108 lines
2.7 KiB
PHP
108 lines
2.7 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\Translation;
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/**
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* Tests if a given number belongs to a given math interval.
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*
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* An interval can represent a finite set of numbers:
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*
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* {1,2,3,4}
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*
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* An interval can represent numbers between two numbers:
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*
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* [1, +Inf]
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* ]-1,2[
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*
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* The left delimiter can be [ (inclusive) or ] (exclusive).
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* The right delimiter can be [ (exclusive) or ] (inclusive).
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* Beside numbers, you can use -Inf and +Inf for the infinite.
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*
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* @author Fabien Potencier <fabien@symfony.com>
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*
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* @see http://en.wikipedia.org/wiki/Interval_%28mathematics%29#The_ISO_notation
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*/
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class Interval
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{
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/**
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* Tests if the given number is in the math interval.
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*
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* @param int $number A number
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* @param string $interval An interval
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*
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* @return bool
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*
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* @throws \InvalidArgumentException
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*/
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public static function test($number, $interval)
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{
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$interval = trim($interval);
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if (!preg_match('/^'.self::getIntervalRegexp().'$/x', $interval, $matches)) {
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throw new \InvalidArgumentException(sprintf('"%s" is not a valid interval.', $interval));
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}
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if ($matches[1]) {
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foreach (explode(',', $matches[2]) as $n) {
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if ($number == $n) {
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return true;
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}
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}
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} else {
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$leftNumber = self::convertNumber($matches['left']);
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$rightNumber = self::convertNumber($matches['right']);
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return
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('[' === $matches['left_delimiter'] ? $number >= $leftNumber : $number > $leftNumber)
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&& (']' === $matches['right_delimiter'] ? $number <= $rightNumber : $number < $rightNumber)
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;
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}
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return false;
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}
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/**
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* Returns a Regexp that matches valid intervals.
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*
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* @return string A Regexp (without the delimiters)
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*/
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public static function getIntervalRegexp()
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{
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return <<<EOF
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({\s*
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(\-?\d+(\.\d+)?[\s*,\s*\-?\d+(\.\d+)?]*)
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\s*})
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(?P<left_delimiter>[\[\]])
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\s*
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(?P<left>-Inf|\-?\d+(\.\d+)?)
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\s*,\s*
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(?P<right>\+?Inf|\-?\d+(\.\d+)?)
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\s*
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(?P<right_delimiter>[\[\]])
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EOF;
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}
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private static function convertNumber($number)
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{
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if ('-Inf' === $number) {
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return log(0);
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} elseif ('+Inf' === $number || 'Inf' === $number) {
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return -log(0);
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}
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return (float) $number;
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}
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}
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