75 lines
1.9 KiB
PHP
75 lines
1.9 KiB
PHP
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<?php
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/**
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* Bitmask
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*
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* Analyzes and sets bitmasks
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*
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* @package Kirby Toolkit
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* @author Lukas Bestle <lukas@getkirby.com>
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* @link http://getkirby.com
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* @copyright Lukas Bestle
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* @license http://www.opensource.org/licenses/mit-license.php MIT License
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*/
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class Bitmask {
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/**
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* Checks if a value can be used as bitmask value (checks for a power of two)
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*
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* @param mixed $value The value to check for
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* @return boolean
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*/
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public static function validValue($value) {
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return is_int($value) && ($value & ($value - 1)) == 0;
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}
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/**
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* Checks if a bitmask includes a value
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*
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* @param int $value The value to check for
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* @param int $bitmask The bitmask to check in
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* @return boolean
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*/
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public static function includes($value, $bitmask) {
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if(!static::validValue($value)) return false;
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return ($bitmask & $value) !== 0;
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}
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/**
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* Adds a value to a bitmask
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*
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* @param int $value The value to add
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* @param int $bitmask The bitmask to add the value to
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* @return int
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*/
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public static function add($value, $bitmask) {
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if(!static::validValue($value)) {
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throw new Exception('The value "' . $value . '" is not appropriate for usage in bitmasks.');
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}
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// check if the bitmask already includes the value
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if(static::includes($value, $bitmask)) return $bitmask;
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return $bitmask | $value;
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}
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/**
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* Removes a value from a bitmask
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*
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* @param int $value The value to remove
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* @param int $bitmask The bitmask to remove the value from
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* @return int
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*/
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public static function remove($value, $bitmask) {
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if(!static::validValue($value)) {
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throw new Exception('The value "' . $value . '" is not appropriate for usage in bitmasks.');
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}
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// check if the bitmask even includes the value
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if(!static::includes($value, $bitmask)) return $bitmask;
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return $bitmask ^ $value;
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}
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}
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