. // // See LICENSE.TXT file for more information. // ------------------------------------------------------------------- // // Description : This is a PHP class for parsing PDF documents. // //============================================================+ /** * @file * This is a PHP class for parsing PDF documents.
* @package com.tecnick.tcpdf * @author Nicola Asuni * @version 1.0.000 */ // include class for decoding filters require_once(dirname(__FILE__).'/tcpdf_filters.php'); /** * @class TCPDF_PARSER * This is a PHP class for parsing PDF documents.
* @package com.tecnick.tcpdf * @brief This is a PHP class for parsing PDF documents.. * @version 1.0.000 * @author Nicola Asuni - info@tecnick.com */ class TCPDF_PARSER { /** * Raw content of the PDF document. * @private */ private $pdfdata = ''; /** * XREF data. * @protected */ protected $xref = array(); /** * Array of PDF objects. * @protected */ protected $objects = array(); /** * Class object for decoding filters. * @private */ private $FilterDecoders; // ----------------------------------------------------------------------------- /** * Parse a PDF document an return an array of objects. * @param $data (string) PDF data to parse. * @public * @since 1.0.000 (2011-05-24) */ public function __construct($data) { if (empty($data)) { $this->Error('Empty PDF data.'); } $this->pdfdata = $data; // get length $pdflen = strlen($this->pdfdata); // initialize class for decoding filters $this->FilterDecoders = new TCPDF_FILTERS(); // get xref and trailer data $this->xref = $this->getXrefData(); // parse all document objects $this->objects = array(); foreach ($this->xref['xref'] as $obj => $offset) { if (!isset($this->objects[$obj])) { $this->objects[$obj] = $this->getIndirectObject($obj, $offset, true); } } // release some memory unset($this->pdfdata); $this->pdfdata = ''; } /** * Return an array of parsed PDF document objects. * @return (array) Array of parsed PDF document objects. * @public * @since 1.0.000 (2011-06-26) */ public function getParsedData() { return array($this->xref, $this->objects); } /** * Get xref (cross-reference table) and trailer data from PDF document data. * @param $offset (int) xref offset (if know). * @param $xref (array) previous xref array (if any). * @return Array containing xref and trailer data. * @protected * @since 1.0.000 (2011-05-24) */ protected function getXrefData($offset=0, $xref=array()) { // find last startxref if (preg_match_all('/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i', $this->pdfdata, $matches, PREG_SET_ORDER, $offset) == 0) { $this->Error('Unable to find startxref'); } $matches = array_pop($matches); $startxref = $matches[1]; // check xref position if (strpos($this->pdfdata, 'xref', $startxref) != $startxref) { $this->Error('Unable to find xref'); } // extract xref data (object indexes and offsets) $offset = $startxref + 5; // initialize object number $obj_num = 0; while (preg_match('/^([0-9]+)[\s]([0-9]+)[\s]?([nf]?)/im', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { $offset = (strlen($matches[0][0]) + $matches[0][1]); if ($matches[3][0] == 'n') { // create unique object index: [object number]_[generation number] $index = $obj_num.'_'.intval($matches[2][0]); // check if object already exist if (!isset($xref['xref'][$index])) { // store object offset position $xref['xref'][$index] = intval($matches[1][0]); } ++$obj_num; $offset += 2; } elseif ($matches[3][0] == 'f') { ++$obj_num; $offset += 2; } else { // object number (index) $obj_num = intval($matches[1][0]); } } // get trailer data if (preg_match('/trailer[\s]*<<(.*)>>[\s]*[\r\n]+startxref[\s]*[\r\n]+/isU', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { $trailer_data = $matches[1][0]; if (!isset($xref['trailer'])) { // get only the last updated version $xref['trailer'] = array(); // parse trailer_data if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) { $xref['trailer']['size'] = intval($matches[1]); } if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { $xref['trailer']['root'] = intval($matches[1]).'_'.intval($matches[2]); } if (preg_match('/Encrypt[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { $xref['trailer']['encrypt'] = intval($matches[1]).'_'.intval($matches[2]); } if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { $xref['trailer']['info'] = intval($matches[1]).'_'.intval($matches[2]); } if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) { $xref['trailer']['id'] = array(); $xref['trailer']['id'][0] = $matches[1]; $xref['trailer']['id'][1] = $matches[2]; } } if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) { // get previous xref $xref = getXrefData(substr($this->pdfdata, 0, $startxref), intval($matches[1]), $xref); } } else { $this->Error('Unable to find trailer'); } return $xref; } /** * Get object type, raw value and offset to next object * @param $offset (int) Object offset. * @return array containing object type, raw value and offset to next object * @protected * @since 1.0.000 (2011-06-20) */ protected function getRawObject($offset=0) { $objtype = ''; // object type to be returned $objval = ''; // object value to be returned // skip initial white space chars: \x00 null (NUL), \x09 horizontal tab (HT), \x0A line feed (LF), \x0C form feed (FF), \x0D carriage return (CR), \x20 space (SP) $offset += strspn($this->pdfdata, "\x00\x09\x0a\x0c\x0d\x20", $offset); // get first char $char = $this->pdfdata{$offset}; // get object type switch ($char) { case '%': { // \x25 PERCENT SIGN // skip comment and search for next token $next = strcspn($this->pdfdata, "\r\n", $offset); if ($next > 0) { $offset += $next; return $this->getRawObject($this->pdfdata, $offset); } break; } case '/': { // \x2F SOLIDUS // name object $objtype = $char; ++$offset; if (preg_match('/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/', substr($this->pdfdata, $offset, 256), $matches) == 1) { $objval = $matches[1]; // unescaped value $offset += strlen($objval); } break; } case '(': // \x28 LEFT PARENTHESIS case ')': { // \x29 RIGHT PARENTHESIS // literal string object $objtype = $char; ++$offset; $strpos = $offset; if ($char == '(') { $open_bracket = 1; while ($open_bracket > 0) { if (!isset($this->pdfdata{$strpos})) { break; } $ch = $this->pdfdata{$strpos}; switch ($ch) { case '\\': { // REVERSE SOLIDUS (5Ch) (Backslash) // skip next character ++$strpos; break; } case '(': { // LEFT PARENHESIS (28h) ++$open_bracket; break; } case ')': { // RIGHT PARENTHESIS (29h) --$open_bracket; break; } } ++$strpos; } $objval = substr($this->pdfdata, $offset, ($strpos - $offset - 1)); $offset = $strpos; } break; } case '[': // \x5B LEFT SQUARE BRACKET case ']': { // \x5D RIGHT SQUARE BRACKET // array object $objtype = $char; ++$offset; if ($char == '[') { // get array content $objval = array(); do { // get element $element = $this->getRawObject($offset); $offset = $element[2]; $objval[] = $element; } while ($element[0] != ']'); // remove closing delimiter array_pop($objval); } break; } case '<': // \x3C LESS-THAN SIGN case '>': { // \x3E GREATER-THAN SIGN if (isset($this->pdfdata{($offset + 1)}) AND ($this->pdfdata{($offset + 1)} == $char)) { // dictionary object $objtype = $char.$char; $offset += 2; if ($char == '<') { // get array content $objval = array(); do { // get element $element = $this->getRawObject($offset); $offset = $element[2]; $objval[] = $element; } while ($element[0] != '>>'); // remove closing delimiter array_pop($objval); } } else { // hexadecimal string object $objtype = $char; ++$offset; if (($char == '<') AND (preg_match('/^([0-9A-Fa-f]+)[>]/iU', substr($this->pdfdata, $offset), $matches) == 1)) { $objval = $matches[1]; $offset += strlen($matches[0]); } } break; } default: { if (substr($this->pdfdata, $offset, 6) == 'endobj') { // indirect object $objtype = 'endobj'; $offset += 6; } elseif (substr($this->pdfdata, $offset, 4) == 'null') { // null object $objtype = 'null'; $offset += 4; $objval = 'null'; } elseif (substr($this->pdfdata, $offset, 4) == 'true') { // boolean true object $objtype = 'boolean'; $offset += 4; $objval = 'true'; } elseif (substr($this->pdfdata, $offset, 5) == 'false') { // boolean false object $objtype = 'boolean'; $offset += 5; $objval = 'false'; } elseif (substr($this->pdfdata, $offset, 6) == 'stream') { // start stream object $objtype = 'stream'; $offset += 6; if (preg_match('/^[\r\n]+(.*)[\r\n]*endstream/isU', substr($this->pdfdata, $offset), $matches) == 1) { $objval = $matches[1]; $offset += strlen($matches[0]); } } elseif (substr($this->pdfdata, $offset, 9) == 'endstream') { // end stream object $objtype = 'endstream'; $offset += 9; } elseif (preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($this->pdfdata, $offset, 33), $matches) == 1) { // indirect object reference $objtype = 'ojbref'; $offset += strlen($matches[0]); $objval = intval($matches[1]).'_'.intval($matches[2]); } elseif (preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($this->pdfdata, $offset, 33), $matches) == 1) { // object start $objtype = 'ojb'; $objval = intval($matches[1]).'_'.intval($matches[2]); $offset += strlen ($matches[0]); } elseif (($numlen = strspn($this->pdfdata, '+-.0123456789', $offset)) > 0) { // numeric object $objtype = 'numeric'; $objval = substr($this->pdfdata, $offset, $numlen); $offset += $numlen; } break; } } return array($objtype, $objval, $offset); } /** * Get content of indirect object. * @param $obj_ref (string) Object number and generation number separated by underscore character. * @param $offset (int) Object offset. * @param $decoding (boolean) If true decode streams. * @return array containing object data. * @protected * @since 1.0.000 (2011-05-24) */ protected function getIndirectObject($obj_ref, $offset=0, $decoding=true) { $obj = explode('_', $obj_ref); if (($obj === false) OR (count($obj) != 2)) { $this->Error('Invalid object reference: '.$obj); return; } $objref = $obj[0].' '.$obj[1].' obj'; if (strpos($this->pdfdata, $objref, $offset) != $offset) { // an indirect reference to an undefined object shall be considered a reference to the null object return array('null', 'null', $offset); } // starting position of object content $offset += strlen($objref); // get array of object content $objdata = array(); $i = 0; // object main index do { // get element $element = $this->getRawObject($offset); $offset = $element[2]; // decode stream using stream's dictionary information if ($decoding AND ($element[0] == 'stream') AND (isset($objdata[($i - 1)][0])) AND ($objdata[($i - 1)][0] == '<<')) { $element[3] = $this->decodeStream($objdata[($i - 1)][1], $element[1]); } $objdata[$i] = $element; ++$i; } while ($element[0] != 'endobj'); // remove closing delimiter array_pop($objdata); // return raw object content return $objdata; } /** * Get the content of object, resolving indect object reference if necessary. * @param $obj (string) Object value. * @return array containing object data. * @protected * @since 1.0.000 (2011-06-26) */ protected function getObjectVal($obj) { if ($obj[0] == 'objref') { // reference to indirect object if (isset($this->objects[$obj[1]])) { // this object has been already parsed return $this->objects[$obj[1]]; } elseif (isset($this->xref[$obj[1]])) { // parse new object $this->objects[$obj[1]] = $this->getIndirectObject($obj[1], $this->xref[$obj[1]], false); return $this->objects[$obj[1]]; } } return $obj; } /** * Decode the specified stream. * @param $sdic (array) Stream's dictionary array. * @param $stream (string) Stream to decode. * @return array containing decoded stream data and remaining filters. * @protected * @since 1.0.000 (2011-06-22) */ protected function decodeStream($sdic, $stream) { // get stream lenght and filters $slength = strlen($stream); $filters = array(); foreach ($sdic as $k => $v) { if ($v[0] == '/') { if (($v[1] == 'Length') AND (isset($sdic[($k + 1)])) AND ($sdic[($k + 1)][0] == 'numeric')) { // get declared stream lenght $declength = intval($sdic[($k + 1)][1]); if ($declength < $slength) { $stream = substr($stream, 0, $declength); $slength = $declength; } } elseif (($v[1] == 'Filter') AND (isset($sdic[($k + 1)]))) { // resolve indirect object $objval = $this->getObjectVal($sdic[($k + 1)]); if ($objval[0] == '/') { // single filter $filters[] = $objval[1]; } elseif ($objval[0] == '[') { // array of filters foreach ($objval[1] as $flt) { if ($flt[0] == '/') { $filters[] = $flt[1]; } } } } } } // decode the stream $remaining_filters = array(); foreach ($filters as $filter) { if (in_array($filter, $this->FilterDecoders->getAvailableFilters())) { $stream = $this->FilterDecoders->decodeFilter($filter, $stream); } else { // add missing filter to array $remaining_filters[] = $filter; } } return array($stream, $remaining_filters); } /** * This method is automatically called in case of fatal error; it simply outputs the message and halts the execution. * @param $msg (string) The error message * @public * @since 1.0.000 (2011-05-23) */ public function Error($msg) { // exit program and print error die('TCPDF_PARSER ERROR: '.$msg); } } // END OF TCPDF_PARSER CLASS //============================================================+ // END OF FILE //============================================================+