BaconQrCode
| BitUtils | General bit utilities. |
<?php
/**
* BaconQrCode
*
* @link http://github.com/Bacon/BaconQrCode For the canonical source repository
* @copyright 2013 Ben 'DASPRiD' Scholzen
* @license http://opensource.org/licenses/BSD-2-Clause Simplified BSD License
*/
namespace BaconQrCode\Common;
/**
* General bit utilities.
*
* All utility methods are based on 32-bit integers and also work on 64-bit
* systems.
*/
class BitUtils
{
/**
* Performs an unsigned right shift.
*
* This is the same as the unsigned right shift operator ">>>" in other
* languages.
*
* @param integer $a
* @param integer $b
* @return integer
*/
public static function unsignedRightShift($a, $b)
{
return (
$a >= 0
? $a >> $b
: (($a & 0x7fffffff) >> $b) | (0x40000000 >> ($b - 1))
);
}
/**
* Gets the number of trailing zeros.
*
* @param integer $i
* @return integer
*/
public static function numberOfTrailingZeros($i)
{
$lastPos = strrpos(str_pad(decbin($i), 32, '0', STR_PAD_LEFT), '1');
return $lastPos === false ? 32 : 31 - $lastPos;
}
}