Micro-optimization for excelToDateTimeObject

Fix #4438. Do some optimization if Excel value is an integer. This is unlikely to make much of a difference, but the use case seems pretty common (cell represents a date rather than date-time), so we may as well do it. There had been no tests for negative integer values, because Excel does not handle those well, but OpenOffice and Gnumeric handle them just fine, so add some tests for them.

Author: oleibman

src/PhpSpreadsheet/Shared/Date.php

@@ -214,6 +214,13 @@ public static function excelToDateTimeObject(float|int $excelTimestamp, null|Dat
             $baseDate = new DateTime('1899-12-30', $timeZone);
         }
 
+        if (is_int($excelTimestamp)) {
+            if ($excelTimestamp >= 0) {
+                return $baseDate->modify("+ $excelTimestamp days");
+            }
+
+            return $baseDate->modify("$excelTimestamp days");
+        }
         $days = floor($excelTimestamp);
         $partDay = $excelTimestamp - $days;
         $hms = 86400 * $partDay;

tests/PhpSpreadsheetTests/Style/NumberFormatTest.php

@@ -4,30 +4,36 @@
 
 namespace PhpOffice\PhpSpreadsheetTests\Style;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Style\NumberFormat;
 use PhpOffice\PhpSpreadsheet\Style\NumberFormat\NumberFormatter;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 
 class NumberFormatTest extends TestCase
 {
+    private string $compatibilityMode;
+
     protected function setUp(): void
     {
         StringHelper::setDecimalSeparator('.');
         StringHelper::setThousandsSeparator(',');
+        $this->compatibilityMode = Functions::getCompatibilityMode();
     }
 
     protected function tearDown(): void
     {
         StringHelper::setCurrencyCode(null);
         StringHelper::setDecimalSeparator(null);
         StringHelper::setThousandsSeparator(null);
+        Functions::setCompatibilityMode($this->compatibilityMode);
     }
 
     /**
      * @param null|bool|float|int|string $args string to be formatted
      */
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerNumberFormat')]
+    #[DataProvider('providerNumberFormat')]
     public function testFormatValueWithMask(mixed $expectedResult, mixed ...$args): void
     {
         $result = NumberFormat::toFormattedString(...$args);
@@ -42,7 +48,7 @@ public static function providerNumberFormat(): array
     /**
      * @param null|bool|float|int|string $args string to be formatted
      */
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerNumberFormatFractions')]
+    #[DataProvider('providerNumberFormatFractions')]
     public function testFormatValueWithMaskFraction(mixed $expectedResult, mixed ...$args): void
     {
         $result = NumberFormat::toFormattedString(...$args);
@@ -57,7 +63,7 @@ public static function providerNumberFormatFractions(): array
     /**
      * @param null|bool|float|int|string $args string to be formatted
      */
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerNumberFormatDates')]
+    #[DataProvider('providerNumberFormatDates')]
     public function testFormatValueWithMaskDate(mixed $expectedResult, mixed ...$args): void
     {
         $result = NumberFormat::toFormattedString(...$args);
@@ -69,6 +75,23 @@ public static function providerNumberFormatDates(): array
         return require 'tests/data/Style/NumberFormatDates.php';
     }
 
+    public function testDatesOpenOfficeGnumericNonPositive(): void
+    {
+        Functions::setCompatibilityMode(
+            Functions::COMPATIBILITY_OPENOFFICE
+        );
+        $fmt1 = 'yyyy-mm-dd';
+        $rslt = NumberFormat::toFormattedString(0, $fmt1);
+        self::assertSame('1899-12-30', $rslt);
+        $rslt = NumberFormat::toFormattedString(-2, $fmt1);
+        self::assertSame('1899-12-28', $rslt);
+        $rslt = NumberFormat::toFormattedString(-2.4, $fmt1);
+        self::assertSame('1899-12-27', $rslt);
+        $fmt2 = 'yyyy-mm-dd hh:mm:ss AM/PM';
+        $rslt = NumberFormat::toFormattedString(-2.4, $fmt2);
+        self::assertSame('1899-12-27 02:24:00 PM', $rslt);
+    }
+
     public function testCurrencyCode(): void
     {
         // "Currency symbol" replaces $ in some cases, not in others
@@ -83,7 +106,7 @@ public function testCurrencyCode(): void
         StringHelper::setCurrencyCode($cur);
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerNoScientific')]
+    #[DataProvider('providerNoScientific')]
     public function testNoScientific(string $expectedResult, string $numericString): void
     {
         $result = NumberFormatter::floatStringConvertScientific($numericString);