# tablepress/3.4/libraries/vendor/PhpSpreadsheet/Calculation/DateTimeExcel/Difference.php

TablePress – Tables in WordPress made easy, version 3.4. 156 lines.

- Page: https://pluginprobe.com/plugins/tablepress/3.4/code/libraries/vendor/PhpSpreadsheet/Calculation/DateTimeExcel/Difference.php
- Raw: https://pluginprobe.com/plugins/tablepress/3.4/raw/libraries/vendor/PhpSpreadsheet/Calculation/DateTimeExcel/Difference.php
- Modified: 2026-09-30T03:50:46+00:00

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```php
<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;

use DateInterval;
use DateTime;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Exception;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
use TablePress\PhpOffice\PhpSpreadsheet\Shared\Date as SharedDateHelper;

class Difference
{
	use ArrayEnabled;

	/**
	 * DATEDIF.
	 *
	 * @param mixed $startDate Excel date serial value, PHP date/time stamp, PHP DateTime object
	 *                                    or a standard date string
	 *                         Or can be an array of date values
	 * @param mixed $endDate Excel date serial value, PHP date/time stamp, PHP DateTime object
	 *                                    or a standard date string
	 *                         Or can be an array of date values
	 * @param array<mixed>|string $unit Or can be an array of unit values
	 *
	 * @return array<mixed>|int|string Interval between the dates
	 *         If an array of values is passed for the $startDate or $endDays,arguments, then the returned result
	 *            will also be an array with matching dimensions
	 */
	public static function interval($startDate, $endDate, $unit = 'D')
	{
		if (is_array($startDate) || is_array($endDate) || is_array($unit)) {
			return self::evaluateArrayArguments([self::class, __FUNCTION__], $startDate, $endDate, $unit);
		}

		try {
			$startDate = Helpers::getDateValue($startDate);
			$endDate = Helpers::getDateValue($endDate);
			$difference = self::initialDiff($startDate, $endDate);
			$unit = strtoupper($unit);
		} catch (Exception $e) {
			return $e->getMessage();
		}

		// Execute function
		$PHPStartDateObject = SharedDateHelper::excelToDateTimeObject($startDate);
		$startDays = (int) $PHPStartDateObject->format('j');
		//$startMonths = (int) $PHPStartDateObject->format('n');
		$startYears = (int) $PHPStartDateObject->format('Y');

		$PHPEndDateObject = SharedDateHelper::excelToDateTimeObject($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) ? ExcelError::VALUE() : $retVal;
	}

	private static function initialDiff(float $startDate, float $endDate): float
	{
		// Validate parameters
		if ($startDate > $endDate) {
			throw new Exception(ExcelError::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 = (int) $PHPEndDateObject->diff($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');
	}
}

```