feature [8.4][bcmath] implement bcround, bcceil and bcfloor

Dean151 · Dean151 · commit 2f043919f460 · 2025-10-16T21:55:30.000+02:00
diff --git a/README.md b/README.md
@@ -74,7 +74,7 @@ Polyfills are provided for:
 - the `ReflectionConstant` class introduced in PHP 8.4
 - the `CURL_HTTP_VERSION_3` and `CURL_HTTP_VERSION_3ONLY` constants introduced in PHP 8.4;
 - the `grapheme_str_split` function introduced in PHP 8.4;
-- the `bcdivmod` function introduced in PHP 8.4;
+- the `bcceil`, `bcdivmod`, `bcfloor` and `bcround` functions introduced in PHP 8.4;
 - the `get_error_handler` and `get_exception_handler` functions introduced in PHP 8.5;
 - the `NoDiscard` attribute introduced in PHP 8.5;
 - the `array_first` and `array_last` functions introduced in PHP 8.5;
diff --git a/src/Php84/Php84.php b/src/Php84/Php84.php
@@ -205,6 +205,14 @@ public static function grapheme_str_split(string $string, int $length)
         return $chunks;
     }
 
+    public static function bcceil(string $num): string
+    {
+        if (!is_numeric($num)) {
+            throw new \ValueError('bcceil(): Argument #1 ($num) is not well-formed');
+        }
+        return self::bcround($num, 0, \RoundingMode::PositiveInfinity);
+    }
+
     public static function bcdivmod(string $num1, string $num2, ?int $scale = null): ?array
     {
         if (null === $quot = \bcdiv($num1, $num2, 0)) {
@@ -214,4 +222,200 @@ public static function bcdivmod(string $num1, string $num2, ?int $scale = null):
 
         return [$quot, \bcmod($num1, $num2, $scale)];
     }
+
+    public static function bcfloor(string $num): string
+    {
+        if (!is_numeric($num)) {
+            throw new \ValueError('bcfloor(): Argument #1 ($num) is not well-formed');
+        }
+        return self::bcround($num, 0, \RoundingMode::NegativeInfinity);
+    }
+
+    /**
+     * @param \RoundingMode|\RoundingMode::* $mode
+     */
+    public static function bcround(string $num, int $precision = 0, $mode = \RoundingMode::HalfAwayFromZero): string
+    {
+        if (!is_numeric($num)) {
+            throw new \ValueError('bcround(): Argument #1 ($num) is not well-formed');
+        }
+
+        $sign = 1;
+        if ('' !== $num && ('-' === $num[0] || '+' === $num[0])) {
+            if ('-' === $num[0]) {
+                $sign = -1;
+            }
+
+            $num = substr($num, 1);
+        }
+
+        if (false !== strpos($num, '.')) {
+            [$intPart, $fracPart] = array_pad(explode('.', $num, 2), 2, '');
+        } else {
+            $intPart = $num;
+            $fracPart = '';
+        }
+
+        if ('' === $intPart) {
+            $intPart = '0';
+        }
+
+        $intPart = self::trimLeadingZeros($intPart);
+        $fracPart = (string) $fracPart;
+
+        if ($precision >= 0) {
+            $fracLength = \strlen($fracPart);
+
+            if ($precision <= $fracLength) {
+                $scaledInt = $intPart.(string) substr($fracPart, 0, $precision);
+                $scaledFrac = (string) substr($fracPart, $precision);
+            } else {
+                $scaledInt = $intPart.$fracPart.str_repeat('0', $precision - $fracLength);
+                $scaledFrac = '';
+            }
+        } else {
+            $shift = -$precision;
+            $intLength = \strlen($intPart);
+
+            if ($shift <= $intLength) {
+                $splitPos = $intLength - $shift;
+                $scaledInt = substr($intPart, 0, $splitPos);
+                $scaledInt = '' === $scaledInt ? '0' : $scaledInt;
+                $scaledFrac = substr($intPart, $splitPos).$fracPart;
+            } else {
+                $scaledInt = '0';
+                $scaledFrac = str_repeat('0', $shift - $intLength).$intPart.$fracPart;
+            }
+        }
+
+        $roundedInt = self::roundIntegerPart($scaledInt, $scaledFrac, $sign, $mode);
+        $isZero = '' === trim($roundedInt, '0');
+        $absResult = self::formatRoundedDigits($roundedInt, $precision);
+
+        if (-1 === $sign && !$isZero) {
+            $absResult = '-'.$absResult;
+        }
+
+        return $absResult;
+    }
+
+    private static function roundIntegerPart(string $intPart, string $fracPart, int $sign, $mode): string
+    {
+        $intPart = self::trimLeadingZeros($intPart);
+
+        if ('' === $fracPart || '' === trim($fracPart, '0')) {
+            return $intPart;
+        }
+
+        $firstDigit = $fracPart[0];
+        $tail = (string) substr($fracPart, 1);
+        $tailNonZero = '' !== trim($tail, '0');
+        $isGreaterThanHalf = $firstDigit > '5' || ('5' === $firstDigit && $tailNonZero);
+        $isExactlyHalf = '5' === $firstDigit && !$tailNonZero;
+        $shouldIncrease = false;
+
+        switch ($mode) {
+            case \RoundingMode::TowardsZero:
+                break;
+
+            case \RoundingMode::AwayFromZero:
+                $shouldIncrease = true;
+                break;
+
+            case \RoundingMode::PositiveInfinity:
+                $shouldIncrease = $sign > 0;
+                break;
+
+            case \RoundingMode::NegativeInfinity:
+                $shouldIncrease = $sign < 0;
+                break;
+
+            case \RoundingMode::HalfAwayFromZero:
+                $shouldIncrease = $isGreaterThanHalf || $isExactlyHalf;
+                break;
+
+            case \RoundingMode::HalfTowardsZero:
+                $shouldIncrease = $isGreaterThanHalf;
+                break;
+
+            case \RoundingMode::HalfEven:
+                if ($isGreaterThanHalf) {
+                    $shouldIncrease = true;
+                } elseif ($isExactlyHalf && self::lastDigit($intPart) % 2 === 1) {
+                    $shouldIncrease = true;
+                }
+                break;
+
+            case \RoundingMode::HalfOdd:
+                if ($isGreaterThanHalf) {
+                    $shouldIncrease = true;
+                } elseif ($isExactlyHalf && self::lastDigit($intPart) % 2 === 0) {
+                    $shouldIncrease = true;
+                }
+                break;
+        }
+
+        if ($shouldIncrease) {
+            $intPart = self::incrementDigits($intPart);
+        }
+
+        return self::trimLeadingZeros($intPart);
+    }
+
+    private static function formatRoundedDigits(string $roundedInt, int $precision): string
+    {
+        if ($precision > 0) {
+            if (\strlen($roundedInt) <= $precision) {
+                $roundedInt = str_pad($roundedInt, $precision + 1, '0', STR_PAD_LEFT);
+            }
+
+            $intDigits = substr($roundedInt, 0, -$precision);
+            $fracDigits = substr($roundedInt, -$precision);
+
+            $intDigits = self::trimLeadingZeros('' === $intDigits ? '0' : $intDigits);
+            $fracDigits = str_pad($fracDigits, $precision, '0', STR_PAD_LEFT);
+
+            return $intDigits.'.'.$fracDigits;
+        }
+
+        if (0 === $precision) {
+            return self::trimLeadingZeros($roundedInt);
+        }
+
+        $shift = -$precision;
+        $digits = $roundedInt.str_repeat('0', $shift);
+
+        return self::trimLeadingZeros($digits);
+    }
+
+    private static function incrementDigits(string $digits): string
+    {
+        $digits = '' === $digits ? '0' : $digits;
+        $index = \strlen($digits) - 1;
+        $result = $digits;
+        $carry = 1;
+
+        while ($index >= 0 && $carry) {
+            $value = ord($result[$index]) - 48 + $carry;
+            $carry = $value >= 10 ? 1 : 0;
+            $result[$index] = chr(48 + ($value % 10));
+            --$index;
+        }
+
+        return $carry ? '1'.$result : $result;
+    }
+
+    private static function trimLeadingZeros(string $digits): string
+    {
+        $digits = ltrim($digits, '0');
+
+        return '' === $digits ? '0' : $digits;
+    }
+
+    private static function lastDigit(string $digits): int
+    {
+        $length = \strlen($digits);
+
+        return $length ? ord($digits[$length - 1]) - 48 : 0;
+    }
 }
diff --git a/src/Php84/Resources/stubs/RoundingMode.php b/src/Php84/Resources/stubs/RoundingMode.php
@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+if (\PHP_VERSION_ID < 80100) {
+    // @author Thomas Durand <github@thomasdurand.fr>
+    final class RoundingMode {
+        const HalfAwayFromZero = 0; // Round to the nearest integer. If the decimal part is 5, round to the integer with the larger absolute value.
+        const HalfTowardsZero = 1; // Round to the nearest integer. If the decimal part is 5, round to the integer with the smaller absolute value.
+        const HalfEven = 2; // Round to the nearest integer. If the decimal part is 5, round to the even integer.
+        const HalfOdd = 3; // Round to the nearest integer. If the decimal part is 5, round to the odd integer.
+        const TowardsZero = 4; // Round to the nearest integer with a smaller or equal absolute value.
+        const AwayFromZero = 5; // Round to the nearest integer with a greater or equal absolute value.
+        const NegativeInfinity = 6; // Round to the largest integer that is smaller or equal.
+        const PositiveInfinity = 7; // Round to the smallest integer that is greater or equal.
+
+        private function __construct() {}
+
+        public static function cases(): array
+        {
+            return [
+                self::HalfAwayFromZero,
+                self::HalfTowardsZero,
+                self::HalfEven,
+                self::HalfOdd,
+                self::TowardsZero,
+                self::AwayFromZero,
+                self::NegativeInfinity,
+                self::PositiveInfinity,
+            ];
+        }
+    }
+} elseif (\PHP_VERSION_ID < 80400) {
+    enum RoundingMode {
+        case HalfAwayFromZero ; // Round to the nearest integer. If the decimal part is 5, round to the integer with the larger absolute value.
+        case HalfTowardsZero ; // Round to the nearest integer. If the decimal part is 5, round to the integer with the smaller absolute value.
+        case HalfEven ; // Round to the nearest integer. If the decimal part is 5, round to the even integer.
+        case HalfOdd ; // Round to the nearest integer. If the decimal part is 5, round to the odd integer.
+        case TowardsZero ; // Round to the nearest integer with a smaller or equal absolute value.
+        case AwayFromZero ; // Round to the nearest integer with a greater or equal absolute value.
+        case NegativeInfinity ; // Round to the largest integer that is smaller or equal.
+        case PositiveInfinity ; // Round to the smallest integer that is greater or equal.
+    }
+}
diff --git a/src/Php84/bootstrap.php b/src/Php84/bootstrap.php
@@ -68,9 +68,21 @@ function mb_rtrim(string $string, ?string $characters = null, ?string $encoding
 }
 
 if (extension_loaded('bcmath')) {
+    if (!function_exists('bcceil')) {
+        function bcceil(string $num): string { return p\Php84::bcceil($num); }
+    }
     if (!function_exists('bcdivmod')) {
         function bcdivmod(string $num1, string $num2, ?int $scale = null): ?array { return p\Php84::bcdivmod($num1, $num2, $scale); }
     }
+    if (!function_exists('bcfloor')) {
+        function bcfloor(string $num): string { return p\Php84::bcfloor($num); }
+    }
+    if (!function_exists('bcround')) {
+        /**
+         * @param \RoundingMode|\RoundingMode::* $mode
+         */
+        function bcround(string $num, int $precision = 0, $mode = RoundingMode::HalfAwayFromZero): string { return p\Php84::bcround($num, $precision, $mode); }
+    }
 }
 
 if (\PHP_VERSION_ID >= 80200) {
diff --git a/tests/Php84/Php84Test.php b/tests/Php84/Php84Test.php
