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<?php |
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///////////////////////////////////////////////////////////////// |
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/// getID3() by James Heinrich <[email protected]> // |
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// available at https://github.com/JamesHeinrich/getID3 // |
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// or https://www.getid3.org // |
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// or http://getid3.sourceforge.net // |
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// see readme.txt for more details // |
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///////////////////////////////////////////////////////////////// |
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// // |
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// module.misc.pdf.php // |
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// module for analyzing PDF files // |
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// dependencies: NONE // |
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// /// |
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///////////////////////////////////////////////////////////////// |
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if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers |
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exit; |
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} |
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class getid3_pdf extends getid3_handler |
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{ |
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public $returnXREF = false; // return full details of PDF Cross-Reference Table (XREF) |
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/** |
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* @return bool |
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*/ |
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public function Analyze() { |
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$info = &$this->getid3->info; |
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$this->fseek(0); |
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if (preg_match('#^%PDF-([0-9\\.]+)$#', rtrim($this->fgets()), $matches)) { |
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$info['pdf']['header']['version'] = floatval($matches[1]); |
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$info['fileformat'] = 'pdf'; |
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// the PDF Cross-Reference Table (XREF) is located near the end of the file |
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// the starting offset is specified in the penultimate section, on the two lines just before "%%EOF" |
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// the first line is "startxref", the second line is the byte offset of the XREF. |
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// We know the length of "%%EOF" and "startxref", but the offset could be 2-10 bytes, |
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// and we're not sure if the line ends are one or two bytes, so we might find "startxref" as little as 18(?) bytes |
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// from EOF, but it could 30 bytes, so we start 40 bytes back just to be safe and do a search for the data we want. |
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$this->fseek(-40, SEEK_END); |
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if (preg_match('#[\r\n]startxref[ \r\n]+([0-9]+)[ \r\n]+#', $this->fread(40), $matches)) { |
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$info['pdf']['trailer']['startxref'] = intval($matches[1]); |
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$this->parseXREF($info['pdf']['trailer']['startxref']); |
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if (!empty($info['pdf']['xref']['offset'])) { |
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while (!$this->feof() && (max(array_keys($info['pdf']['xref']['offset'])) > $info['pdf']['xref']['count'])) { |
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// suspect that there may be another XREF entry somewhere in the file, brute-force scan for it |
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/* |
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// starting at last known entry of main XREF table |
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$this->fseek(max($info['pdf']['xref']['offset'])); |
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*/ |
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// starting at the beginning of the file |
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$this->fseek(0); |
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while (!$this->feof()) { |
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$XREFoffset = $this->ftell(); |
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if (rtrim($this->fgets()) == 'xref') { |
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if (empty($info['pdf']['xref']['xref_offsets']) || !in_array($XREFoffset, $info['pdf']['xref']['xref_offsets'])) { |
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$this->parseXREF($XREFoffset); |
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break; |
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} |
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} |
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} |
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} |
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foreach ($info['pdf']['xref']['offset'] as $objectNumber => $offset) { |
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if ($info['pdf']['xref']['entry'][$objectNumber] == 'f') { |
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// "free" object means "deleted", ignore |
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continue; |
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} |
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$this->fseek($offset); |
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$line = rtrim($this->fgets()); |
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if (preg_match('#^'.$objectNumber.' ([0-9]+) obj#', $line, $matches)) { |
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if (strlen($line) > strlen($matches[0])) { |
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// object header line not actually on its own line, rewind file pointer to start reading data |
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$this->fseek($offset + strlen($matches[0])); |
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} |
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$objectData = ''; |
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while (true) { |
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$line = $this->fgets(); |
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if (rtrim($line) == 'endobj') { |
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break; |
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} |
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$objectData .= $line; |
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} |
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if (preg_match('#^<<[\r\n\s]*(/Type|/Pages|/Parent [0-9]+ [0-9]+ [A-Z]|/Count [0-9]+|/Kids *\\[[0-9A-Z ]+\\]|[\r\n\s])+[\r\n\s]*>>#', $objectData, $matches)) { |
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if (preg_match('#/Count ([0-9]+)#', $objectData, $matches)) { |
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$info['pdf']['pages'] = (int) $matches[1]; |
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break; // for now this is the only data we're looking for in the PDF not need to loop through every object in the file (and a large PDF may contain MANY objects). And it MAY be possible that there are other objects elsewhere in the file that define additional (or removed?) pages |
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} |
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} |
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} else { |
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$this->error('Unexpected structure "'.$line.'" at offset '.$offset); |
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break; |
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} |
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} |
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if (!$this->returnXREF) { |
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unset($info['pdf']['xref']['offset'], $info['pdf']['xref']['generation'], $info['pdf']['xref']['entry']); |
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} |
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} else { |
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$this->error('Did not find "xref" at offset '.$info['pdf']['trailer']['startxref']); |
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} |
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} else { |
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$this->error('Did not find "startxref" in the last 40 bytes of the PDF'); |
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} |
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$this->warning('PDF parsing incomplete in this version of getID3() ['.$this->getid3->version().']'); |
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return true; |
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} |
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$this->error('Did not find "%PDF" at the beginning of the PDF'); |
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return false; |
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} |
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/** |
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* @return bool |
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*/ |
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private function parseXREF($XREFoffset) { |
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$info = &$this->getid3->info; |
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$this->fseek($XREFoffset); |
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if (rtrim($this->fgets()) == 'xref') { |
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$info['pdf']['xref']['xref_offsets'][$XREFoffset] = $XREFoffset; |
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list($firstObjectNumber, $XREFcount) = explode(' ', rtrim($this->fgets())); |
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$XREFcount = (int) $XREFcount; |
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$info['pdf']['xref']['count'] = $XREFcount + (!empty($info['pdf']['xref']['count']) ? $info['pdf']['xref']['count'] : 0); |
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for ($i = 0; $i < $XREFcount; $i++) { |
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$line = rtrim($this->fgets()); |
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if (preg_match('#^([0-9]+) ([0-9]+) ([nf])$#', $line, $matches)) { |
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$info['pdf']['xref']['offset'][($firstObjectNumber + $i)] = (int) $matches[1]; |
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$info['pdf']['xref']['generation'][($firstObjectNumber + $i)] = (int) $matches[2]; |
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$info['pdf']['xref']['entry'][($firstObjectNumber + $i)] = $matches[3]; |
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} else { |
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$this->error('failed to parse XREF entry #'.$i.' in XREF table at offset '.$XREFoffset); |
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return false; |
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} |
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} |
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sort($info['pdf']['xref']['xref_offsets']); |
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return true; |
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} |
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$this->warning('failed to find expected XREF structure at offset '.$XREFoffset); |
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return false; |
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} |
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} |
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owncloud /
music
