1<?php 2 3///////////////////////////////////////////////////////////////// 4/// getID3() by James Heinrich <info@getid3.org> // 5// available at https://github.com/JamesHeinrich/getID3 // 6// or https://www.getid3.org // 7// or http://getid3.sourceforge.net // 8// see readme.txt for more details // 9///////////////////////////////////////////////////////////////// 10// // 11// module.graphic.gif.php // 12// module for analyzing GIF Image files // 13// dependencies: NONE // 14// /// 15///////////////////////////////////////////////////////////////// 16 17/** 18 * @link https://www.w3.org/Graphics/GIF/spec-gif89a.txt 19 * @link http://www.matthewflickinger.com/lab/whatsinagif/bits_and_bytes.asp 20 */ 21 22if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers 23 exit; 24} 25 26class getid3_gif extends getid3_handler 27{ 28 /** 29 * @return bool 30 */ 31 public function Analyze() { 32 $info = &$this->getid3->info; 33 34 $info['fileformat'] = 'gif'; 35 $info['video']['dataformat'] = 'gif'; 36 $info['video']['lossless'] = true; 37 $info['video']['pixel_aspect_ratio'] = (float) 1; 38 39 $this->fseek($info['avdataoffset']); 40 $GIFheader = $this->fread(13); 41 $offset = 0; 42 43 $info['gif']['header']['raw']['identifier'] = substr($GIFheader, $offset, 3); 44 $offset += 3; 45 46 $magic = 'GIF'; 47 if ($info['gif']['header']['raw']['identifier'] != $magic) { 48 $this->error('Expecting "'.getid3_lib::PrintHexBytes($magic).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($info['gif']['header']['raw']['identifier']).'"'); 49 unset($info['fileformat']); 50 unset($info['gif']); 51 return false; 52 } 53 54 //if (!$this->getid3->option_extra_info) { 55 // $this->warning('GIF Extensions and Global Color Table not returned due to !getid3->option_extra_info'); 56 //} 57 58 $info['gif']['header']['raw']['version'] = substr($GIFheader, $offset, 3); 59 $offset += 3; 60 $info['gif']['header']['raw']['width'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 2)); 61 $offset += 2; 62 $info['gif']['header']['raw']['height'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 2)); 63 $offset += 2; 64 $info['gif']['header']['raw']['flags'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1)); 65 $offset += 1; 66 $info['gif']['header']['raw']['bg_color_index'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1)); 67 $offset += 1; 68 $info['gif']['header']['raw']['aspect_ratio'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1)); 69 $offset += 1; 70 71 $info['video']['resolution_x'] = $info['gif']['header']['raw']['width']; 72 $info['video']['resolution_y'] = $info['gif']['header']['raw']['height']; 73 $info['gif']['version'] = $info['gif']['header']['raw']['version']; 74 $info['gif']['header']['flags']['global_color_table'] = (bool) ($info['gif']['header']['raw']['flags'] & 0x80); 75 if ($info['gif']['header']['raw']['flags'] & 0x80) { 76 // Number of bits per primary color available to the original image, minus 1 77 $info['gif']['header']['bits_per_pixel'] = 3 * ((($info['gif']['header']['raw']['flags'] & 0x70) >> 4) + 1); 78 } else { 79 $info['gif']['header']['bits_per_pixel'] = 0; 80 } 81 $info['gif']['header']['flags']['global_color_sorted'] = (bool) ($info['gif']['header']['raw']['flags'] & 0x40); 82 if ($info['gif']['header']['flags']['global_color_table']) { 83 // the number of bytes contained in the Global Color Table. To determine that 84 // actual size of the color table, raise 2 to [the value of the field + 1] 85 $info['gif']['header']['global_color_size'] = pow(2, ($info['gif']['header']['raw']['flags'] & 0x07) + 1); 86 $info['video']['bits_per_sample'] = ($info['gif']['header']['raw']['flags'] & 0x07) + 1; 87 } else { 88 $info['gif']['header']['global_color_size'] = 0; 89 } 90 if ($info['gif']['header']['raw']['aspect_ratio'] != 0) { 91 // Aspect Ratio = (Pixel Aspect Ratio + 15) / 64 92 $info['gif']['header']['aspect_ratio'] = ($info['gif']['header']['raw']['aspect_ratio'] + 15) / 64; 93 } 94 95 if ($info['gif']['header']['flags']['global_color_table']) { 96 $GIFcolorTable = $this->fread(3 * $info['gif']['header']['global_color_size']); 97 if ($this->getid3->option_extra_info) { 98 $offset = 0; 99 for ($i = 0; $i < $info['gif']['header']['global_color_size']; $i++) { 100 $red = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1)); 101 $green = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1)); 102 $blue = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1)); 103 $info['gif']['global_color_table'][$i] = (($red << 16) | ($green << 8) | ($blue)); 104 $info['gif']['global_color_table_rgb'][$i] = sprintf('%02X%02X%02X', $red, $green, $blue); 105 } 106 } 107 } 108 109 // Image Descriptor 110 $info['gif']['animation']['animated'] = false; 111 while (!feof($this->getid3->fp)) { 112 $NextBlockTest = $this->fread(1); 113 switch ($NextBlockTest) { 114 115/* 116 case ',': // ',' - Image separator character 117 $ImageDescriptorData = $NextBlockTest.$this->fread(9); 118 $ImageDescriptor = array(); 119 $ImageDescriptor['image_left'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 1, 2)); 120 $ImageDescriptor['image_top'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 3, 2)); 121 $ImageDescriptor['image_width'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 5, 2)); 122 $ImageDescriptor['image_height'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 7, 2)); 123 $ImageDescriptor['flags_raw'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 9, 1)); 124 $ImageDescriptor['flags']['use_local_color_map'] = (bool) ($ImageDescriptor['flags_raw'] & 0x80); 125 $ImageDescriptor['flags']['image_interlaced'] = (bool) ($ImageDescriptor['flags_raw'] & 0x40); 126 $info['gif']['image_descriptor'][] = $ImageDescriptor; 127 128 if ($ImageDescriptor['flags']['use_local_color_map']) { 129 130 $this->warning('This version of getID3() cannot parse local color maps for GIFs'); 131 return true; 132 133 } 134 $RasterData = array(); 135 $RasterData['code_size'] = getid3_lib::LittleEndian2Int($this->fread(1)); 136 $RasterData['block_byte_count'] = getid3_lib::LittleEndian2Int($this->fread(1)); 137 $info['gif']['raster_data'][count($info['gif']['image_descriptor']) - 1] = $RasterData; 138 139 $CurrentCodeSize = $RasterData['code_size'] + 1; 140 for ($i = 0; $i < pow(2, $RasterData['code_size']); $i++) { 141 $DefaultDataLookupTable[$i] = chr($i); 142 } 143 $DefaultDataLookupTable[pow(2, $RasterData['code_size']) + 0] = ''; // Clear Code 144 $DefaultDataLookupTable[pow(2, $RasterData['code_size']) + 1] = ''; // End Of Image Code 145 146 $NextValue = $this->GetLSBits($CurrentCodeSize); 147 echo 'Clear Code: '.$NextValue.'<BR>'; 148 149 $NextValue = $this->GetLSBits($CurrentCodeSize); 150 echo 'First Color: '.$NextValue.'<BR>'; 151 152 $Prefix = $NextValue; 153 $i = 0; 154 while ($i++ < 20) { 155 $NextValue = $this->GetLSBits($CurrentCodeSize); 156 echo $NextValue.'<br>'; 157 } 158 echo 'escaping<br>'; 159 return true; 160 break; 161*/ 162 163 case '!': 164 // GIF Extension Block 165 $ExtensionBlockData = $NextBlockTest.$this->fread(2); 166 $ExtensionBlock = array(); 167 $ExtensionBlock['function_code'] = getid3_lib::LittleEndian2Int(substr($ExtensionBlockData, 1, 1)); 168 $ExtensionBlock['byte_length'] = getid3_lib::LittleEndian2Int(substr($ExtensionBlockData, 2, 1)); 169 $ExtensionBlock['data'] = (($ExtensionBlock['byte_length'] > 0) ? $this->fread($ExtensionBlock['byte_length']) : null); 170 171 if (substr($ExtensionBlock['data'], 0, 11) == 'NETSCAPE2.0') { // Netscape Application Block (NAB) 172 $ExtensionBlock['data'] .= $this->fread(4); 173 if (substr($ExtensionBlock['data'], 11, 2) == "\x03\x01") { 174 $info['gif']['animation']['animated'] = true; 175 $info['gif']['animation']['loop_count'] = getid3_lib::LittleEndian2Int(substr($ExtensionBlock['data'], 13, 2)); 176 } else { 177 $this->warning('Expecting 03 01 at offset '.($this->ftell() - 4).', found "'.getid3_lib::PrintHexBytes(substr($ExtensionBlock['data'], 11, 2)).'"'); 178 } 179 } 180 181 if ($this->getid3->option_extra_info) { 182 $info['gif']['extension_blocks'][] = $ExtensionBlock; 183 } 184 break; 185 186 case ';': 187 $info['gif']['terminator_offset'] = $this->ftell() - 1; 188 // GIF Terminator 189 break; 190 191 default: 192 break; 193 194 195 } 196 } 197 198 return true; 199 } 200 201 /** 202 * @param int $bits 203 * 204 * @return float|int 205 */ 206 public function GetLSBits($bits) { 207 static $bitbuffer = ''; 208 while (strlen($bitbuffer) < $bits) { 209 $bitbuffer = str_pad(decbin(ord($this->fread(1))), 8, '0', STR_PAD_LEFT).$bitbuffer; 210 } 211 $value = bindec(substr($bitbuffer, 0 - $bits)); 212 $bitbuffer = substr($bitbuffer, 0, 0 - $bits); 213 214 return $value; 215 } 216 217} 218