106 lines
2.6 KiB
PHP
106 lines
2.6 KiB
PHP
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<?php
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/**
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* This file is part of FPDI
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*
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* @package FPDI
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* @copyright Copyright (c) 2017 Setasign - Jan Slabon (https://www.setasign.com)
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* @license http://opensource.org/licenses/mit-license The MIT License
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* @version 1.6.2
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*/
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/**
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* Class FilterASCII85
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*/
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class FilterASCII85
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{
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/**
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* Decode ASCII85 encoded string
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*
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* @param string $in
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* @return string
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* @throws Exception
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*/
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public function decode($in)
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{
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$ord = array(
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'~' => ord('~'),
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'z' => ord('z'),
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'u' => ord('u'),
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'!' => ord('!')
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);
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$out = '';
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$state = 0;
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$chn = null;
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$l = strlen($in);
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for ($k = 0; $k < $l; ++$k) {
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$ch = ord($in[$k]) & 0xff;
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if ($ch == $ord['~']) {
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break;
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}
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if (preg_match('/^\s$/',chr($ch))) {
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continue;
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}
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if ($ch == $ord['z'] && $state == 0) {
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$out .= chr(0) . chr(0) . chr(0) . chr(0);
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continue;
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}
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if ($ch < $ord['!'] || $ch > $ord['u']) {
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throw new Exception('Illegal character in ASCII85Decode.');
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}
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$chn[$state++] = $ch - $ord['!'];
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if ($state == 5) {
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$state = 0;
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$r = 0;
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for ($j = 0; $j < 5; ++$j) {
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$r = (int)($r * 85 + $chn[$j]);
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}
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$out .= chr($r >> 24);
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$out .= chr($r >> 16);
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$out .= chr($r >> 8);
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$out .= chr($r);
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}
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}
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$r = 0;
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if ($state == 1) {
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throw new Exception('Illegal length in ASCII85Decode.');
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}
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if ($state == 2) {
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$r = $chn[0] * 85 * 85 * 85 * 85 + ($chn[1]+1) * 85 * 85 * 85;
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$out .= chr($r >> 24);
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} else if ($state == 3) {
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$r = $chn[0] * 85 * 85 * 85 * 85 + $chn[1] * 85 * 85 * 85 + ($chn[2]+1) * 85 * 85;
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$out .= chr($r >> 24);
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$out .= chr($r >> 16);
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} else if ($state == 4) {
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$r = $chn[0] * 85 * 85 * 85 * 85 + $chn[1] * 85 * 85 * 85 + $chn[2] * 85 * 85 + ($chn[3]+1) * 85 ;
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$out .= chr($r >> 24);
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$out .= chr($r >> 16);
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$out .= chr($r >> 8);
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}
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return $out;
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}
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/**
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* NOT IMPLEMENTED
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*
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* @param string $in
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* @return string
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* @throws LogicException
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*/
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public function encode($in)
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{
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throw new LogicException("ASCII85 encoding not implemented.");
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}
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}
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