/framework/vendor/zend/Zend/Pdf/Filter/RunLength.php

  1<?php
  2/**
  3 * Zend Framework
  4 *
  5 * LICENSE
  6 *
  7 * This source file is subject to the new BSD license that is bundled
  8 * with this package in the file LICENSE.txt.
  9 * It is also available through the world-wide-web at this URL:
 10 * http://framework.zend.com/license/new-bsd
 11 * If you did not receive a copy of the license and are unable to
 12 * obtain it through the world-wide-web, please send an email
 13 * to license@zend.com so we can send you a copy immediately.
 14 *
 15 * @category   Zend
 16 * @package    Zend_Pdf
 17 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
 18 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 19 */
 20
 21
 22/** Zend_Pdf_Filter_Interface */
 23require_once 'Zend/Pdf/Filter/Interface.php';
 24
 25/**
 26 * RunLength stream filter
 27 *
 28 * @package    Zend_Pdf
 29 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
 30 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 31 */
 32class Zend_Pdf_Filter_RunLength implements Zend_Pdf_Filter_Interface
 33{
 34    /**
 35     * Encode data
 36     *
 37     * @param string $data
 38     * @param array $params
 39     * @return string
 40     * @throws Zend_Pdf_Exception
 41     */
 42    public static function encode($data, $params = null)
 43    {
 44        $output = '';
 45
 46        $chainStartOffset = 0;
 47        $offset = 0;
 48
 49        while ($offset < strlen($data)) {
 50            // Do not encode 2 char chains since they produce 2 char run sequence,
 51            // but it takes more time to decode such output (because of processing additional run)
 52            if (($repeatedCharChainLength = strspn($data, $data[$offset], $offset + 1, 127) + 1)  >  2) {
 53                if ($chainStartOffset != $offset) {
 54                    // Drop down previouse (non-repeatable chars) run
 55                    $output .= chr($offset - $chainStartOffset - 1)
 56                             . substr($data, $chainStartOffset, $offset - $chainStartOffset);
 57                }
 58
 59                $output .= chr(257 - $repeatedCharChainLength) . $data[$offset];
 60
 61                $offset += $repeatedCharChainLength;
 62                $chainStartOffset = $offset;
 63            } else {
 64                $offset++;
 65
 66                if ($offset - $chainStartOffset == 128) {
 67                    // Maximum run length is reached
 68                    // Drop down non-repeatable chars run
 69                    $output .= "\x7F" . substr($data, $chainStartOffset, 128);
 70
 71                    $chainStartOffset = $offset;
 72                }
 73            }
 74        }
 75
 76        if ($chainStartOffset != $offset) {
 77            // Drop down non-repeatable chars run
 78            $output .= chr($offset - $chainStartOffset - 1) . substr($data, $chainStartOffset, $offset - $chainStartOffset);
 79        }
 80
 81        $output .= "\x80";
 82
 83        return $output;
 84    }
 85
 86    /**
 87     * Decode data
 88     *
 89     * @param string $data
 90     * @param array $params
 91     * @return string
 92     * @throws Zend_Pdf_Exception
 93     */
 94    public static function decode($data, $params = null)
 95    {
 96        $dataLength = strlen($data);
 97        $output = '';
 98        $offset = 0;
 99
100        while($offset < $dataLength) {
101            $length = ord($data[$offset]);
102
103            $offset++;
104
105            if ($length == 128) {
106                // EOD byte
107                break;
108            } else if ($length < 128) {
109                $length++;
110
111                $output .= substr($data, $offset, $length);
112
113                $offset += $length;
114            } else if ($length > 128) {
115                $output .= str_repeat($data[$offset], 257 - $length);
116
117                $offset++;
118            }
119        }
120
121        return $output;
122    }
123}
124