PhpCalculator.php
198 lines
| 1 | <?php |
| 2 | |
| 3 | namespace Money\Calculator; |
| 4 | |
| 5 | use Money\Calculator; |
| 6 | use Money\Money; |
| 7 | use Money\Number; |
| 8 | |
| 9 | /** |
| 10 | * @author Frederik Bosch <f.bosch@genkgo.nl> |
| 11 | */ |
| 12 | final class PhpCalculator implements Calculator |
| 13 | { |
| 14 | /** |
| 15 | * {@inheritdoc} |
| 16 | */ |
| 17 | public static function supported() |
| 18 | { |
| 19 | return true; |
| 20 | } |
| 21 | |
| 22 | /** |
| 23 | * {@inheritdoc} |
| 24 | */ |
| 25 | public function compare($a, $b) |
| 26 | { |
| 27 | return ($a < $b) ? -1 : (($a > $b) ? 1 : 0); |
| 28 | } |
| 29 | |
| 30 | /** |
| 31 | * {@inheritdoc} |
| 32 | */ |
| 33 | public function add($amount, $addend) |
| 34 | { |
| 35 | $result = $amount + $addend; |
| 36 | |
| 37 | $this->assertInteger($result); |
| 38 | |
| 39 | return (string) $result; |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * {@inheritdoc} |
| 44 | */ |
| 45 | public function subtract($amount, $subtrahend) |
| 46 | { |
| 47 | $result = $amount - $subtrahend; |
| 48 | |
| 49 | $this->assertInteger($result); |
| 50 | |
| 51 | return (string) $result; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * {@inheritdoc} |
| 56 | */ |
| 57 | public function multiply($amount, $multiplier) |
| 58 | { |
| 59 | $result = $amount * $multiplier; |
| 60 | |
| 61 | $this->assertIntegerBounds($result); |
| 62 | |
| 63 | return (string) Number::fromNumber($result); |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * {@inheritdoc} |
| 68 | */ |
| 69 | public function divide($amount, $divisor) |
| 70 | { |
| 71 | $result = $amount / $divisor; |
| 72 | |
| 73 | $this->assertIntegerBounds($result); |
| 74 | |
| 75 | return (string) Number::fromNumber($result); |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * {@inheritdoc} |
| 80 | */ |
| 81 | public function ceil($number) |
| 82 | { |
| 83 | return $this->castInteger(ceil($number)); |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * {@inheritdoc} |
| 88 | */ |
| 89 | public function floor($number) |
| 90 | { |
| 91 | return $this->castInteger(floor($number)); |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * {@inheritdoc} |
| 96 | */ |
| 97 | public function absolute($number) |
| 98 | { |
| 99 | $result = ltrim($number, '-'); |
| 100 | |
| 101 | $this->assertIntegerBounds($result); |
| 102 | |
| 103 | return (string) $result; |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * {@inheritdoc} |
| 108 | */ |
| 109 | public function round($number, $roundingMode) |
| 110 | { |
| 111 | if (Money::ROUND_HALF_POSITIVE_INFINITY === $roundingMode) { |
| 112 | $number = Number::fromNumber($number); |
| 113 | |
| 114 | if ($number->isHalf()) { |
| 115 | return $this->castInteger(ceil((string) $number)); |
| 116 | } |
| 117 | |
| 118 | return $this->castInteger(round((string) $number, 0, Money::ROUND_HALF_UP)); |
| 119 | } |
| 120 | |
| 121 | if (Money::ROUND_HALF_NEGATIVE_INFINITY === $roundingMode) { |
| 122 | $number = Number::fromNumber($number); |
| 123 | |
| 124 | if ($number->isHalf()) { |
| 125 | return $this->castInteger(floor((string) $number)); |
| 126 | } |
| 127 | |
| 128 | return $this->castInteger(round((string) $number, 0, Money::ROUND_HALF_DOWN)); |
| 129 | } |
| 130 | |
| 131 | return $this->castInteger(round($number, 0, $roundingMode)); |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * {@inheritdoc} |
| 136 | */ |
| 137 | public function share($amount, $ratio, $total) |
| 138 | { |
| 139 | return $this->castInteger(floor($amount * $ratio / $total)); |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * {@inheritdoc} |
| 144 | */ |
| 145 | public function mod($amount, $divisor) |
| 146 | { |
| 147 | $result = $amount % $divisor; |
| 148 | |
| 149 | $this->assertIntegerBounds($result); |
| 150 | |
| 151 | return (string) $result; |
| 152 | } |
| 153 | |
| 154 | /** |
| 155 | * Asserts that an integer value didn't become something else |
| 156 | * (after some arithmetic operation). |
| 157 | * |
| 158 | * @param int $amount |
| 159 | * |
| 160 | * @throws \OverflowException If integer overflow occured |
| 161 | * @throws \UnderflowException If integer underflow occured |
| 162 | */ |
| 163 | private function assertIntegerBounds($amount) |
| 164 | { |
| 165 | if ($amount > PHP_INT_MAX) { |
| 166 | throw new \OverflowException('You overflowed the maximum allowed integer (PHP_INT_MAX)'); |
| 167 | } elseif ($amount < ~PHP_INT_MAX) { |
| 168 | throw new \UnderflowException('You underflowed the minimum allowed integer (PHP_INT_MAX)'); |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Casts an amount to integer ensuring that an overflow/underflow did not occur. |
| 174 | * |
| 175 | * @param int $amount |
| 176 | * |
| 177 | * @return string |
| 178 | */ |
| 179 | private function castInteger($amount) |
| 180 | { |
| 181 | $this->assertIntegerBounds($amount); |
| 182 | |
| 183 | return (string) intval($amount); |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Asserts that integer remains integer after arithmetic operations. |
| 188 | * |
| 189 | * @param int $amount |
| 190 | */ |
| 191 | private function assertInteger($amount) |
| 192 | { |
| 193 | if (filter_var($amount, FILTER_VALIDATE_INT) === false) { |
| 194 | throw new \UnexpectedValueException('The result of arithmetic operation is not an integer'); |
| 195 | } |
| 196 | } |
| 197 | } |
| 198 |