Current File : /home/graphicd/public_html/vebto/vendor/google/crc32/src/PHPSlicedBy4.php
<?php
/**
* Copyright 2019 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace Google\CRC32;
use Google\CRC32\CRCInterface;
use Google\CRC32\CRCTrait;
use Google\CRC32\Table;
/**
* PHP implementation of the CRC32 sliced-by-4 algorithm.
*
* This is typically faster, but the PHP implementation seems slower than the
* simple implementation.
*/
final class PHPSlicedBy4 implements CRCInterface
{
use CRCTrait;
public static function supports($algo)
{
return true;
}
private $table;
public function __construct($polynomial)
{
$this->polynomial = $polynomial;
$this->table = Table::create4($polynomial);
$this->reset();
}
public function reset()
{
$this->crc = ~0;
}
public function update($data)
{
$crc = $this->crc;
$table0 = $this->table[0];
$table1 = $this->table[1];
$table2 = $this->table[2];
$table3 = $this->table[3];
$len = strlen($data);
$remain = ($len % 4);
$len1 = $len - $remain;
for ($i = 0; $i < $len1; $i += 4) {
$b = (ord($data[$i+3])<<24) |
(ord($data[$i+2])<<16) |
(ord($data[$i+1])<<8) |
(ord($data[$i]));
$crc = ($crc ^ $b) & 0xffffffff;
$crc = $table3[ $crc & 0xff] ^
$table2[($crc>>8) & 0xff] ^
$table1[($crc>>16) & 0xff] ^
$table0[($crc>>24) & 0xff];
}
switch ($remain) {
case 3:
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i])) & 0xff];
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i+1])) & 0xff];
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i+2])) & 0xff];
break;
case 2:
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i])) & 0xff];
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i+1])) & 0xff];
break;
case 1:
$crc = (($crc >> 8) & 0xffffff) ^ $table0[($crc ^ ord($data[$i])) & 0xff];
break;
case 0:
}
$this->crc = $crc;
}
public function hash($raw_output = null)
{
return $this->crcHash(~$this->crc, $raw_output === true);
}
public function version()
{
return 'crc32(' . $this->int2hex($this->polynomial) . ') software version';
}
}
Mini Shell