsheet/pull/1876)
 - Implemented DataBar for conditional formatting in Xlsx, providing read/write and creation of (type, value, direction, fills, border, axis position, color settings) as DataBar options in Excel. [#1754](https://github.com/PHPOffice/PhpSpreadsheet/pull/1754)
 - Alignment for ODS Writer [#1796](https://github.com/PHPOffice/PhpSpreadsheet/issues/1796)
 - Basic implementation of the PERMUTATIONA() Statistical Function
@@ -43,6 +75,8 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Nothing.
 
 ### Fixed
+
+- Avoid Duplicate Titles When Reading Multiple HTML Files.[Issue #1823](https://github.com/PHPOffice/PhpSpreadsheet/issues/1823) [PR #1829](https://github.com/PHPOffice/PhpSpreadsheet/pull/1829)
 - Fixed issue with Worksheet's `getCell()` method when trying to get a cell by defined name. [#1858](https://github.com/PHPOffice/PhpSpreadsheet/issues/1858)
 - Fix possible endless loop in NumberFormat Masks [#1792](https://github.com/PHPOffice/PhpSpreadsheet/issues/1792)
 - Fix problem resulting from  literal dot inside quotes in number format masks. [PR #1830](https://github.com/PHPOffice/PhpSpreadsheet/pull/1830)
@@ -670,4 +704,4 @@ For a comprehensive list of all class changes, and a semi-automated migration pa
 
 ## Previous versions of PHPExcel
 
-The changelog for the project when it was called PHPExcel is [still available](./CHANGELOG.PHPExcel.md).
+The changelog for the project when it was called PHPExcel is [still available](./CHANGELOG.PHPExcel.md).

CONTRIBUTING.md

@@ -9,3 +9,12 @@ If you would like to contribute, here are some notes and guidelines:
  - All code changes must be validated by `composer check`
  - [Helpful article about forking](https://help.github.com/articles/fork-a-repo/ "Forking a GitHub repository")
  - [Helpful article about pull requests](https://help.github.com/articles/using-pull-requests/ "Pull Requests")
+
+## How to release
+
+1. Complete CHANGELOG.md and commit
+2. Create an annotated tag
+    1. `git tag -a 1.2.3`
+    2. Tag subject must be the version number, eg: `1.2.3`
+    3. Tag body must be a copy-paste of the changelog entries
+3. Push tag with `git push --tags`, GitHub Actions will create a GitHub release automatically

composer.json

@@ -1,7 +1,19 @@
 {
     "name": "phpoffice/phpspreadsheet",
     "description": "PHPSpreadsheet - Read, Create and Write Spreadsheet documents in PHP - Spreadsheet engine",
-    "keywords": ["PHP", "OpenXML", "Excel", "xlsx", "xls", "ods", "gnumeric", "spreadsheet"],
+    "keywords": [
+        "PHP",
+        "OpenXML",
+        "Excel",
+        "xlsx",
+        "xls",
+        "ods",
+        "gnumeric",
+        "spreadsheet"
+    ],
+    "config": {
+        "sort-packages": true
+    },
     "homepage": "https://github.com/PHPOffice/PhpSpreadsheet",
     "type": "library",
     "license": "MIT",
@@ -29,7 +41,8 @@
         "check": [
             "php-cs-fixer fix --ansi --dry-run --diff",
             "phpcs",
-            "phpunit --color=always"
+            "phpunit --color=always",
+            "phpstan analyse --ansi"
         ],
         "fix": [
             "php-cs-fixer fix --ansi"
@@ -39,35 +52,36 @@
         ]
     },
     "require": {
-        "php": "^7.2||^8.0",
+        "php": "^7.2 || ^8.0",
+        "ext-simplexml": "*",
         "ext-ctype": "*",
         "ext-dom": "*",
+        "ext-fileinfo": "*",
         "ext-gd": "*",
         "ext-iconv": "*",
-        "ext-fileinfo": "*",
         "ext-libxml": "*",
         "ext-mbstring": "*",
-        "ext-SimpleXML": "*",
         "ext-xml": "*",
         "ext-xmlreader": "*",
         "ext-xmlwriter": "*",
         "ext-zip": "*",
         "ext-zlib": "*",
+        "ezyang/htmlpurifier": "^4.13",
         "maennchen/zipstream-php": "^2.1",
-        "markbaker/complex": "^1.5||^2.0",
-        "markbaker/matrix": "^1.2||^2.0",
-        "psr/simple-cache": "^1.0",
+        "markbaker/complex": "^2.0",
+        "markbaker/matrix": "^2.0",
         "psr/http-client": "^1.0",
         "psr/http-factory": "^1.0",
-        "ezyang/htmlpurifier": "^4.13"
+        "psr/simple-cache": "^1.0"
     },
     "require-dev": {
-        "dompdf/dompdf": "^0.8.5",
+        "dompdf/dompdf": "^1.0",
         "friendsofphp/php-cs-fixer": "^2.18",
         "jpgraph/jpgraph": "^4.0",
         "mpdf/mpdf": "^8.0",
         "phpcompatibility/php-compatibility": "^9.3",
-        "phpunit/phpunit": "^8.5||^9.3",
+        "phpstan/phpstan": "^0.12.82",
+        "phpunit/phpunit": "^8.5",
         "squizlabs/php_codesniffer": "^3.5",
         "tecnickcom/tcpdf": "^6.3"
     },

phpstan.neon.dist

@@ -0,0 +1,16 @@
+parameters:
+    level: 2
+    paths:
+        - src/
+        - tests/
+    ignoreErrors:
+        - '~^Class GdImage not found\.$~'
+        - '~^Return typehint of method .* has invalid type GdImage\.$~'
+        - '~^Property .* has unknown class GdImage as its type\.$~'
+        - '~^Parameter .* of method .* has invalid typehint type GdImage\.$~'
+
+        # Ignore all JpGraph issues
+        - '~^Constant (MARK_CIRCLE|MARK_CROSS|MARK_DIAMOND|MARK_DTRIANGLE|MARK_FILLEDCIRCLE|MARK_SQUARE|MARK_STAR|MARK_UTRIANGLE|MARK_X|SIDE_RIGHT) not found\.$~'
+        - '~^Instantiated class (AccBarPlot|AccLinePlot|BarPlot|ContourPlot|Graph|GroupBarPlot|GroupBarPlot|LinePlot|LinePlot|PieGraph|PiePlot|PiePlot3D|PiePlotC|RadarGraph|RadarPlot|ScatterPlot|Spline|StockPlot) not found\.$~'
+        - '~^Call to method .*\(\) on an unknown class (AccBarPlot|AccLinePlot|BarPlot|ContourPlot|Graph|GroupBarPlot|GroupBarPlot|LinePlot|LinePlot|PieGraph|PiePlot|PiePlot3D|PiePlotC|RadarGraph|RadarPlot|ScatterPlot|Spline|StockPlot)\.$~'
+        - '~^Access to property .* on an unknown class (AccBarPlot|AccLinePlot|BarPlot|ContourPlot|Graph|GroupBarPlot|GroupBarPlot|LinePlot|LinePlot|PieGraph|PiePlot|PiePlot3D|PiePlotC|RadarGraph|RadarPlot|ScatterPlot|Spline|StockPlot)\.$~'

samples/Basic/40_Duplicate_style.php

@@ -30,7 +30,7 @@ for ($col = 1; $col <= 50; ++$col) {
     }
 }
 $d = microtime(true) - $t;
-$helper->log('Add data (end) . time: ' . round((string) ($d . 2)) . ' s');
+$helper->log('Add data (end) . time: ' . (string) round($d, 2) . ' s');
 
 // Save
 $helper->write($spreadsheet, __FILE__);

samples/Basic/43_Merge_workbooks.php

@@ -18,6 +18,10 @@ $helper->logRead('Xlsx', $filename2, $callStartTime);
 
 foreach ($spreadsheet2->getSheetNames() as $sheetName) {
     $sheet = $spreadsheet2->getSheetByName($sheetName);
+    if ($sheet === null) {
+        continue;
+    }
+
     $sheet->setTitle($sheet->getTitle() . ' copied');
     $spreadsheet1->addExternalSheet($sheet);
 }

samples/Calculations/LookupRef/ADDRESS.php

@@ -0,0 +1,22 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns a text reference to a single cell in a worksheet.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ADDRESS(2,3)');
+$worksheet->getCell('A2')->setValue('=ADDRESS(2,3,2)');
+$worksheet->getCell('A3')->setValue('=ADDRESS(2,3,2,FALSE)');
+$worksheet->getCell('A4')->setValue('=ADDRESS(2,3,1,FALSE,"[Book1]Sheet1")');
+$worksheet->getCell('A5')->setValue('=ADDRESS(2,3,1,FALSE,"EXCEL SHEET")');
+
+for ($row = 1; $row <= 5; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/COLUMN.php

@@ -0,0 +1,23 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the column index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=COLUMN(C13)');
+$worksheet->getCell('A2')->setValue('=COLUMN(E13:G15)');
+$worksheet->getCell('F1')->setValue('=COLUMN()');
+
+for ($row = 1; $row <= 2; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
+
+$cell = $worksheet->getCell('F1');
+$helper->log("F1: {$cell->getValue()} => {$cell->getCalculatedValue()}");

samples/Calculations/LookupRef/COLUMNS.php

@@ -0,0 +1,21 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the number of columns in an array or reference.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=COLUMNS(C1:G4)');
+$worksheet->getCell('A2')->setValue('=COLUMNS({1,2,3;4,5,6})');
+$worksheet->getCell('A3')->setValue('=ROWS(C1:E4 D3:G5)');
+$worksheet->getCell('A4')->setValue('=COLUMNS(1:1)');
+
+for ($row = 1; $row <= 4; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/INDEX.php

@@ -0,0 +1,39 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$data1 = [
+    ['Apples', 'Lemons'],
+    ['Bananas', 'Pears'],
+];
+
+$data2 = [
+    [4, 6],
+    [5, 3],
+    [6, 9],
+    [7, 5],
+    [8, 3],
+];
+
+$worksheet->fromArray($data1, null, 'A1');
+$worksheet->fromArray($data2, null, 'C1');
+
+$worksheet->getCell('A11')->setValue('=INDEX(A1:B2, 2, 2)');
+$worksheet->getCell('A12')->setValue('=INDEX(A1:B2, 2, 1)');
+$worksheet->getCell('A13')->setValue('=INDEX({1,2;3,4}, 0, 2)');
+$worksheet->getCell('A14')->setValue('=INDEX(C1:C5, 5)');
+$worksheet->getCell('A15')->setValue('=INDEX(C1:D5, 5, 2)');
+$worksheet->getCell('A16')->setValue('=SUM(INDEX(C1:D5, 5, 0))');
+
+for ($row = 11; $row <= 16; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/INDIRECT.php

@@ -0,0 +1,33 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\NamedRange;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the cell specified by a text string.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$data = [
+    [8, 9, 0],
+    [3, 4, 5],
+    [9, 1, 3],
+    [4, 6, 2],
+];
+$worksheet->fromArray($data, null, 'C1');
+
+$spreadsheet->addNamedRange(new NamedRange('NAMED_RANGE_FOR_CELL_D4', $worksheet, '="$D$4"'));
+
+$worksheet->getCell('A1')->setValue('=INDIRECT("C1")');
+$worksheet->getCell('A2')->setValue('=INDIRECT("D"&4)');
+$worksheet->getCell('A3')->setValue('=INDIRECT("E"&ROW())');
+$worksheet->getCell('A4')->setValue('=SUM(INDIRECT("$C$4:$E$4"))');
+$worksheet->getCell('A5')->setValue('=INDIRECT(NAMED_RANGE_FOR_CELL_D4)');
+
+for ($row = 1; $row <= 5; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/OFFSET.php

@@ -0,0 +1,33 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns a cell range that is a specified number of rows and columns from a cell or range of cells.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$data = [
+    [null, 'Week 1', 'Week 2', 'Week 3', 'Week 4'],
+    ['Sunday', 4500, 2200, 3800, 1500],
+    ['Monday', 5500, 6100, 5200, 4800],
+    ['Tuesday', 7000, 6200, 5000, 7100],
+    ['Wednesday', 8000, 4000, 3900, 7600],
+    ['Thursday', 5900, 5500, 6900, 7100],
+    ['Friday', 4900, 6300, 6900, 5200],
+    ['Saturday', 3500, 3900, 5100, 4100],
+];
+$worksheet->fromArray($data, null, 'A3');
+
+$worksheet->getCell('H1')->setValue('=OFFSET(A3, 3, 1)');
+$worksheet->getCell('H2')->setValue('=SUM(OFFSET(A3, 3, 1, 1, 4))');
+$worksheet->getCell('H3')->setValue('=SUM(OFFSET(B3:E3, 3, 0))');
+$worksheet->getCell('H4')->setValue('=SUM(OFFSET(E3, 1, -3, 7))');
+
+for ($row = 1; $row <= 4; ++$row) {
+    $cell = $worksheet->getCell("H{$row}");
+    $helper->log("H{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/ROW.php

@@ -0,0 +1,20 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ROW(C13)');
+$worksheet->getCell('A2')->setValue('=ROW(E19:G21)');
+$worksheet->getCell('A3')->setValue('=ROW()');
+
+for ($row = 1; $row <= 3; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Calculations/LookupRef/ROWS.php

@@ -0,0 +1,20 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ROWS(C1:E4)');
+$worksheet->getCell('A2')->setValue('=ROWS({1,2,3;4,5,6})');
+$worksheet->getCell('A3')->setValue('=ROWS(C1:E4 D3:G5)');
+
+for ($row = 1; $row <= 3; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}

samples/Chart/35_Chart_render.php

@@ -5,6 +5,11 @@ use PhpOffice\PhpSpreadsheet\Settings;
 
 require __DIR__ . '/../Header.php';
 
+if (PHP_VERSION_ID >= 80000) {
+    $helper->log('Jpgraph no longer runs against PHP8');
+    exit;
+}
+
 // Change these values to select the Rendering library that you wish to use
 Settings::setChartRenderer(\PhpOffice\PhpSpreadsheet\Chart\Renderer\JpGraph::class);
 

src/PhpSpreadsheet/Calculation/Database.php

@@ -2,126 +2,11 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation;
 
+/**
+ * @deprecated 1.17.0
+ */
 class Database
 {
-    /**
-     * fieldExtract.
-     *
-     * Extracts the column ID to use for the data field.
-     *
-     * @param mixed[] $database The range of cells that makes up the list or database.
-     *                                        A database is a list of related data in which rows of related
-     *                                        information are records, and columns of data are fields. The
-     *                                        first row of the list contains labels for each column.
-     * @param mixed $field Indicates which column is used in the function. Enter the
-     *                                        column label enclosed between double quotation marks, such as
-     *                                        "Age" or "Yield," or a number (without quotation marks) that
-     *                                        represents the position of the column within the list: 1 for
-     *                                        the first column, 2 for the second column, and so on.
-     *
-     * @return null|string
-     */
-    private static function fieldExtract($database, $field)
-    {
-        $field = strtoupper(Functions::flattenSingleValue($field));
-        $fieldNames = array_map('strtoupper', array_shift($database));
-
-        if (is_numeric($field)) {
-            $keys = array_keys($fieldNames);
-
-            return $keys[$field - 1];
-        }
-        $key = array_search($field, $fieldNames);
-
-        return $key ?: null;
-    }
-
-    /**
-     * filter.
-     *
-     * Parses the selection criteria, extracts the database rows that match those criteria, and
-     * returns that subset of rows.
-     *
-     * @param mixed[] $database The range of cells that makes up the list or database.
-     *                                        A database is a list of related data in which rows of related
-     *                                        information are records, and columns of data are fields. The
-     *                                        first row of the list contains labels for each column.
-     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
-     *                                        You can use any range for the criteria argument, as long as it
-     *                                        includes at least one column label and at least one cell below
-     *                                        the column label in which you specify a condition for the
-     *                                        column.
-     *
-     * @return array of mixed
-     */
-    private static function filter($database, $criteria)
-    {
-        $fieldNames = array_shift($database);
-        $criteriaNames = array_shift($criteria);
-
-        //    Convert the criteria into a set of AND/OR conditions with [:placeholders]
-        $testConditions = $testValues = [];
-        $testConditionsCount = 0;
-        foreach ($criteriaNames as $key => $criteriaName) {
-            $testCondition = [];
-            $testConditionCount = 0;
-            foreach ($criteria as $row => $criterion) {
-                if ($criterion[$key] > '') {
-                    $testCondition[] = '[:' . $criteriaName . ']' . Functions::ifCondition($criterion[$key]);
-                    ++$testConditionCount;
-                }
-            }
-            if ($testConditionCount > 1) {
-                $testConditions[] = 'OR(' . implode(',', $testCondition) . ')';
-                ++$testConditionsCount;
-            } elseif ($testConditionCount == 1) {
-                $testConditions[] = $testCondition[0];
-                ++$testConditionsCount;
-            }
-        }
-
-        if ($testConditionsCount > 1) {
-            $testConditionSet = 'AND(' . implode(',', $testConditions) . ')';
-        } elseif ($testConditionsCount == 1) {
-            $testConditionSet = $testConditions[0];
-        }
-
-        //    Loop through each row of the database
-        foreach ($database as $dataRow => $dataValues) {
-            //    Substitute actual values from the database row for our [:placeholders]
-            $testConditionList = $testConditionSet;
-            foreach ($criteriaNames as $key => $criteriaName) {
-                $k = array_search($criteriaName, $fieldNames);
-                if (isset($dataValues[$k])) {
-                    $dataValue = $dataValues[$k];
-                    $dataValue = (is_string($dataValue)) ? Calculation::wrapResult(strtoupper($dataValue)) : $dataValue;
-                    $testConditionList = str_replace('[:' . $criteriaName . ']', $dataValue, $testConditionList);
-                }
-            }
-            //    evaluate the criteria against the row data
-            $result = Calculation::getInstance()->_calculateFormulaValue('=' . $testConditionList);
-            //    If the row failed to meet the criteria, remove it from the database
-            if (!$result) {
-                unset($database[$dataRow]);
-            }
-        }
-
-        return $database;
-    }
-
-    private static function getFilteredColumn($database, $field, $criteria)
-    {
-        //    reduce the database to a set of rows that match all the criteria
-        $database = self::filter($database, $criteria);
-        //    extract an array of values for the requested column
-        $colData = [];
-        foreach ($database as $row) {
-            $colData[] = $row[$field];
-        }
-
-        return $colData;
-    }
-
     /**
      * DAVERAGE.
      *
@@ -130,6 +15,10 @@ class Database
      * Excel Function:
      *        DAVERAGE(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DAverage class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -145,19 +34,11 @@ class Database
      *                                        the column label in which you specify a condition for the
      *                                        column.
      *
-     * @return float|string
+     * @return null|float|string
      */
     public static function DAVERAGE($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::AVERAGE(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DAverage::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -169,14 +50,15 @@ class Database
      * Excel Function:
      *        DCOUNT(database,[field],criteria)
      *
-     * Excel Function:
-     *        DAVERAGE(database,field,criteria)
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DCount class instead
      *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
      *                                        first row of the list contains labels for each column.
-     * @param int|string $field Indicates which column is used in the function. Enter the
+     * @param null|int|string $field Indicates which column is used in the function. Enter the
      *                                        column label enclosed between double quotation marks, such as
      *                                        "Age" or "Yield," or a number (without quotation marks) that
      *                                        represents the position of the column within the list: 1 for
@@ -194,15 +76,7 @@ class Database
      */
     public static function DCOUNT($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::COUNT(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DCount::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -213,11 +87,15 @@ class Database
      * Excel Function:
      *        DCOUNTA(database,[field],criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DCountA class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
      *                                        first row of the list contains labels for each column.
-     * @param int|string $field Indicates which column is used in the function. Enter the
+     * @param null|int|string $field Indicates which column is used in the function. Enter the
      *                                        column label enclosed between double quotation marks, such as
      *                                        "Age" or "Yield," or a number (without quotation marks) that
      *                                        represents the position of the column within the list: 1 for
@@ -229,29 +107,10 @@ class Database
      *                                        column.
      *
      * @return int
-     *
-     * @TODO    The field argument is optional. If field is omitted, DCOUNTA counts all records in the
-     *            database that match the criteria.
      */
     public static function DCOUNTA($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        //    reduce the database to a set of rows that match all the criteria
-        $database = self::filter($database, $criteria);
-        //    extract an array of values for the requested column
-        $colData = [];
-        foreach ($database as $row) {
-            $colData[] = $row[$field];
-        }
-
-        // Return
-        return Statistical::COUNTA(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DCountA::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -263,6 +122,10 @@ class Database
      * Excel Function:
      *        DGET(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DGet class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -282,18 +145,7 @@ class Database
      */
     public static function DGET($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        $colData = self::getFilteredColumn($database, $field, $criteria);
-        if (count($colData) > 1) {
-            return Functions::NAN();
-        }
-
-        return $colData[0];
+        return Database\DGet::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -305,6 +157,10 @@ class Database
      * Excel Function:
      *        DMAX(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DMax class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -324,15 +180,7 @@ class Database
      */
     public static function DMAX($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::MAX(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DMax::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -344,6 +192,10 @@ class Database
      * Excel Function:
      *        DMIN(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DMin class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -363,15 +215,7 @@ class Database
      */
     public static function DMIN($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::MIN(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DMin::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -382,6 +226,10 @@ class Database
      * Excel Function:
      *        DPRODUCT(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DProduct class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -397,19 +245,11 @@ class Database
      *                                        the column label in which you specify a condition for the
      *                                        column.
      *
-     * @return float
+     * @return float|string
      */
     public static function DPRODUCT($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return MathTrig::PRODUCT(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DProduct::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -421,6 +261,10 @@ class Database
      * Excel Function:
      *        DSTDEV(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DStDev class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -440,15 +284,7 @@ class Database
      */
     public static function DSTDEV($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::STDEV(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DStDev::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -460,6 +296,10 @@ class Database
      * Excel Function:
      *        DSTDEVP(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DStDevP class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -479,15 +319,7 @@ class Database
      */
     public static function DSTDEVP($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::STDEVP(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DStDevP::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -498,6 +330,10 @@ class Database
      * Excel Function:
      *        DSUM(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DSum class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -513,19 +349,11 @@ class Database
      *                                        the column label in which you specify a condition for the
      *                                        column.
      *
-     * @return float
+     * @return float|string
      */
     public static function DSUM($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return MathTrig::SUM(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DSum::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -537,6 +365,10 @@ class Database
      * Excel Function:
      *        DVAR(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DVar class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -556,15 +388,7 @@ class Database
      */
     public static function DVAR($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::VARFunc(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DVar::evaluate($database, $field, $criteria);
     }
 
     /**
@@ -576,6 +400,10 @@ class Database
      * Excel Function:
      *        DVARP(database,field,criteria)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Use the evaluate() method in the Database\DVarP class instead
+     *
      * @param mixed[] $database The range of cells that makes up the list or database.
      *                                        A database is a list of related data in which rows of related
      *                                        information are records, and columns of data are fields. The
@@ -595,14 +423,6 @@ class Database
      */
     public static function DVARP($database, $field, $criteria)
     {
-        $field = self::fieldExtract($database, $field);
-        if ($field === null) {
-            return null;
-        }
-
-        // Return
-        return Statistical::VARP(
-            self::getFilteredColumn($database, $field, $criteria)
-        );
+        return Database\DVarP::evaluate($database, $field, $criteria);
     }
 }

src/PhpSpreadsheet/Calculation/Database/DAverage.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Averages;
+
+class DAverage extends DatabaseAbstract
+{
+    /**
+     * DAVERAGE.
+     *
+     * Averages the values in a column of a list or database that match conditions you specify.
+     *
+     * Excel Function:
+     *        DAVERAGE(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                          A database is a list of related data in which rows of related
+     *                              information are records, and columns of data are fields. The
+     *                              first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                              column label enclosed between double quotation marks, such as
+     *                              "Age" or "Yield," or a number (without quotation marks) that
+     *                              represents the position of the column within the list: 1 for
+     *                              the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                          You can use any range for the criteria argument, as long as it
+     *                              includes at least one column label and at least one cell below
+     *                              the column label in which you specify a condition for the
+     *                              column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return Averages::average(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DCount.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
+
+class DCount extends DatabaseAbstract
+{
+    /**
+     * DCOUNT.
+     *
+     * Counts the cells that contain numbers in a column of a list or database that match conditions
+     * that you specify.
+     *
+     * Excel Function:
+     *        DCOUNT(database,[field],criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param null|int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return int
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+
+        return Counts::COUNT(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DCountA.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
+
+class DCountA extends DatabaseAbstract
+{
+    /**
+     * DCOUNTA.
+     *
+     * Counts the nonblank cells in a column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DCOUNTA(database,[field],criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return int
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+
+        return Counts::COUNTA(
+            self::getFilteredColumn($database, $field ?? 0, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DGet.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class DGet extends DatabaseAbstract
+{
+    /**
+     * DGET.
+     *
+     * Extracts a single value from a column of a list or database that matches conditions that you
+     * specify.
+     *
+     * Excel Function:
+     *        DGET(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return mixed
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        $columnData = self::getFilteredColumn($database, $field, $criteria);
+        if (count($columnData) > 1) {
+            return Functions::NAN();
+        }
+
+        $row = array_pop($columnData);
+
+        return array_pop($row);
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DMax.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Maximum;
+
+class DMax extends DatabaseAbstract
+{
+    /**
+     * DMAX.
+     *
+     * Returns the largest number in a column of a list or database that matches conditions you that
+     * specify.
+     *
+     * Excel Function:
+     *        DMAX(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return Maximum::MAX(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DMin.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Minimum;
+
+class DMin extends DatabaseAbstract
+{
+    /**
+     * DMIN.
+     *
+     * Returns the smallest number in a column of a list or database that matches conditions you that
+     * specify.
+     *
+     * Excel Function:
+     *        DMIN(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return Minimum::MIN(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DProduct.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
+
+class DProduct extends DatabaseAbstract
+{
+    /**
+     * DPRODUCT.
+     *
+     * Multiplies the values in a column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DPRODUCT(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return MathTrig\Product::funcProduct(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DStDev.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\StandardDeviations;
+
+class DStDev extends DatabaseAbstract
+{
+    /**
+     * DSTDEV.
+     *
+     * Estimates the standard deviation of a population based on a sample by using the numbers in a
+     * column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DSTDEV(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return StandardDeviations::STDEV(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DStDevP.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\StandardDeviations;
+
+class DStDevP extends DatabaseAbstract
+{
+    /**
+     * DSTDEVP.
+     *
+     * Calculates the standard deviation of a population based on the entire population by using the
+     * numbers in a column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DSTDEVP(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return StandardDeviations::STDEVP(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DSum.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
+
+class DSum extends DatabaseAbstract
+{
+    /**
+     * DSUM.
+     *
+     * Adds the numbers in a column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DSUM(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return MathTrig\Sum::funcSum(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DVar.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances;
+
+class DVar extends DatabaseAbstract
+{
+    /**
+     * DVAR.
+     *
+     * Estimates the variance of a population based on a sample by using the numbers in a column
+     * of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DVAR(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string (string if result is an error)
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return Variances::VAR(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DVarP.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances;
+
+class DVarP extends DatabaseAbstract
+{
+    /**
+     * DVARP.
+     *
+     * Calculates the variance of a population based on the entire population by using the numbers
+     * in a column of a list or database that match conditions that you specify.
+     *
+     * Excel Function:
+     *        DVARP(database,field,criteria)
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param int|string $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return null|float|string (string if result is an error)
+     */
+    public static function evaluate($database, $field, $criteria)
+    {
+        $field = self::fieldExtract($database, $field);
+        if ($field === null) {
+            return null;
+        }
+
+        return Variances::VARP(
+            self::getFilteredColumn($database, $field, $criteria)
+        );
+    }
+}

src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php

@@ -0,0 +1,174 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Internal\WildcardMatch;
+
+abstract class DatabaseAbstract
+{
+    abstract public static function evaluate($database, $field, $criteria);
+
+    /**
+     * fieldExtract.
+     *
+     * Extracts the column ID to use for the data field.
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param mixed $field Indicates which column is used in the function. Enter the
+     *                                        column label enclosed between double quotation marks, such as
+     *                                        "Age" or "Yield," or a number (without quotation marks) that
+     *                                        represents the position of the column within the list: 1 for
+     *                                        the first column, 2 for the second column, and so on.
+     */
+    protected static function fieldExtract(array $database, $field): ?int
+    {
+        $field = strtoupper(Functions::flattenSingleValue($field));
+        if ($field === '') {
+            return null;
+        }
+
+        $fieldNames = array_map('strtoupper', array_shift($database));
+        if (is_numeric($field)) {
+            return ((int) $field) - 1;
+        }
+        $key = array_search($field, array_values($fieldNames), true);
+
+        return ($key !== false) ? (int) $key : null;
+    }
+
+    /**
+     * filter.
+     *
+     * Parses the selection criteria, extracts the database rows that match those criteria, and
+     * returns that subset of rows.
+     *
+     * @param mixed[] $database The range of cells that makes up the list or database.
+     *                                        A database is a list of related data in which rows of related
+     *                                        information are records, and columns of data are fields. The
+     *                                        first row of the list contains labels for each column.
+     * @param mixed[] $criteria The range of cells that contains the conditions you specify.
+     *                                        You can use any range for the criteria argument, as long as it
+     *                                        includes at least one column label and at least one cell below
+     *                                        the column label in which you specify a condition for the
+     *                                        column.
+     *
+     * @return array of mixed
+     */
+    protected static function filter(array $database, array $criteria): array
+    {
+        $fieldNames = array_shift($database);
+        $criteriaNames = array_shift($criteria);
+
+        //    Convert the criteria into a set of AND/OR conditions with [:placeholders]
+        $query = self::buildQuery($criteriaNames, $criteria);
+
+        //    Loop through each row of the database
+        return self::executeQuery($database, $query, $criteriaNames, $fieldNames);
+    }
+
+    protected static function getFilteredColumn(array $database, ?int $field, array $criteria): array
+    {
+        //    reduce the database to a set of rows that match all the criteria
+        $database = self::filter($database, $criteria);
+        $defaultReturnColumnValue = ($field === null) ? 1 : null;
+
+        //    extract an array of values for the requested column
+        $columnData = [];
+        foreach ($database as $rowKey => $row) {
+            $keys = array_keys($row);
+            $key = $keys[$field] ?? null;
+            $columnKey = $key ?? 'A';
+            $columnData[$rowKey][$columnKey] = $row[$key] ?? $defaultReturnColumnValue;
+        }
+
+        return $columnData;
+    }
+
+    private static function buildQuery(array $criteriaNames, array $criteria): string
+    {
+        $baseQuery = [];
+        foreach ($criteria as $key => $criterion) {
+            foreach ($criterion as $field => $value) {
+                $criterionName = $criteriaNames[$field];
+                if ($value !== null && $value !== '') {
+                    $condition = self::buildCondition($value, $criterionName);
+                    $baseQuery[$key][] = $condition;
+                }
+            }
+        }
+
+        $rowQuery = array_map(
+            function ($rowValue) {
+                return (count($rowValue) > 1) ? 'AND(' . implode(',', $rowValue) . ')' : $rowValue[0];
+            },
+            $baseQuery
+        );
+
+        return (count($rowQuery) > 1) ? 'OR(' . implode(',', $rowQuery) . ')' : $rowQuery[0];
+    }
+
+    private static function buildCondition($criterion, string $criterionName): string
+    {
+        $ifCondition = Functions::ifCondition($criterion);
+
+        // Check for wildcard characters used in the condition
+        $result = preg_match('/(?<operator>[^"]*)(?<operand>".*[*?].*")/ui', $ifCondition, $matches);
+        if ($result !== 1) {
+            return "[:{$criterionName}]{$ifCondition}";
+        }
+
+        $trueFalse = ($matches['operator'] !== '<>');
+        $wildcard = WildcardMatch::wildcard($matches['operand']);
+        $condition = "WILDCARDMATCH([:{$criterionName}],{$wildcard})";
+        if ($trueFalse === false) {
+            $condition = "NOT({$condition})";
+        }
+
+        return $condition;
+    }
+
+    private static function executeQuery(array $database, string $query, array $criteria, array $fields): array
+    {
+        foreach ($database as $dataRow => $dataValues) {
+            //    Substitute actual values from the database row for our [:placeholders]
+            $conditions = $query;
+            foreach ($criteria as $criterion) {
+                $conditions = self::processCondition($criterion, $fields, $dataValues, $conditions);
+            }
+
+            //    evaluate the criteria against the row data
+            $result = Calculation::getInstance()->_calculateFormulaValue('=' . $conditions);
+
+            //    If the row failed to meet the criteria, remove it from the database
+            if ($result !== true) {
+                unset($database[$dataRow]);
+            }
+        }
+
+        return $database;
+    }
+
+    private static function processCondition(string $criterion, array $fields, array $dataValues, string $conditions)
+    {
+        $key = array_search($criterion, $fields, true);
+
+        $dataValue = 'NULL';
+        if (is_bool($dataValues[$key])) {
+            $dataValue = ($dataValues[$key]) ? 'TRUE' : 'FALSE';
+        } elseif ($dataValues[$key] !== null) {
+            $dataValue = $dataValues[$key];
+            // escape quotes if we have a string containing quotes
+            if (is_string($dataValue) && strpos($dataValue, '"') !== false) {
+                $dataValue = str_replace('"', '""', $dataValue);
+            }
+            $dataValue = (is_string($dataValue)) ? Calculation::wrapResult(strtoupper($dataValue)) : $dataValue;
+        }
+
+        return str_replace('[:' . $criterion . ']', $dataValue, $conditions);
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Constants.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+class Constants
+{
+    // Constants currently used by WeekNum; will eventually be used by WEEKDAY
+    const STARTWEEK_SUNDAY = 1;
+    const STARTWEEK_MONDAY = 2;
+    const STARTWEEK_MONDAY_ALT = 11;
+    const STARTWEEK_TUESDAY = 12;
+    const STARTWEEK_WEDNESDAY = 13;
+    const STARTWEEK_THURSDAY = 14;
+    const STARTWEEK_FRIDAY = 15;
+    const STARTWEEK_SATURDAY = 16;
+    const STARTWEEK_SUNDAY_ALT = 17;
+    const DOW_SUNDAY = 1;
+    const DOW_MONDAY = 2;
+    const DOW_TUESDAY = 3;
+    const DOW_WEDNESDAY = 4;
+    const DOW_THURSDAY = 5;
+    const DOW_FRIDAY = 6;
+    const DOW_SATURDAY = 7;
+    const STARTWEEK_MONDAY_ISO = 21;
+    const METHODARR = [
+        self::STARTWEEK_SUNDAY => self::DOW_SUNDAY,
+        self::DOW_MONDAY,
+        self::STARTWEEK_MONDAY_ALT => self::DOW_MONDAY,
+        self::DOW_TUESDAY,
+        self::DOW_WEDNESDAY,
+        self::DOW_THURSDAY,
+        self::DOW_FRIDAY,
+        self::DOW_SATURDAY,
+        self::DOW_SUNDAY,
+        self::STARTWEEK_MONDAY_ISO => self::STARTWEEK_MONDAY_ISO,
+    ];
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/DateDif.php

@@ -0,0 +1,146 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateInterval;
+use DateTime;
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class DateDif
+{
+    /**
+     * DATEDIF.
+     *
+     * @param mixed $startDate Excel date serial value, PHP date/time stamp, PHP DateTime object
+     *                                    or a standard date string
+     * @param mixed $endDate Excel date serial value, PHP date/time stamp, PHP DateTime object
+     *                                    or a standard date string
+     * @param string $unit
+     *
+     * @return int|string Interval between the dates
+     */
+    public static function funcDateDif($startDate, $endDate, $unit = 'D')
+    {
+        try {
+            $startDate = Helpers::getDateValue($startDate);
+            $endDate = Helpers::getDateValue($endDate);
+            $difference = self::initialDiff($startDate, $endDate);
+            $unit = strtoupper(Functions::flattenSingleValue($unit));
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPStartDateObject = Date::excelToDateTimeObject($startDate);
+        $startDays = (int) $PHPStartDateObject->format('j');
+        $startMonths = (int) $PHPStartDateObject->format('n');
+        $startYears = (int) $PHPStartDateObject->format('Y');
+
+        $PHPEndDateObject = Date::excelToDateTimeObject($endDate);
+        $endDays = (int) $PHPEndDateObject->format('j');
+        $endMonths = (int) $PHPEndDateObject->format('n');
+        $endYears = (int) $PHPEndDateObject->format('Y');
+
+        $PHPDiffDateObject = $PHPEndDateObject->diff($PHPStartDateObject);
+
+        $retVal = false;
+        $retVal = self::replaceRetValue($retVal, $unit, 'D') ?? self::datedifD($difference);
+        $retVal = self::replaceRetValue($retVal, $unit, 'M') ?? self::datedifM($PHPDiffDateObject);
+        $retVal = self::replaceRetValue($retVal, $unit, 'MD') ?? self::datedifMD($startDays, $endDays, $PHPEndDateObject, $PHPDiffDateObject);
+        $retVal = self::replaceRetValue($retVal, $unit, 'Y') ?? self::datedifY($PHPDiffDateObject);
+        $retVal = self::replaceRetValue($retVal, $unit, 'YD') ?? self::datedifYD($difference, $startYears, $endYears, $PHPStartDateObject, $PHPEndDateObject);
+        $retVal = self::replaceRetValue($retVal, $unit, 'YM') ?? self::datedifYM($PHPDiffDateObject);
+
+        return is_bool($retVal) ? Functions::VALUE() : $retVal;
+    }
+
+    private static function initialDiff(float $startDate, float $endDate): float
+    {
+        // Validate parameters
+        if ($startDate > $endDate) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $endDate - $startDate;
+    }
+
+    /**
+     * Decide whether it's time to set retVal.
+     *
+     * @param bool|int $retVal
+     *
+     * @return null|bool|int
+     */
+    private static function replaceRetValue($retVal, string $unit, string $compare)
+    {
+        if ($retVal !== false || $unit !== $compare) {
+            return $retVal;
+        }
+
+        return null;
+    }
+
+    private static function datedifD(float $difference): int
+    {
+        return (int) $difference;
+    }
+
+    private static function datedifM(DateInterval $PHPDiffDateObject): int
+    {
+        return 12 * (int) $PHPDiffDateObject->format('%y') + (int) $PHPDiffDateObject->format('%m');
+    }
+
+    private static function datedifMD(int $startDays, int $endDays, DateTime $PHPEndDateObject, DateInterval $PHPDiffDateObject): int
+    {
+        if ($endDays < $startDays) {
+            $retVal = $endDays;
+            $PHPEndDateObject->modify('-' . $endDays . ' days');
+            $adjustDays = (int) $PHPEndDateObject->format('j');
+            $retVal += ($adjustDays - $startDays);
+        } else {
+            $retVal = (int) $PHPDiffDateObject->format('%d');
+        }
+
+        return $retVal;
+    }
+
+    private static function datedifY(DateInterval $PHPDiffDateObject): int
+    {
+        return (int) $PHPDiffDateObject->format('%y');
+    }
+
+    private static function datedifYD(float $difference, int $startYears, int $endYears, DateTime $PHPStartDateObject, DateTime $PHPEndDateObject): int
+    {
+        $retVal = (int) $difference;
+        if ($endYears > $startYears) {
+            $isLeapStartYear = $PHPStartDateObject->format('L');
+            $wasLeapEndYear = $PHPEndDateObject->format('L');
+
+            // Adjust end year to be as close as possible as start year
+            while ($PHPEndDateObject >= $PHPStartDateObject) {
+                $PHPEndDateObject->modify('-1 year');
+                $endYears = $PHPEndDateObject->format('Y');
+            }
+            $PHPEndDateObject->modify('+1 year');
+
+            // Get the result
+            $retVal = $PHPEndDateObject->diff($PHPStartDateObject)->days;
+
+            // Adjust for leap years cases
+            $isLeapEndYear = $PHPEndDateObject->format('L');
+            $limit = new DateTime($PHPEndDateObject->format('Y-02-29'));
+            if (!$isLeapStartYear && !$wasLeapEndYear && $isLeapEndYear && $PHPEndDateObject >= $limit) {
+                --$retVal;
+            }
+        }
+
+        return (int) $retVal;
+    }
+
+    private static function datedifYM(DateInterval $PHPDiffDateObject): int
+    {
+        return (int) $PHPDiffDateObject->format('%m');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/DateValue.php

@@ -0,0 +1,151 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTimeImmutable;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class DateValue
+{
+    /**
+     * DATEVALUE.
+     *
+     * Returns a value that represents a particular date.
+     * Use DATEVALUE to convert a date represented by a text string to an Excel or PHP date/time stamp
+     * value.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the date
+     * format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        DATEVALUE(dateValue)
+     *
+     * @param string $dateValue Text that represents a date in a Microsoft Excel date format.
+     *                                    For example, "1/30/2008" or "30-Jan-2008" are text strings within
+     *                                    quotation marks that represent dates. Using the default date
+     *                                    system in Excel for Windows, date_text must represent a date from
+     *                                    January 1, 1900, to December 31, 9999. Using the default date
+     *                                    system in Excel for the Macintosh, date_text must represent a date
+     *                                    from January 1, 1904, to December 31, 9999. DATEVALUE returns the
+     *                                    #VALUE! error value if date_text is out of this range.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcDateValue($dateValue)
+    {
+        $dti = new DateTimeImmutable();
+        $baseYear = Date::getExcelCalendar();
+        $dateValue = trim(Functions::flattenSingleValue($dateValue), '"');
+        //    Strip any ordinals because they're allowed in Excel (English only)
+        $dateValue = preg_replace('/(\d)(st|nd|rd|th)([ -\/])/Ui', '$1$3', $dateValue);
+        //    Convert separators (/ . or space) to hyphens (should also handle dot used for ordinals in some countries, e.g. Denmark, Germany)
+        $dateValue = str_replace(['/', '.', '-', '  '], ' ', $dateValue);
+
+        $yearFound = false;
+        $t1 = explode(' ', $dateValue);
+        $t = '';
+        foreach ($t1 as &$t) {
+            if ((is_numeric($t)) && ($t > 31)) {
+                if ($yearFound) {
+                    return Functions::VALUE();
+                }
+                if ($t < 100) {
+                    $t += 1900;
+                }
+                $yearFound = true;
+            }
+        }
+        if (count($t1) === 1) {
+            //    We've been fed a time value without any date
+            return ((strpos($t, ':') === false)) ? Functions::Value() : 0.0;
+        }
+        unset($t);
+
+        $dateValue = self::t1ToString($t1, $dti, $yearFound);
+
+        $PHPDateArray = self::setUpArray($dateValue, $dti);
+
+        return self::finalResults($PHPDateArray, $dti, $baseYear);
+    }
+
+    private static function t1ToString(array $t1, DateTimeImmutable $dti, bool $yearFound): string
+    {
+        if (count($t1) == 2) {
+            //    We only have two parts of the date: either day/month or month/year
+            if ($yearFound) {
+                array_unshift($t1, 1);
+            } else {
+                if (is_numeric($t1[1]) && $t1[1] > 29) {
+                    $t1[1] += 1900;
+                    array_unshift($t1, 1);
+                } else {
+                    $t1[] = $dti->format('Y');
+                }
+            }
+        }
+        $dateValue = implode(' ', $t1);
+
+        return $dateValue;
+    }
+
+    /**
+     * Parse date.
+     *
+     * @return array|bool
+     */
+    private static function setUpArray(string $dateValue, DateTimeImmutable $dti)
+    {
+        $PHPDateArray = date_parse($dateValue);
+        if (($PHPDateArray === false) || ($PHPDateArray['error_count'] > 0)) {
+            // If original count was 1, we've already returned.
+            // If it was 2, we added another.
+            // Therefore, neither of the first 2 stroks below can fail.
+            $testVal1 = strtok($dateValue, '- ');
+            $testVal2 = strtok('- ');
+            $testVal3 = strtok('- ') ?: $dti->format('Y');
+            Helpers::adjustYear($testVal1, $testVal2, $testVal3);
+            $PHPDateArray = date_parse($testVal1 . '-' . $testVal2 . '-' . $testVal3);
+            if (($PHPDateArray === false) || ($PHPDateArray['error_count'] > 0)) {
+                $PHPDateArray = date_parse($testVal2 . '-' . $testVal1 . '-' . $testVal3);
+            }
+        }
+
+        return $PHPDateArray;
+    }
+
+    /**
+     * Final results.
+     *
+     * @param array|false $PHPDateArray
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    private static function finalResults($PHPDateArray, DateTimeImmutable $dti, int $baseYear)
+    {
+        $retValue = Functions::Value();
+        if (($PHPDateArray !== false) && ($PHPDateArray['error_count'] == 0)) {
+            // Execute function
+            Helpers::replaceIfEmpty($PHPDateArray['year'], $dti->format('Y'));
+            if ($PHPDateArray['year'] < $baseYear) {
+                return Functions::VALUE();
+            }
+            Helpers::replaceIfEmpty($PHPDateArray['month'], $dti->format('m'));
+            Helpers::replaceIfEmpty($PHPDateArray['day'], $dti->format('d'));
+            $PHPDateArray['hour'] = 0;
+            $PHPDateArray['minute'] = 0;
+            $PHPDateArray['second'] = 0;
+            $month = (int) $PHPDateArray['month'];
+            $day = (int) $PHPDateArray['day'];
+            $year = (int) $PHPDateArray['year'];
+            if (!checkdate($month, $day, $year)) {
+                return ($year === 1900 && $month === 2 && $day === 29) ? Helpers::returnIn3FormatsFloat(60.0) : Functions::VALUE();
+            }
+            $retValue = Helpers::returnIn3FormatsArray($PHPDateArray, true);
+        }
+
+        return $retValue;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Datefunc.php

@@ -0,0 +1,168 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
+
+class Datefunc
+{
+    /**
+     * DATE.
+     *
+     * The DATE function returns a value that represents a particular date.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the date
+     * format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        DATE(year,month,day)
+     *
+     * PhpSpreadsheet is a lot more forgiving than MS Excel when passing non numeric values to this function.
+     * A Month name or abbreviation (English only at this point) such as 'January' or 'Jan' will still be accepted,
+     *     as will a day value with a suffix (e.g. '21st' rather than simply 21); again only English language.
+     *
+     * @param int $year The value of the year argument can include one to four digits.
+     *                                Excel interprets the year argument according to the configured
+     *                                date system: 1900 or 1904.
+     *                                If year is between 0 (zero) and 1899 (inclusive), Excel adds that
+     *                                value to 1900 to calculate the year. For example, DATE(108,1,2)
+     *                                returns January 2, 2008 (1900+108).
+     *                                If year is between 1900 and 9999 (inclusive), Excel uses that
+     *                                value as the year. For example, DATE(2008,1,2) returns January 2,
+     *                                2008.
+     *                                If year is less than 0 or is 10000 or greater, Excel returns the
+     *                                #NUM! error value.
+     * @param int $month A positive or negative integer representing the month of the year
+     *                                from 1 to 12 (January to December).
+     *                                If month is greater than 12, month adds that number of months to
+     *                                the first month in the year specified. For example, DATE(2008,14,2)
+     *                                returns the serial number representing February 2, 2009.
+     *                                If month is less than 1, month subtracts the magnitude of that
+     *                                number of months, plus 1, from the first month in the year
+     *                                specified. For example, DATE(2008,-3,2) returns the serial number
+     *                                representing September 2, 2007.
+     * @param int $day A positive or negative integer representing the day of the month
+     *                                from 1 to 31.
+     *                                If day is greater than the number of days in the month specified,
+     *                                day adds that number of days to the first day in the month. For
+     *                                example, DATE(2008,1,35) returns the serial number representing
+     *                                February 4, 2008.
+     *                                If day is less than 1, day subtracts the magnitude that number of
+     *                                days, plus one, from the first day of the month specified. For
+     *                                example, DATE(2008,1,-15) returns the serial number representing
+     *                                December 16, 2007.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcDate($year, $month, $day)
+    {
+        $baseYear = Date::getExcelCalendar();
+
+        try {
+            $year = self::getYear($year, $baseYear);
+            $month = self::getMonth($month);
+            $day = self::getDay($day);
+            self::adjustYearMonth($year, $month, $baseYear);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $excelDateValue = Date::formattedPHPToExcel($year, $month, $day);
+
+        return Helpers::returnIn3FormatsFloat($excelDateValue);
+    }
+
+    /**
+     * Convert year from multiple formats to int.
+     *
+     * @param mixed $year
+     */
+    private static function getYear($year, int $baseYear): int
+    {
+        $year = Functions::flattenSingleValue($year);
+        $year = ($year !== null) ? StringHelper::testStringAsNumeric($year) : 0;
+        if (!is_numeric($year)) {
+            throw new Exception(Functions::VALUE());
+        }
+        $year = (int) $year;
+
+        if ($year < ($baseYear - 1900)) {
+            throw new Exception(Functions::NAN());
+        }
+        if ((($baseYear - 1900) !== 0) && ($year < $baseYear) && ($year >= 1900)) {
+            throw new Exception(Functions::NAN());
+        }
+
+        if (($year < $baseYear) && ($year >= ($baseYear - 1900))) {
+            $year += 1900;
+        }
+
+        return $year;
+    }
+
+    /**
+     * Convert month from multiple formats to int.
+     *
+     * @param mixed $month
+     */
+    private static function getMonth($month): int
+    {
+        $month = Functions::flattenSingleValue($month);
+
+        if (($month !== null) && (!is_numeric($month))) {
+            $month = Date::monthStringToNumber($month);
+        }
+
+        $month = ($month !== null) ? StringHelper::testStringAsNumeric($month) : 0;
+        if (!is_numeric($month)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (int) $month;
+    }
+
+    /**
+     * Convert day from multiple formats to int.
+     *
+     * @param mixed $day
+     */
+    private static function getDay($day): int
+    {
+        $day = Functions::flattenSingleValue($day);
+
+        if (($day !== null) && (!is_numeric($day))) {
+            $day = Date::dayStringToNumber($day);
+        }
+
+        $day = ($day !== null) ? StringHelper::testStringAsNumeric($day) : 0;
+        if (!is_numeric($day)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (int) $day;
+    }
+
+    private static function adjustYearMonth(int &$year, int &$month, int $baseYear): void
+    {
+        if ($month < 1) {
+            //    Handle year/month adjustment if month < 1
+            --$month;
+            $year += ceil($month / 12) - 1;
+            $month = 13 - abs($month % 12);
+        } elseif ($month > 12) {
+            //    Handle year/month adjustment if month > 12
+            $year += floor($month / 12);
+            $month = ($month % 12);
+        }
+
+        // Re-validate the year parameter after adjustments
+        if (($year < $baseYear) || ($year >= 10000)) {
+            throw new Exception(Functions::NAN());
+        }
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Day.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Day
+{
+    /**
+     * DAYOFMONTH.
+     *
+     * Returns the day of the month, for a specified date. The day is given as an integer
+     * ranging from 1 to 31.
+     *
+     * Excel Function:
+     *        DAY(dateValue)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     *
+     * @return int|string Day of the month
+     */
+    public static function funcDay($dateValue)
+    {
+        $weirdResult = self::weirdCondition($dateValue);
+        if ($weirdResult >= 0) {
+            return $weirdResult;
+        }
+
+        try {
+            $dateValue = Helpers::getDateValue($dateValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+
+        return (int) $PHPDateObject->format('j');
+    }
+
+    private static function weirdCondition($dateValue): int
+    {
+        // Excel does not treat 0 consistently for DAY vs. (MONTH or YEAR)
+        if (Date::getExcelCalendar() === DATE::CALENDAR_WINDOWS_1900 && Functions::getCompatibilityMode() == Functions::COMPATIBILITY_EXCEL) {
+            if (is_bool($dateValue)) {
+                return (int) $dateValue;
+            }
+            if ($dateValue === null) {
+                return 0;
+            }
+            if (is_numeric($dateValue) && $dateValue < 1 && $dateValue >= 0) {
+                return 0;
+            }
+        }
+
+        return -1;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Days.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTimeInterface;
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Days
+{
+    /**
+     * DAYS.
+     *
+     * Returns the number of days between two dates
+     *
+     * Excel Function:
+     *        DAYS(endDate, startDate)
+     *
+     * @param DateTimeInterface|float|int|string $endDate Excel date serial value (float),
+     * PHP date timestamp (integer), PHP DateTime object, or a standard date string
+     * @param DateTimeInterface|float|int|string $startDate Excel date serial value (float),
+     * PHP date timestamp (integer), PHP DateTime object, or a standard date string
+     *
+     * @return int|string Number of days between start date and end date or an error
+     */
+    public static function funcDays($endDate, $startDate)
+    {
+        try {
+            $startDate = Helpers::getDateValue($startDate);
+            $endDate = Helpers::getDateValue($endDate);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPStartDateObject = Date::excelToDateTimeObject($startDate);
+        $PHPEndDateObject = Date::excelToDateTimeObject($endDate);
+
+        $days = Functions::VALUE();
+        $diff = $PHPStartDateObject->diff($PHPEndDateObject);
+        if ($diff !== false && !is_bool($diff->days)) {
+            $days = $diff->days;
+            if ($diff->invert) {
+                $days = -$days;
+            }
+        }
+
+        return $days;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Days360.php

@@ -0,0 +1,106 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Days360
+{
+    /**
+     * DAYS360.
+     *
+     * Returns the number of days between two dates based on a 360-day year (twelve 30-day months),
+     * which is used in some accounting calculations. Use this function to help compute payments if
+     * your accounting system is based on twelve 30-day months.
+     *
+     * Excel Function:
+     *        DAYS360(startDate,endDate[,method])
+     *
+     * @param mixed $startDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                        PHP DateTime object, or a standard date string
+     * @param mixed $endDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                        PHP DateTime object, or a standard date string
+     * @param mixed $method US or European Method as a bool
+     *                                        FALSE or omitted: U.S. (NASD) method. If the starting date is
+     *                                        the last day of a month, it becomes equal to the 30th of the
+     *                                        same month. If the ending date is the last day of a month and
+     *                                        the starting date is earlier than the 30th of a month, the
+     *                                        ending date becomes equal to the 1st of the next month;
+     *                                        otherwise the ending date becomes equal to the 30th of the
+     *                                        same month.
+     *                                        TRUE: European method. Starting dates and ending dates that
+     *                                        occur on the 31st of a month become equal to the 30th of the
+     *                                        same month.
+     *
+     * @return int|string Number of days between start date and end date
+     */
+    public static function funcDays360($startDate = 0, $endDate = 0, $method = false)
+    {
+        try {
+            $startDate = Helpers::getDateValue($startDate);
+            $endDate = Helpers::getDateValue($endDate);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if (!is_bool($method)) {
+            return Functions::VALUE();
+        }
+
+        // Execute function
+        $PHPStartDateObject = Date::excelToDateTimeObject($startDate);
+        $startDay = $PHPStartDateObject->format('j');
+        $startMonth = $PHPStartDateObject->format('n');
+        $startYear = $PHPStartDateObject->format('Y');
+
+        $PHPEndDateObject = Date::excelToDateTimeObject($endDate);
+        $endDay = $PHPEndDateObject->format('j');
+        $endMonth = $PHPEndDateObject->format('n');
+        $endYear = $PHPEndDateObject->format('Y');
+
+        return self::dateDiff360((int) $startDay, (int) $startMonth, (int) $startYear, (int) $endDay, (int) $endMonth, (int) $endYear, !$method);
+    }
+
+    /**
+     * Return the number of days between two dates based on a 360 day calendar.
+     */
+    private static function dateDiff360(int $startDay, int $startMonth, int $startYear, int $endDay, int $endMonth, int $endYear, bool $methodUS): int
+    {
+        $startDay = self::getStartDay($startDay, $startMonth, $startYear, $methodUS);
+        $endDay = self::getEndDay($endDay, $endMonth, $endYear, $startDay, $methodUS);
+
+        return $endDay + $endMonth * 30 + $endYear * 360 - $startDay - $startMonth * 30 - $startYear * 360;
+    }
+
+    private static function getStartDay(int $startDay, int $startMonth, int $startYear, bool $methodUS): int
+    {
+        if ($startDay == 31) {
+            --$startDay;
+        } elseif ($methodUS && ($startMonth == 2 && ($startDay == 29 || ($startDay == 28 && !Helpers::isLeapYear($startYear))))) {
+            $startDay = 30;
+        }
+
+        return $startDay;
+    }
+
+    private static function getEndDay(int $endDay, int &$endMonth, int &$endYear, int $startDay, bool $methodUS): int
+    {
+        if ($endDay == 31) {
+            if ($methodUS && $startDay != 30) {
+                $endDay = 1;
+                if ($endMonth == 12) {
+                    ++$endYear;
+                    $endMonth = 1;
+                } else {
+                    ++$endMonth;
+                }
+            } else {
+                $endDay = 30;
+            }
+        }
+
+        return $endDay;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/EDate.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class EDate
+{
+    /**
+     * EDATE.
+     *
+     * Returns the serial number that represents the date that is the indicated number of months
+     * before or after a specified date (the start_date).
+     * Use EDATE to calculate maturity dates or due dates that fall on the same day of the month
+     * as the date of issue.
+     *
+     * Excel Function:
+     *        EDATE(dateValue,adjustmentMonths)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                        PHP DateTime object, or a standard date string
+     * @param int $adjustmentMonths The number of months before or after start_date.
+     *                                        A positive value for months yields a future date;
+     *                                        a negative value yields a past date.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcEDate($dateValue, $adjustmentMonths)
+    {
+        try {
+            $dateValue = Helpers::getDateValue($dateValue, false);
+            $adjustmentMonths = Helpers::validateNumericNull($adjustmentMonths);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+        $adjustmentMonths = floor($adjustmentMonths);
+
+        // Execute function
+        $PHPDateObject = Helpers::adjustDateByMonths($dateValue, $adjustmentMonths);
+
+        return Helpers::returnIn3FormatsObject($PHPDateObject);
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/EoMonth.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class EoMonth
+{
+    /**
+     * EOMONTH.
+     *
+     * Returns the date value for the last day of the month that is the indicated number of months
+     * before or after start_date.
+     * Use EOMONTH to calculate maturity dates or due dates that fall on the last day of the month.
+     *
+     * Excel Function:
+     *        EOMONTH(dateValue,adjustmentMonths)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                        PHP DateTime object, or a standard date string
+     * @param int $adjustmentMonths The number of months before or after start_date.
+     *                                        A positive value for months yields a future date;
+     *                                        a negative value yields a past date.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcEoMonth($dateValue, $adjustmentMonths)
+    {
+        try {
+            $dateValue = Helpers::getDateValue($dateValue, false);
+            $adjustmentMonths = Helpers::validateNumericNull($adjustmentMonths);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+        $adjustmentMonths = floor($adjustmentMonths);
+
+        // Execute function
+        $PHPDateObject = Helpers::adjustDateByMonths($dateValue, $adjustmentMonths + 1);
+        $adjustDays = (int) $PHPDateObject->format('d');
+        $adjustDaysString = '-' . $adjustDays . ' days';
+        $PHPDateObject->modify($adjustDaysString);
+
+        return Helpers::returnIn3FormatsObject($PHPDateObject);
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Helpers.php

@@ -0,0 +1,275 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTime;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Helpers
+{
+    /**
+     * Identify if a year is a leap year or not.
+     *
+     * @param int|string $year The year to test
+     *
+     * @return bool TRUE if the year is a leap year, otherwise FALSE
+     */
+    public static function isLeapYear($year)
+    {
+        return (($year % 4) === 0) && (($year % 100) !== 0) || (($year % 400) === 0);
+    }
+
+    /**
+     * getDateValue.
+     *
+     * @param mixed $dateValue
+     *
+     * @return float Excel date/time serial value
+     */
+    public static function getDateValue($dateValue, bool $allowBool = true)
+    {
+        if (is_object($dateValue)) {
+            $retval = Date::PHPToExcel($dateValue);
+            if (is_bool($retval)) {
+                throw new Exception(Functions::VALUE());
+            }
+
+            return $retval;
+        }
+
+        self::nullFalseTrueToNumber($dateValue, $allowBool);
+        if (!is_numeric($dateValue)) {
+            $saveReturnDateType = Functions::getReturnDateType();
+            Functions::setReturnDateType(Functions::RETURNDATE_EXCEL);
+            $dateValue = DateValue::funcDateValue($dateValue);
+            Functions::setReturnDateType($saveReturnDateType);
+            if (!is_numeric($dateValue)) {
+                throw new Exception(Functions::VALUE());
+            }
+        }
+        if ($dateValue < 0 && Functions::getCompatibilityMode() !== Functions::COMPATIBILITY_OPENOFFICE) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return (float) $dateValue;
+    }
+
+    /**
+     * getTimeValue.
+     *
+     * @param string $timeValue
+     *
+     * @return mixed Excel date/time serial value, or string if error
+     */
+    public static function getTimeValue($timeValue)
+    {
+        $saveReturnDateType = Functions::getReturnDateType();
+        Functions::setReturnDateType(Functions::RETURNDATE_EXCEL);
+        $timeValue = TimeValue::funcTimeValue($timeValue);
+        Functions::setReturnDateType($saveReturnDateType);
+
+        return $timeValue;
+    }
+
+    public static function adjustDateByMonths($dateValue = 0, $adjustmentMonths = 0)
+    {
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+        $oMonth = (int) $PHPDateObject->format('m');
+        $oYear = (int) $PHPDateObject->format('Y');
+
+        $adjustmentMonthsString = (string) $adjustmentMonths;
+        if ($adjustmentMonths > 0) {
+            $adjustmentMonthsString = '+' . $adjustmentMonths;
+        }
+        if ($adjustmentMonths != 0) {
+            $PHPDateObject->modify($adjustmentMonthsString . ' months');
+        }
+        $nMonth = (int) $PHPDateObject->format('m');
+        $nYear = (int) $PHPDateObject->format('Y');
+
+        $monthDiff = ($nMonth - $oMonth) + (($nYear - $oYear) * 12);
+        if ($monthDiff != $adjustmentMonths) {
+            $adjustDays = (int) $PHPDateObject->format('d');
+            $adjustDaysString = '-' . $adjustDays . ' days';
+            $PHPDateObject->modify($adjustDaysString);
+        }
+
+        return $PHPDateObject;
+    }
+
+    /**
+     * Help reduce perceived complexity of some tests.
+     *
+     * @param mixed $value
+     * @param mixed $altValue
+     */
+    public static function replaceIfEmpty(&$value, $altValue): void
+    {
+        $value = $value ?: $altValue;
+    }
+
+    /**
+     * Adjust year in ambiguous situations.
+     */
+    public static function adjustYear(string $testVal1, string $testVal2, string &$testVal3): void
+    {
+        if (!is_numeric($testVal1) || $testVal1 < 31) {
+            if (!is_numeric($testVal2) || $testVal2 < 12) {
+                if (is_numeric($testVal3) && $testVal3 < 12) {
+                    $testVal3 += 2000;
+                }
+            }
+        }
+    }
+
+    /**
+     * Return result in one of three formats.
+     *
+     * @return mixed
+     */
+    public static function returnIn3FormatsArray(array $dateArray, bool $noFrac = false)
+    {
+        $retType = Functions::getReturnDateType();
+        if ($retType === Functions::RETURNDATE_PHP_DATETIME_OBJECT) {
+            return new DateTime(
+                $dateArray['year']
+                . '-' . $dateArray['month']
+                . '-' . $dateArray['day']
+                . ' ' . $dateArray['hour']
+                . ':' . $dateArray['minute']
+                . ':' . $dateArray['second']
+            );
+        }
+        $excelDateValue =
+            Date::formattedPHPToExcel(
+                $dateArray['year'],
+                $dateArray['month'],
+                $dateArray['day'],
+                $dateArray['hour'],
+                $dateArray['minute'],
+                $dateArray['second']
+            );
+        if ($retType === Functions::RETURNDATE_EXCEL) {
+            return $noFrac ? floor($excelDateValue) : (float) $excelDateValue;
+        }
+        // RETURNDATE_UNIX_TIMESTAMP)
+
+        return (int) Date::excelToTimestamp($excelDateValue);
+    }
+
+    /**
+     * Return result in one of three formats.
+     *
+     * @return mixed
+     */
+    public static function returnIn3FormatsFloat(float $excelDateValue)
+    {
+        $retType = Functions::getReturnDateType();
+        if ($retType === Functions::RETURNDATE_EXCEL) {
+            return $excelDateValue;
+        }
+        if ($retType === Functions::RETURNDATE_UNIX_TIMESTAMP) {
+            return (int) Date::excelToTimestamp($excelDateValue);
+        }
+        // RETURNDATE_PHP_DATETIME_OBJECT
+
+        return Date::excelToDateTimeObject($excelDateValue);
+    }
+
+    /**
+     * Return result in one of three formats.
+     *
+     * @return mixed
+     */
+    public static function returnIn3FormatsObject(DateTime $PHPDateObject)
+    {
+        $retType = Functions::getReturnDateType();
+        if ($retType === Functions::RETURNDATE_PHP_DATETIME_OBJECT) {
+            return $PHPDateObject;
+        }
+        if ($retType === Functions::RETURNDATE_EXCEL) {
+            return (float) Date::PHPToExcel($PHPDateObject);
+        }
+        // RETURNDATE_UNIX_TIMESTAMP
+
+        return (int) Date::excelToTimestamp(Date::PHPToExcel($PHPDateObject));
+    }
+
+    private static function baseDate(): int
+    {
+        if (Functions::getCompatibilityMode() === Functions::COMPATIBILITY_OPENOFFICE) {
+            return 0;
+        }
+        if (Date::getExcelCalendar() === Date::CALENDAR_MAC_1904) {
+            return 0;
+        }
+
+        return 1;
+    }
+
+    /**
+     * Many functions accept null/false/true argument treated as 0/0/1.
+     *
+     * @param mixed $number
+     */
+    public static function nullFalseTrueToNumber(&$number, bool $allowBool = true): void
+    {
+        $number = Functions::flattenSingleValue($number);
+        $nullVal = self::baseDate();
+        if ($number === null) {
+            $number = $nullVal;
+        } elseif ($allowBool && is_bool($number)) {
+            $number = $nullVal + (int) $number;
+        }
+    }
+
+    /**
+     * Many functions accept null argument treated as 0.
+     *
+     * @param mixed $number
+     *
+     * @return float|int
+     */
+    public static function validateNumericNull($number)
+    {
+        $number = Functions::flattenSingleValue($number);
+        if ($number === null) {
+            return 0;
+        }
+        if (is_numeric($number)) {
+            return $number;
+        }
+
+        throw new Exception(Functions::VALUE());
+    }
+
+    /**
+     * Many functions accept null/false/true argument treated as 0/0/1.
+     *
+     * @param mixed $number
+     *
+     * @return float
+     */
+    public static function validateNotNegative($number)
+    {
+        if (!is_numeric($number)) {
+            throw new Exception(Functions::VALUE());
+        }
+        if ($number >= 0) {
+            return (float) $number;
+        }
+
+        throw new Exception(Functions::NAN());
+    }
+
+    public static function silly1900(DateTime $PHPDateObject, string $mod = '-1 day'): void
+    {
+        $isoDate = $PHPDateObject->format('c');
+        if ($isoDate < '1900-03-01') {
+            $PHPDateObject->modify($mod);
+        }
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Hour.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Hour
+{
+    /**
+     * HOUROFDAY.
+     *
+     * Returns the hour of a time value.
+     * The hour is given as an integer, ranging from 0 (12:00 A.M.) to 23 (11:00 P.M.).
+     *
+     * Excel Function:
+     *        HOUR(timeValue)
+     *
+     * @param mixed $timeValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard time string
+     *
+     * @return int|string Hour
+     */
+    public static function funcHour($timeValue)
+    {
+        try {
+            $timeValue = Functions::flattenSingleValue($timeValue);
+            Helpers::nullFalseTrueToNumber($timeValue);
+            if (!is_numeric($timeValue)) {
+                $timeValue = Helpers::getTimeValue($timeValue);
+            }
+            Helpers::validateNotNegative($timeValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $timeValue = fmod($timeValue, 1);
+        $timeValue = Date::excelToDateTimeObject($timeValue);
+
+        return (int) $timeValue->format('H');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/IsoWeekNum.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class IsoWeekNum
+{
+    /**
+     * ISOWEEKNUM.
+     *
+     * Returns the ISO 8601 week number of the year for a specified date.
+     *
+     * Excel Function:
+     *        ISOWEEKNUM(dateValue)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     *
+     * @return int|string Week Number
+     */
+    public static function funcIsoWeekNum($dateValue)
+    {
+        if (self::apparentBug($dateValue)) {
+            return 52;
+        }
+
+        try {
+            $dateValue = Helpers::getDateValue($dateValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+        Helpers::silly1900($PHPDateObject);
+
+        return (int) $PHPDateObject->format('W');
+    }
+
+    private static function apparentBug($dateValue): bool
+    {
+        if (Date::getExcelCalendar() !== DATE::CALENDAR_MAC_1904) {
+            if (is_bool($dateValue)) {
+                return true;
+            }
+            if (is_numeric($dateValue) && !((int) $dateValue)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Minute.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Minute
+{
+    /**
+     * MINUTE.
+     *
+     * Returns the minutes of a time value.
+     * The minute is given as an integer, ranging from 0 to 59.
+     *
+     * Excel Function:
+     *        MINUTE(timeValue)
+     *
+     * @param mixed $timeValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard time string
+     *
+     * @return int|string Minute
+     */
+    public static function funcMinute($timeValue)
+    {
+        try {
+            $timeValue = Functions::flattenSingleValue($timeValue);
+            Helpers::nullFalseTrueToNumber($timeValue);
+            if (!is_numeric($timeValue)) {
+                $timeValue = Helpers::getTimeValue($timeValue);
+            }
+            Helpers::validateNotNegative($timeValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $timeValue = fmod($timeValue, 1);
+        $timeValue = Date::excelToDateTimeObject($timeValue);
+
+        return (int) $timeValue->format('i');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Month.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Month
+{
+    /**
+     * MONTHOFYEAR.
+     *
+     * Returns the month of a date represented by a serial number.
+     * The month is given as an integer, ranging from 1 (January) to 12 (December).
+     *
+     * Excel Function:
+     *        MONTH(dateValue)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     *
+     * @return int|string Month of the year
+     */
+    public static function funcMonth($dateValue)
+    {
+        try {
+            $dateValue = Helpers::getDateValue($dateValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+        if ($dateValue < 1 && Date::getExcelCalendar() === DATE::CALENDAR_WINDOWS_1900) {
+            return 1;
+        }
+
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+
+        return (int) $PHPDateObject->format('n');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/NetworkDays.php

@@ -0,0 +1,102 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class NetworkDays
+{
+    /**
+     * NETWORKDAYS.
+     *
+     * Returns the number of whole working days between start_date and end_date. Working days
+     * exclude weekends and any dates identified in holidays.
+     * Use NETWORKDAYS to calculate employee benefits that accrue based on the number of days
+     * worked during a specific term.
+     *
+     * Excel Function:
+     *        NETWORKDAYS(startDate,endDate[,holidays[,holiday[,...]]])
+     *
+     * @param mixed $startDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                            PHP DateTime object, or a standard date string
+     * @param mixed $endDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                            PHP DateTime object, or a standard date string
+     *
+     * @return int|string Interval between the dates
+     */
+    public static function funcNetworkDays($startDate, $endDate, ...$dateArgs)
+    {
+        try {
+            //    Retrieve the mandatory start and end date that are referenced in the function definition
+            $sDate = Helpers::getDateValue($startDate);
+            $eDate = Helpers::getDateValue($endDate);
+            $startDate = min($sDate, $eDate);
+            $endDate = max($sDate, $eDate);
+            //    Get the optional days
+            $dateArgs = Functions::flattenArray($dateArgs);
+            //    Test any extra holiday parameters
+            $holidayArray = [];
+            foreach ($dateArgs as $holidayDate) {
+                $holidayArray[] = Helpers::getDateValue($holidayDate);
+            }
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $startDow = self::calcStartDow($startDate);
+        $endDow = self::calcEndDow($endDate);
+        $wholeWeekDays = (int) floor(($endDate - $startDate) / 7) * 5;
+        $partWeekDays = self::calcPartWeekDays($startDow, $endDow);
+
+        //    Test any extra holiday parameters
+        $holidayCountedArray = [];
+        foreach ($holidayArray as $holidayDate) {
+            if (($holidayDate >= $startDate) && ($holidayDate <= $endDate)) {
+                if ((WeekDay::funcWeekDay($holidayDate, 2) < 6) && (!in_array($holidayDate, $holidayCountedArray))) {
+                    --$partWeekDays;
+                    $holidayCountedArray[] = $holidayDate;
+                }
+            }
+        }
+
+        return self::applySign($wholeWeekDays + $partWeekDays, $sDate, $eDate);
+    }
+
+    private static function calcStartDow(float $startDate): int
+    {
+        $startDow = 6 - (int) WeekDay::funcWeekDay($startDate, 2);
+        if ($startDow < 0) {
+            $startDow = 5;
+        }
+
+        return $startDow;
+    }
+
+    private static function calcEndDow(float $endDate): int
+    {
+        $endDow = (int) WeekDay::funcWeekDay($endDate, 2);
+        if ($endDow >= 6) {
+            $endDow = 0;
+        }
+
+        return $endDow;
+    }
+
+    private static function calcPartWeekDays(int $startDow, int $endDow): int
+    {
+        $partWeekDays = $endDow + $startDow;
+        if ($partWeekDays > 5) {
+            $partWeekDays -= 5;
+        }
+
+        return $partWeekDays;
+    }
+
+    private static function applySign(int $result, float $sDate, float $eDate)
+    {
+        return ($sDate > $eDate) ? -$result : $result;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Now.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTimeImmutable;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Now
+{
+    /**
+     * DATETIMENOW.
+     *
+     * Returns the current date and time.
+     * The NOW function is useful when you need to display the current date and time on a worksheet or
+     * calculate a value based on the current date and time, and have that value updated each time you
+     * open the worksheet.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the date
+     * and time format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        NOW()
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcNow()
+    {
+        $dti = new DateTimeImmutable();
+        $dateArray = date_parse($dti->format('c'));
+
+        return is_array($dateArray) ? Helpers::returnIn3FormatsArray($dateArray) : Functions::VALUE();
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Second.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Second
+{
+    /**
+     * MINUTE.
+     *
+     * Returns the minutes of a time value.
+     * The minute is given as an integer, ranging from 0 to 59.
+     *
+     * Excel Function:
+     *        MINUTE(timeValue)
+     *
+     * @param mixed $timeValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard time string
+     *
+     * @return int|string Minute
+     */
+    public static function funcSecond($timeValue)
+    {
+        try {
+            $timeValue = Functions::flattenSingleValue($timeValue);
+            Helpers::nullFalseTrueToNumber($timeValue);
+            if (!is_numeric($timeValue)) {
+                $timeValue = Helpers::getTimeValue($timeValue);
+            }
+            Helpers::validateNotNegative($timeValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $timeValue = fmod($timeValue, 1);
+        $timeValue = Date::excelToDateTimeObject($timeValue);
+
+        return (int) $timeValue->format('s');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Time.php

@@ -0,0 +1,116 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTime;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Time
+{
+    /**
+     * TIME.
+     *
+     * The TIME function returns a value that represents a particular time.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the time
+     * format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        TIME(hour,minute,second)
+     *
+     * @param int $hour A number from 0 (zero) to 32767 representing the hour.
+     *                                    Any value greater than 23 will be divided by 24 and the remainder
+     *                                    will be treated as the hour value. For example, TIME(27,0,0) =
+     *                                    TIME(3,0,0) = .125 or 3:00 AM.
+     * @param int $minute A number from 0 to 32767 representing the minute.
+     *                                    Any value greater than 59 will be converted to hours and minutes.
+     *                                    For example, TIME(0,750,0) = TIME(12,30,0) = .520833 or 12:30 PM.
+     * @param int $second A number from 0 to 32767 representing the second.
+     *                                    Any value greater than 59 will be converted to hours, minutes,
+     *                                    and seconds. For example, TIME(0,0,2000) = TIME(0,33,22) = .023148
+     *                                    or 12:33:20 AM
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcTime($hour, $minute, $second)
+    {
+        try {
+            $hour = self::toIntWithNullBool($hour);
+            $minute = self::toIntWithNullBool($minute);
+            $second = self::toIntWithNullBool($second);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        self::adjustSecond($second, $minute);
+        self::adjustMinute($minute, $hour);
+
+        if ($hour > 23) {
+            $hour = $hour % 24;
+        } elseif ($hour < 0) {
+            return Functions::NAN();
+        }
+
+        // Execute function
+        $retType = Functions::getReturnDateType();
+        if ($retType === Functions::RETURNDATE_EXCEL) {
+            $calendar = Date::getExcelCalendar();
+            $date = (int) ($calendar !== Date::CALENDAR_WINDOWS_1900);
+
+            return (float) Date::formattedPHPToExcel($calendar, 1, $date, $hour, $minute, $second);
+        }
+        if ($retType === Functions::RETURNDATE_UNIX_TIMESTAMP) {
+            return (int) Date::excelToTimestamp(Date::formattedPHPToExcel(1970, 1, 1, $hour, $minute, $second)); // -2147468400; //    -2147472000 + 3600
+        }
+        // RETURNDATE_PHP_DATETIME_OBJECT
+        // Hour has already been normalized (0-23) above
+        $phpDateObject = new DateTime('1900-01-01 ' . $hour . ':' . $minute . ':' . $second);
+
+        return $phpDateObject;
+    }
+
+    private static function adjustSecond(int &$second, int &$minute): void
+    {
+        if ($second < 0) {
+            $minute += floor($second / 60);
+            $second = 60 - abs($second % 60);
+            if ($second == 60) {
+                $second = 0;
+            }
+        } elseif ($second >= 60) {
+            $minute += floor($second / 60);
+            $second = $second % 60;
+        }
+    }
+
+    private static function adjustMinute(int &$minute, int &$hour): void
+    {
+        if ($minute < 0) {
+            $hour += floor($minute / 60);
+            $minute = 60 - abs($minute % 60);
+            if ($minute == 60) {
+                $minute = 0;
+            }
+        } elseif ($minute >= 60) {
+            $hour += floor($minute / 60);
+            $minute = $minute % 60;
+        }
+    }
+
+    private static function toIntWithNullBool($value): int
+    {
+        $value = Functions::flattenSingleValue($value);
+        $value = $value ?? 0;
+        if (is_bool($value)) {
+            $value = (int) $value;
+        }
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (int) $value;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Datetime;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class TimeValue
+{
+    /**
+     * TIMEVALUE.
+     *
+     * Returns a value that represents a particular time.
+     * Use TIMEVALUE to convert a time represented by a text string to an Excel or PHP date/time stamp
+     * value.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the time
+     * format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        TIMEVALUE(timeValue)
+     *
+     * @param string $timeValue A text string that represents a time in any one of the Microsoft
+     *                                    Excel time formats; for example, "6:45 PM" and "18:45" text strings
+     *                                    within quotation marks that represent time.
+     *                                    Date information in time_text is ignored.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcTimeValue($timeValue)
+    {
+        $timeValue = trim(Functions::flattenSingleValue($timeValue), '"');
+        $timeValue = str_replace(['/', '.'], '-', $timeValue);
+
+        $arraySplit = preg_split('/[\/:\-\s]/', $timeValue);
+        if ((count($arraySplit) == 2 || count($arraySplit) == 3) && $arraySplit[0] > 24) {
+            $arraySplit[0] = ($arraySplit[0] % 24);
+            $timeValue = implode(':', $arraySplit);
+        }
+
+        $PHPDateArray = date_parse($timeValue);
+        $retValue = Functions::VALUE();
+        if (($PHPDateArray !== false) && ($PHPDateArray['error_count'] == 0)) {
+            // OpenOffice-specific code removed - it works just like Excel
+            $excelDateValue = Date::formattedPHPToExcel(1900, 1, 1, $PHPDateArray['hour'], $PHPDateArray['minute'], $PHPDateArray['second']) - 1;
+
+            $retType = Functions::getReturnDateType();
+            if ($retType === Functions::RETURNDATE_EXCEL) {
+                $retValue = (float) $excelDateValue;
+            } elseif ($retType === Functions::RETURNDATE_UNIX_TIMESTAMP) {
+                $retValue = (int) $phpDateValue = Date::excelToTimestamp($excelDateValue + 25569) - 3600;
+            } else {
+                $retValue = new DateTime('1900-01-01 ' . $PHPDateArray['hour'] . ':' . $PHPDateArray['minute'] . ':' . $PHPDateArray['second']);
+            }
+        }
+
+        return $retValue;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Today.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTimeImmutable;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Today
+{
+    /**
+     * DATENOW.
+     *
+     * Returns the current date.
+     * The NOW function is useful when you need to display the current date and time on a worksheet or
+     * calculate a value based on the current date and time, and have that value updated each time you
+     * open the worksheet.
+     *
+     * NOTE: When used in a Cell Formula, MS Excel changes the cell format so that it matches the date
+     * and time format of your regional settings. PhpSpreadsheet does not change cell formatting in this way.
+     *
+     * Excel Function:
+     *        TODAY()
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcToday()
+    {
+        $dti = new DateTimeImmutable();
+        $dateArray = date_parse($dti->format('c'));
+
+        return is_array($dateArray) ? Helpers::returnIn3FormatsArray($dateArray, true) : Functions::VALUE();
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/WeekDay.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class WeekDay
+{
+    /**
+     * WEEKDAY.
+     *
+     * Returns the day of the week for a specified date. The day is given as an integer
+     * ranging from 0 to 7 (dependent on the requested style).
+     *
+     * Excel Function:
+     *        WEEKDAY(dateValue[,style])
+     *
+     * @param float|int|string $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     * @param int $style A number that determines the type of return value
+     *                                        1 or omitted    Numbers 1 (Sunday) through 7 (Saturday).
+     *                                        2                Numbers 1 (Monday) through 7 (Sunday).
+     *                                        3                Numbers 0 (Monday) through 6 (Sunday).
+     *
+     * @return int|string Day of the week value
+     */
+    public static function funcWeekDay($dateValue, $style = 1)
+    {
+        try {
+            $dateValue = Helpers::getDateValue($dateValue);
+            $style = self::validateStyle($style);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+        Helpers::silly1900($PHPDateObject);
+        $DoW = (int) $PHPDateObject->format('w');
+
+        switch ($style) {
+            case 1:
+                ++$DoW;
+
+                break;
+            case 2:
+                $DoW = self::dow0Becomes7($DoW);
+
+                break;
+            case 3:
+                $DoW = self::dow0Becomes7($DoW) - 1;
+
+                break;
+        }
+
+        return $DoW;
+    }
+
+    private static function validateStyle($style): int
+    {
+        $style = Functions::flattenSingleValue($style);
+
+        if (!is_numeric($style)) {
+            throw new Exception(Functions::VALUE());
+        }
+        $style = (int) $style;
+        if (($style < 1) || ($style > 3)) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $style;
+    }
+
+    private static function dow0Becomes7(int $DoW): int
+    {
+        return ($DoW === 0) ? 7 : $DoW;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/WeekNum.php

@@ -0,0 +1,130 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use DateTime;
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class WeekNum
+{
+    /**
+     * WEEKNUM.
+     *
+     * Returns the week of the year for a specified date.
+     * The WEEKNUM function considers the week containing January 1 to be the first week of the year.
+     * However, there is a European standard that defines the first week as the one with the majority
+     * of days (four or more) falling in the new year. This means that for years in which there are
+     * three days or less in the first week of January, the WEEKNUM function returns week numbers
+     * that are incorrect according to the European standard.
+     *
+     * Excel Function:
+     *        WEEKNUM(dateValue[,style])
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     * @param int $method Week begins on Sunday or Monday
+     *                                        1 or omitted    Week begins on Sunday.
+     *                                        2                Week begins on Monday.
+     *                                        11               Week begins on Monday.
+     *                                        12               Week begins on Tuesday.
+     *                                        13               Week begins on Wednesday.
+     *                                        14               Week begins on Thursday.
+     *                                        15               Week begins on Friday.
+     *                                        16               Week begins on Saturday.
+     *                                        17               Week begins on Sunday.
+     *                                        21               ISO (Jan. 4 is week 1, begins on Monday).
+     *
+     * @return int|string Week Number
+     */
+    public static function funcWeekNum($dateValue, $method = Constants::STARTWEEK_SUNDAY)
+    {
+        $origDateValueNull = empty($dateValue);
+
+        try {
+            $method = self::validateMethod($method);
+            if ($dateValue === null) { // boolean not allowed
+                $dateValue = (Date::getExcelCalendar() === DATE::CALENDAR_MAC_1904 || $method === Constants::DOW_SUNDAY) ? 0 : 1;
+            }
+            $dateValue = self::validateDateValue($dateValue);
+            if (!$dateValue && self::buggyWeekNum1900($method)) {
+                // This seems to be an additional Excel bug.
+                return 0;
+            }
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+        if ($method == Constants::STARTWEEK_MONDAY_ISO) {
+            Helpers::silly1900($PHPDateObject);
+
+            return (int) $PHPDateObject->format('W');
+        }
+        if (self::buggyWeekNum1904($method, $origDateValueNull, $PHPDateObject)) {
+            return 0;
+        }
+        Helpers::silly1900($PHPDateObject, '+ 5 years'); // 1905 calendar matches
+        $dayOfYear = (int) $PHPDateObject->format('z');
+        $PHPDateObject->modify('-' . $dayOfYear . ' days');
+        $firstDayOfFirstWeek = (int) $PHPDateObject->format('w');
+        $daysInFirstWeek = (6 - $firstDayOfFirstWeek + $method) % 7;
+        $daysInFirstWeek += 7 * !$daysInFirstWeek;
+        $endFirstWeek = $daysInFirstWeek - 1;
+        $weekOfYear = floor(($dayOfYear - $endFirstWeek + 13) / 7);
+
+        return (int) $weekOfYear;
+    }
+
+    /**
+     * Validate dateValue parameter.
+     *
+     * @param mixed $dateValue
+     */
+    private static function validateDateValue($dateValue): float
+    {
+        if (is_bool($dateValue)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return Helpers::getDateValue($dateValue);
+    }
+
+    /**
+     * Validate method parameter.
+     *
+     * @param mixed $method
+     */
+    private static function validateMethod($method): int
+    {
+        if ($method === null) {
+            $method = Constants::STARTWEEK_SUNDAY;
+        }
+        $method = Functions::flattenSingleValue($method);
+        if (!is_numeric($method)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        $method = (int) $method;
+        if (!array_key_exists($method, Constants::METHODARR)) {
+            throw new Exception(Functions::NAN());
+        }
+        $method = Constants::METHODARR[$method];
+
+        return $method;
+    }
+
+    private static function buggyWeekNum1900(int $method): bool
+    {
+        return $method === Constants::DOW_SUNDAY && Date::getExcelCalendar() === Date::CALENDAR_WINDOWS_1900;
+    }
+
+    private static function buggyWeekNum1904(int $method, bool $origNull, DateTime $dateObject): bool
+    {
+        // This appears to be another Excel bug.
+
+        return $method === Constants::DOW_SUNDAY && Date::getExcelCalendar() === Date::CALENDAR_MAC_1904 && !$origNull && $dateObject->format('Y-m-d') === '1904-01-01';
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/WorkDay.php

@@ -0,0 +1,184 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class WorkDay
+{
+    /**
+     * WORKDAY.
+     *
+     * Returns the date that is the indicated number of working days before or after a date (the
+     * starting date). Working days exclude weekends and any dates identified as holidays.
+     * Use WORKDAY to exclude weekends or holidays when you calculate invoice due dates, expected
+     * delivery times, or the number of days of work performed.
+     *
+     * Excel Function:
+     *        WORKDAY(startDate,endDays[,holidays[,holiday[,...]]])
+     *
+     * @param mixed $startDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                        PHP DateTime object, or a standard date string
+     * @param int $endDays The number of nonweekend and nonholiday days before or after
+     *                                        startDate. A positive value for days yields a future date; a
+     *                                        negative value yields a past date.
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                        depending on the value of the ReturnDateType flag
+     */
+    public static function funcWorkDay($startDate, $endDays, ...$dateArgs)
+    {
+        //    Retrieve the mandatory start date and days that are referenced in the function definition
+        try {
+            $startDate = Helpers::getDateValue($startDate);
+            $endDays = Helpers::validateNumericNull($endDays);
+            $dateArgs = Functions::flattenArray($dateArgs);
+            $holidayArray = [];
+            foreach ($dateArgs as $holidayDate) {
+                $holidayArray[] = Helpers::getDateValue($holidayDate);
+            }
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $startDate = (float) floor($startDate);
+        $endDays = (int) floor($endDays);
+        //    If endDays is 0, we always return startDate
+        if ($endDays == 0) {
+            return $startDate;
+        }
+        if ($endDays < 0) {
+            return self::decrementing($startDate, $endDays, $holidayArray);
+        }
+
+        return self::incrementing($startDate, $endDays, $holidayArray);
+    }
+
+    /**
+     * Use incrementing logic to determine Workday.
+     *
+     * @return mixed
+     */
+    private static function incrementing(float $startDate, int $endDays, array $holidayArray)
+    {
+        //    Adjust the start date if it falls over a weekend
+
+        $startDoW = WeekDay::funcWeekDay($startDate, 3);
+        if (WeekDay::funcWeekDay($startDate, 3) >= 5) {
+            $startDate += 7 - $startDoW;
+            --$endDays;
+        }
+
+        //    Add endDays
+        $endDate = (float) $startDate + ((int) ($endDays / 5) * 7);
+        $endDays = $endDays % 5;
+        while ($endDays > 0) {
+            ++$endDate;
+            //    Adjust the calculated end date if it falls over a weekend
+            $endDow = WeekDay::funcWeekDay($endDate, 3);
+            if ($endDow >= 5) {
+                $endDate += 7 - $endDow;
+            }
+            --$endDays;
+        }
+
+        //    Test any extra holiday parameters
+        if (!empty($holidayArray)) {
+            $endDate = self::incrementingArray($startDate, $endDate, $holidayArray);
+        }
+
+        return Helpers::returnIn3FormatsFloat($endDate);
+    }
+
+    private static function incrementingArray(float $startDate, float $endDate, array $holidayArray): float
+    {
+        $holidayCountedArray = $holidayDates = [];
+        foreach ($holidayArray as $holidayDate) {
+            if (WeekDay::funcWeekDay($holidayDate, 3) < 5) {
+                $holidayDates[] = $holidayDate;
+            }
+        }
+        sort($holidayDates, SORT_NUMERIC);
+        foreach ($holidayDates as $holidayDate) {
+            if (($holidayDate >= $startDate) && ($holidayDate <= $endDate)) {
+                if (!in_array($holidayDate, $holidayCountedArray)) {
+                    ++$endDate;
+                    $holidayCountedArray[] = $holidayDate;
+                }
+            }
+            //    Adjust the calculated end date if it falls over a weekend
+            $endDoW = WeekDay::funcWeekDay($endDate, 3);
+            if ($endDoW >= 5) {
+                $endDate += 7 - $endDoW;
+            }
+        }
+
+        return $endDate;
+    }
+
+    /**
+     * Use decrementing logic to determine Workday.
+     *
+     * @return mixed
+     */
+    private static function decrementing(float $startDate, int $endDays, array $holidayArray)
+    {
+        //    Adjust the start date if it falls over a weekend
+
+        $startDoW = WeekDay::funcWeekDay($startDate, 3);
+        if (WeekDay::funcWeekDay($startDate, 3) >= 5) {
+            // @phpstan-ignore-next-line
+            $startDate += -$startDoW + 4;
+            ++$endDays;
+        }
+
+        //    Add endDays
+        $endDate = (float) $startDate + ((int) ($endDays / 5) * 7);
+        $endDays = $endDays % 5;
+        while ($endDays < 0) {
+            --$endDate;
+            //    Adjust the calculated end date if it falls over a weekend
+            $endDow = WeekDay::funcWeekDay($endDate, 3);
+            if ($endDow >= 5) {
+                $endDate += 4 - $endDow;
+            }
+            ++$endDays;
+        }
+
+        //    Test any extra holiday parameters
+        if (!empty($holidayArray)) {
+            $endDate = self::decrementingArray($startDate, $endDate, $holidayArray);
+        }
+
+        return Helpers::returnIn3FormatsFloat($endDate);
+    }
+
+    private static function decrementingArray(float $startDate, float $endDate, array $holidayArray): float
+    {
+        $holidayCountedArray = $holidayDates = [];
+        foreach ($holidayArray as $holidayDate) {
+            if (WeekDay::funcWeekDay($holidayDate, 3) < 5) {
+                $holidayDates[] = $holidayDate;
+            }
+        }
+        rsort($holidayDates, SORT_NUMERIC);
+        foreach ($holidayDates as $holidayDate) {
+            if (($holidayDate <= $startDate) && ($holidayDate >= $endDate)) {
+                if (!in_array($holidayDate, $holidayCountedArray)) {
+                    --$endDate;
+                    $holidayCountedArray[] = $holidayDate;
+                }
+            }
+            //    Adjust the calculated end date if it falls over a weekend
+            $endDoW = WeekDay::funcWeekDay($endDate, 3);
+            if ($endDoW >= 5) {
+                // @phpstan-ignore-next-line
+                $endDate += -$endDoW + 4;
+            }
+        }
+
+        return $endDate;
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/Year.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Year
+{
+    /**
+     * YEAR.
+     *
+     * Returns the year corresponding to a date.
+     * The year is returned as an integer in the range 1900-9999.
+     *
+     * Excel Function:
+     *        YEAR(dateValue)
+     *
+     * @param mixed $dateValue Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     *
+     * @return int|string Year
+     */
+    public static function funcYear($dateValue)
+    {
+        try {
+            $dateValue = Helpers::getDateValue($dateValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($dateValue < 1 && Date::getExcelCalendar() === DATE::CALENDAR_WINDOWS_1900) {
+            return 1900;
+        }
+        // Execute function
+        $PHPDateObject = Date::excelToDateTimeObject($dateValue);
+
+        return (int) $PHPDateObject->format('Y');
+    }
+}

src/PhpSpreadsheet/Calculation/DateTimeExcel/YearFrac.php

@@ -0,0 +1,120 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+
+use Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class YearFrac
+{
+    /**
+     * YEARFRAC.
+     *
+     * Calculates the fraction of the year represented by the number of whole days between two dates
+     * (the start_date and the end_date).
+     * Use the YEARFRAC worksheet function to identify the proportion of a whole year's benefits or
+     * obligations to assign to a specific term.
+     *
+     * Excel Function:
+     *        YEARFRAC(startDate,endDate[,method])
+     * See https://lists.oasis-open.org/archives/office-formula/200806/msg00039.html
+     *     for description of algorithm used in Excel
+     *
+     * @param mixed $startDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     * @param mixed $endDate Excel date serial value (float), PHP date timestamp (integer),
+     *                                    PHP DateTime object, or a standard date string
+     * @param int $method Method used for the calculation
+     *                                        0 or omitted    US (NASD) 30/360
+     *                                        1                Actual/actual
+     *                                        2                Actual/360
+     *                                        3                Actual/365
+     *                                        4                European 30/360
+     *
+     * @return float|string fraction of the year, or a string containing an error
+     */
+    public static function funcYearFrac($startDate, $endDate, $method = 0)
+    {
+        try {
+            $method = (int) Helpers::validateNumericNull($method);
+            $sDate = Helpers::getDateValue($startDate);
+            $eDate = Helpers::getDateValue($endDate);
+            $sDate = self::excelBug($sDate, $startDate, $endDate, $method);
+            $eDate = self::excelBug($eDate, $endDate, $startDate, $method);
+            $startDate = min($sDate, $eDate);
+            $endDate = max($sDate, $eDate);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        switch ($method) {
+            case 0:
+                return Days360::funcDays360($startDate, $endDate) / 360;
+            case 1:
+                return self::method1($startDate, $endDate);
+            case 2:
+                return DateDif::funcDateDif($startDate, $endDate) / 360;
+            case 3:
+                return DateDif::funcDateDif($startDate, $endDate) / 365;
+            case 4:
+                return Days360::funcDays360($startDate, $endDate, true) / 360;
+        }
+
+        return Functions::NAN();
+    }
+
+    /**
+     * Excel 1900 calendar treats date argument of null as 1900-01-00. Really.
+     *
+     * @param mixed $startDate
+     * @param mixed $endDate
+     */
+    private static function excelBug(float $sDate, $startDate, $endDate, int $method): float
+    {
+        if (Functions::getCompatibilityMode() !== Functions::COMPATIBILITY_OPENOFFICE && Date::getExcelCalendar() !== Date::CALENDAR_MAC_1904) {
+            if ($endDate === null && $startDate !== null) {
+                if (Month::funcMonth($sDate) == 12 && Day::funcDay($sDate) === 31 && $method === 0) {
+                    $sDate += 2;
+                } else {
+                    ++$sDate;
+                }
+            }
+        }
+
+        return $sDate;
+    }
+
+    private static function method1(float $startDate, float $endDate): float
+    {
+        $days = DateDif::funcDateDif($startDate, $endDate);
+        $startYear = Year::funcYear($startDate);
+        $endYear = Year::funcYear($endDate);
+        $years = $endYear - $startYear + 1;
+        $startMonth = Month::funcMonth($startDate);
+        $startDay = Day::funcDay($startDate);
+        $endMonth = Month::funcMonth($endDate);
+        $endDay = Day::funcDay($endDate);
+        $startMonthDay = 100 * $startMonth + $startDay;
+        $endMonthDay = 100 * $endMonth + $endDay;
+        if ($years == 1) {
+            $tmpCalcAnnualBasis = 365 + (int) Helpers::isLeapYear($endYear);
+        } elseif ($years == 2 && $startMonthDay >= $endMonthDay) {
+            if (Helpers::isLeapYear($startYear)) {
+                $tmpCalcAnnualBasis = 365 + (int) ($startMonthDay <= 229);
+            } elseif (Helpers::isLeapYear($endYear)) {
+                $tmpCalcAnnualBasis = 365 + (int) ($endMonthDay >= 229);
+            } else {
+                $tmpCalcAnnualBasis = 365;
+            }
+        } else {
+            $tmpCalcAnnualBasis = 0;
+            for ($year = $startYear; $year <= $endYear; ++$year) {
+                $tmpCalcAnnualBasis += 365 + (int) Helpers::isLeapYear($year);
+            }
+            $tmpCalcAnnualBasis /= $years;
+        }
+
+        return $days / $tmpCalcAnnualBasis;
+    }
+}

src/PhpSpreadsheet/Calculation/Engineering.php

@@ -3,14 +3,21 @@
 namespace PhpOffice\PhpSpreadsheet\Calculation;
 
 use Complex\Complex;
-use Complex\Exception as ComplexException;
+use PhpOffice\PhpSpreadsheet\Calculation\Engineering\ComplexFunctions;
+use PhpOffice\PhpSpreadsheet\Calculation\Engineering\ComplexOperations;
 
+/**
+ * @deprecated 1.18.0
+ */
 class Engineering
 {
     /**
      * EULER.
+     *
+     * @deprecated 1.18.0
+     * @see Use Engineering\Constants\EULER instead
      */
-    const EULER = 2.71828182845904523536;
+    public const EULER = 2.71828182845904523536;
 
     /**
      * parseComplex.
@@ -149,7 +156,7 @@ class Engineering
      *
      * @see Use the toDecimal() method in the Engineering\ConvertBinary class instead
      *
-     * @param string $x The binary number (as a string) that you want to convert. The number
+     * @param mixed $x The binary number (as a string) that you want to convert. The number
      *                                cannot contain more than 10 characters (10 bits). The most significant
      *                                bit of number is the sign bit. The remaining 9 bits are magnitude bits.
      *                                Negative numbers are represented using two's-complement notation.
@@ -175,13 +182,13 @@ class Engineering
      *
      * @see Use the toHex() method in the Engineering\ConvertBinary class instead
      *
-     * @param string $x The binary number (as a string) that you want to convert. The number
+     * @param mixed $x The binary number (as a string) that you want to convert. The number
      *                                cannot contain more than 10 characters (10 bits). The most significant
      *                                bit of number is the sign bit. The remaining 9 bits are magnitude bits.
      *                                Negative numbers are represented using two's-complement notation.
      *                                If number is not a valid binary number, or if number contains more than
      *                                10 characters (10 bits), BIN2HEX returns the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, BIN2HEX uses the
+     * @param mixed $places The number of characters to use. If places is omitted, BIN2HEX uses the
      *                                minimum number of characters necessary. Places is useful for padding the
      *                                return value with leading 0s (zeros).
      *                                If places is not an integer, it is truncated.
@@ -207,13 +214,13 @@ class Engineering
      *
      * @see Use the toOctal() method in the Engineering\ConvertBinary class instead
      *
-     * @param string $x The binary number (as a string) that you want to convert. The number
+     * @param mixed $x The binary number (as a string) that you want to convert. The number
      *                                cannot contain more than 10 characters (10 bits). The most significant
      *                                bit of number is the sign bit. The remaining 9 bits are magnitude bits.
      *                                Negative numbers are represented using two's-complement notation.
      *                                If number is not a valid binary number, or if number contains more than
      *                                10 characters (10 bits), BIN2OCT returns the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, BIN2OCT uses the
+     * @param mixed $places The number of characters to use. If places is omitted, BIN2OCT uses the
      *                                minimum number of characters necessary. Places is useful for padding the
      *                                return value with leading 0s (zeros).
      *                                If places is not an integer, it is truncated.
@@ -239,7 +246,7 @@ class Engineering
      *
      * @see Use the toBinary() method in the Engineering\ConvertDecimal class instead
      *
-     * @param string $x The decimal integer you want to convert. If number is negative,
+     * @param mixed $x The decimal integer you want to convert. If number is negative,
      *                                valid place values are ignored and DEC2BIN returns a 10-character
      *                                (10-bit) binary number in which the most significant bit is the sign
      *                                bit. The remaining 9 bits are magnitude bits. Negative numbers are
@@ -249,7 +256,7 @@ class Engineering
      *                                If number is nonnumeric, DEC2BIN returns the #VALUE! error value.
      *                                If DEC2BIN requires more than places characters, it returns the #NUM!
      *                                error value.
-     * @param int $places The number of characters to use. If places is omitted, DEC2BIN uses
+     * @param mixed $places The number of characters to use. If places is omitted, DEC2BIN uses
      *                                the minimum number of characters necessary. Places is useful for
      *                                padding the return value with leading 0s (zeros).
      *                                If places is not an integer, it is truncated.
@@ -275,7 +282,7 @@ class Engineering
      *
      * @see Use the toHex() method in the Engineering\ConvertDecimal class instead
      *
-     * @param string $x The decimal integer you want to convert. If number is negative,
+     * @param mixed $x The decimal integer you want to convert. If number is negative,
      *                                places is ignored and DEC2HEX returns a 10-character (40-bit)
      *                                hexadecimal number in which the most significant bit is the sign
      *                                bit. The remaining 39 bits are magnitude bits. Negative numbers
@@ -285,7 +292,7 @@ class Engineering
      *                                If number is nonnumeric, DEC2HEX returns the #VALUE! error value.
      *                                If DEC2HEX requires more than places characters, it returns the
      *                                #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, DEC2HEX uses
+     * @param mixed $places The number of characters to use. If places is omitted, DEC2HEX uses
      *                                the minimum number of characters necessary. Places is useful for
      *                                padding the return value with leading 0s (zeros).
      *                                If places is not an integer, it is truncated.
@@ -311,7 +318,7 @@ class Engineering
      *
      * @see Use the toOctal() method in the Engineering\ConvertDecimal class instead
      *
-     * @param string $x The decimal integer you want to convert. If number is negative,
+     * @param mixed $x The decimal integer you want to convert. If number is negative,
      *                                places is ignored and DEC2OCT returns a 10-character (30-bit)
      *                                octal number in which the most significant bit is the sign bit.
      *                                The remaining 29 bits are magnitude bits. Negative numbers are
@@ -321,7 +328,7 @@ class Engineering
      *                                If number is nonnumeric, DEC2OCT returns the #VALUE! error value.
      *                                If DEC2OCT requires more than places characters, it returns the
      *                                #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, DEC2OCT uses
+     * @param mixed $places The number of characters to use. If places is omitted, DEC2OCT uses
      *                                the minimum number of characters necessary. Places is useful for
      *                                padding the return value with leading 0s (zeros).
      *                                If places is not an integer, it is truncated.
@@ -347,7 +354,7 @@ class Engineering
      *
      * @see Use the toBinary() method in the Engineering\ConvertHex class instead
      *
-     * @param string $x the hexadecimal number you want to convert.
+     * @param mixed $x the hexadecimal number (as a string) that you want to convert.
      *                  Number cannot contain more than 10 characters.
      *                  The most significant bit of number is the sign bit (40th bit from the right).
      *                  The remaining 9 bits are magnitude bits.
@@ -357,7 +364,7 @@ class Engineering
      *                      and if number is positive, it cannot be greater than 1FF.
      *                  If number is not a valid hexadecimal number, HEX2BIN returns the #NUM! error value.
      *                  If HEX2BIN requires more than places characters, it returns the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted,
+     * @param mixed $places The number of characters to use. If places is omitted,
      *                                    HEX2BIN uses the minimum number of characters necessary. Places
      *                                    is useful for padding the return value with leading 0s (zeros).
      *                                    If places is not an integer, it is truncated.
@@ -383,7 +390,7 @@ class Engineering
      *
      * @see Use the toDecimal() method in the Engineering\ConvertHex class instead
      *
-     * @param string $x The hexadecimal number you want to convert. This number cannot
+     * @param mixed $x The hexadecimal number (as a string) that you want to convert. This number cannot
      *                                contain more than 10 characters (40 bits). The most significant
      *                                bit of number is the sign bit. The remaining 39 bits are magnitude
      *                                bits. Negative numbers are represented using two's-complement
@@ -410,7 +417,7 @@ class Engineering
      *
      * @see Use the toOctal() method in the Engineering\ConvertHex class instead
      *
-     * @param string $x The hexadecimal number you want to convert. Number cannot
+     * @param mixed $x The hexadecimal number (as a string) that you want to convert. Number cannot
      *                                    contain more than 10 characters. The most significant bit of
      *                                    number is the sign bit. The remaining 39 bits are magnitude
      *                                    bits. Negative numbers are represented using two's-complement
@@ -423,7 +430,7 @@ class Engineering
      *                                    the #NUM! error value.
      *                                    If HEX2OCT requires more than places characters, it returns
      *                                    the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, HEX2OCT
+     * @param mixed $places The number of characters to use. If places is omitted, HEX2OCT
      *                                    uses the minimum number of characters necessary. Places is
      *                                    useful for padding the return value with leading 0s (zeros).
      *                                    If places is not an integer, it is truncated.
@@ -450,7 +457,7 @@ class Engineering
      *
      * @see Use the toBinary() method in the Engineering\ConvertOctal class instead
      *
-     * @param string $x The octal number you want to convert. Number may not
+     * @param mixed $x The octal number you want to convert. Number may not
      *                                    contain more than 10 characters. The most significant
      *                                    bit of number is the sign bit. The remaining 29 bits
      *                                    are magnitude bits. Negative numbers are represented
@@ -463,7 +470,7 @@ class Engineering
      *                                    the #NUM! error value.
      *                                    If OCT2BIN requires more than places characters, it
      *                                    returns the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted,
+     * @param mixed $places The number of characters to use. If places is omitted,
      *                                    OCT2BIN uses the minimum number of characters necessary.
      *                                    Places is useful for padding the return value with
      *                                    leading 0s (zeros).
@@ -492,7 +499,7 @@ class Engineering
      *
      * @see Use the toDecimal() method in the Engineering\ConvertOctal class instead
      *
-     * @param string $x The octal number you want to convert. Number may not contain
+     * @param mixed $x The octal number you want to convert. Number may not contain
      *                                more than 10 octal characters (30 bits). The most significant
      *                                bit of number is the sign bit. The remaining 29 bits are
      *                                magnitude bits. Negative numbers are represented using
@@ -519,7 +526,7 @@ class Engineering
      *
      * @see Use the toHex() method in the Engineering\ConvertOctal class instead
      *
-     * @param string $x The octal number you want to convert. Number may not contain
+     * @param mixed $x The octal number you want to convert. Number may not contain
      *                                    more than 10 octal characters (30 bits). The most significant
      *                                    bit of number is the sign bit. The remaining 29 bits are
      *                                    magnitude bits. Negative numbers are represented using
@@ -530,7 +537,7 @@ class Engineering
      *                                    #NUM! error value.
      *                                    If OCT2HEX requires more than places characters, it returns
      *                                    the #NUM! error value.
-     * @param int $places The number of characters to use. If places is omitted, OCT2HEX
+     * @param mixed $places The number of characters to use. If places is omitted, OCT2HEX
      *                                    uses the minimum number of characters necessary. Places is useful
      *                                    for padding the return value with leading 0s (zeros).
      *                                    If places is not an integer, it is truncated.
@@ -552,6 +559,10 @@ class Engineering
      * Excel Function:
      *        COMPLEX(realNumber,imaginary[,suffix])
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the COMPLEX() method in the Engineering\Complex class instead
+     *
      * @param float $realNumber the real coefficient of the complex number
      * @param float $imaginary the imaginary coefficient of the complex number
      * @param string $suffix The suffix for the imaginary component of the complex number.
@@ -561,20 +572,7 @@ class Engineering
      */
     public static function COMPLEX($realNumber = 0.0, $imaginary = 0.0, $suffix = 'i')
     {
-        $realNumber = ($realNumber === null) ? 0.0 : Functions::flattenSingleValue($realNumber);
-        $imaginary = ($imaginary === null) ? 0.0 : Functions::flattenSingleValue($imaginary);
-        $suffix = ($suffix === null) ? 'i' : Functions::flattenSingleValue($suffix);
-
-        if (
-            ((is_numeric($realNumber)) && (is_numeric($imaginary))) &&
-            (($suffix == 'i') || ($suffix == 'j') || ($suffix == ''))
-        ) {
-            $complex = new Complex($realNumber, $imaginary, $suffix);
-
-            return (string) $complex;
-        }
-
-        return Functions::VALUE();
+        return Engineering\Complex::COMPLEX($realNumber, $imaginary, $suffix);
     }
 
     /**
@@ -585,16 +583,18 @@ class Engineering
      * Excel Function:
      *        IMAGINARY(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMAGINARY() method in the Engineering\Complex class instead
+     *
      * @param string $complexNumber the complex number for which you want the imaginary
      *                                         coefficient
      *
-     * @return float
+     * @return float|string
      */
     public static function IMAGINARY($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (new Complex($complexNumber))->getImaginary();
+        return Engineering\Complex::IMAGINARY($complexNumber);
     }
 
     /**
@@ -605,15 +605,17 @@ class Engineering
      * Excel Function:
      *        IMREAL(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMREAL() method in the Engineering\Complex class instead
+     *
      * @param string $complexNumber the complex number for which you want the real coefficient
      *
-     * @return float
+     * @return float|string
      */
     public static function IMREAL($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (new Complex($complexNumber))->getReal();
+        return Engineering\Complex::IMREAL($complexNumber);
     }
 
     /**
@@ -624,15 +626,17 @@ class Engineering
      * Excel Function:
      *        IMABS(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMABS() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the absolute value
      *
-     * @return float
+     * @return float|string
      */
     public static function IMABS($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (new Complex($complexNumber))->abs();
+        return ComplexFunctions::IMABS($complexNumber);
     }
 
     /**
@@ -644,20 +648,17 @@ class Engineering
      * Excel Function:
      *        IMARGUMENT(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMARGUMENT() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the argument theta
      *
      * @return float|string
      */
     public static function IMARGUMENT($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        $complex = new Complex($complexNumber);
-        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
-            return Functions::DIV0();
-        }
-
-        return $complex->argument();
+        return ComplexFunctions::IMARGUMENT($complexNumber);
     }
 
     /**
@@ -668,15 +669,17 @@ class Engineering
      * Excel Function:
      *        IMCONJUGATE(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMARGUMENT() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the conjugate
      *
      * @return string
      */
     public static function IMCONJUGATE($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->conjugate();
+        return ComplexFunctions::IMCONJUGATE($complexNumber);
     }
 
     /**
@@ -687,15 +690,17 @@ class Engineering
      * Excel Function:
      *        IMCOS(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMCOS() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the cosine
      *
      * @return float|string
      */
     public static function IMCOS($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->cos();
+        return ComplexFunctions::IMCOS($complexNumber);
     }
 
     /**
@@ -706,15 +711,17 @@ class Engineering
      * Excel Function:
      *        IMCOSH(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMCOSH() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the hyperbolic cosine
      *
      * @return float|string
      */
     public static function IMCOSH($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->cosh();
+        return ComplexFunctions::IMCOSH($complexNumber);
     }
 
     /**
@@ -725,15 +732,17 @@ class Engineering
      * Excel Function:
      *        IMCOT(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMCOT() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the cotangent
      *
      * @return float|string
      */
     public static function IMCOT($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->cot();
+        return ComplexFunctions::IMCOT($complexNumber);
     }
 
     /**
@@ -744,15 +753,17 @@ class Engineering
      * Excel Function:
      *        IMCSC(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMCSC() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the cosecant
      *
      * @return float|string
      */
     public static function IMCSC($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->csc();
+        return ComplexFunctions::IMCSC($complexNumber);
     }
 
     /**
@@ -763,15 +774,17 @@ class Engineering
      * Excel Function:
      *        IMCSCH(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMCSCH() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the hyperbolic cosecant
      *
      * @return float|string
      */
     public static function IMCSCH($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->csch();
+        return ComplexFunctions::IMCSCH($complexNumber);
     }
 
     /**
@@ -782,15 +795,17 @@ class Engineering
      * Excel Function:
      *        IMSIN(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSIN() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the sine
      *
      * @return float|string
      */
     public static function IMSIN($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->sin();
+        return ComplexFunctions::IMSIN($complexNumber);
     }
 
     /**
@@ -801,15 +816,17 @@ class Engineering
      * Excel Function:
      *        IMSINH(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSINH() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the hyperbolic sine
      *
      * @return float|string
      */
     public static function IMSINH($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->sinh();
+        return ComplexFunctions::IMSINH($complexNumber);
     }
 
     /**
@@ -820,15 +837,17 @@ class Engineering
      * Excel Function:
      *        IMSEC(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSEC() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the secant
      *
      * @return float|string
      */
     public static function IMSEC($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->sec();
+        return ComplexFunctions::IMSEC($complexNumber);
     }
 
     /**
@@ -839,15 +858,17 @@ class Engineering
      * Excel Function:
      *        IMSECH(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSECH() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the hyperbolic secant
      *
      * @return float|string
      */
     public static function IMSECH($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->sech();
+        return ComplexFunctions::IMSECH($complexNumber);
     }
 
     /**
@@ -858,15 +879,17 @@ class Engineering
      * Excel Function:
      *        IMTAN(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMTAN() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the tangent
      *
      * @return float|string
      */
     public static function IMTAN($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->tan();
+        return ComplexFunctions::IMTAN($complexNumber);
     }
 
     /**
@@ -877,20 +900,17 @@ class Engineering
      * Excel Function:
      *        IMSQRT(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSQRT() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the square root
      *
      * @return string
      */
     public static function IMSQRT($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        $theta = self::IMARGUMENT($complexNumber);
-        if ($theta === Functions::DIV0()) {
-            return '0';
-        }
-
-        return (string) (new Complex($complexNumber))->sqrt();
+        return ComplexFunctions::IMSQRT($complexNumber);
     }
 
     /**
@@ -901,20 +921,17 @@ class Engineering
      * Excel Function:
      *        IMLN(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMLN() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the natural logarithm
      *
      * @return string
      */
     public static function IMLN($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        $complex = new Complex($complexNumber);
-        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
-            return Functions::NAN();
-        }
-
-        return (string) (new Complex($complexNumber))->ln();
+        return ComplexFunctions::IMLN($complexNumber);
     }
 
     /**
@@ -925,20 +942,17 @@ class Engineering
      * Excel Function:
      *        IMLOG10(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMLOG10() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the common logarithm
      *
      * @return string
      */
     public static function IMLOG10($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        $complex = new Complex($complexNumber);
-        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
-            return Functions::NAN();
-        }
-
-        return (string) (new Complex($complexNumber))->log10();
+        return ComplexFunctions::IMLOG10($complexNumber);
     }
 
     /**
@@ -949,20 +963,17 @@ class Engineering
      * Excel Function:
      *        IMLOG2(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMLOG2() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the base-2 logarithm
      *
      * @return string
      */
     public static function IMLOG2($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        $complex = new Complex($complexNumber);
-        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
-            return Functions::NAN();
-        }
-
-        return (string) (new Complex($complexNumber))->log2();
+        return ComplexFunctions::IMLOG2($complexNumber);
     }
 
     /**
@@ -973,15 +984,17 @@ class Engineering
      * Excel Function:
      *        IMEXP(complexNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMEXP() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number for which you want the exponential
      *
      * @return string
      */
     public static function IMEXP($complexNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-
-        return (string) (new Complex($complexNumber))->exp();
+        return ComplexFunctions::IMEXP($complexNumber);
     }
 
     /**
@@ -992,6 +1005,10 @@ class Engineering
      * Excel Function:
      *        IMPOWER(complexNumber,realNumber)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMPOWER() method in the Engineering\ComplexFunctions class instead
+     *
      * @param string $complexNumber the complex number you want to raise to a power
      * @param float $realNumber the power to which you want to raise the complex number
      *
@@ -999,14 +1016,7 @@ class Engineering
      */
     public static function IMPOWER($complexNumber, $realNumber)
     {
-        $complexNumber = Functions::flattenSingleValue($complexNumber);
-        $realNumber = Functions::flattenSingleValue($realNumber);
-
-        if (!is_numeric($realNumber)) {
-            return Functions::VALUE();
-        }
-
-        return (string) (new Complex($complexNumber))->pow($realNumber);
+        return ComplexFunctions::IMPOWER($complexNumber, $realNumber);
     }
 
     /**
@@ -1017,6 +1027,10 @@ class Engineering
      * Excel Function:
      *        IMDIV(complexDividend,complexDivisor)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMDIV() method in the Engineering\ComplexOperations class instead
+     *
      * @param string $complexDividend the complex numerator or dividend
      * @param string $complexDivisor the complex denominator or divisor
      *
@@ -1024,14 +1038,7 @@ class Engineering
      */
     public static function IMDIV($complexDividend, $complexDivisor)
     {
-        $complexDividend = Functions::flattenSingleValue($complexDividend);
-        $complexDivisor = Functions::flattenSingleValue($complexDivisor);
-
-        try {
-            return (string) (new Complex($complexDividend))->divideby(new Complex($complexDivisor));
-        } catch (ComplexException $e) {
-            return Functions::NAN();
-        }
+        return ComplexOperations::IMDIV($complexDividend, $complexDivisor);
     }
 
     /**
@@ -1042,6 +1049,10 @@ class Engineering
      * Excel Function:
      *        IMSUB(complexNumber1,complexNumber2)
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSUB() method in the Engineering\ComplexOperations class instead
+     *
      * @param string $complexNumber1 the complex number from which to subtract complexNumber2
      * @param string $complexNumber2 the complex number to subtract from complexNumber1
      *
@@ -1049,14 +1060,7 @@ class Engineering
      */
     public static function IMSUB($complexNumber1, $complexNumber2)
     {
-        $complexNumber1 = Functions::flattenSingleValue($complexNumber1);
-        $complexNumber2 = Functions::flattenSingleValue($complexNumber2);
-
-        try {
-            return (string) (new Complex($complexNumber1))->subtract(new Complex($complexNumber2));
-        } catch (ComplexException $e) {
-            return Functions::NAN();
-        }
+        return ComplexOperations::IMSUB($complexNumber1, $complexNumber2);
     }
 
     /**
@@ -1067,26 +1071,17 @@ class Engineering
      * Excel Function:
      *        IMSUM(complexNumber[,complexNumber[,...]])
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMSUM() method in the Engineering\ComplexOperations class instead
+     *
      * @param string ...$complexNumbers Series of complex numbers to add
      *
      * @return string
      */
     public static function IMSUM(...$complexNumbers)
     {
-        // Return value
-        $returnValue = new Complex(0.0);
-        $aArgs = Functions::flattenArray($complexNumbers);
-
-        try {
-            // Loop through the arguments
-            foreach ($aArgs as $complex) {
-                $returnValue = $returnValue->add(new Complex($complex));
-            }
-        } catch (ComplexException $e) {
-            return Functions::NAN();
-        }
-
-        return (string) $returnValue;
+        return ComplexOperations::IMSUM(...$complexNumbers);
     }
 
     /**
@@ -1097,26 +1092,17 @@ class Engineering
      * Excel Function:
      *        IMPRODUCT(complexNumber[,complexNumber[,...]])
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the IMPRODUCT() method in the Engineering\ComplexOperations class instead
+     *
      * @param string ...$complexNumbers Series of complex numbers to multiply
      *
      * @return string
      */
     public static function IMPRODUCT(...$complexNumbers)
     {
-        // Return value
-        $returnValue = new Complex(1.0);
-        $aArgs = Functions::flattenArray($complexNumbers);
-
-        try {
-            // Loop through the arguments
-            foreach ($aArgs as $complex) {
-                $returnValue = $returnValue->multiply(new Complex($complex));
-            }
-        } catch (ComplexException $e) {
-            return Functions::NAN();
-        }
-
-        return (string) $returnValue;
+        return ComplexOperations::IMPRODUCT(...$complexNumbers);
     }
 
     /**

src/PhpSpreadsheet/Calculation/Engineering/BaseValidations.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+trait BaseValidations
+{
+    protected static function validateFloat($value): float
+    {
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (float) $value;
+    }
+
+    protected static function validateInt($value): int
+    {
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (int) floor($value);
+    }
+}

src/PhpSpreadsheet/Calculation/Engineering/BesselI.php

@@ -2,11 +2,13 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
-use PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
 
 class BesselI
 {
+    use BaseValidations;
+
     /**
      * BESSELI.
      *
@@ -16,9 +18,12 @@ class BesselI
      *    Excel Function:
      *        BESSELI(x,ord)
      *
-     * @param float $x The value at which to evaluate the function.
+     * NOTE: The MS Excel implementation of the BESSELI function is still not accurate.
+     *       This code provides a more accurate calculation
+     *
+     * @param mixed $x A float value at which to evaluate the function.
      *                                If x is nonnumeric, BESSELI returns the #VALUE! error value.
-     * @param int $ord The order of the Bessel function.
+     * @param mixed $ord The integer order of the Bessel function.
      *                                If ord is not an integer, it is truncated.
      *                                If $ord is nonnumeric, BESSELI returns the #VALUE! error value.
      *                                If $ord < 0, BESSELI returns the #NUM! error value.
@@ -28,45 +33,107 @@ class BesselI
     public static function BESSELI($x, $ord)
     {
         $x = ($x === null) ? 0.0 : Functions::flattenSingleValue($x);
-        $ord = ($ord === null) ? 0.0 : Functions::flattenSingleValue($ord);
+        $ord = ($ord === null) ? 0 : Functions::flattenSingleValue($ord);
 
-        if ((is_numeric($x)) && (is_numeric($ord))) {
-            $ord = (int) floor($ord);
-            if ($ord < 0) {
-                return Functions::NAN();
-            }
-
-            $fResult = self::calculate($x, $ord);
-
-            return (is_nan($fResult)) ? Functions::NAN() : $fResult;
+        try {
+            $x = self::validateFloat($x);
+            $ord = self::validateInt($ord);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
-        return Functions::VALUE();
+        if ($ord < 0) {
+            return Functions::NAN();
+        }
+
+        $fResult = self::calculate($x, $ord);
+
+        return (is_nan($fResult)) ? Functions::NAN() : $fResult;
     }
 
     private static function calculate(float $x, int $ord): float
     {
-        if (abs($x) <= 30) {
-            $fResult = $fTerm = ($x / 2) ** $ord / MathTrig::FACT($ord);
-            $ordK = 1;
-            $fSqrX = ($x * $x) / 4;
-            do {
-                $fTerm *= $fSqrX;
-                $fTerm /= ($ordK * ($ordK + $ord));
-                $fResult += $fTerm;
-            } while ((abs($fTerm) > 1e-12) && (++$ordK < 100));
-
-            return $fResult;
+        // special cases
+        switch ($ord) {
+            case 0:
+                return self::besselI0($x);
+            case 1:
+                return self::besselI1($x);
         }
 
-        $f_2_PI = 2 * M_PI;
+        return self::besselI2($x, $ord);
+    }
 
-        $fXAbs = abs($x);
-        $fResult = exp($fXAbs) / sqrt($f_2_PI * $fXAbs);
-        if (($ord & 1) && ($x < 0)) {
-            $fResult = -$fResult;
+    private static function besselI0(float $x): float
+    {
+        $ax = abs($x);
+
+        if ($ax < 3.75) {
+            $y = $x / 3.75;
+            $y = $y * $y;
+
+            return 1.0 + $y * (3.5156229 + $y * (3.0899424 + $y * (1.2067492
+                                + $y * (0.2659732 + $y * (0.360768e-1 + $y * 0.45813e-2)))));
         }
 
-        return $fResult;
+        $y = 3.75 / $ax;
+
+        return (exp($ax) / sqrt($ax)) * (0.39894228 + $y * (0.1328592e-1 + $y * (0.225319e-2 + $y * (-0.157565e-2
+                            + $y * (0.916281e-2 + $y * (-0.2057706e-1 + $y * (0.2635537e-1 +
+                                        $y * (-0.1647633e-1 + $y * 0.392377e-2))))))));
+    }
+
+    private static function besselI1(float $x): float
+    {
+        $ax = abs($x);
+
+        if ($ax < 3.75) {
+            $y = $x / 3.75;
+            $y = $y * $y;
+            $ans = $ax * (0.5 + $y * (0.87890594 + $y * (0.51498869 + $y * (0.15084934 + $y * (0.2658733e-1 +
+                                    $y * (0.301532e-2 + $y * 0.32411e-3))))));
+
+            return ($x < 0.0) ? -$ans : $ans;
+        }
+
+        $y = 3.75 / $ax;
+        $ans = 0.2282967e-1 + $y * (-0.2895312e-1 + $y * (0.1787654e-1 - $y * 0.420059e-2));
+        $ans = 0.39894228 + $y * (-0.3988024e-1 + $y * (-0.362018e-2 + $y * (0.163801e-2 +
+                        $y * (-0.1031555e-1 + $y * $ans))));
+        $ans *= exp($ax) / sqrt($ax);
+
+        return ($x < 0.0) ? -$ans : $ans;
+    }
+
+    private static function besselI2(float $x, int $ord): float
+    {
+        if ($x === 0.0) {
+            return 0.0;
+        }
+
+        $tox = 2.0 / abs($x);
+        $bip = 0;
+        $ans = 0.0;
+        $bi = 1.0;
+
+        for ($j = 2 * ($ord + (int) sqrt(40.0 * $ord)); $j > 0; --$j) {
+            $bim = $bip + $j * $tox * $bi;
+            $bip = $bi;
+            $bi = $bim;
+
+            if (abs($bi) > 1.0e+12) {
+                $ans *= 1.0e-12;
+                $bi *= 1.0e-12;
+                $bip *= 1.0e-12;
+            }
+
+            if ($j === $ord) {
+                $ans = $bip;
+            }
+        }
+
+        $ans *= self::besselI0($x) / $bi;
+
+        return ($x < 0.0 && (($ord % 2) === 1)) ? -$ans : $ans;
     }
 }

src/PhpSpreadsheet/Calculation/Engineering/BesselJ.php

@@ -2,11 +2,13 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
-use PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
 
 class BesselJ
 {
+    use BaseValidations;
+
     /**
      * BESSELJ.
      *
@@ -15,9 +17,13 @@ class BesselJ
      *    Excel Function:
      *        BESSELJ(x,ord)
      *
-     * @param float $x The value at which to evaluate the function.
+     * NOTE: The MS Excel implementation of the BESSELJ function is still not accurate, particularly for higher order
+     *       values with x < -8 and x > 8. This code provides a more accurate calculation
+     *
+     * @param mixed $x A float value at which to evaluate the function.
      *                                If x is nonnumeric, BESSELJ returns the #VALUE! error value.
-     * @param int $ord The order of the Bessel function. If n is not an integer, it is truncated.
+     * @param mixed $ord The integer order of the Bessel function.
+     *                       If ord is not an integer, it is truncated.
      *                                If $ord is nonnumeric, BESSELJ returns the #VALUE! error value.
      *                                If $ord < 0, BESSELJ returns the #NUM! error value.
      *
@@ -28,44 +34,141 @@ class BesselJ
         $x = ($x === null) ? 0.0 : Functions::flattenSingleValue($x);
         $ord = ($ord === null) ? 0.0 : Functions::flattenSingleValue($ord);
 
-        if ((is_numeric($x)) && (is_numeric($ord))) {
-            $ord = (int) floor($ord);
-            if ($ord < 0) {
-                return Functions::NAN();
-            }
-
-            $fResult = self::calculate($x, $ord);
-
-            return (is_nan($fResult)) ? Functions::NAN() : $fResult;
+        try {
+            $x = self::validateFloat($x);
+            $ord = self::validateInt($ord);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
-        return Functions::VALUE();
+        if ($ord < 0) {
+            return Functions::NAN();
+        }
+
+        $fResult = self::calculate($x, $ord);
+
+        return (is_nan($fResult)) ? Functions::NAN() : $fResult;
     }
 
     private static function calculate(float $x, int $ord): float
     {
-        if (abs($x) <= 30) {
-            $fResult = $fTerm = ($x / 2) ** $ord / MathTrig::FACT($ord);
-            $ordK = 1;
-            $fSqrX = ($x * $x) / -4;
-            do {
-                $fTerm *= $fSqrX;
-                $fTerm /= ($ordK * ($ordK + $ord));
-                $fResult += $fTerm;
-            } while ((abs($fTerm) > 1e-12) && (++$ordK < 100));
-
-            return $fResult;
+        // special cases
+        switch ($ord) {
+            case 0:
+                return self::besselJ0($x);
+            case 1:
+                return self::besselJ1($x);
         }
 
-        $f_PI_DIV_2 = M_PI / 2;
-        $f_PI_DIV_4 = M_PI / 4;
+        return self::besselJ2($x, $ord);
+    }
 
-        $fXAbs = abs($x);
-        $fResult = sqrt(Functions::M_2DIVPI / $fXAbs) * cos($fXAbs - $ord * $f_PI_DIV_2 - $f_PI_DIV_4);
-        if (($ord & 1) && ($x < 0)) {
-            $fResult = -$fResult;
+    private static function besselJ0(float $x): float
+    {
+        $ax = abs($x);
+
+        if ($ax < 8.0) {
+            $y = $x * $x;
+            $ans1 = 57568490574.0 + $y * (-13362590354.0 + $y * (651619640.7 + $y * (-11214424.18 + $y *
+                            (77392.33017 + $y * (-184.9052456)))));
+            $ans2 = 57568490411.0 + $y * (1029532985.0 + $y * (9494680.718 + $y * (59272.64853 + $y *
+                            (267.8532712 + $y * 1.0))));
+
+            return $ans1 / $ans2;
         }
 
-        return $fResult;
+        $z = 8.0 / $ax;
+        $y = $z * $z;
+        $xx = $ax - 0.785398164;
+        $ans1 = 1.0 + $y * (-0.1098628627e-2 + $y * (0.2734510407e-4 + $y * (-0.2073370639e-5 + $y * 0.2093887211e-6)));
+        $ans2 = -0.1562499995e-1 + $y * (0.1430488765e-3 + $y * (-0.6911147651e-5 + $y *
+                    (0.7621095161e-6 - $y * 0.934935152e-7)));
+
+        return sqrt(0.636619772 / $ax) * (cos($xx) * $ans1 - $z * sin($xx) * $ans2);
+    }
+
+    private static function besselJ1(float $x): float
+    {
+        $ax = abs($x);
+
+        if ($ax < 8.0) {
+            $y = $x * $x;
+            $ans1 = $x * (72362614232.0 + $y * (-7895059235.0 + $y * (242396853.1 + $y *
+                            (-2972611.439 + $y * (15704.48260 + $y * (-30.16036606))))));
+            $ans2 = 144725228442.0 + $y * (2300535178.0 + $y * (18583304.74 + $y * (99447.43394 + $y *
+                            (376.9991397 + $y * 1.0))));
+
+            return $ans1 / $ans2;
+        }
+
+        $z = 8.0 / $ax;
+        $y = $z * $z;
+        $xx = $ax - 2.356194491;
+
+        $ans1 = 1.0 + $y * (0.183105e-2 + $y * (-0.3516396496e-4 + $y * (0.2457520174e-5 + $y * (-0.240337019e-6))));
+        $ans2 = 0.04687499995 + $y * (-0.2002690873e-3 + $y * (0.8449199096e-5 + $y *
+                    (-0.88228987e-6 + $y * 0.105787412e-6)));
+        $ans = sqrt(0.636619772 / $ax) * (cos($xx) * $ans1 - $z * sin($xx) * $ans2);
+
+        return ($x < 0.0) ? -$ans : $ans;
+    }
+
+    private static function besselJ2(float $x, int $ord): float
+    {
+        $ax = abs($x);
+        if ($ax === 0.0) {
+            return 0.0;
+        }
+
+        if ($ax > $ord) {
+            return self::besselj2a($ax, $ord, $x);
+        }
+
+        return self::besselj2b($ax, $ord, $x);
+    }
+
+    private static function besselj2a(float $ax, int $ord, float $x)
+    {
+        $tox = 2.0 / $ax;
+        $bjm = self::besselJ0($ax);
+        $bj = self::besselJ1($ax);
+        for ($j = 1; $j < $ord; ++$j) {
+            $bjp = $j * $tox * $bj - $bjm;
+            $bjm = $bj;
+            $bj = $bjp;
+        }
+        $ans = $bj;
+
+        return ($x < 0.0 && ($ord % 2) == 1) ? -$ans : $ans;
+    }
+
+    private static function besselj2b(float $ax, int $ord, float $x)
+    {
+        $tox = 2.0 / $ax;
+        $jsum = false;
+        $bjp = $ans = $sum = 0.0;
+        $bj = 1.0;
+        for ($j = 2 * ($ord + (int) sqrt(40.0 * $ord)); $j > 0; --$j) {
+            $bjm = $j * $tox * $bj - $bjp;
+            $bjp = $bj;
+            $bj = $bjm;
+            if (abs($bj) > 1.0e+10) {
+                $bj *= 1.0e-10;
+                $bjp *= 1.0e-10;
+                $ans *= 1.0e-10;
+                $sum *= 1.0e-10;
+            }
+            if ($jsum === true) {
+                $sum += $bj;
+            }
+            $jsum = !$jsum;
+            if ($j === $ord) {
+                $ans = $bjp;
+            }
+        }
+        $sum = 2.0 * $sum - $bj;
+        $ans /= $sum;
+
+        return ($x < 0.0 && ($ord % 2) === 1) ? -$ans : $ans;
     }
 }

src/PhpSpreadsheet/Calculation/Engineering/BesselK.php

@@ -2,10 +2,13 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class BesselK
 {
+    use BaseValidations;
+
     /**
      * BESSELK.
      *
@@ -15,11 +18,12 @@ class BesselK
      *    Excel Function:
      *        BESSELK(x,ord)
      *
-     * @param float $x The value at which to evaluate the function.
+     * @param mixed $x A float value at which to evaluate the function.
      *                                If x is nonnumeric, BESSELK returns the #VALUE! error value.
-     * @param int $ord The order of the Bessel function. If n is not an integer, it is truncated.
+     * @param mixed $ord The integer order of the Bessel function.
+     *                       If ord is not an integer, it is truncated.
      *                                If $ord is nonnumeric, BESSELK returns the #VALUE! error value.
-     *                                If $ord < 0, BESSELK returns the #NUM! error value.
+     *                       If $ord < 0, BESSELKI returns the #NUM! error value.
      *
      * @return float|string Result, or a string containing an error
      */
@@ -28,62 +32,67 @@ class BesselK
         $x = ($x === null) ? 0.0 : Functions::flattenSingleValue($x);
         $ord = ($ord === null) ? 0 : Functions::flattenSingleValue($ord);
 
-        if ((is_numeric($x)) && (is_numeric($ord))) {
-            if (($ord < 0) || ($x == 0.0)) {
-                return Functions::NAN();
-            }
-
-            switch (floor($ord)) {
-                case 0:
-                    $fBk = self::besselK0($x);
-
-                    break;
-                case 1:
-                    $fBk = self::besselK1($x);
-
-                    break;
-                default:
-                    $fBk = self::besselK2($x, $ord);
-            }
-
-            return (is_nan($fBk)) ? Functions::NAN() : $fBk;
+        try {
+            $x = self::validateFloat($x);
+            $ord = self::validateInt($ord);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
-        return Functions::VALUE();
+        if (($ord < 0) || ($x <= 0.0)) {
+            return Functions::NAN();
+        }
+
+        $fBk = self::calculate($x, $ord);
+
+        return (is_nan($fBk)) ? Functions::NAN() : $fBk;
     }
 
-    private static function besselK0(float $fNum): float
+    private static function calculate(float $x, int $ord): float
     {
-        if ($fNum <= 2) {
-            $fNum2 = $fNum * 0.5;
+        // special cases
+        switch ($ord) {
+            case 0:
+                return self::besselK0($x);
+            case 1:
+                return self::besselK1($x);
+        }
+
+        return self::besselK2($x, $ord);
+    }
+
+    private static function besselK0(float $x): float
+    {
+        if ($x <= 2) {
+            $fNum2 = $x * 0.5;
             $y = ($fNum2 * $fNum2);
 
-            return -log($fNum2) * BesselI::BESSELI($fNum, 0) +
+            return -log($fNum2) * BesselI::BESSELI($x, 0) +
                 (-0.57721566 + $y * (0.42278420 + $y * (0.23069756 + $y * (0.3488590e-1 + $y * (0.262698e-2 + $y *
                                     (0.10750e-3 + $y * 0.74e-5))))));
         }
 
-        $y = 2 / $fNum;
+        $y = 2 / $x;
 
-        return exp(-$fNum) / sqrt($fNum) *
+        return exp(-$x) / sqrt($x) *
             (1.25331414 + $y * (-0.7832358e-1 + $y * (0.2189568e-1 + $y * (-0.1062446e-1 + $y *
                             (0.587872e-2 + $y * (-0.251540e-2 + $y * 0.53208e-3))))));
     }
 
-    private static function besselK1(float $fNum): float
+    private static function besselK1(float $x): float
     {
-        if ($fNum <= 2) {
-            $fNum2 = $fNum * 0.5;
+        if ($x <= 2) {
+            $fNum2 = $x * 0.5;
             $y = ($fNum2 * $fNum2);
 
-            return log($fNum2) * BesselI::BESSELI($fNum, 1) +
+            return log($fNum2) * BesselI::BESSELI($x, 1) +
                 (1 + $y * (0.15443144 + $y * (-0.67278579 + $y * (-0.18156897 + $y * (-0.1919402e-1 + $y *
-                                    (-0.110404e-2 + $y * (-0.4686e-4))))))) / $fNum;
+                                    (-0.110404e-2 + $y * (-0.4686e-4))))))) / $x;
         }
 
-        $y = 2 / $fNum;
+        $y = 2 / $x;
 
-        return exp(-$fNum) / sqrt($fNum) *
+        return exp(-$x) / sqrt($x) *
             (1.25331414 + $y * (0.23498619 + $y * (-0.3655620e-1 + $y * (0.1504268e-1 + $y * (-0.780353e-2 + $y *
                                 (0.325614e-2 + $y * (-0.68245e-3)))))));
     }

src/PhpSpreadsheet/Calculation/Engineering/BesselY.php

@@ -2,10 +2,13 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class BesselY
 {
+    use BaseValidations;
+
     /**
      * BESSELY.
      *
@@ -14,11 +17,12 @@ class BesselY
      *    Excel Function:
      *        BESSELY(x,ord)
      *
-     * @param float $x The value at which to evaluate the function.
-     *                                If x is nonnumeric, BESSELY returns the #VALUE! error value.
-     * @param int $ord The order of the Bessel function. If n is not an integer, it is truncated.
-     *                                If $ord is nonnumeric, BESSELY returns the #VALUE! error value.
-     *                                If $ord < 0, BESSELY returns the #NUM! error value.
+     * @param mixed $x A float value at which to evaluate the function.
+     *                   If x is nonnumeric, BESSELY returns the #VALUE! error value.
+     * @param mixed $ord The integer order of the Bessel function.
+     *                       If ord is not an integer, it is truncated.
+     *                       If $ord is nonnumeric, BESSELY returns the #VALUE! error value.
+     *                       If $ord < 0, BESSELY returns the #NUM! error value.
      *
      * @return float|string Result, or a string containing an error
      */
@@ -27,70 +31,82 @@ class BesselY
         $x = ($x === null) ? 0.0 : Functions::flattenSingleValue($x);
         $ord = ($ord === null) ? 0 : Functions::flattenSingleValue($ord);
 
-        if ((is_numeric($x)) && (is_numeric($ord))) {
-            if (($ord < 0) || ($x == 0.0)) {
-                return Functions::NAN();
-            }
-
-            switch (floor($ord)) {
-                case 0:
-                    $fBy = self::besselY0($x);
-
-                    break;
-                case 1:
-                    $fBy = self::besselY1($x);
-
-                    break;
-                default:
-                    $fBy = self::besselY2($x, $ord);
-            }
-
-            return (is_nan($fBy)) ? Functions::NAN() : $fBy;
+        try {
+            $x = self::validateFloat($x);
+            $ord = self::validateInt($ord);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
-        return Functions::VALUE();
+        if (($ord < 0) || ($x <= 0.0)) {
+            return Functions::NAN();
+        }
+
+        $fBy = self::calculate($x, $ord);
+
+        return (is_nan($fBy)) ? Functions::NAN() : $fBy;
     }
 
-    private static function besselY0(float $fNum): float
+    private static function calculate(float $x, int $ord): float
     {
-        if ($fNum < 8.0) {
-            $y = ($fNum * $fNum);
-            $f1 = -2957821389.0 + $y * (7062834065.0 + $y * (-512359803.6 + $y * (10879881.29 + $y *
+        // special cases
+        switch ($ord) {
+            case 0:
+                return self::besselY0($x);
+            case 1:
+                return self::besselY1($x);
+        }
+
+        return self::besselY2($x, $ord);
+    }
+
+    private static function besselY0(float $x): float
+    {
+        if ($x < 8.0) {
+            $y = ($x * $x);
+            $ans1 = -2957821389.0 + $y * (7062834065.0 + $y * (-512359803.6 + $y * (10879881.29 + $y *
                             (-86327.92757 + $y * 228.4622733))));
-            $f2 = 40076544269.0 + $y * (745249964.8 + $y * (7189466.438 + $y *
+            $ans2 = 40076544269.0 + $y * (745249964.8 + $y * (7189466.438 + $y *
                         (47447.26470 + $y * (226.1030244 + $y))));
 
-            return $f1 / $f2 + 0.636619772 * BesselJ::BESSELJ($fNum, 0) * log($fNum);
+            return $ans1 / $ans2 + 0.636619772 * BesselJ::BESSELJ($x, 0) * log($x);
         }
 
-        $z = 8.0 / $fNum;
+        $z = 8.0 / $x;
         $y = ($z * $z);
-        $xx = $fNum - 0.785398164;
-        $f1 = 1 + $y * (-0.1098628627e-2 + $y * (0.2734510407e-4 + $y * (-0.2073370639e-5 + $y * 0.2093887211e-6)));
-        $f2 = -0.1562499995e-1 + $y * (0.1430488765e-3 + $y * (-0.6911147651e-5 + $y * (0.7621095161e-6 + $y *
+        $xx = $x - 0.785398164;
+        $ans1 = 1 + $y * (-0.1098628627e-2 + $y * (0.2734510407e-4 + $y * (-0.2073370639e-5 + $y * 0.2093887211e-6)));
+        $ans2 = -0.1562499995e-1 + $y * (0.1430488765e-3 + $y * (-0.6911147651e-5 + $y * (0.7621095161e-6 + $y *
                         (-0.934945152e-7))));
 
-        return sqrt(0.636619772 / $fNum) * (sin($xx) * $f1 + $z * cos($xx) * $f2);
+        return sqrt(0.636619772 / $x) * (sin($xx) * $ans1 + $z * cos($xx) * $ans2);
     }
 
-    private static function besselY1(float $fNum): float
+    private static function besselY1(float $x): float
     {
-        if ($fNum < 8.0) {
-            $y = ($fNum * $fNum);
-            $f1 = $fNum * (-0.4900604943e13 + $y * (0.1275274390e13 + $y * (-0.5153438139e11 + $y *
+        if ($x < 8.0) {
+            $y = ($x * $x);
+            $ans1 = $x * (-0.4900604943e13 + $y * (0.1275274390e13 + $y * (-0.5153438139e11 + $y *
                             (0.7349264551e9 + $y * (-0.4237922726e7 + $y * 0.8511937935e4)))));
-            $f2 = 0.2499580570e14 + $y * (0.4244419664e12 + $y * (0.3733650367e10 + $y * (0.2245904002e8 + $y *
+            $ans2 = 0.2499580570e14 + $y * (0.4244419664e12 + $y * (0.3733650367e10 + $y * (0.2245904002e8 + $y *
                             (0.1020426050e6 + $y * (0.3549632885e3 + $y)))));
 
-            return $f1 / $f2 + 0.636619772 * (BesselJ::BESSELJ($fNum, 1) * log($fNum) - 1 / $fNum);
+            return ($ans1 / $ans2) + 0.636619772 * (BesselJ::BESSELJ($x, 1) * log($x) - 1 / $x);
         }
 
-        return sqrt(0.636619772 / $fNum) * sin($fNum - 2.356194491);
+        $z = 8.0 / $x;
+        $y = $z * $z;
+        $xx = $x - 2.356194491;
+        $ans1 = 1.0 + $y * (0.183105e-2 + $y * (-0.3516396496e-4 + $y * (0.2457520174e-5 + $y * (-0.240337019e-6))));
+        $ans2 = 0.04687499995 + $y * (-0.2002690873e-3 + $y * (0.8449199096e-5 + $y *
+                    (-0.88228987e-6 + $y * 0.105787412e-6)));
+
+        return sqrt(0.636619772 / $x) * (sin($xx) * $ans1 + $z * cos($xx) * $ans2);
     }
 
-    private static function besselY2(float $x, int $ord)
+    private static function besselY2(float $x, int $ord): float
     {
-        $fTox = 2 / $x;
+        $fTox = 2.0 / $x;
         $fBym = self::besselY0($x);
         $fBy = self::besselY1($x);
         for ($n = 1; $n < $ord; ++$n) {

src/PhpSpreadsheet/Calculation/Engineering/BitWise.php

@@ -7,6 +7,18 @@ use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class BitWise
 {
+    const SPLIT_DIVISOR = 2 ** 24;
+
+    /**
+     * Split a number into upper and lower portions for full 32-bit support.
+     *
+     * @param float|int $number
+     */
+    private static function splitNumber($number): array
+    {
+        return [floor($number / self::SPLIT_DIVISOR), fmod($number, self::SPLIT_DIVISOR)];
+    }
+
     /**
      * BITAND.
      *
@@ -28,8 +40,10 @@ class BitWise
         } catch (Exception $e) {
             return $e->getMessage();
         }
+        $split1 = self::splitNumber($number1);
+        $split2 = self::splitNumber($number2);
 
-        return $number1 & $number2;
+        return  self::SPLIT_DIVISOR * ($split1[0] & $split2[0]) + ($split1[1] & $split2[1]);
     }
 
     /**
@@ -54,7 +68,10 @@ class BitWise
             return $e->getMessage();
         }
 
-        return $number1 | $number2;
+        $split1 = self::splitNumber($number1);
+        $split2 = self::splitNumber($number2);
+
+        return  self::SPLIT_DIVISOR * ($split1[0] | $split2[0]) + ($split1[1] | $split2[1]);
     }
 
     /**
@@ -79,7 +96,10 @@ class BitWise
             return $e->getMessage();
         }
 
-        return $number1 ^ $number2;
+        $split1 = self::splitNumber($number1);
+        $split2 = self::splitNumber($number2);
+
+        return  self::SPLIT_DIVISOR * ($split1[0] ^ $split2[0]) + ($split1[1] ^ $split2[1]);
     }
 
     /**
@@ -93,19 +113,18 @@ class BitWise
      * @param int $number
      * @param int $shiftAmount
      *
-     * @return int|string
+     * @return float|int|string
      */
     public static function BITLSHIFT($number, $shiftAmount)
     {
         try {
             $number = self::validateBitwiseArgument($number);
+            $shiftAmount = self::validateShiftAmount($shiftAmount);
         } catch (Exception $e) {
             return $e->getMessage();
         }
 
-        $shiftAmount = Functions::flattenSingleValue($shiftAmount);
-
-        $result = $number << $shiftAmount;
+        $result = floor($number * (2 ** $shiftAmount));
         if ($result > 2 ** 48 - 1) {
             return Functions::NAN();
         }
@@ -124,19 +143,49 @@ class BitWise
      * @param int $number
      * @param int $shiftAmount
      *
-     * @return int|string
+     * @return float|int|string
      */
     public static function BITRSHIFT($number, $shiftAmount)
     {
         try {
             $number = self::validateBitwiseArgument($number);
+            $shiftAmount = self::validateShiftAmount($shiftAmount);
         } catch (Exception $e) {
             return $e->getMessage();
         }
 
-        $shiftAmount = Functions::flattenSingleValue($shiftAmount);
+        $result = floor($number / (2 ** $shiftAmount));
+        if ($result > 2 ** 48 - 1) { // possible because shiftAmount can be negative
+            return Functions::NAN();
+        }
 
-        return $number >> $shiftAmount;
+        return $result;
+    }
+
+    /**
+     * Validate arguments passed to the bitwise functions.
+     *
+     * @param mixed $value
+     *
+     * @return float|int
+     */
+    private static function validateBitwiseArgument($value)
+    {
+        self::nullFalseTrueToNumber($value);
+
+        if (is_numeric($value)) {
+            if ($value == floor($value)) {
+                if (($value > 2 ** 48 - 1) || ($value < 0)) {
+                    throw new Exception(Functions::NAN());
+                }
+
+                return floor($value);
+            }
+
+            throw new Exception(Functions::NAN());
+        }
+
+        throw new Exception(Functions::VALUE());
     }
 
     /**
@@ -146,25 +195,33 @@ class BitWise
      *
      * @return int
      */
-    private static function validateBitwiseArgument($value)
+    private static function validateShiftAmount($value)
     {
-        $value = Functions::flattenSingleValue($value);
+        self::nullFalseTrueToNumber($value);
 
-        if (is_int($value)) {
-            return $value;
-        } elseif (is_numeric($value)) {
-            if ($value == (int) ($value)) {
-                $value = (int) ($value);
-                if (($value > 2 ** 48 - 1) || ($value < 0)) {
-                    throw new Exception(Functions::NAN());
-                }
-
-                return $value;
+        if (is_numeric($value)) {
+            if (abs($value) > 53) {
+                throw new Exception(Functions::NAN());
             }
 
-            throw new Exception(Functions::NAN());
+            return (int) $value;
         }
 
         throw new Exception(Functions::VALUE());
     }
+
+    /**
+     * Many functions accept null/false/true argument treated as 0/0/1.
+     *
+     * @param mixed $number
+     */
+    public static function nullFalseTrueToNumber(&$number): void
+    {
+        $number = Functions::flattenSingleValue($number);
+        if ($number === null) {
+            $number = 0;
+        } elseif (is_bool($number)) {
+            $number = (int) $number;
+        }
+    }
 }

src/PhpSpreadsheet/Calculation/Engineering/Compare.php

@@ -2,10 +2,13 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class Compare
 {
+    use BaseValidations;
+
     /**
      * DELTA.
      *
@@ -27,8 +30,11 @@ class Compare
         $a = Functions::flattenSingleValue($a);
         $b = Functions::flattenSingleValue($b);
 
-        if (!is_numeric($a) || !is_numeric($b)) {
-            return Functions::VALUE();
+        try {
+            $a = self::validateFloat($a);
+            $b = self::validateFloat($b);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
         return (int) ($a == $b);
@@ -54,8 +60,11 @@ class Compare
         $number = Functions::flattenSingleValue($number);
         $step = Functions::flattenSingleValue($step);
 
-        if (!is_numeric($number) || !is_numeric($step)) {
-            return Functions::VALUE();
+        try {
+            $number = self::validateFloat($number);
+            $step = self::validateFloat($step);
+        } catch (Exception $e) {
+            return $e->getMessage();
         }
 
         return (int) ($number >= $step);

src/PhpSpreadsheet/Calculation/Engineering/Complex.php

@@ -0,0 +1,101 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
+
+use Complex\Complex as ComplexObject;
+use Complex\Exception as ComplexException;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Complex
+{
+    use BaseValidations;
+
+    /**
+     * COMPLEX.
+     *
+     * Converts real and imaginary coefficients into a complex number of the form x +/- yi or x +/- yj.
+     *
+     * Excel Function:
+     *        COMPLEX(realNumber,imaginary[,suffix])
+     *
+     * @param mixed $realNumber the real float coefficient of the complex number
+     * @param mixed $imaginary the imaginary float coefficient of the complex number
+     * @param mixed $suffix The character suffix for the imaginary component of the complex number.
+     *                          If omitted, the suffix is assumed to be "i".
+     *
+     * @return string
+     */
+    public static function COMPLEX($realNumber = 0.0, $imaginary = 0.0, $suffix = 'i')
+    {
+        $realNumber = ($realNumber === null) ? 0.0 : Functions::flattenSingleValue($realNumber);
+        $imaginary = ($imaginary === null) ? 0.0 : Functions::flattenSingleValue($imaginary);
+        $suffix = ($suffix === null) ? 'i' : Functions::flattenSingleValue($suffix);
+
+        try {
+            $realNumber = self::validateFloat($realNumber);
+            $imaginary = self::validateFloat($imaginary);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if (($suffix == 'i') || ($suffix == 'j') || ($suffix == '')) {
+            $complex = new ComplexObject($realNumber, $imaginary, $suffix);
+
+            return (string) $complex;
+        }
+
+        return Functions::VALUE();
+    }
+
+    /**
+     * IMAGINARY.
+     *
+     * Returns the imaginary coefficient of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMAGINARY(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the imaginary
+     *                                         coefficient
+     *
+     * @return float|string
+     */
+    public static function IMAGINARY($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return $complex->getImaginary();
+    }
+
+    /**
+     * IMREAL.
+     *
+     * Returns the real coefficient of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMREAL(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the real coefficient
+     *
+     * @return float|string
+     */
+    public static function IMREAL($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return $complex->getReal();
+    }
+}

src/PhpSpreadsheet/Calculation/Engineering/ComplexFunctions.php

@@ -0,0 +1,513 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
+
+use Complex\Complex as ComplexObject;
+use Complex\Exception as ComplexException;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class ComplexFunctions
+{
+    /**
+     * IMABS.
+     *
+     * Returns the absolute value (modulus) of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMABS(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the absolute value
+     *
+     * @return float|string
+     */
+    public static function IMABS($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return $complex->abs();
+    }
+
+    /**
+     * IMARGUMENT.
+     *
+     * Returns the argument theta of a complex number, i.e. the angle in radians from the real
+     * axis to the representation of the number in polar coordinates.
+     *
+     * Excel Function:
+     *        IMARGUMENT(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the argument theta
+     *
+     * @return float|string
+     */
+    public static function IMARGUMENT($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
+            return Functions::DIV0();
+        }
+
+        return $complex->argument();
+    }
+
+    /**
+     * IMCONJUGATE.
+     *
+     * Returns the complex conjugate of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCONJUGATE(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the conjugate
+     *
+     * @return string
+     */
+    public static function IMCONJUGATE($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->conjugate();
+    }
+
+    /**
+     * IMCOS.
+     *
+     * Returns the cosine of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCOS(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the cosine
+     *
+     * @return float|string
+     */
+    public static function IMCOS($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->cos();
+    }
+
+    /**
+     * IMCOSH.
+     *
+     * Returns the hyperbolic cosine of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCOSH(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the hyperbolic cosine
+     *
+     * @return float|string
+     */
+    public static function IMCOSH($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->cosh();
+    }
+
+    /**
+     * IMCOT.
+     *
+     * Returns the cotangent of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCOT(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the cotangent
+     *
+     * @return float|string
+     */
+    public static function IMCOT($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->cot();
+    }
+
+    /**
+     * IMCSC.
+     *
+     * Returns the cosecant of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCSC(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the cosecant
+     *
+     * @return float|string
+     */
+    public static function IMCSC($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->csc();
+    }
+
+    /**
+     * IMCSCH.
+     *
+     * Returns the hyperbolic cosecant of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMCSCH(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the hyperbolic cosecant
+     *
+     * @return float|string
+     */
+    public static function IMCSCH($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->csch();
+    }
+
+    /**
+     * IMSIN.
+     *
+     * Returns the sine of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSIN(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the sine
+     *
+     * @return float|string
+     */
+    public static function IMSIN($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->sin();
+    }
+
+    /**
+     * IMSINH.
+     *
+     * Returns the hyperbolic sine of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSINH(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the hyperbolic sine
+     *
+     * @return float|string
+     */
+    public static function IMSINH($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->sinh();
+    }
+
+    /**
+     * IMSEC.
+     *
+     * Returns the secant of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSEC(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the secant
+     *
+     * @return float|string
+     */
+    public static function IMSEC($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->sec();
+    }
+
+    /**
+     * IMSECH.
+     *
+     * Returns the hyperbolic secant of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSECH(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the hyperbolic secant
+     *
+     * @return float|string
+     */
+    public static function IMSECH($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->sech();
+    }
+
+    /**
+     * IMTAN.
+     *
+     * Returns the tangent of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMTAN(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the tangent
+     *
+     * @return float|string
+     */
+    public static function IMTAN($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->tan();
+    }
+
+    /**
+     * IMSQRT.
+     *
+     * Returns the square root of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSQRT(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the square root
+     *
+     * @return string
+     */
+    public static function IMSQRT($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        $theta = self::IMARGUMENT($complexNumber);
+        if ($theta === Functions::DIV0()) {
+            return '0';
+        }
+
+        return (string) $complex->sqrt();
+    }
+
+    /**
+     * IMLN.
+     *
+     * Returns the natural logarithm of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMLN(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the natural logarithm
+     *
+     * @return string
+     */
+    public static function IMLN($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->ln();
+    }
+
+    /**
+     * IMLOG10.
+     *
+     * Returns the common logarithm (base 10) of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMLOG10(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the common logarithm
+     *
+     * @return string
+     */
+    public static function IMLOG10($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->log10();
+    }
+
+    /**
+     * IMLOG2.
+     *
+     * Returns the base-2 logarithm of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMLOG2(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the base-2 logarithm
+     *
+     * @return string
+     */
+    public static function IMLOG2($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->log2();
+    }
+
+    /**
+     * IMEXP.
+     *
+     * Returns the exponential of a complex number in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMEXP(complexNumber)
+     *
+     * @param string $complexNumber the complex number for which you want the exponential
+     *
+     * @return string
+     */
+    public static function IMEXP($complexNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $complex->exp();
+    }
+
+    /**
+     * IMPOWER.
+     *
+     * Returns a complex number in x + yi or x + yj text format raised to a power.
+     *
+     * Excel Function:
+     *        IMPOWER(complexNumber,realNumber)
+     *
+     * @param string $complexNumber the complex number you want to raise to a power
+     * @param float $realNumber the power to which you want to raise the complex number
+     *
+     * @return string
+     */
+    public static function IMPOWER($complexNumber, $realNumber)
+    {
+        $complexNumber = Functions::flattenSingleValue($complexNumber);
+        $realNumber = Functions::flattenSingleValue($realNumber);
+
+        try {
+            $complex = new ComplexObject($complexNumber);
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        if (!is_numeric($realNumber)) {
+            return Functions::VALUE();
+        }
+
+        return (string) $complex->pow($realNumber);
+    }
+}

src/PhpSpreadsheet/Calculation/Engineering/ComplexOperations.php

@@ -0,0 +1,120 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
+
+use Complex\Complex as ComplexObject;
+use Complex\Exception as ComplexException;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class ComplexOperations
+{
+    /**
+     * IMDIV.
+     *
+     * Returns the quotient of two complex numbers in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMDIV(complexDividend,complexDivisor)
+     *
+     * @param string $complexDividend the complex numerator or dividend
+     * @param string $complexDivisor the complex denominator or divisor
+     *
+     * @return string
+     */
+    public static function IMDIV($complexDividend, $complexDivisor)
+    {
+        $complexDividend = Functions::flattenSingleValue($complexDividend);
+        $complexDivisor = Functions::flattenSingleValue($complexDivisor);
+
+        try {
+            return (string) (new ComplexObject($complexDividend))->divideby(new ComplexObject($complexDivisor));
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+    }
+
+    /**
+     * IMSUB.
+     *
+     * Returns the difference of two complex numbers in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSUB(complexNumber1,complexNumber2)
+     *
+     * @param string $complexNumber1 the complex number from which to subtract complexNumber2
+     * @param string $complexNumber2 the complex number to subtract from complexNumber1
+     *
+     * @return string
+     */
+    public static function IMSUB($complexNumber1, $complexNumber2)
+    {
+        $complexNumber1 = Functions::flattenSingleValue($complexNumber1);
+        $complexNumber2 = Functions::flattenSingleValue($complexNumber2);
+
+        try {
+            return (string) (new ComplexObject($complexNumber1))->subtract(new ComplexObject($complexNumber2));
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+    }
+
+    /**
+     * IMSUM.
+     *
+     * Returns the sum of two or more complex numbers in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMSUM(complexNumber[,complexNumber[,...]])
+     *
+     * @param string ...$complexNumbers Series of complex numbers to add
+     *
+     * @return string
+     */
+    public static function IMSUM(...$complexNumbers)
+    {
+        // Return value
+        $returnValue = new ComplexObject(0.0);
+        $aArgs = Functions::flattenArray($complexNumbers);
+
+        try {
+            // Loop through the arguments
+            foreach ($aArgs as $complex) {
+                $returnValue = $returnValue->add(new ComplexObject($complex));
+            }
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $returnValue;
+    }
+
+    /**
+     * IMPRODUCT.
+     *
+     * Returns the product of two or more complex numbers in x + yi or x + yj text format.
+     *
+     * Excel Function:
+     *        IMPRODUCT(complexNumber[,complexNumber[,...]])
+     *
+     * @param string ...$complexNumbers Series of complex numbers to multiply
+     *
+     * @return string
+     */
+    public static function IMPRODUCT(...$complexNumbers)
+    {
+        // Return value
+        $returnValue = new ComplexObject(1.0);
+        $aArgs = Functions::flattenArray($complexNumbers);
+
+        try {
+            // Loop through the arguments
+            foreach ($aArgs as $complex) {
+                $returnValue = $returnValue->multiply(new ComplexObject($complex));
+            }
+        } catch (ComplexException $e) {
+            return Functions::NAN();
+        }
+
+        return (string) $returnValue;
+    }
+}

src/PhpSpreadsheet/Calculation/Engineering/Constants.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
+
+class Constants
+{
+    /**
+     * EULER.
+     */
+    public const EULER = 2.71828182845904523536;
+}

src/PhpSpreadsheet/Calculation/Engineering/ConvertBase.php

@@ -7,7 +7,7 @@ use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class ConvertBase
 {
-    protected static function validateValue($value, bool $gnumericCheck = false): string
+    protected static function validateValue($value): string
     {
         if (is_bool($value)) {
             if (Functions::getCompatibilityMode() !== Functions::COMPATIBILITY_OPENOFFICE) {
@@ -16,8 +16,10 @@ class ConvertBase
             $value = (int) $value;
         }
 
-        if ($gnumericCheck && Functions::getCompatibilityMode() == Functions::COMPATIBILITY_GNUMERIC) {
-            $value = floor((float) $value);
+        if (is_numeric($value)) {
+            if (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_GNUMERIC) {
+                $value = floor((float) $value);
+            }
         }
 
         return strtoupper((string) $value);
@@ -30,7 +32,7 @@ class ConvertBase
         }
 
         if (is_numeric($places)) {
-            if ($places < 0) {
+            if ($places < 0 || $places > 10) {
                 throw new Exception(Functions::NAN());
             }
 

src/PhpSpreadsheet/Calculation/Engineering/ConvertBinary.php

@@ -25,7 +25,7 @@ class ConvertBinary extends ConvertBase
     public static function toDecimal($value): string
     {
         try {
-            $value = self::validateValue(Functions::flattenSingleValue($value), true);
+            $value = self::validateValue(Functions::flattenSingleValue($value));
             $value = self::validateBinary($value);
         } catch (Exception $e) {
             return $e->getMessage();
@@ -65,7 +65,7 @@ class ConvertBinary extends ConvertBase
     public static function toHex($value, $places = null): string
     {
         try {
-            $value = self::validateValue(Functions::flattenSingleValue($value), true);
+            $value = self::validateValue(Functions::flattenSingleValue($value));
             $value = self::validateBinary($value);
             $places = self::validatePlaces(Functions::flattenSingleValue($places));
         } catch (Exception $e) {
@@ -73,8 +73,11 @@ class ConvertBinary extends ConvertBase
         }
 
         if (strlen($value) == 10) {
-            //    Two's Complement
-            return str_repeat('F', 8) . substr(strtoupper(dechex((int) bindec(substr($value, -9)))), -2);
+            $high2 = substr($value, 0, 2);
+            $low8 = substr($value, 2);
+            $xarr = ['00' => '00000000', '01' => '00000001', '10' => 'FFFFFFFE', '11' => 'FFFFFFFF'];
+
+            return $xarr[$high2] . strtoupper(substr('0' . dechex((int) bindec($low8)), -2));
         }
         $hexVal = (string) strtoupper(dechex((int) bindec($value)));
 
@@ -105,16 +108,15 @@ class ConvertBinary extends ConvertBase
     public static function toOctal($value, $places = null): string
     {
         try {
-            $value = self::validateValue(Functions::flattenSingleValue($value), true);
+            $value = self::validateValue(Functions::flattenSingleValue($value));
             $value = self::validateBinary($value);
             $places = self::validatePlaces(Functions::flattenSingleValue($places));
         } catch (Exception $e) {
             return $e->getMessage();
         }
 
-        if (strlen($value) == 10) {
-            //    Two's Complement
-            return str_repeat('7', 7) . substr(strtoupper(decoct((int) bindec(substr($value, -9)))), -3);
+        if (strlen($value) == 10 && substr($value, 0, 1) === '1') { //    Two's Complement
+            return str_repeat('7', 6) . strtoupper(decoct((int) bindec("11$value")));
         }
         $octVal = (string) decoct((int) bindec($value));
 

src/PhpSpreadsheet/Calculation/Engineering/ConvertDecimal.php

@@ -7,6 +7,13 @@ use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
 class ConvertDecimal extends ConvertBase
 {
+    const LARGEST_OCTAL_IN_DECIMAL = 536870911;
+    const SMALLEST_OCTAL_IN_DECIMAL = -536870912;
+    const LARGEST_BINARY_IN_DECIMAL = 511;
+    const SMALLEST_BINARY_IN_DECIMAL = -512;
+    const LARGEST_HEX_IN_DECIMAL = 549755813887;
+    const SMALLEST_HEX_IN_DECIMAL = -549755813888;
+
     /**
      * toBinary.
      *
@@ -43,16 +50,13 @@ class ConvertDecimal extends ConvertBase
         }
 
         $value = (int) floor((float) $value);
-        if ($value < -512 || $value > 511) {
+        if ($value > self::LARGEST_BINARY_IN_DECIMAL || $value < self::SMALLEST_BINARY_IN_DECIMAL) {
             return Functions::NAN();
         }
 
         $r = decbin($value);
         // Two's Complement
         $r = substr($r, -10);
-        if (strlen($r) >= 11) {
-            return Functions::NAN();
-        }
 
         return self::nbrConversionFormat($r, $places);
     }
@@ -92,16 +96,37 @@ class ConvertDecimal extends ConvertBase
             return $e->getMessage();
         }
 
-        $value = (int) floor((float) $value);
-        $r = strtoupper(dechex($value));
-        if (strlen($r) == 8) {
-            //    Two's Complement
-            $r = 'FF' . $r;
+        $value = floor((float) $value);
+        if ($value > self::LARGEST_HEX_IN_DECIMAL || $value < self::SMALLEST_HEX_IN_DECIMAL) {
+            return Functions::NAN();
         }
+        $r = strtoupper(dechex((int) $value));
+        $r = self::hex32bit($value, $r);
 
         return self::nbrConversionFormat($r, $places);
     }
 
+    public static function hex32bit(float $value, string $hexstr, bool $force = false): string
+    {
+        if (PHP_INT_SIZE === 4 || $force) {
+            if ($value >= 2 ** 32) {
+                $quotient = (int) ($value / (2 ** 32));
+
+                return strtoupper(substr('0' . dechex($quotient), -2) . $hexstr);
+            }
+            if ($value < -(2 ** 32)) {
+                $quotient = 256 - (int) ceil((-$value) / (2 ** 32));
+
+                return strtoupper(substr('0' . dechex($quotient), -2) . substr("00000000$hexstr", -8));
+            }
+            if ($value < 0) {
+                return "FF$hexstr";
+            }
+        }
+
+        return $hexstr;
+    }
+
     /**
      * toOctal.
      *
@@ -138,11 +163,11 @@ class ConvertDecimal extends ConvertBase
         }
 
         $value = (int) floor((float) $value);
-        $r = decoct($value);
-        if (strlen($r) == 11) {
-            //    Two's Complement
-            $r = substr($r, -10);
+        if ($value > self::LARGEST_OCTAL_IN_DECIMAL || $value < self::SMALLEST_OCTAL_IN_DECIMAL) {
+            return Functions::NAN();
         }
+        $r = decoct($value);
+        $r = substr($r, -10);
 
         return self::nbrConversionFormat($r, $places);
     }

src/PhpSpreadsheet/Calculation/Engineering/ConvertHex.php

@@ -42,7 +42,9 @@ class ConvertHex extends ConvertBase
             return $e->getMessage();
         }
 
-        return ConvertDecimal::toBinary(self::toDecimal($value), $places);
+        $dec = self::toDecimal($value);
+
+        return ConvertDecimal::toBinary($dec, $places);
     }
 
     /**
@@ -129,9 +131,6 @@ class ConvertHex extends ConvertBase
         }
 
         $decimal = self::toDecimal($value);
-        if ($decimal < -536870912 || $decimal > 536870911) {
-            return Functions::NAN();
-        }
 
         return ConvertDecimal::toOctal($decimal, $places);
     }

src/PhpSpreadsheet/Calculation/Engineering/ConvertOctal.php

@@ -127,14 +127,16 @@ class ConvertOctal extends ConvertBase
             return $e->getMessage();
         }
 
-        $hexVal = strtoupper(dechex((int) self::toDecimal((int) $value)));
+        $hexVal = strtoupper(dechex((int) self::toDecimal($value)));
+        $hexVal = (PHP_INT_SIZE === 4 && strlen($value) === 10 && $value[0] >= '4') ? "FF$hexVal" : $hexVal;
 
         return self::nbrConversionFormat($hexVal, $places);
     }
 
     protected static function validateOctal(string $value): string
     {
-        if (strlen($value) > preg_match_all('/[01234567]/', $value)) {
+        $numDigits = (int) preg_match_all('/[01234567]/', $value);
+        if (strlen($value) > $numDigits || $numDigits > 10) {
             throw new Exception(Functions::NAN());
         }
 

src/PhpSpreadsheet/Calculation/Engineering/Erf.php

@@ -21,9 +21,9 @@ class Erf
      *    Excel Function:
      *        ERF(lower[,upper])
      *
-     * @param float $lower lower bound for integrating ERF
-     * @param float $upper upper bound for integrating ERF.
-     *                                If omitted, ERF integrates between zero and lower_limit
+     * @param mixed $lower Lower bound float for integrating ERF
+     * @param mixed $upper Upper bound float for integrating ERF.
+     *                           If omitted, ERF integrates between zero and lower_limit
      *
      * @return float|string
      */
@@ -52,7 +52,7 @@ class Erf
      *    Excel Function:
      *        ERF.PRECISE(limit)
      *
-     * @param float $limit bound for integrating ERF
+     * @param mixed $limit Float bound for integrating ERF, other bound is zero
      *
      * @return float|string
      */

src/PhpSpreadsheet/Calculation/Engineering/ErfC.php

@@ -19,7 +19,7 @@ class ErfC
      *    Excel Function:
      *        ERFC(x)
      *
-     * @param float $value The lower bound for integrating ERFC
+     * @param mixed $value The float lower bound for integrating ERFC
      *
      * @return float|string
      */

src/PhpSpreadsheet/Calculation/Financial/Amortization.php

@@ -0,0 +1,190 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Amortization
+{
+    use BaseValidations;
+
+    /**
+     * AMORDEGRC.
+     *
+     * Returns the depreciation for each accounting period.
+     * This function is provided for the French accounting system. If an asset is purchased in
+     * the middle of the accounting period, the prorated depreciation is taken into account.
+     * The function is similar to AMORLINC, except that a depreciation coefficient is applied in
+     * the calculation depending on the life of the assets.
+     * This function will return the depreciation until the last period of the life of the assets
+     * or until the cumulated value of depreciation is greater than the cost of the assets minus
+     * the salvage value.
+     *
+     * Excel Function:
+     *        AMORDEGRC(cost,purchased,firstPeriod,salvage,period,rate[,basis])
+     *
+     * @param mixed $cost The float cost of the asset
+     * @param mixed $purchased Date of the purchase of the asset
+     * @param mixed $firstPeriod Date of the end of the first period
+     * @param mixed $salvage The salvage value at the end of the life of the asset
+     * @param mixed $period the period (float)
+     * @param mixed $rate rate of depreciation (float)
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string (string containing the error type if there is an error)
+     */
+    public static function AMORDEGRC($cost, $purchased, $firstPeriod, $salvage, $period, $rate, $basis = 0)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $purchased = Functions::flattenSingleValue($purchased);
+        $firstPeriod = Functions::flattenSingleValue($firstPeriod);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $period = floor(Functions::flattenSingleValue($period));
+        $rate = Functions::flattenSingleValue($rate);
+        $basis = ($basis === null) ? 0 : (int) Functions::flattenSingleValue($basis);
+
+        try {
+            $cost = self::validateFloat($cost);
+            $purchased = self::validateDate($purchased);
+            $firstPeriod = self::validateDate($firstPeriod);
+            $salvage = self::validateFloat($salvage);
+            $period = self::validateFloat($period);
+            $rate = self::validateFloat($rate);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $yearFrac = DateTimeExcel\YearFrac::funcYearFrac($purchased, $firstPeriod, $basis);
+        if (is_string($yearFrac)) {
+            return $yearFrac;
+        }
+
+        $amortiseCoeff = self::getAmortizationCoefficient($rate);
+
+        $rate *= $amortiseCoeff;
+        $fNRate = round($yearFrac * $rate * $cost, 0);
+        $cost -= $fNRate;
+        $fRest = $cost - $salvage;
+
+        for ($n = 0; $n < $period; ++$n) {
+            $fNRate = round($rate * $cost, 0);
+            $fRest -= $fNRate;
+
+            if ($fRest < 0.0) {
+                switch ($period - $n) {
+                    case 0:
+                    case 1:
+                        return round($cost * 0.5, 0);
+                    default:
+                        return 0.0;
+                }
+            }
+            $cost -= $fNRate;
+        }
+
+        return $fNRate;
+    }
+
+    /**
+     * AMORLINC.
+     *
+     * Returns the depreciation for each accounting period.
+     * This function is provided for the French accounting system. If an asset is purchased in
+     * the middle of the accounting period, the prorated depreciation is taken into account.
+     *
+     * Excel Function:
+     *        AMORLINC(cost,purchased,firstPeriod,salvage,period,rate[,basis])
+     *
+     * @param mixed $cost The cost of the asset as a float
+     * @param mixed $purchased Date of the purchase of the asset
+     * @param mixed $firstPeriod Date of the end of the first period
+     * @param mixed $salvage The salvage value at the end of the life of the asset
+     * @param mixed $period The period as a float
+     * @param mixed $rate Rate of depreciation as  float
+     * @param mixed $basis Integer indicating the type of day count to use.
+     *                             0 or omitted    US (NASD) 30/360
+     *                             1               Actual/actual
+     *                             2               Actual/360
+     *                             3               Actual/365
+     *                             4               European 30/360
+     *
+     * @return float|string (string containing the error type if there is an error)
+     */
+    public static function AMORLINC($cost, $purchased, $firstPeriod, $salvage, $period, $rate, $basis = 0)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $purchased = Functions::flattenSingleValue($purchased);
+        $firstPeriod = Functions::flattenSingleValue($firstPeriod);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $period = Functions::flattenSingleValue($period);
+        $rate = Functions::flattenSingleValue($rate);
+        $basis = ($basis === null) ? 0 : (int) Functions::flattenSingleValue($basis);
+
+        try {
+            $cost = self::validateFloat($cost);
+            $purchased = self::validateDate($purchased);
+            $firstPeriod = self::validateDate($firstPeriod);
+            $salvage = self::validateFloat($salvage);
+            $period = self::validateFloat($period);
+            $rate = self::validateFloat($rate);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $fOneRate = $cost * $rate;
+        $fCostDelta = $cost - $salvage;
+        //    Note, quirky variation for leap years on the YEARFRAC for this function
+        $purchasedYear = DateTimeExcel\Year::funcYear($purchased);
+        $yearFrac = DateTimeExcel\YearFrac::funcYearFrac($purchased, $firstPeriod, $basis);
+        if (is_string($yearFrac)) {
+            return $yearFrac;
+        }
+
+        if (($basis == 1) && ($yearFrac < 1) && (DateTimeExcel\Helpers::isLeapYear($purchasedYear))) {
+            $yearFrac *= 365 / 366;
+        }
+
+        $f0Rate = $yearFrac * $rate * $cost;
+        $nNumOfFullPeriods = (int) (($cost - $salvage - $f0Rate) / $fOneRate);
+
+        if ($period == 0) {
+            return $f0Rate;
+        } elseif ($period <= $nNumOfFullPeriods) {
+            return $fOneRate;
+        } elseif ($period == ($nNumOfFullPeriods + 1)) {
+            return $fCostDelta - $fOneRate * $nNumOfFullPeriods - $f0Rate;
+        }
+
+        return 0.0;
+    }
+
+    private static function getAmortizationCoefficient(float $rate): float
+    {
+        //    The depreciation coefficients are:
+        //    Life of assets (1/rate)        Depreciation coefficient
+        //    Less than 3 years            1
+        //    Between 3 and 4 years        1.5
+        //    Between 5 and 6 years        2
+        //    More than 6 years            2.5
+        $fUsePer = 1.0 / $rate;
+
+        if ($fUsePer < 3.0) {
+            return 1.0;
+        } elseif ($fUsePer < 4.0) {
+            return 1.5;
+        } elseif ($fUsePer <= 6.0) {
+            return 2.0;
+        }
+
+        return 2.5;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/BaseValidations.php

@@ -0,0 +1,72 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities\Constants as SecuritiesConstants;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+trait BaseValidations
+{
+    protected static function validateDate($date)
+    {
+        return DateTimeExcel\Helpers::getDateValue($date);
+    }
+
+    protected static function validateSettlementDate($settlement)
+    {
+        return self::validateDate($settlement);
+    }
+
+    protected static function validateMaturityDate($maturity)
+    {
+        return self::validateDate($maturity);
+    }
+
+    protected static function validateFloat($value): float
+    {
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (float) $value;
+    }
+
+    protected static function validateInt($value): int
+    {
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (int) floor($value);
+    }
+
+    protected static function validateFrequency($frequency): int
+    {
+        $frequency = self::validateInt($frequency);
+        if (
+            ($frequency !== SecuritiesConstants::FREQUENCY_ANNUAL) &&
+            ($frequency !== SecuritiesConstants::FREQUENCY_SEMI_ANNUAL) &&
+            ($frequency !== SecuritiesConstants::FREQUENCY_QUARTERLY)
+        ) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $frequency;
+    }
+
+    protected static function validateBasis($basis): int
+    {
+        if (!is_numeric($basis)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        $basis = (int) $basis;
+        if (($basis < 0) || ($basis > 4)) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $basis;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic.php

@@ -0,0 +1,190 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Constant;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\BaseValidations;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Periodic
+{
+    use BaseValidations;
+
+    /**
+     * FV.
+     *
+     * Returns the Future Value of a cash flow with constant payments and interest rate (annuities).
+     *
+     * Excel Function:
+     *        FV(rate,nper,pmt[,pv[,type]])
+     *
+     * @param mixed $rate The interest rate per period
+     * @param mixed $numberOfPeriods Total number of payment periods in an annuity as an integer
+     * @param mixed $payment The payment made each period: it cannot change over the
+     *                            life of the annuity. Typically, pmt contains principal
+     *                            and interest but no other fees or taxes.
+     * @param mixed $presentValue present Value, or the lump-sum amount that a series of
+     *                            future payments is worth right now
+     * @param mixed $type A number 0 or 1 and indicates when payments are due:
+     *                                0 or omitted    At the end of the period.
+     *                                1                At the beginning of the period.
+     *
+     * @return float|string
+     */
+    public static function futureValue($rate, $numberOfPeriods, $payment = 0, $presentValue = 0, $type = 0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $payment = ($payment === null) ? 0.0 : Functions::flattenSingleValue($payment);
+        $presentValue = ($presentValue === null) ? 0.0 : Functions::flattenSingleValue($presentValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $payment = self::validateFloat($payment);
+            $presentValue = self::validateFloat($presentValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($numberOfPeriods < 0 || ($type !== 0 && $type !== 1)) {
+            return Functions::NAN();
+        }
+
+        return self::calculateFutureValue($rate, $numberOfPeriods, $payment, $presentValue, $type);
+    }
+
+    /**
+     * PV.
+     *
+     * Returns the Present Value of a cash flow with constant payments and interest rate (annuities).
+     *
+     * @param mixed $rate Interest rate per period
+     * @param mixed $numberOfPeriods Number of periods as an integer
+     * @param mixed $payment Periodic payment (annuity)
+     * @param mixed $futureValue Future Value
+     * @param mixed $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function presentValue($rate, $numberOfPeriods, $payment = 0, $futureValue = 0, $type = 0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $payment = ($payment === null) ? 0.0 : Functions::flattenSingleValue($payment);
+        $futureValue = ($futureValue === null) ? 0.0 : Functions::flattenSingleValue($futureValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $payment = self::validateFloat($payment);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($numberOfPeriods < 0 || ($type !== 0 && $type !== 1)) {
+            return Functions::NAN();
+        }
+
+        return self::calculatePresentValue($rate, $numberOfPeriods, $payment, $futureValue, $type);
+    }
+
+    /**
+     * NPER.
+     *
+     * Returns the number of periods for a cash flow with constant periodic payments (annuities), and interest rate.
+     *
+     * @param mixed $rate Interest rate per period
+     * @param mixed $payment Periodic payment (annuity)
+     * @param mixed $presentValue Present Value
+     * @param mixed $futureValue Future Value
+     * @param mixed $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function periods($rate, $payment, $presentValue, $futureValue = 0, $type = 0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $payment = Functions::flattenSingleValue($payment);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = ($futureValue === null) ? 0.0 : Functions::flattenSingleValue($futureValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $payment = self::validateFloat($payment);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($payment == 0.0 || ($type != 0 && $type != 1)) {
+            return Functions::NAN();
+        }
+
+        return self::calculatePeriods($rate, $payment, $presentValue, $futureValue, $type);
+    }
+
+    private static function calculateFutureValue(
+        float $rate,
+        int $numberOfPeriods,
+        float $payment,
+        float $presentValue,
+        int $type
+    ): float {
+        if ($rate !== null && $rate != 0) {
+            return -$presentValue *
+                (1 + $rate) ** $numberOfPeriods - $payment * (1 + $rate * $type) * ((1 + $rate) ** $numberOfPeriods - 1)
+                    / $rate;
+        }
+
+        return -$presentValue - $payment * $numberOfPeriods;
+    }
+
+    private static function calculatePresentValue(
+        float $rate,
+        int $numberOfPeriods,
+        float $payment,
+        float $futureValue,
+        int $type
+    ): float {
+        if ($rate != 0.0) {
+            return (-$payment * (1 + $rate * $type)
+                    * (((1 + $rate) ** $numberOfPeriods - 1) / $rate) - $futureValue) / (1 + $rate) ** $numberOfPeriods;
+        }
+
+        return -$futureValue - $payment * $numberOfPeriods;
+    }
+
+    /**
+     * @return float|string
+     */
+    private static function calculatePeriods(
+        float $rate,
+        float $payment,
+        float $presentValue,
+        float $futureValue,
+        int $type
+    ) {
+        if ($rate != 0.0) {
+            if ($presentValue == 0.0) {
+                return Functions::NAN();
+            }
+
+            return log(($payment * (1 + $rate * $type) / $rate - $futureValue) /
+                    ($presentValue + $payment * (1 + $rate * $type) / $rate)) / log(1 + $rate);
+        }
+
+        return (-$presentValue - $futureValue) / $payment;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/Cumulative.php

@@ -0,0 +1,136 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Constant\Periodic;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Cumulative
+{
+    use Financial\BaseValidations;
+
+    /**
+     * CUMIPMT.
+     *
+     * Returns the cumulative interest paid on a loan between the start and end periods.
+     *
+     * Excel Function:
+     *        CUMIPMT(rate,nper,pv,start,end[,type])
+     *
+     * @param mixed $rate The Interest rate
+     * @param mixed $periods The total number of payment periods
+     * @param mixed $presentValue Present Value
+     * @param mixed $start The first period in the calculation.
+     *                       Payment periods are numbered beginning with 1.
+     * @param mixed $end the last period in the calculation
+     * @param mixed $type A number 0 or 1 and indicates when payments are due:
+     *                    0 or omitted    At the end of the period.
+     *                    1               At the beginning of the period.
+     *
+     * @return float|string
+     */
+    public static function interest($rate, $periods, $presentValue, $start, $end, $type = 0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $periods = Functions::flattenSingleValue($periods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $start = Functions::flattenSingleValue($start);
+        $end = Functions::flattenSingleValue($end);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $periods = self::validateInt($periods);
+            $presentValue = self::validateFloat($presentValue);
+            $start = self::validateInt($start);
+            $end = self::validateInt($end);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($type !== 0 && $type !== 1) {
+            return Functions::NAN();
+        }
+        if ($start < 1 || $start > $end) {
+            return Functions::NAN();
+        }
+
+        // Calculate
+        $interest = 0;
+        for ($per = $start; $per <= $end; ++$per) {
+            $ipmt = Financial::IPMT($rate, $per, $periods, $presentValue, 0, $type);
+            if (is_string($ipmt)) {
+                return $ipmt;
+            }
+
+            $interest += $ipmt;
+        }
+
+        return $interest;
+    }
+
+    /**
+     * CUMPRINC.
+     *
+     * Returns the cumulative principal paid on a loan between the start and end periods.
+     *
+     * Excel Function:
+     *        CUMPRINC(rate,nper,pv,start,end[,type])
+     *
+     * @param mixed $rate The Interest rate
+     * @param mixed $periods The total number of payment periods as an integer
+     * @param mixed $presentValue Present Value
+     * @param mixed $start The first period in the calculation.
+     *                       Payment periods are numbered beginning with 1.
+     * @param mixed $end the last period in the calculation
+     * @param mixed $type A number 0 or 1 and indicates when payments are due:
+     *                    0 or omitted    At the end of the period.
+     *                    1               At the beginning of the period.
+     *
+     * @return float|string
+     */
+    public static function principal($rate, $periods, $presentValue, $start, $end, $type = 0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $periods = Functions::flattenSingleValue($periods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $start = Functions::flattenSingleValue($start);
+        $end = Functions::flattenSingleValue($end);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $periods = self::validateInt($periods);
+            $presentValue = self::validateFloat($presentValue);
+            $start = self::validateInt($start);
+            $end = self::validateInt($end);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($type !== 0 && $type !== 1) {
+            return Functions::NAN();
+        }
+        if ($start < 1 || $start > $end) {
+            return Functions::VALUE();
+        }
+
+        // Calculate
+        $principal = 0;
+        for ($per = $start; $per <= $end; ++$per) {
+            $ppmt = Payments::interestPayment($rate, $per, $periods, $presentValue, 0, $type);
+            if (is_string($ppmt)) {
+                return $ppmt;
+            }
+
+            $principal += $ppmt;
+        }
+
+        return $principal;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/Interest.php

@@ -0,0 +1,209 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Constant\Periodic;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\BaseValidations;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Interest
+{
+    use BaseValidations;
+
+    private const FINANCIAL_MAX_ITERATIONS = 128;
+
+    private const FINANCIAL_PRECISION = 1.0e-08;
+
+    /**
+     * IPMT.
+     *
+     * Returns the interest payment for a given period for an investment based on periodic, constant payments
+     *         and a constant interest rate.
+     *
+     * Excel Function:
+     *        IPMT(rate,per,nper,pv[,fv][,type])
+     *
+     * @param float $interestRate Interest rate per period
+     * @param int $period Period for which we want to find the interest
+     * @param int $numberOfPeriods Number of periods
+     * @param float $presentValue Present Value
+     * @param float $futureValue Future Value
+     * @param int $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period
+     *
+     * @return float|string
+     */
+    public static function payment($interestRate, $period, $numberOfPeriods, $presentValue, $futureValue = 0, $type = 0)
+    {
+        $interestRate = Functions::flattenSingleValue($interestRate);
+        $period = Functions::flattenSingleValue($period);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = Functions::flattenSingleValue($futureValue);
+        $type = Functions::flattenSingleValue($type);
+
+        try {
+            $interestRate = self::validateFloat($interestRate);
+            $period = self::validateInt($period);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($type != 0 && $type != 1) {
+            return Functions::NAN();
+        }
+        if ($period <= 0 || $period > $numberOfPeriods) {
+            return Functions::NAN();
+        }
+
+        // Calculate
+        $interestAndPrincipal = new InterestAndPrincipal(
+            $interestRate,
+            $period,
+            $numberOfPeriods,
+            $presentValue,
+            $futureValue,
+            $type
+        );
+
+        return $interestAndPrincipal->interest();
+    }
+
+    /**
+     * ISPMT.
+     *
+     * Returns the interest payment for an investment based on an interest rate and a constant payment schedule.
+     *
+     * Excel Function:
+     *     =ISPMT(interest_rate, period, number_payments, pv)
+     *
+     * interest_rate is the interest rate for the investment
+     *
+     * period is the period to calculate the interest rate.  It must be betweeen 1 and number_payments.
+     *
+     * number_payments is the number of payments for the annuity
+     *
+     * pv is the loan amount or present value of the payments
+     */
+    public static function schedulePayment($interestRate, $period, $numberOfPeriods, $principleRemaining)
+    {
+        $interestRate = Functions::flattenSingleValue($interestRate);
+        $period = Functions::flattenSingleValue($period);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $principleRemaining = Functions::flattenSingleValue($principleRemaining);
+
+        try {
+            $interestRate = self::validateFloat($interestRate);
+            $period = self::validateInt($period);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $principleRemaining = self::validateFloat($principleRemaining);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($period <= 0 || $period > $numberOfPeriods) {
+            return Functions::NAN();
+        }
+        // Return value
+        $returnValue = 0;
+
+        // Calculate
+        $principlePayment = ($principleRemaining * 1.0) / ($numberOfPeriods * 1.0);
+        for ($i = 0; $i <= $period; ++$i) {
+            $returnValue = $interestRate * $principleRemaining * -1;
+            $principleRemaining -= $principlePayment;
+            // principle needs to be 0 after the last payment, don't let floating point screw it up
+            if ($i == $numberOfPeriods) {
+                $returnValue = 0.0;
+            }
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * RATE.
+     *
+     * Returns the interest rate per period of an annuity.
+     * RATE is calculated by iteration and can have zero or more solutions.
+     * If the successive results of RATE do not converge to within 0.0000001 after 20 iterations,
+     * RATE returns the #NUM! error value.
+     *
+     * Excel Function:
+     *        RATE(nper,pmt,pv[,fv[,type[,guess]]])
+     *
+     * @param mixed $numberOfPeriods The total number of payment periods in an annuity
+     * @param mixed $payment The payment made each period and cannot change over the life of the annuity.
+     *                           Typically, pmt includes principal and interest but no other fees or taxes.
+     * @param mixed $presentValue The present value - the total amount that a series of future payments is worth now
+     * @param mixed $futureValue The future value, or a cash balance you want to attain after the last payment is made.
+     *                               If fv is omitted, it is assumed to be 0 (the future value of a loan,
+     *                               for example, is 0).
+     * @param mixed $type A number 0 or 1 and indicates when payments are due:
+     *                      0 or omitted    At the end of the period.
+     *                      1               At the beginning of the period.
+     * @param mixed $guess Your guess for what the rate will be.
+     *                          If you omit guess, it is assumed to be 10 percent.
+     *
+     * @return float|string
+     */
+    public static function rate($numberOfPeriods, $payment, $presentValue, $futureValue = 0.0, $type = 0, $guess = 0.1)
+    {
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $payment = Functions::flattenSingleValue($payment);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = ($futureValue === null) ? 0.0 : Functions::flattenSingleValue($futureValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+        $guess = ($guess === null) ? 0.1 : Functions::flattenSingleValue($guess);
+
+        try {
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $payment = self::validateFloat($payment);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+            $guess = self::validateFloat($guess);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $rate = $guess;
+        // rest of code adapted from python/numpy
+        $close = false;
+        $iter = 0;
+        while (!$close && $iter < self::FINANCIAL_MAX_ITERATIONS) {
+            $nextdiff = self::rateNextGuess($rate, $numberOfPeriods, $payment, $presentValue, $futureValue, $type);
+            if (!is_numeric($nextdiff)) {
+                break;
+            }
+            $rate1 = $rate - $nextdiff;
+            $close = abs($rate1 - $rate) < self::FINANCIAL_PRECISION;
+            ++$iter;
+            $rate = $rate1;
+        }
+
+        return $close ? $rate : Functions::NAN();
+    }
+
+    private static function rateNextGuess($rate, $nper, $pmt, $pv, $fv, $type)
+    {
+        if ($rate == 0) {
+            return Functions::NAN();
+        }
+        $tt1 = ($rate + 1) ** $nper;
+        $tt2 = ($rate + 1) ** ($nper - 1);
+        $numerator = $fv + $tt1 * $pv + $pmt * ($tt1 - 1) * ($rate * $type + 1) / $rate;
+        $denominator = $nper * $tt2 * $pv - $pmt * ($tt1 - 1) * ($rate * $type + 1) / ($rate * $rate)
+            + $nper * $pmt * $tt2 * ($rate * $type + 1) / $rate
+            + $pmt * ($tt1 - 1) * $type / $rate;
+        if ($denominator == 0) {
+            return Functions::NAN();
+        }
+
+        return $numerator / $denominator;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Constant\Periodic;
+
+class InterestAndPrincipal
+{
+    protected $interest;
+
+    protected $principal;
+
+    public function __construct(
+        float $rate = 0.0,
+        int $period = 0,
+        int $numberOfPeriods = 0,
+        float $presentValue = 0,
+        float $futureValue = 0,
+        int $type = 0
+    ) {
+        $payment = Payments::annuity($rate, $numberOfPeriods, $presentValue, $futureValue, $type);
+        $capital = $presentValue;
+        $interest = 0.0;
+        $principal = 0.0;
+        for ($i = 1; $i <= $period; ++$i) {
+            $interest = ($type && $i == 1) ? 0 : -$capital * $rate;
+            $principal = $payment - $interest;
+            $capital += $principal;
+        }
+
+        $this->interest = $interest;
+        $this->principal = $principal;
+    }
+
+    public function interest(): float
+    {
+        return $this->interest;
+    }
+
+    public function principal(): float
+    {
+        return $this->principal;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/Payments.php

@@ -0,0 +1,119 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Constant\Periodic;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\BaseValidations;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Payments
+{
+    use BaseValidations;
+
+    /**
+     * PMT.
+     *
+     * Returns the constant payment (annuity) for a cash flow with a constant interest rate.
+     *
+     * @param mixed $interestRate Interest rate per period
+     * @param mixed $numberOfPeriods Number of periods
+     * @param mixed $presentValue Present Value
+     * @param mixed $futureValue Future Value
+     * @param mixed $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function annuity($interestRate, $numberOfPeriods, $presentValue, $futureValue = 0, $type = 0)
+    {
+        $interestRate = Functions::flattenSingleValue($interestRate);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = ($futureValue === null) ? 0.0 : Functions::flattenSingleValue($futureValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $interestRate = self::validateFloat($interestRate);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($type != 0 && $type != 1) {
+            return Functions::NAN();
+        }
+
+        // Calculate
+        if ($interestRate != 0.0) {
+            return (-$futureValue - $presentValue * (1 + $interestRate) ** $numberOfPeriods) /
+                (1 + $interestRate * $type) / (((1 + $interestRate) ** $numberOfPeriods - 1) / $interestRate);
+        }
+
+        return (-$presentValue - $futureValue) / $numberOfPeriods;
+    }
+
+    /**
+     * PPMT.
+     *
+     * Returns the interest payment for a given period for an investment based on periodic, constant payments
+     *         and a constant interest rate.
+     *
+     * @param mixed $interestRate Interest rate per period
+     * @param mixed $period Period for which we want to find the interest
+     * @param mixed $numberOfPeriods Number of periods
+     * @param mixed $presentValue Present Value
+     * @param mixed $futureValue Future Value
+     * @param mixed $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function interestPayment(
+        $interestRate,
+        $period,
+        $numberOfPeriods,
+        $presentValue,
+        $futureValue = 0,
+        $type = 0
+    ) {
+        $interestRate = Functions::flattenSingleValue($interestRate);
+        $period = Functions::flattenSingleValue($period);
+        $numberOfPeriods = Functions::flattenSingleValue($numberOfPeriods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = ($futureValue === null) ? 0.0 : Functions::flattenSingleValue($futureValue);
+        $type = ($type === null) ? 0 : Functions::flattenSingleValue($type);
+
+        try {
+            $interestRate = self::validateFloat($interestRate);
+            $period = self::validateInt($period);
+            $numberOfPeriods = self::validateInt($numberOfPeriods);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+            $type = self::validateInt($type);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($type != 0 && $type != 1) {
+            return Functions::NAN();
+        }
+        if ($period <= 0 || $period > $numberOfPeriods) {
+            return Functions::NAN();
+        }
+
+        // Calculate
+        $interestAndPrincipal = new InterestAndPrincipal(
+            $interestRate,
+            $period,
+            $numberOfPeriods,
+            $presentValue,
+            $futureValue,
+            $type
+        );
+
+        return $interestAndPrincipal->principal();
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Single.php

@@ -0,0 +1,111 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\BaseValidations;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Single
+{
+    use BaseValidations;
+
+    /**
+     * FVSCHEDULE.
+     *
+     * Returns the future value of an initial principal after applying a series of compound interest rates.
+     * Use FVSCHEDULE to calculate the future value of an investment with a variable or adjustable rate.
+     *
+     * Excel Function:
+     *        FVSCHEDULE(principal,schedule)
+     *
+     * @param mixed $principal the present value
+     * @param float[] $schedule an array of interest rates to apply
+     *
+     * @return float|string
+     */
+    public static function futureValue($principal, $schedule)
+    {
+        $principal = Functions::flattenSingleValue($principal);
+        $schedule = Functions::flattenArray($schedule);
+
+        try {
+            $principal = self::validateFloat($principal);
+
+            foreach ($schedule as $rate) {
+                $rate = self::validateFloat($rate);
+                $principal *= 1 + $rate;
+            }
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        return $principal;
+    }
+
+    /**
+     * PDURATION.
+     *
+     * Calculates the number of periods required for an investment to reach a specified value.
+     *
+     * @param float $rate Interest rate per period
+     * @param float $presentValue Present Value
+     * @param float $futureValue Future Value
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function periods($rate = 0.0, $presentValue = 0.0, $futureValue = 0.0)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = Functions::flattenSingleValue($futureValue);
+
+        try {
+            $rate = self::validateFloat($rate);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($rate <= 0.0 || $presentValue <= 0.0 || $futureValue <= 0.0) {
+            return Functions::NAN();
+        }
+
+        return (log($futureValue) - log($presentValue)) / log(1 + $rate);
+    }
+
+    /**
+     * RRI.
+     *
+     * Calculates the interest rate required for an investment to grow to a specified future value .
+     *
+     * @param float $periods The number of periods over which the investment is made
+     * @param float $presentValue Present Value
+     * @param float $futureValue Future Value
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function interestRate($periods = 0.0, $presentValue = 0.0, $futureValue = 0.0)
+    {
+        $periods = Functions::flattenSingleValue($periods);
+        $presentValue = Functions::flattenSingleValue($presentValue);
+        $futureValue = Functions::flattenSingleValue($futureValue);
+
+        try {
+            $periods = self::validateFloat($periods);
+            $presentValue = self::validateFloat($presentValue);
+            $futureValue = self::validateFloat($futureValue);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        // Validate parameters
+        if ($periods <= 0.0 || $presentValue <= 0.0 || $futureValue < 0.0) {
+            return Functions::NAN();
+        }
+
+        return ($futureValue / $presentValue) ** (1 / $periods) - 1;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php

@@ -0,0 +1,226 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Variable;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class NonPeriodic
+{
+    const FINANCIAL_MAX_ITERATIONS = 128;
+
+    const FINANCIAL_PRECISION = 1.0e-08;
+
+    /**
+     * XIRR.
+     *
+     * Returns the internal rate of return for a schedule of cash flows that is not necessarily periodic.
+     *
+     * Excel Function:
+     *        =XIRR(values,dates,guess)
+     *
+     * @param float[] $values     A series of cash flow payments
+     *                                The series of values must contain at least one positive value & one negative value
+     * @param mixed[] $dates      A series of payment dates
+     *                                The first payment date indicates the beginning of the schedule of payments
+     *                                All other dates must be later than this date, but they may occur in any order
+     * @param float $guess        An optional guess at the expected answer
+     *
+     * @return float|string
+     */
+    public static function rate($values, $dates, $guess = 0.1)
+    {
+        $rslt = self::xirrPart1($values, $dates);
+        if ($rslt) {
+            return $rslt;
+        }
+
+        // create an initial range, with a root somewhere between 0 and guess
+        $guess = Functions::flattenSingleValue($guess);
+        $x1 = 0.0;
+        $x2 = $guess ?: 0.1;
+        $f1 = self::xnpvOrdered($x1, $values, $dates, false);
+        $f2 = self::xnpvOrdered($x2, $values, $dates, false);
+        $found = false;
+        for ($i = 0; $i < self::FINANCIAL_MAX_ITERATIONS; ++$i) {
+            if (!is_numeric($f1) || !is_numeric($f2)) {
+                break;
+            }
+            if (($f1 * $f2) < 0.0) {
+                $found = true;
+
+                break;
+            } elseif (abs($f1) < abs($f2)) {
+                $f1 = self::xnpvOrdered($x1 += 1.6 * ($x1 - $x2), $values, $dates, false);
+            } else {
+                $f2 = self::xnpvOrdered($x2 += 1.6 * ($x2 - $x1), $values, $dates, false);
+            }
+        }
+        if (!$found) {
+            return Functions::NAN();
+        }
+
+        return self::xirrPart3($values, $dates, $x1, $x2);
+    }
+
+    /**
+     * XNPV.
+     *
+     * Returns the net present value for a schedule of cash flows that is not necessarily periodic.
+     * To calculate the net present value for a series of cash flows that is periodic, use the NPV function.
+     *
+     * Excel Function:
+     *        =XNPV(rate,values,dates)
+     *
+     * @param float $rate the discount rate to apply to the cash flows
+     * @param float[] $values A series of cash flows that corresponds to a schedule of payments in dates.
+     *                          The first payment is optional and corresponds to a cost or payment that occurs
+     *                              at the beginning of the investment.
+     *                          If the first value is a cost or payment, it must be a negative value.
+     *                             All succeeding payments are discounted based on a 365-day year.
+     *                          The series of values must contain at least one positive value and one negative value.
+     * @param mixed[] $dates A schedule of payment dates that corresponds to the cash flow payments.
+     *                         The first payment date indicates the beginning of the schedule of payments.
+     *                         All other dates must be later than this date, but they may occur in any order.
+     *
+     * @return float|string
+     */
+    public static function presentValue($rate, $values, $dates)
+    {
+        return self::xnpvOrdered($rate, $values, $dates, true);
+    }
+
+    private static function bothNegAndPos($neg, $pos)
+    {
+        return $neg && $pos;
+    }
+
+    private static function xirrPart1(&$values, &$dates)
+    {
+        if ((!is_array($values)) && (!is_array($dates))) {
+            return Functions::NA();
+        }
+        $values = Functions::flattenArray($values);
+        $dates = Functions::flattenArray($dates);
+        if (count($values) != count($dates)) {
+            return Functions::NAN();
+        }
+
+        $datesCount = count($dates);
+        for ($i = 0; $i < $datesCount; ++$i) {
+            try {
+                $dates[$i] = DateTimeExcel\Helpers::getDateValue($dates[$i]);
+            } catch (Exception $e) {
+                return $e->getMessage();
+            }
+        }
+
+        return self::xirrPart2($values);
+    }
+
+    private static function xirrPart2(&$values)
+    {
+        $valCount = count($values);
+        $foundpos = false;
+        $foundneg = false;
+        for ($i = 0; $i < $valCount; ++$i) {
+            $fld = $values[$i];
+            if (!is_numeric($fld)) {
+                return Functions::VALUE();
+            } elseif ($fld > 0) {
+                $foundpos = true;
+            } elseif ($fld < 0) {
+                $foundneg = true;
+            }
+        }
+        if (!self::bothNegAndPos($foundneg, $foundpos)) {
+            return Functions::NAN();
+        }
+
+        return '';
+    }
+
+    private static function xirrPart3($values, $dates, $x1, $x2)
+    {
+        $f = self::xnpvOrdered($x1, $values, $dates, false);
+        if ($f < 0.0) {
+            $rtb = $x1;
+            $dx = $x2 - $x1;
+        } else {
+            $rtb = $x2;
+            $dx = $x1 - $x2;
+        }
+
+        $rslt = Functions::VALUE();
+        for ($i = 0; $i < self::FINANCIAL_MAX_ITERATIONS; ++$i) {
+            $dx *= 0.5;
+            $x_mid = $rtb + $dx;
+            $f_mid = self::xnpvOrdered($x_mid, $values, $dates, false);
+            if ($f_mid <= 0.0) {
+                $rtb = $x_mid;
+            }
+            if ((abs($f_mid) < self::FINANCIAL_PRECISION) || (abs($dx) < self::FINANCIAL_PRECISION)) {
+                $rslt = $x_mid;
+
+                break;
+            }
+        }
+
+        return $rslt;
+    }
+
+    private static function xnpvOrdered($rate, $values, $dates, $ordered = true)
+    {
+        $rate = Functions::flattenSingleValue($rate);
+        $values = Functions::flattenArray($values);
+        $dates = Functions::flattenArray($dates);
+        $valCount = count($values);
+
+        try {
+            self::validateXnpv($rate, $values, $dates);
+            $date0 = DateTimeExcel\Helpers::getDateValue($dates[0]);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $xnpv = 0.0;
+        for ($i = 0; $i < $valCount; ++$i) {
+            if (!is_numeric($values[$i])) {
+                return Functions::VALUE();
+            }
+
+            try {
+                $datei = DateTimeExcel\Helpers::getDateValue($dates[$i]);
+            } catch (Exception $e) {
+                return $e->getMessage();
+            }
+            if ($date0 > $datei) {
+                /** @phpstan-ignore-next-line */
+                $dif = $ordered ? Functions::NAN() : -DateTimeExcel\DateDif::funcDateDif($datei, $date0, 'd');
+            } else {
+                $dif = DateTimeExcel\DateDif::funcDateDif($date0, $datei, 'd');
+            }
+            if (!is_numeric($dif)) {
+                return $dif;
+            }
+            $xnpv += $values[$i] / (1 + $rate) ** ($dif / 365);
+        }
+
+        return is_finite($xnpv) ? $xnpv : Functions::VALUE();
+    }
+
+    private static function validateXnpv($rate, $values, $dates): void
+    {
+        if (!is_numeric($rate)) {
+            throw new Exception(Functions::VALUE());
+        }
+        $valCount = count($values);
+        if ($valCount != count($dates)) {
+            throw new Exception(Functions::NAN());
+        }
+        if ($valCount > 1 && ((min($values) > 0) || (max($values) < 0))) {
+            throw new Exception(Functions::NAN());
+        }
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/Periodic.php

@@ -0,0 +1,160 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\CashFlow\Variable;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Periodic
+{
+    const FINANCIAL_MAX_ITERATIONS = 128;
+
+    const FINANCIAL_PRECISION = 1.0e-08;
+
+    /**
+     * IRR.
+     *
+     * Returns the internal rate of return for a series of cash flows represented by the numbers in values.
+     * These cash flows do not have to be even, as they would be for an annuity. However, the cash flows must occur
+     * at regular intervals, such as monthly or annually. The internal rate of return is the interest rate received
+     * for an investment consisting of payments (negative values) and income (positive values) that occur at regular
+     * periods.
+     *
+     * Excel Function:
+     *        IRR(values[,guess])
+     *
+     * @param mixed $values An array or a reference to cells that contain numbers for which you want
+     *                                    to calculate the internal rate of return.
+     *                                Values must contain at least one positive value and one negative value to
+     *                                    calculate the internal rate of return.
+     * @param mixed $guess A number that you guess is close to the result of IRR
+     *
+     * @return float|string
+     */
+    public static function rate($values, $guess = 0.1)
+    {
+        if (!is_array($values)) {
+            return Functions::VALUE();
+        }
+        $values = Functions::flattenArray($values);
+        $guess = Functions::flattenSingleValue($guess);
+
+        // create an initial range, with a root somewhere between 0 and guess
+        $x1 = 0.0;
+        $x2 = $guess;
+        $f1 = self::presentValue($x1, $values);
+        $f2 = self::presentValue($x2, $values);
+        for ($i = 0; $i < self::FINANCIAL_MAX_ITERATIONS; ++$i) {
+            if (($f1 * $f2) < 0.0) {
+                break;
+            }
+            if (abs($f1) < abs($f2)) {
+                $f1 = self::presentValue($x1 += 1.6 * ($x1 - $x2), $values);
+            } else {
+                $f2 = self::presentValue($x2 += 1.6 * ($x2 - $x1), $values);
+            }
+        }
+        if (($f1 * $f2) > 0.0) {
+            return Functions::VALUE();
+        }
+
+        $f = self::presentValue($x1, $values);
+        if ($f < 0.0) {
+            $rtb = $x1;
+            $dx = $x2 - $x1;
+        } else {
+            $rtb = $x2;
+            $dx = $x1 - $x2;
+        }
+
+        for ($i = 0; $i < self::FINANCIAL_MAX_ITERATIONS; ++$i) {
+            $dx *= 0.5;
+            $x_mid = $rtb + $dx;
+            $f_mid = self::presentValue($x_mid, $values);
+            if ($f_mid <= 0.0) {
+                $rtb = $x_mid;
+            }
+            if ((abs($f_mid) < self::FINANCIAL_PRECISION) || (abs($dx) < self::FINANCIAL_PRECISION)) {
+                return $x_mid;
+            }
+        }
+
+        return Functions::VALUE();
+    }
+
+    /**
+     * MIRR.
+     *
+     * Returns the modified internal rate of return for a series of periodic cash flows. MIRR considers both
+     *        the cost of the investment and the interest received on reinvestment of cash.
+     *
+     * Excel Function:
+     *        MIRR(values,finance_rate, reinvestment_rate)
+     *
+     * @param mixed $values An array or a reference to cells that contain a series of payments and
+     *                         income occurring at regular intervals.
+     *                      Payments are negative value, income is positive values.
+     * @param mixed $financeRate The interest rate you pay on the money used in the cash flows
+     * @param mixed $reinvestmentRate The interest rate you receive on the cash flows as you reinvest them
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function modifiedRate($values, $financeRate, $reinvestmentRate)
+    {
+        if (!is_array($values)) {
+            return Functions::VALUE();
+        }
+        $values = Functions::flattenArray($values);
+        $financeRate = Functions::flattenSingleValue($financeRate);
+        $reinvestmentRate = Functions::flattenSingleValue($reinvestmentRate);
+        $n = count($values);
+
+        $rr = 1.0 + $reinvestmentRate;
+        $fr = 1.0 + $financeRate;
+
+        $npvPos = $npvNeg = 0.0;
+        foreach ($values as $i => $v) {
+            if ($v >= 0) {
+                $npvPos += $v / $rr ** $i;
+            } else {
+                $npvNeg += $v / $fr ** $i;
+            }
+        }
+
+        if (($npvNeg === 0.0) || ($npvPos === 0.0) || ($reinvestmentRate <= -1.0)) {
+            return Functions::VALUE();
+        }
+
+        $mirr = ((-$npvPos * $rr ** $n)
+                / ($npvNeg * ($rr))) ** (1.0 / ($n - 1)) - 1.0;
+
+        return is_finite($mirr) ? $mirr : Functions::VALUE();
+    }
+
+    /**
+     * NPV.
+     *
+     * Returns the Net Present Value of a cash flow series given a discount rate.
+     *
+     * @param mixed $rate
+     *
+     * @return float
+     */
+    public static function presentValue($rate, ...$args)
+    {
+        $returnValue = 0;
+
+        $rate = Functions::flattenSingleValue($rate);
+        $aArgs = Functions::flattenArray($args);
+
+        // Calculate
+        $countArgs = count($aArgs);
+        for ($i = 1; $i <= $countArgs; ++$i) {
+            // Is it a numeric value?
+            if (is_numeric($aArgs[$i - 1])) {
+                $returnValue += $aArgs[$i - 1] / (1 + $rate) ** $i;
+            }
+        }
+
+        return $returnValue;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Coupons.php

@@ -0,0 +1,374 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class Coupons
+{
+    use BaseValidations;
+
+    public const FREQUENCY_ANNUAL = 1;
+    public const FREQUENCY_SEMI_ANNUAL = 2;
+    public const FREQUENCY_QUARTERLY = 4;
+
+    private const PERIOD_DATE_PREVIOUS = false;
+    private const PERIOD_DATE_NEXT = true;
+
+    /**
+     * COUPDAYBS.
+     *
+     * Returns the number of days from the beginning of the coupon period to the settlement date.
+     *
+     * Excel Function:
+     *        COUPDAYBS(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                                  date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year (int).
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string
+     */
+    public static function COUPDAYBS($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+        if (is_string($daysPerYear)) {
+            return Functions::VALUE();
+        }
+        $prev = self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_PREVIOUS);
+
+        if ($basis === Helpers::DAYS_PER_YEAR_ACTUAL) {
+            return abs(DateTimeExcel\Days::funcDays($prev, $settlement));
+        }
+
+        return DateTimeExcel\YearFrac::funcYearFrac($prev, $settlement, $basis) * $daysPerYear;
+    }
+
+    /**
+     * COUPDAYS.
+     *
+     * Returns the number of days in the coupon period that contains the settlement date.
+     *
+     * Excel Function:
+     *        COUPDAYS(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                                  date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string
+     */
+    public static function COUPDAYS($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        switch ($basis) {
+            case Helpers::DAYS_PER_YEAR_365:
+                // Actual/365
+                return 365 / $frequency;
+            case Helpers::DAYS_PER_YEAR_ACTUAL:
+                // Actual/actual
+                if ($frequency == self::FREQUENCY_ANNUAL) {
+                    $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+
+                    return $daysPerYear / $frequency;
+                }
+                $prev = self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_PREVIOUS);
+                $next = self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_NEXT);
+
+                return $next - $prev;
+            default:
+                // US (NASD) 30/360, Actual/360 or European 30/360
+                return 360 / $frequency;
+        }
+    }
+
+    /**
+     * COUPDAYSNC.
+     *
+     * Returns the number of days from the settlement date to the next coupon date.
+     *
+     * Excel Function:
+     *        COUPDAYSNC(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                                  date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int) .
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string
+     */
+    public static function COUPDAYSNC($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+        $next = self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_NEXT);
+
+        if ($basis === Helpers::DAYS_PER_YEAR_NASD) {
+            $settlementDate = Date::excelToDateTimeObject($settlement);
+            $settlementEoM = Helpers::isLastDayOfMonth($settlementDate);
+            if ($settlementEoM) {
+                ++$settlement;
+            }
+        }
+
+        return DateTimeExcel\YearFrac::funcYearFrac($settlement, $next, $basis) * $daysPerYear;
+    }
+
+    /**
+     * COUPNCD.
+     *
+     * Returns the next coupon date after the settlement date.
+     *
+     * Excel Function:
+     *        COUPNCD(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                                  date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                     depending on the value of the ReturnDateType flag
+     */
+    public static function COUPNCD($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        return self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_NEXT);
+    }
+
+    /**
+     * COUPNUM.
+     *
+     * Returns the number of coupons payable between the settlement date and maturity date,
+     * rounded up to the nearest whole coupon.
+     *
+     * Excel Function:
+     *        COUPNUM(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                                  date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return int|string
+     */
+    public static function COUPNUM($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $yearsBetweenSettlementAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($settlement, $maturity, 0);
+
+        return (int) ceil($yearsBetweenSettlementAndMaturity * $frequency);
+    }
+
+    /**
+     * COUPPCD.
+     *
+     * Returns the previous coupon date before the settlement date.
+     *
+     * Excel Function:
+     *        COUPPCD(settlement,maturity,frequency[,basis])
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue
+     *                              date when the security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use (int).
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return mixed Excel date/time serial value, PHP date/time serial value or PHP date/time object,
+     *                     depending on the value of the ReturnDateType flag
+     */
+    public static function COUPPCD($settlement, $maturity, $frequency, $basis = Helpers::DAYS_PER_YEAR_NASD)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateCouponPeriod($settlement, $maturity);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        return self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_PREVIOUS);
+    }
+
+    private static function couponFirstPeriodDate($settlement, $maturity, int $frequency, $next)
+    {
+        $months = 12 / $frequency;
+
+        $result = Date::excelToDateTimeObject($maturity);
+        $maturityEoM = Helpers::isLastDayOfMonth($result);
+
+        while ($settlement < Date::PHPToExcel($result)) {
+            $result->modify('-' . $months . ' months');
+        }
+        if ($next === true) {
+            $result->modify('+' . $months . ' months');
+        }
+
+        if ($maturityEoM === true) {
+            $result->modify('-1 day');
+        }
+
+        return Date::PHPToExcel($result);
+    }
+
+    private static function validateCouponPeriod($settlement, $maturity): void
+    {
+        if ($settlement >= $maturity) {
+            throw new Exception(Functions::NAN());
+        }
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Depreciation.php

@@ -0,0 +1,265 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Depreciation
+{
+    use BaseValidations;
+
+    /**
+     * DB.
+     *
+     * Returns the depreciation of an asset for a specified period using the
+     * fixed-declining balance method.
+     * This form of depreciation is used if you want to get a higher depreciation value
+     * at the beginning of the depreciation (as opposed to linear depreciation). The
+     * depreciation value is reduced with every depreciation period by the depreciation
+     * already deducted from the initial cost.
+     *
+     * Excel Function:
+     *        DB(cost,salvage,life,period[,month])
+     *
+     * @param mixed $cost Initial cost of the asset
+     * @param mixed $salvage Value at the end of the depreciation.
+     *                             (Sometimes called the salvage value of the asset)
+     * @param mixed $life Number of periods over which the asset is depreciated.
+     *                           (Sometimes called the useful life of the asset)
+     * @param mixed $period The period for which you want to calculate the
+     *                          depreciation. Period must use the same units as life.
+     * @param mixed $month Number of months in the first year. If month is omitted,
+     *                         it defaults to 12.
+     *
+     * @return float|string
+     */
+    public static function DB($cost, $salvage, $life, $period, $month = 12)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $life = Functions::flattenSingleValue($life);
+        $period = Functions::flattenSingleValue($period);
+        $month = Functions::flattenSingleValue($month);
+
+        try {
+            $cost = self::validateCost($cost);
+            $salvage = self::validateSalvage($salvage);
+            $life = self::validateLife($life);
+            $period = self::validatePeriod($period);
+            $month = self::validateMonth($month);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($cost === 0.0) {
+            return 0.0;
+        }
+
+        //    Set Fixed Depreciation Rate
+        $fixedDepreciationRate = 1 - ($salvage / $cost) ** (1 / $life);
+        $fixedDepreciationRate = round($fixedDepreciationRate, 3);
+
+        //    Loop through each period calculating the depreciation
+        // TODO Handle period value between 0 and 1 (e.g. 0.5)
+        $previousDepreciation = 0;
+        $depreciation = 0;
+        for ($per = 1; $per <= $period; ++$per) {
+            if ($per == 1) {
+                $depreciation = $cost * $fixedDepreciationRate * $month / 12;
+            } elseif ($per == ($life + 1)) {
+                $depreciation = ($cost - $previousDepreciation) * $fixedDepreciationRate * (12 - $month) / 12;
+            } else {
+                $depreciation = ($cost - $previousDepreciation) * $fixedDepreciationRate;
+            }
+            $previousDepreciation += $depreciation;
+        }
+
+        return $depreciation;
+    }
+
+    /**
+     * DDB.
+     *
+     * Returns the depreciation of an asset for a specified period using the
+     * double-declining balance method or some other method you specify.
+     *
+     * Excel Function:
+     *        DDB(cost,salvage,life,period[,factor])
+     *
+     * @param mixed $cost Initial cost of the asset
+     * @param mixed $salvage Value at the end of the depreciation.
+     *                                (Sometimes called the salvage value of the asset)
+     * @param mixed $life Number of periods over which the asset is depreciated.
+     *                                (Sometimes called the useful life of the asset)
+     * @param mixed $period The period for which you want to calculate the
+     *                                depreciation. Period must use the same units as life.
+     * @param mixed $factor The rate at which the balance declines.
+     *                                If factor is omitted, it is assumed to be 2 (the
+     *                                double-declining balance method).
+     *
+     * @return float|string
+     */
+    public static function DDB($cost, $salvage, $life, $period, $factor = 2.0)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $life = Functions::flattenSingleValue($life);
+        $period = Functions::flattenSingleValue($period);
+        $factor = Functions::flattenSingleValue($factor);
+
+        try {
+            $cost = self::validateCost($cost);
+            $salvage = self::validateSalvage($salvage);
+            $life = self::validateLife($life);
+            $period = self::validatePeriod($period);
+            $factor = self::validateFactor($factor);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($period > $life) {
+            return Functions::NAN();
+        }
+
+        // Loop through each period calculating the depreciation
+        // TODO Handling for fractional $period values
+        $previousDepreciation = 0;
+        $depreciation = 0;
+        for ($per = 1; $per <= $period; ++$per) {
+            $depreciation = min(($cost - $previousDepreciation) * ($factor / $life), ($cost - $salvage - $previousDepreciation));
+            $previousDepreciation += $depreciation;
+        }
+
+        return $depreciation;
+    }
+
+    /**
+     * SLN.
+     *
+     * Returns the straight-line depreciation of an asset for one period
+     *
+     * @param mixed $cost Initial cost of the asset
+     * @param mixed $salvage Value at the end of the depreciation
+     * @param mixed $life Number of periods over which the asset is depreciated
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function SLN($cost, $salvage, $life)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $life = Functions::flattenSingleValue($life);
+
+        try {
+            $cost = self::validateCost($cost, true);
+            $salvage = self::validateSalvage($salvage, true);
+            $life = self::validateLife($life, true);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($life === 0.0) {
+            return Functions::DIV0();
+        }
+
+        return ($cost - $salvage) / $life;
+    }
+
+    /**
+     * SYD.
+     *
+     * Returns the sum-of-years' digits depreciation of an asset for a specified period.
+     *
+     * @param mixed $cost Initial cost of the asset
+     * @param mixed $salvage Value at the end of the depreciation
+     * @param mixed $life Number of periods over which the asset is depreciated
+     * @param mixed $period Period
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function SYD($cost, $salvage, $life, $period)
+    {
+        $cost = Functions::flattenSingleValue($cost);
+        $salvage = Functions::flattenSingleValue($salvage);
+        $life = Functions::flattenSingleValue($life);
+        $period = Functions::flattenSingleValue($period);
+
+        try {
+            $cost = self::validateCost($cost, true);
+            $salvage = self::validateSalvage($salvage);
+            $life = self::validateLife($life);
+            $period = self::validatePeriod($period);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($period > $life) {
+            return Functions::NAN();
+        }
+
+        $syd = (($cost - $salvage) * ($life - $period + 1) * 2) / ($life * ($life + 1));
+
+        return $syd;
+    }
+
+    private static function validateCost($cost, bool $negativeValueAllowed = false): float
+    {
+        $cost = self::validateFloat($cost);
+        if ($cost < 0.0 && $negativeValueAllowed === false) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $cost;
+    }
+
+    private static function validateSalvage($salvage, bool $negativeValueAllowed = false): float
+    {
+        $salvage = self::validateFloat($salvage);
+        if ($salvage < 0.0 && $negativeValueAllowed === false) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $salvage;
+    }
+
+    private static function validateLife($life, bool $negativeValueAllowed = false): float
+    {
+        $life = self::validateFloat($life);
+        if ($life < 0.0 && $negativeValueAllowed === false) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $life;
+    }
+
+    private static function validatePeriod($period, bool $negativeValueAllowed = false): float
+    {
+        $period = self::validateFloat($period);
+        if ($period <= 0.0 && $negativeValueAllowed === false) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $period;
+    }
+
+    private static function validateMonth($month): int
+    {
+        $month = self::validateInt($month);
+        if ($month < 1) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $month;
+    }
+
+    private static function validateFactor($factor): float
+    {
+        $factor = self::validateFloat($factor);
+        if ($factor <= 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $factor;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Dollar.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Dollar
+{
+    /**
+     * DOLLARDE.
+     *
+     * Converts a dollar price expressed as an integer part and a fraction
+     *        part into a dollar price expressed as a decimal number.
+     * Fractional dollar numbers are sometimes used for security prices.
+     *
+     * Excel Function:
+     *        DOLLARDE(fractional_dollar,fraction)
+     *
+     * @param mixed $fractionalDollar Fractional Dollar
+     * @param mixed $fraction Fraction
+     *
+     * @return float|string
+     */
+    public static function decimal($fractionalDollar = null, $fraction = 0)
+    {
+        $fractionalDollar = Functions::flattenSingleValue($fractionalDollar);
+        $fraction = (int) Functions::flattenSingleValue($fraction);
+
+        // Validate parameters
+        if ($fractionalDollar === null || $fraction < 0) {
+            return Functions::NAN();
+        }
+        if ($fraction == 0) {
+            return Functions::DIV0();
+        }
+
+        $dollars = floor($fractionalDollar);
+        $cents = fmod($fractionalDollar, 1);
+        $cents /= $fraction;
+        $cents *= 10 ** ceil(log10($fraction));
+
+        return $dollars + $cents;
+    }
+
+    /**
+     * DOLLARFR.
+     *
+     * Converts a dollar price expressed as a decimal number into a dollar price
+     *        expressed as a fraction.
+     * Fractional dollar numbers are sometimes used for security prices.
+     *
+     * Excel Function:
+     *        DOLLARFR(decimal_dollar,fraction)
+     *
+     * @param mixed $decimalDollar Decimal Dollar
+     * @param mixed $fraction Fraction
+     *
+     * @return float|string
+     */
+    public static function fractional($decimalDollar = null, $fraction = 0)
+    {
+        $decimalDollar = Functions::flattenSingleValue($decimalDollar);
+        $fraction = (int) Functions::flattenSingleValue($fraction);
+
+        // Validate parameters
+        if ($decimalDollar === null || $fraction < 0) {
+            return Functions::NAN();
+        }
+        if ($fraction == 0) {
+            return Functions::DIV0();
+        }
+
+        $dollars = floor($decimalDollar);
+        $cents = fmod($decimalDollar, 1);
+        $cents *= $fraction;
+        $cents *= 10 ** (-ceil(log10($fraction)));
+
+        return $dollars + $cents;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Helpers.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use DateTimeInterface;
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Helpers
+{
+    public const DAYS_PER_YEAR_NASD = 0;
+    public const DAYS_PER_YEAR_ACTUAL = 1;
+    public const DAYS_PER_YEAR_360 = 2;
+    public const DAYS_PER_YEAR_365 = 3;
+    public const DAYS_PER_YEAR_360_EUROPEAN = 4;
+
+    /**
+     * daysPerYear.
+     *
+     * Returns the number of days in a specified year, as defined by the "basis" value
+     *
+     * @param int|string $year The year against which we're testing
+     * @param int|string $basis The type of day count:
+     *                                    0 or omitted US (NASD)    360
+     *                                    1                        Actual (365 or 366 in a leap year)
+     *                                    2                        360
+     *                                    3                        365
+     *                                    4                        European 360
+     *
+     * @return int|string Result, or a string containing an error
+     */
+    public static function daysPerYear($year, $basis = 0)
+    {
+        if (!is_numeric($basis)) {
+            return Functions::NAN();
+        }
+
+        switch ($basis) {
+            case self::DAYS_PER_YEAR_NASD:
+            case self::DAYS_PER_YEAR_360:
+            case self::DAYS_PER_YEAR_360_EUROPEAN:
+                return 360;
+            case self::DAYS_PER_YEAR_365:
+                return 365;
+            case self::DAYS_PER_YEAR_ACTUAL:
+                return (DateTimeExcel\Helpers::isLeapYear($year)) ? 366 : 365;
+        }
+
+        return Functions::NAN();
+    }
+
+    /**
+     * isLastDayOfMonth.
+     *
+     * Returns a boolean TRUE/FALSE indicating if this date is the last date of the month
+     *
+     * @param DateTimeInterface $date The date for testing
+     *
+     * @return bool
+     */
+    public static function isLastDayOfMonth(DateTimeInterface $date)
+    {
+        return $date->format('d') === $date->format('t');
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/InterestRate.php

@@ -0,0 +1,74 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class InterestRate
+{
+    use BaseValidations;
+
+    /**
+     * EFFECT.
+     *
+     * Returns the effective interest rate given the nominal rate and the number of
+     *        compounding payments per year.
+     *
+     * Excel Function:
+     *        EFFECT(nominal_rate,npery)
+     *
+     * @param mixed $nominalRate Nominal interest rate as a float
+     * @param mixed $periodsPerYear Integer number of compounding payments per year
+     *
+     * @return float|string
+     */
+    public static function effective($nominalRate = 0, $periodsPerYear = 0)
+    {
+        $nominalRate = Functions::flattenSingleValue($nominalRate);
+        $periodsPerYear = Functions::flattenSingleValue($periodsPerYear);
+
+        try {
+            $nominalRate = self::validateFloat($nominalRate);
+            $periodsPerYear = self::validateInt($periodsPerYear);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($nominalRate <= 0 || $periodsPerYear < 1) {
+            return Functions::NAN();
+        }
+
+        return ((1 + $nominalRate / $periodsPerYear) ** $periodsPerYear) - 1;
+    }
+
+    /**
+     * NOMINAL.
+     *
+     * Returns the nominal interest rate given the effective rate and the number of compounding payments per year.
+     *
+     * @param mixed $effectiveRate Effective interest rate as a float
+     * @param mixed $periodsPerYear Integer number of compounding payments per year
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function nominal($effectiveRate = 0, $periodsPerYear = 0)
+    {
+        $effectiveRate = Functions::flattenSingleValue($effectiveRate);
+        $periodsPerYear = Functions::flattenSingleValue($periodsPerYear);
+
+        try {
+            $effectiveRate = self::validateFloat($effectiveRate);
+            $periodsPerYear = self::validateInt($periodsPerYear);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        if ($effectiveRate <= 0 || $periodsPerYear < 1) {
+            return Functions::NAN();
+        }
+
+        // Calculate
+        return $periodsPerYear * (($effectiveRate + 1) ** (1 / $periodsPerYear) - 1);
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Securities/AccruedInterest.php

@@ -0,0 +1,141 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel\YearFrac;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class AccruedInterest
+{
+    use BaseValidations;
+
+    public const ACCRINT_CALCMODE_ISSUE_TO_SETTLEMENT = true;
+
+    public const ACCRINT_CALCMODE_FIRST_INTEREST_TO_SETTLEMENT = false;
+
+    /**
+     * ACCRINT.
+     *
+     * Returns the accrued interest for a security that pays periodic interest.
+     *
+     * Excel Function:
+     *        ACCRINT(issue,firstinterest,settlement,rate,par,frequency[,basis][,calc_method])
+     *
+     * @param mixed $issue the security's issue date
+     * @param mixed $firstinterest the security's first interest date
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue date
+     *                                  when the security is traded to the buyer.
+     * @param mixed $rate The security's annual coupon rate
+     * @param mixed $parValue The security's par value.
+     *                            If you omit par, ACCRINT uses $1,000.
+     * @param mixed $frequency The number of coupon payments per year.
+     *                             Valid frequency values are:
+     *                               1    Annual
+     *                               2    Semi-Annual
+     *                               4    Quarterly
+     * @param mixed $basis The type of day count to use.
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     * @param mixed $calcMethod
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function periodic(
+        $issue,
+        $firstinterest,
+        $settlement,
+        $rate,
+        $parValue = 1000,
+        $frequency = 1,
+        $basis = 0,
+        $calcMethod = self::ACCRINT_CALCMODE_ISSUE_TO_SETTLEMENT
+    ) {
+        $issue = Functions::flattenSingleValue($issue);
+        $firstinterest = Functions::flattenSingleValue($firstinterest);
+        $settlement = Functions::flattenSingleValue($settlement);
+        $rate = Functions::flattenSingleValue($rate);
+        $parValue = ($parValue === null) ? 1000 : Functions::flattenSingleValue($parValue);
+        $frequency = ($frequency === null) ? 1 : Functions::flattenSingleValue($frequency);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $issue = self::validateIssueDate($issue);
+            $settlement = self::validateSettlementDate($settlement);
+            self::validateSecurityPeriod($issue, $settlement);
+            $rate = self::validateRate($rate);
+            $parValue = self::validateParValue($parValue);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysBetweenIssueAndSettlement = YearFrac::funcYearFrac($issue, $settlement, $basis);
+        if (!is_numeric($daysBetweenIssueAndSettlement)) {
+            //    return date error
+            return $daysBetweenIssueAndSettlement;
+        }
+        $daysBetweenFirstInterestAndSettlement = YearFrac::funcYearFrac($firstinterest, $settlement, $basis);
+        if (!is_numeric($daysBetweenFirstInterestAndSettlement)) {
+            //    return date error
+            return $daysBetweenFirstInterestAndSettlement;
+        }
+
+        return $parValue * $rate * $daysBetweenIssueAndSettlement;
+    }
+
+    /**
+     * ACCRINTM.
+     *
+     * Returns the accrued interest for a security that pays interest at maturity.
+     *
+     * Excel Function:
+     *        ACCRINTM(issue,settlement,rate[,par[,basis]])
+     *
+     * @param mixed $issue The security's issue date
+     * @param mixed $settlement The security's settlement (or maturity) date
+     * @param mixed $rate The security's annual coupon rate
+     * @param mixed $parValue The security's par value.
+     *                            If you omit par, ACCRINT uses $1,000.
+     * @param mixed $basis The type of day count to use.
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function atMaturity($issue, $settlement, $rate, $parValue = 1000, $basis = 0)
+    {
+        $issue = Functions::flattenSingleValue($issue);
+        $settlement = Functions::flattenSingleValue($settlement);
+        $rate = Functions::flattenSingleValue($rate);
+        $parValue = ($parValue === null) ? 1000 : Functions::flattenSingleValue($parValue);
+        $basis = ($basis === null) ? 0 : Functions::flattenSingleValue($basis);
+
+        try {
+            $issue = self::validateIssueDate($issue);
+            $settlement = self::validateSettlementDate($settlement);
+            self::validateSecurityPeriod($issue, $settlement);
+            $rate = self::validateRate($rate);
+            $parValue = self::validateParValue($parValue);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysBetweenIssueAndSettlement = YearFrac::funcYearFrac($issue, $settlement, $basis);
+        if (!is_numeric($daysBetweenIssueAndSettlement)) {
+            //    return date error
+            return $daysBetweenIssueAndSettlement;
+        }
+
+        return $parValue * $rate * $daysBetweenIssueAndSettlement;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Securities/BaseValidations.php

@@ -0,0 +1,139 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities\Constants as SecuritiesConstants;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+trait BaseValidations
+{
+    protected static function validateDate($date)
+    {
+        return DateTimeExcel\Helpers::getDateValue($date);
+    }
+
+    protected static function validateFloat($value): float
+    {
+        if (!is_numeric($value)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        return (float) $value;
+    }
+
+    protected static function validateSettlementDate($settlement)
+    {
+        return self::validateDate($settlement);
+    }
+
+    protected static function validateMaturityDate($maturity)
+    {
+        return self::validateDate($maturity);
+    }
+
+    protected static function validateIssueDate($issue)
+    {
+        return self::validateDate($issue);
+    }
+
+    protected static function validateSecurityPeriod($settlement, $maturity): void
+    {
+        if ($settlement >= $maturity) {
+            throw new Exception(Functions::NAN());
+        }
+    }
+
+    protected static function validateRate($rate): float
+    {
+        $rate = self::validateFloat($rate);
+        if ($rate < 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $rate;
+    }
+
+    protected static function validateParValue($parValue): float
+    {
+        $parValue = self::validateFloat($parValue);
+        if ($parValue < 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $parValue;
+    }
+
+    protected static function validatePrice($price): float
+    {
+        $price = self::validateFloat($price);
+        if ($price < 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $price;
+    }
+
+    protected static function validateYield($yield): float
+    {
+        $yield = self::validateFloat($yield);
+        if ($yield < 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $yield;
+    }
+
+    protected static function validateRedemption($redemption): float
+    {
+        $redemption = self::validateFloat($redemption);
+        if ($redemption <= 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $redemption;
+    }
+
+    protected static function validateDiscount($discount): float
+    {
+        $discount = self::validateFloat($discount);
+        if ($discount <= 0.0) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $discount;
+    }
+
+    protected static function validateFrequency($frequency): int
+    {
+        if (!is_numeric($frequency)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        $frequency = (int) $frequency;
+        if (
+            ($frequency !== SecuritiesConstants::FREQUENCY_ANNUAL) &&
+            ($frequency !== SecuritiesConstants::FREQUENCY_SEMI_ANNUAL) &&
+            ($frequency !== SecuritiesConstants::FREQUENCY_QUARTERLY)
+        ) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $frequency;
+    }
+
+    protected static function validateBasis($basis): int
+    {
+        if (!is_numeric($basis)) {
+            throw new Exception(Functions::VALUE());
+        }
+
+        $basis = (int) $basis;
+        if (($basis < 0) || ($basis > 4)) {
+            throw new Exception(Functions::NAN());
+        }
+
+        return $basis;
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Securities/Constants.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities;
+
+class Constants
+{
+    public const FREQUENCY_ANNUAL = 1;
+    public const FREQUENCY_SEMI_ANNUAL = 2;
+    public const FREQUENCY_QUARTERLY = 4;
+}

src/PhpSpreadsheet/Calculation/Financial/Securities/Price.php

@@ -0,0 +1,201 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\Coupons;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\Helpers;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Price
+{
+    use BaseValidations;
+
+    /**
+     * PRICE.
+     *
+     * Returns the price per $100 face value of a security that pays periodic interest.
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue date when the security
+     *                              is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                                The maturity date is the date when the security expires.
+     * @param mixed $rate the security's annual coupon rate
+     * @param mixed $yield the security's annual yield
+     * @param mixed $redemption The number of coupon payments per year.
+     *                              For annual payments, frequency = 1;
+     *                              for semiannual, frequency = 2;
+     *                              for quarterly, frequency = 4.
+     * @param mixed $frequency
+     * @param mixed $basis The type of day count to use.
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function price($settlement, $maturity, $rate, $yield, $redemption, $frequency, $basis = 0)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $rate = Functions::flattenSingleValue($rate);
+        $yield = Functions::flattenSingleValue($yield);
+        $redemption = Functions::flattenSingleValue($redemption);
+        $frequency = Functions::flattenSingleValue($frequency);
+        $basis = Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateSecurityPeriod($settlement, $maturity);
+            $rate = self::validateRate($rate);
+            $yield = self::validateYield($yield);
+            $redemption = self::validateRedemption($redemption);
+            $frequency = self::validateFrequency($frequency);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $dsc = Coupons::COUPDAYSNC($settlement, $maturity, $frequency, $basis);
+        $e = Coupons::COUPDAYS($settlement, $maturity, $frequency, $basis);
+        $n = Coupons::COUPNUM($settlement, $maturity, $frequency, $basis);
+        $a = Coupons::COUPDAYBS($settlement, $maturity, $frequency, $basis);
+
+        $baseYF = 1.0 + ($yield / $frequency);
+        $rfp = 100 * ($rate / $frequency);
+        $de = $dsc / $e;
+
+        $result = $redemption / $baseYF ** (--$n + $de);
+        for ($k = 0; $k <= $n; ++$k) {
+            $result += $rfp / ($baseYF ** ($k + $de));
+        }
+        $result -= $rfp * ($a / $e);
+
+        return $result;
+    }
+
+    /**
+     * PRICEDISC.
+     *
+     * Returns the price per $100 face value of a discounted security.
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security settlement date is the date after the issue date when the security
+     *                              is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                                The maturity date is the date when the security expires.
+     * @param mixed $discount The security's discount rate
+     * @param mixed $redemption The security's redemption value per $100 face value
+     * @param mixed $basis The type of day count to use.
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function priceDiscounted($settlement, $maturity, $discount, $redemption, $basis = 0)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $discount = Functions::flattenSingleValue($discount);
+        $redemption = Functions::flattenSingleValue($redemption);
+        $basis = Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateSecurityPeriod($settlement, $maturity);
+            $discount = self::validateDiscount($discount);
+            $redemption = self::validateRedemption($redemption);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysBetweenSettlementAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($settlement, $maturity, $basis);
+        if (!is_numeric($daysBetweenSettlementAndMaturity)) {
+            //    return date error
+            return $daysBetweenSettlementAndMaturity;
+        }
+
+        return $redemption * (1 - $discount * $daysBetweenSettlementAndMaturity);
+    }
+
+    /**
+     * PRICEMAT.
+     *
+     * Returns the price per $100 face value of a security that pays interest at maturity.
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security's settlement date is the date after the issue date when the
+     *                              security is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                                The maturity date is the date when the security expires.
+     * @param mixed $issue The security's issue date
+     * @param mixed $rate The security's interest rate at date of issue
+     * @param mixed $yield The security's annual yield
+     * @param mixed $basis The type of day count to use.
+     *                         0 or omitted    US (NASD) 30/360
+     *                         1               Actual/actual
+     *                         2               Actual/360
+     *                         3               Actual/365
+     *                         4               European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function priceAtMaturity($settlement, $maturity, $issue, $rate, $yield, $basis = 0)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $issue = Functions::flattenSingleValue($issue);
+        $rate = Functions::flattenSingleValue($rate);
+        $yield = Functions::flattenSingleValue($yield);
+        $basis = Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateSecurityPeriod($settlement, $maturity);
+            $issue = self::validateIssueDate($issue);
+            $rate = self::validateRate($rate);
+            $yield = self::validateYield($yield);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+        if (!is_numeric($daysPerYear)) {
+            return $daysPerYear;
+        }
+        $daysBetweenIssueAndSettlement = DateTimeExcel\YearFrac::funcYearFrac($issue, $settlement, $basis);
+        if (!is_numeric($daysBetweenIssueAndSettlement)) {
+            //    return date error
+            return $daysBetweenIssueAndSettlement;
+        }
+        $daysBetweenIssueAndSettlement *= $daysPerYear;
+        $daysBetweenIssueAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($issue, $maturity, $basis);
+        if (!is_numeric($daysBetweenIssueAndMaturity)) {
+            //    return date error
+            return $daysBetweenIssueAndMaturity;
+        }
+        $daysBetweenIssueAndMaturity *= $daysPerYear;
+        $daysBetweenSettlementAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($settlement, $maturity, $basis);
+        if (!is_numeric($daysBetweenSettlementAndMaturity)) {
+            //    return date error
+            return $daysBetweenSettlementAndMaturity;
+        }
+        $daysBetweenSettlementAndMaturity *= $daysPerYear;
+
+        return (100 + (($daysBetweenIssueAndMaturity / $daysPerYear) * $rate * 100)) /
+            (1 + (($daysBetweenSettlementAndMaturity / $daysPerYear) * $yield)) -
+            (($daysBetweenIssueAndSettlement / $daysPerYear) * $rate * 100);
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/Securities/Yields.php

@@ -0,0 +1,138 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial\Securities;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Financial\Helpers;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Yields
+{
+    use BaseValidations;
+
+    /**
+     * YIELDDISC.
+     *
+     * Returns the annual yield of a security that pays interest at maturity.
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security's settlement date is the date after the issue date when the security
+     *                              is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param int $price The security's price per $100 face value
+     * @param int $redemption The security's redemption value per $100 face value
+     * @param int $basis The type of day count to use.
+     *                                        0 or omitted    US (NASD) 30/360
+     *                                        1                Actual/actual
+     *                                        2                Actual/360
+     *                                        3                Actual/365
+     *                                        4                European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function yieldDiscounted($settlement, $maturity, $price, $redemption, $basis = 0)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $price = Functions::flattenSingleValue($price);
+        $redemption = Functions::flattenSingleValue($redemption);
+        $basis = (int) Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateSecurityPeriod($settlement, $maturity);
+            $price = self::validatePrice($price);
+            $redemption = self::validateRedemption($redemption);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+        if (!is_numeric($daysPerYear)) {
+            return $daysPerYear;
+        }
+        $daysBetweenSettlementAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($settlement, $maturity, $basis);
+        if (!is_numeric($daysBetweenSettlementAndMaturity)) {
+            //    return date error
+            return $daysBetweenSettlementAndMaturity;
+        }
+        $daysBetweenSettlementAndMaturity *= $daysPerYear;
+
+        return (($redemption - $price) / $price) * ($daysPerYear / $daysBetweenSettlementAndMaturity);
+    }
+
+    /**
+     * YIELDMAT.
+     *
+     * Returns the annual yield of a security that pays interest at maturity.
+     *
+     * @param mixed $settlement The security's settlement date.
+     *                              The security's settlement date is the date after the issue date when the security
+     *                              is traded to the buyer.
+     * @param mixed $maturity The security's maturity date.
+     *                            The maturity date is the date when the security expires.
+     * @param mixed $issue The security's issue date
+     * @param int $rate The security's interest rate at date of issue
+     * @param int $price The security's price per $100 face value
+     * @param int $basis The type of day count to use.
+     *                                        0 or omitted    US (NASD) 30/360
+     *                                        1                Actual/actual
+     *                                        2                Actual/360
+     *                                        3                Actual/365
+     *                                        4                European 30/360
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function yieldAtMaturity($settlement, $maturity, $issue, $rate, $price, $basis = 0)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $issue = Functions::flattenSingleValue($issue);
+        $rate = Functions::flattenSingleValue($rate);
+        $price = Functions::flattenSingleValue($price);
+        $basis = Functions::flattenSingleValue($basis);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+            self::validateSecurityPeriod($settlement, $maturity);
+            $issue = self::validateIssueDate($issue);
+            $rate = self::validateRate($rate);
+            $price = self::validatePrice($price);
+            $basis = self::validateBasis($basis);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($settlement), $basis);
+        if (!is_numeric($daysPerYear)) {
+            return $daysPerYear;
+        }
+        $daysBetweenIssueAndSettlement = DateTimeExcel\YearFrac::funcYearFrac($issue, $settlement, $basis);
+        if (!is_numeric($daysBetweenIssueAndSettlement)) {
+            //    return date error
+            return $daysBetweenIssueAndSettlement;
+        }
+        $daysBetweenIssueAndSettlement *= $daysPerYear;
+        $daysBetweenIssueAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($issue, $maturity, $basis);
+        if (!is_numeric($daysBetweenIssueAndMaturity)) {
+            //    return date error
+            return $daysBetweenIssueAndMaturity;
+        }
+        $daysBetweenIssueAndMaturity *= $daysPerYear;
+        $daysBetweenSettlementAndMaturity = DateTimeExcel\YearFrac::funcYearFrac($settlement, $maturity, $basis);
+        if (!is_numeric($daysBetweenSettlementAndMaturity)) {
+            //    return date error
+            return $daysBetweenSettlementAndMaturity;
+        }
+        $daysBetweenSettlementAndMaturity *= $daysPerYear;
+
+        return ((1 + (($daysBetweenIssueAndMaturity / $daysPerYear) * $rate) - (($price / 100) + (($daysBetweenIssueAndSettlement / $daysPerYear) * $rate))) /
+                (($price / 100) + (($daysBetweenIssueAndSettlement / $daysPerYear) * $rate))) *
+            ($daysPerYear / $daysBetweenSettlementAndMaturity);
+    }
+}

src/PhpSpreadsheet/Calculation/Financial/TreasuryBill.php

@@ -0,0 +1,155 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class TreasuryBill
+{
+    use BaseValidations;
+
+    /**
+     * TBILLEQ.
+     *
+     * Returns the bond-equivalent yield for a Treasury bill.
+     *
+     * @param mixed $settlement The Treasury bill's settlement date.
+     *                                The Treasury bill's settlement date is the date after the issue date
+     *                                    when the Treasury bill is traded to the buyer.
+     * @param mixed $maturity The Treasury bill's maturity date.
+     *                                The maturity date is the date when the Treasury bill expires.
+     * @param mixed $discount The Treasury bill's discount rate
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function bondEquivalentYield($settlement, $maturity, $discount)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $discount = Functions::flattenSingleValue($discount);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        //    Validate
+        if (is_numeric($discount)) {
+            if ($discount <= 0) {
+                return Functions::NAN();
+            }
+
+            $daysBetweenSettlementAndMaturity = $maturity - $settlement;
+            $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($maturity), Helpers::DAYS_PER_YEAR_ACTUAL);
+
+            if ($daysBetweenSettlementAndMaturity > $daysPerYear || $daysBetweenSettlementAndMaturity < 0) {
+                return Functions::NAN();
+            }
+
+            return (365 * $discount) / (360 - $discount * $daysBetweenSettlementAndMaturity);
+        }
+
+        return Functions::VALUE();
+    }
+
+    /**
+     * TBILLPRICE.
+     *
+     * Returns the price per $100 face value for a Treasury bill.
+     *
+     * @param mixed $settlement The Treasury bill's settlement date.
+     *                                The Treasury bill's settlement date is the date after the issue date
+     *                                    when the Treasury bill is traded to the buyer.
+     * @param mixed $maturity The Treasury bill's maturity date.
+     *                                The maturity date is the date when the Treasury bill expires.
+     * @param mixed $discount The Treasury bill's discount rate
+     *
+     * @return float|string Result, or a string containing an error
+     */
+    public static function price($settlement, $maturity, $discount)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $discount = Functions::flattenSingleValue($discount);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        //    Validate
+        if (is_numeric($discount)) {
+            if ($discount <= 0) {
+                return Functions::NAN();
+            }
+
+            $daysBetweenSettlementAndMaturity = $maturity - $settlement;
+            $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($maturity), Helpers::DAYS_PER_YEAR_ACTUAL);
+
+            if ($daysBetweenSettlementAndMaturity > $daysPerYear || $daysBetweenSettlementAndMaturity < 0) {
+                return Functions::NAN();
+            }
+
+            $price = 100 * (1 - (($discount * $daysBetweenSettlementAndMaturity) / 360));
+            if ($price < 0.0) {
+                return Functions::NAN();
+            }
+
+            return $price;
+        }
+
+        return Functions::VALUE();
+    }
+
+    /**
+     * TBILLYIELD.
+     *
+     * Returns the yield for a Treasury bill.
+     *
+     * @param mixed $settlement The Treasury bill's settlement date.
+     *                                The Treasury bill's settlement date is the date after the issue date when
+     *                                    the Treasury bill is traded to the buyer.
+     * @param mixed $maturity The Treasury bill's maturity date.
+     *                                The maturity date is the date when the Treasury bill expires.
+     * @param mixed $price The Treasury bill's price per $100 face value
+     *
+     * @return float|string
+     */
+    public static function yield($settlement, $maturity, $price)
+    {
+        $settlement = Functions::flattenSingleValue($settlement);
+        $maturity = Functions::flattenSingleValue($maturity);
+        $price = Functions::flattenSingleValue($price);
+
+        try {
+            $settlement = self::validateSettlementDate($settlement);
+            $maturity = self::validateMaturityDate($maturity);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        //    Validate
+        if (is_numeric($price)) {
+            if ($price <= 0) {
+                return Functions::NAN();
+            }
+
+            $daysBetweenSettlementAndMaturity = $maturity - $settlement;
+            $daysPerYear = Helpers::daysPerYear(DateTimeExcel\Year::funcYear($maturity), Helpers::DAYS_PER_YEAR_ACTUAL);
+
+            if ($daysBetweenSettlementAndMaturity > $daysPerYear || $daysBetweenSettlementAndMaturity < 0) {
+                return Functions::NAN();
+            }
+
+            return ((100 - $price) / $price) * (360 / $daysBetweenSettlementAndMaturity);
+        }
+
+        return Functions::VALUE();
+    }
+}