root / drupal7 / sites / all / libraries / simplepie / library / SimplePie / gzdecode.php @ 41cc1b08
1 | 41cc1b08 | Assos Assos | <?php
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2 | /**
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3 | * SimplePie
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4 | *
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5 | * A PHP-Based RSS and Atom Feed Framework.
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6 | * Takes the hard work out of managing a complete RSS/Atom solution.
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7 | *
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8 | * Copyright (c) 2004-2012, Ryan Parman, Geoffrey Sneddon, Ryan McCue, and contributors
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9 | * All rights reserved.
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10 | *
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11 | * Redistribution and use in source and binary forms, with or without modification, are
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12 | * permitted provided that the following conditions are met:
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13 | *
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14 | * * Redistributions of source code must retain the above copyright notice, this list of
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15 | * conditions and the following disclaimer.
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16 | *
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17 | * * Redistributions in binary form must reproduce the above copyright notice, this list
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18 | * of conditions and the following disclaimer in the documentation and/or other materials
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19 | * provided with the distribution.
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20 | *
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21 | * * Neither the name of the SimplePie Team nor the names of its contributors may be used
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22 | * to endorse or promote products derived from this software without specific prior
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23 | * written permission.
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24 | *
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25 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
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26 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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27 | * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
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28 | * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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29 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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30 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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31 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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32 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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33 | * POSSIBILITY OF SUCH DAMAGE.
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34 | *
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35 | * @package SimplePie
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36 | * @version 1.3.1
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37 | * @copyright 2004-2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue
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38 | * @author Ryan Parman
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39 | * @author Geoffrey Sneddon
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40 | * @author Ryan McCue
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41 | * @link http://simplepie.org/ SimplePie
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42 | * @license http://www.opensource.org/licenses/bsd-license.php BSD License
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43 | */
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44 | |||
45 | |||
46 | /**
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47 | * Decode 'gzip' encoded HTTP data
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48 | *
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49 | * @package SimplePie
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50 | * @subpackage HTTP
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51 | * @link http://www.gzip.org/format.txt
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52 | */
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53 | class SimplePie_gzdecode |
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54 | { |
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55 | /**
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56 | * Compressed data
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57 | *
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58 | * @access private
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59 | * @var string
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60 | * @see gzdecode::$data
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61 | */
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62 | var $compressed_data; |
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63 | |||
64 | /**
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65 | * Size of compressed data
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66 | *
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67 | * @access private
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68 | * @var int
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69 | */
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70 | var $compressed_size; |
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71 | |||
72 | /**
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73 | * Minimum size of a valid gzip string
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74 | *
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75 | * @access private
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76 | * @var int
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77 | */
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78 | var $min_compressed_size = 18; |
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79 | |||
80 | /**
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81 | * Current position of pointer
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82 | *
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83 | * @access private
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84 | * @var int
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85 | */
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86 | var $position = 0; |
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87 | |||
88 | /**
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89 | * Flags (FLG)
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90 | *
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91 | * @access private
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92 | * @var int
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93 | */
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94 | var $flags; |
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95 | |||
96 | /**
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97 | * Uncompressed data
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98 | *
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99 | * @access public
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100 | * @see gzdecode::$compressed_data
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101 | * @var string
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102 | */
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103 | var $data; |
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104 | |||
105 | /**
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106 | * Modified time
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107 | *
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108 | * @access public
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109 | * @var int
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110 | */
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111 | var $MTIME; |
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112 | |||
113 | /**
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114 | * Extra Flags
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115 | *
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116 | * @access public
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117 | * @var int
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118 | */
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119 | var $XFL; |
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120 | |||
121 | /**
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122 | * Operating System
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123 | *
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124 | * @access public
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125 | * @var int
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126 | */
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127 | var $OS; |
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128 | |||
129 | /**
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130 | * Subfield ID 1
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131 | *
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132 | * @access public
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133 | * @see gzdecode::$extra_field
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134 | * @see gzdecode::$SI2
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135 | * @var string
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136 | */
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137 | var $SI1; |
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138 | |||
139 | /**
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140 | * Subfield ID 2
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141 | *
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142 | * @access public
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143 | * @see gzdecode::$extra_field
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144 | * @see gzdecode::$SI1
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145 | * @var string
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146 | */
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147 | var $SI2; |
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148 | |||
149 | /**
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150 | * Extra field content
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151 | *
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152 | * @access public
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153 | * @see gzdecode::$SI1
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154 | * @see gzdecode::$SI2
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155 | * @var string
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156 | */
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157 | var $extra_field; |
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158 | |||
159 | /**
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160 | * Original filename
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161 | *
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162 | * @access public
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163 | * @var string
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164 | */
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165 | var $filename; |
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166 | |||
167 | /**
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168 | * Human readable comment
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169 | *
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170 | * @access public
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171 | * @var string
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172 | */
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173 | var $comment; |
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174 | |||
175 | /**
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176 | * Don't allow anything to be set
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177 | *
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178 | * @param string $name
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179 | * @param mixed $value
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180 | */
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181 | public function __set($name, $value) |
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182 | { |
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183 | trigger_error("Cannot write property $name", E_USER_ERROR); |
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184 | } |
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185 | |||
186 | /**
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187 | * Set the compressed string and related properties
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188 | *
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189 | * @param string $data
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190 | */
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191 | public function __construct($data) |
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192 | { |
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193 | $this->compressed_data = $data; |
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194 | $this->compressed_size = strlen($data); |
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195 | } |
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196 | |||
197 | /**
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198 | * Decode the GZIP stream
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199 | *
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200 | * @return bool Successfulness
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201 | */
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202 | public function parse() |
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203 | { |
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204 | if ($this->compressed_size >= $this->min_compressed_size) |
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205 | { |
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206 | // Check ID1, ID2, and CM
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207 | if (substr($this->compressed_data, 0, 3) !== "\x1F\x8B\x08") |
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208 | { |
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209 | return false; |
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210 | } |
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211 | |||
212 | // Get the FLG (FLaGs)
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213 | $this->flags = ord($this->compressed_data[3]); |
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214 | |||
215 | // FLG bits above (1 << 4) are reserved
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216 | if ($this->flags > 0x1F) |
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217 | { |
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218 | return false; |
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219 | } |
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220 | |||
221 | // Advance the pointer after the above
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222 | $this->position += 4; |
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223 | |||
224 | // MTIME
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225 | $mtime = substr($this->compressed_data, $this->position, 4); |
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226 | // Reverse the string if we're on a big-endian arch because l is the only signed long and is machine endianness
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227 | if (current(unpack('S', "\x00\x01")) === 1) |
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228 | { |
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229 | $mtime = strrev($mtime); |
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230 | } |
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231 | $this->MTIME = current(unpack('l', $mtime)); |
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232 | $this->position += 4; |
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233 | |||
234 | // Get the XFL (eXtra FLags)
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235 | $this->XFL = ord($this->compressed_data[$this->position++]); |
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236 | |||
237 | // Get the OS (Operating System)
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238 | $this->OS = ord($this->compressed_data[$this->position++]); |
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239 | |||
240 | // Parse the FEXTRA
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241 | if ($this->flags & 4) |
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242 | { |
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243 | // Read subfield IDs
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244 | $this->SI1 = $this->compressed_data[$this->position++]; |
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245 | $this->SI2 = $this->compressed_data[$this->position++]; |
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246 | |||
247 | // SI2 set to zero is reserved for future use
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248 | if ($this->SI2 === "\x00") |
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249 | { |
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250 | return false; |
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251 | } |
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252 | |||
253 | // Get the length of the extra field
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254 | $len = current(unpack('v', substr($this->compressed_data, $this->position, 2))); |
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255 | $this->position += 2; |
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256 | |||
257 | // Check the length of the string is still valid
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258 | $this->min_compressed_size += $len + 4; |
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259 | if ($this->compressed_size >= $this->min_compressed_size) |
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260 | { |
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261 | // Set the extra field to the given data
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262 | $this->extra_field = substr($this->compressed_data, $this->position, $len); |
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263 | $this->position += $len; |
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264 | } |
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265 | else
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266 | { |
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267 | return false; |
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268 | } |
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269 | } |
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270 | |||
271 | // Parse the FNAME
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272 | if ($this->flags & 8) |
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273 | { |
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274 | // Get the length of the filename
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275 | $len = strcspn($this->compressed_data, "\x00", $this->position); |
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276 | |||
277 | // Check the length of the string is still valid
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278 | $this->min_compressed_size += $len + 1; |
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279 | if ($this->compressed_size >= $this->min_compressed_size) |
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280 | { |
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281 | // Set the original filename to the given string
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282 | $this->filename = substr($this->compressed_data, $this->position, $len); |
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283 | $this->position += $len + 1; |
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284 | } |
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285 | else
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286 | { |
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287 | return false; |
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288 | } |
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289 | } |
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290 | |||
291 | // Parse the FCOMMENT
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292 | if ($this->flags & 16) |
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293 | { |
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294 | // Get the length of the comment
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295 | $len = strcspn($this->compressed_data, "\x00", $this->position); |
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296 | |||
297 | // Check the length of the string is still valid
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298 | $this->min_compressed_size += $len + 1; |
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299 | if ($this->compressed_size >= $this->min_compressed_size) |
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300 | { |
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301 | // Set the original comment to the given string
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302 | $this->comment = substr($this->compressed_data, $this->position, $len); |
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303 | $this->position += $len + 1; |
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304 | } |
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305 | else
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306 | { |
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307 | return false; |
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308 | } |
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309 | } |
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310 | |||
311 | // Parse the FHCRC
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312 | if ($this->flags & 2) |
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313 | { |
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314 | // Check the length of the string is still valid
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315 | $this->min_compressed_size += $len + 2; |
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316 | if ($this->compressed_size >= $this->min_compressed_size) |
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317 | { |
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318 | // Read the CRC
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319 | $crc = current(unpack('v', substr($this->compressed_data, $this->position, 2))); |
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320 | |||
321 | // Check the CRC matches
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322 | if ((crc32(substr($this->compressed_data, 0, $this->position)) & 0xFFFF) === $crc) |
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323 | { |
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324 | $this->position += 2; |
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325 | } |
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326 | else
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327 | { |
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328 | return false; |
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329 | } |
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330 | } |
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331 | else
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332 | { |
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333 | return false; |
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334 | } |
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335 | } |
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336 | |||
337 | // Decompress the actual data
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338 | if (($this->data = gzinflate(substr($this->compressed_data, $this->position, -8))) === false) |
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339 | { |
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340 | return false; |
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341 | } |
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342 | else
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343 | { |
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344 | $this->position = $this->compressed_size - 8; |
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345 | } |
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346 | |||
347 | // Check CRC of data
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348 | $crc = current(unpack('V', substr($this->compressed_data, $this->position, 4))); |
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349 | $this->position += 4; |
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350 | /*if (extension_loaded('hash') && sprintf('%u', current(unpack('V', hash('crc32b', $this->data)))) !== sprintf('%u', $crc))
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351 | {
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352 | return false;
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353 | }*/
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354 | |||
355 | // Check ISIZE of data
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356 | $isize = current(unpack('V', substr($this->compressed_data, $this->position, 4))); |
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357 | $this->position += 4; |
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358 | if (sprintf('%u', strlen($this->data) & 0xFFFFFFFF) !== sprintf('%u', $isize)) |
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359 | { |
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360 | return false; |
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361 | } |
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362 | |||
363 | // Wow, against all odds, we've actually got a valid gzip string
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364 | return true; |
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365 | } |
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366 | else
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367 | { |
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368 | return false; |
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369 | } |
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370 | } |
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371 | } |