deal with integer limits

composer.json

@@ -16,12 +16,16 @@
     },
     "require-dev": {
         "kriswallsmith/buzz": "~0.15",
-        "phpunit/phpunit": "^4.5"
+        "phpunit/phpunit": "^4.5",
+        "ext-bcmath": "*",
+        "ext-gmp": "*"
     },
     "suggest": {
         "TheBigBrainsCompany/TbbcMoneyBundle": "Very complete Symfony2 bundle with support for Twig, Doctrine, Forms, ...",
         "pink-tie/money-bundle": "Pink-Tie's Symfony2 integration with Money library",
-        "Sylius/SyliusMoneyBundle": "Sylius' Symfony2 integration with Money library"
+        "Sylius/SyliusMoneyBundle": "Sylius' Symfony2 integration with Money library",
+        "ext-bcmath": "Calculate without integer limits",
+        "ext-gmp": "Calculate without integer limits"
     },
     "autoload": {
         "psr-4": {

src/Calculator.php

@@ -0,0 +1,95 @@
+<?php
+namespace Money;
+
+/**
+ * Interface Calculator
+ * @package Money
+ */
+interface Calculator
+{
+
+    /**
+     * @return bool
+     */
+    public static function supported();
+
+    /**
+     * Compare a to b
+     *
+     * @param int|string $a
+     * @param int|string $b
+     * @return int
+     */
+    public function compare($a, $b);
+
+    /**
+     * Add added to amount
+     *
+     * @param int|string $amount
+     * @param int|string $addend
+     * @return int|string
+     */
+    public function add($amount, $addend);
+
+    /**
+     * Subtract subtrahend from amount
+     * @param int|string $amount
+     * @param int|string $subtrahend
+     * @return int|string
+     */
+    public function subtract($amount, $subtrahend);
+
+    /**
+     * Multiply amount with multiplier
+     *
+     * @param int|string $amount
+     * @param int|float $multiplier
+     * @return int|string
+     */
+    public function multiply($amount, $multiplier);
+
+    /**
+     * Divide amount with divisor
+     *
+     * @param int|string $amount
+     * @param int|float $divisor
+     * @return int|string
+     */
+    public function divide($amount, $divisor);
+
+    /**
+     * Round number to following integer
+     *
+     * @param int|string|float $number
+     * @return int|string
+     */
+    public function ceil($number);
+
+    /**
+     * Round number to preceding integer
+     *
+     * @param int|string|float $number
+     * @return int|string
+     */
+    public function floor($number);
+
+    /**
+     * Round number, use rounding mode for tie-breaker
+     *
+     * @param int|string|float $number
+     * @param int|string $roundingMode
+     * @return int|string
+     */
+    public function round($number, $roundingMode);
+
+    /**
+     * Share amount among ratio / total portions
+     *
+     * @param int|string $amount
+     * @param int|float $ratio
+     * @param int|float $total
+     * @return int|string
+     */
+    public function share($amount, $ratio, $total);
+
+}

src/Calculator/BcMathCalculator.php

@@ -0,0 +1,195 @@
+<?php
+namespace Money\Calculator;
+
+use Money\Calculator;
+use Money\Money;
+use Money\Number;
+
+/**
+ * Class BcMathCalculator
+ * @package Money\Calculator
+ */
+final class BcMathCalculator implements Calculator
+{
+    /**
+     * @var string
+     */
+    private $scale;
+
+    /**
+     * @param int $scale
+     */
+    public function __construct($scale = 14)
+    {
+        $this->scale = $scale;
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @return bool
+     */
+    public static function supported()
+    {
+        return extension_loaded('bcmath');
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $a
+     * @param $b
+     * @return int
+     */
+    public function compare($a, $b)
+    {
+        return bccomp($a, $b);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $amount
+     * @param $addend
+     * @return string
+     */
+    public function add($amount, $addend)
+    {
+        return bcadd($amount, $addend);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $amount
+     * @param $subtrahend
+     * @return string
+     */
+    public function subtract($amount, $subtrahend)
+    {
+        return bcsub($amount, $subtrahend);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $amount
+     * @param $multiplier
+     * @return string
+     */
+    public function multiply($amount, $multiplier)
+    {
+        return bcmul($amount, $multiplier, $this->scale);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $amount
+     * @param $divisor
+     * @return string
+     */
+    public function divide($amount, $divisor)
+    {
+        return bcdiv($amount, $divisor, $this->scale);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $number
+     * @return string
+     */
+    public function ceil($number)
+    {
+        $decimalSeparatorPosition = strpos($number, '.');
+        if ($decimalSeparatorPosition === false) {
+            return $number;
+        }
+
+        return bcadd($number, '1', 0);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $number
+     * @return string
+     */
+    public function floor($number)
+    {
+        return bcadd($number, '0', 0);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $number
+     * @param $roundingMode
+     * @return string
+     */
+    public function round($number, $roundingMode)
+    {
+        $number = new Number($number);
+        if ($number->isDecimal() === false) {
+            return (string) $number;
+        }
+
+        if ($number->isHalf() === false) {
+            return $this->roundDigit($number);
+        }
+
+        if ($roundingMode === Money::ROUND_HALF_DOWN) {
+            return $this->floor((string) $number);
+        }
+
+        if ($roundingMode === Money::ROUND_HALF_UP) {
+            return $this->ceil((string) $number);
+        }
+
+        if ($roundingMode === Money::ROUND_HALF_EVEN) {
+            if ($number->isCurrentEven() === true) {
+                return $this->floor((string) $number);
+            } else {
+                return $this->ceil((string) $number);
+            }
+        }
+
+        if ($roundingMode === Money::ROUND_HALF_ODD) {
+            if ($number->isCurrentEven() === true) {
+                return $this->ceil((string) $number);
+            } else {
+                return $this->floor((string) $number);
+            }
+        }
+
+        throw new \InvalidArgumentException('Unknown rounding mode');
+    }
+
+    /**
+     * @param $number
+     * @return string
+     */
+    private function roundDigit(Number $number)
+    {
+        if ($number->isCloserToNext()) {
+            return $this->ceil((string) $number);
+        }
+
+        return $this->floor((string) $number);
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @param $amount
+     * @param $ratio
+     * @param $total
+     * @return string
+     */
+    public function share($amount, $ratio, $total)
+    {
+        return $this->floor(bcdiv(bcmul($amount, $ratio, $this->scale), $total, $this->scale));
+    }
+
+}