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