tcpdf_parser.php

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<?php
//============================================================+
// File name   : tcpdf_parser.php
// Version     : 1.0.16
// Begin       : 2011-05-23
// Last Update : 2015-04-28
// Author      : Nicola Asuni - Tecnick.com LTD - www.tecnick.com - info@tecnick.com
// License     : http://www.tecnick.com/pagefiles/tcpdf/LICENSE.TXT GNU-LGPLv3
// -------------------------------------------------------------------
// Copyright (C) 2011-2015 Nicola Asuni - Tecnick.com LTD
//
// This file is part of TCPDF software library.
//
// TCPDF is free software: you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// TCPDF is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the License
// along with TCPDF. If not, see
// <http://www.tecnick.com/pagefiles/tcpdf/LICENSE.TXT>.
//
// See LICENSE.TXT file for more information.
// -------------------------------------------------------------------
//
// Description : This is a PHP class for parsing PDF documents.
//
//============================================================+

// include class for decoding filters
require_once(dirname(__FILE__).'/include/tcpdf_filters.php');

class TCPDF_PARSER {

        private $pdfdata = '';

        protected $xref = array();

        protected $objects = array();

        private $FilterDecoders;

        private $cfg = array(
                'die_for_errors' => false,
                'ignore_filter_decoding_errors' => true,
                'ignore_missing_filter_decoders' => true,
        );

// -----------------------------------------------------------------------------

        public function __construct($data, $cfg=array()) {
                if (empty($data)) {
                        $this->Error('Empty PDF data.');
                }
                // find the pdf header starting position
                if (($trimpos = strpos($data, '%PDF-')) === FALSE) {
                        $this->Error('Invalid PDF data: missing %PDF header.');
                }
                // get PDF content string
                $this->pdfdata = substr($data, $trimpos);
                // get length
                $pdflen = strlen($this->pdfdata);
                // set configuration parameters
                $this->setConfig($cfg);
                // 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[$obj]) AND ($offset > 0)) {
                                // decode objects with positive offset
                                $this->objects[$obj] = $this->getIndirectObject($obj, $offset, true);
                        }
                }
                // release some memory
                unset($this->pdfdata);
                $this->pdfdata = '';
        }

        protected function setConfig($cfg) {
                if (isset($cfg['die_for_errors'])) {
                        $this->cfg['die_for_errors'] = !!$cfg['die_for_errors'];
                }
                if (isset($cfg['ignore_filter_decoding_errors'])) {
                        $this->cfg['ignore_filter_decoding_errors'] = !!$cfg['ignore_filter_decoding_errors'];
                }
                if (isset($cfg['ignore_missing_filter_decoders'])) {
                        $this->cfg['ignore_missing_filter_decoders'] = !!$cfg['ignore_missing_filter_decoders'];
                }
        }

        public function getParsedData() {
                return array($this->xref, $this->objects);
        }

        protected function getXrefData($offset=0, $xref=array()) {
                if ($offset == 0) {
                        // 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 = $matches[1];
                } elseif (strpos($this->pdfdata, 'xref', $offset) == $offset) {
                        // Already pointing at the xref table
                        $startxref = $offset;
                } elseif (preg_match('/([0-9]+[\s][0-9]+[\s]obj)/i', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset)) {
                        // Cross-Reference Stream object
                        $startxref = $offset;
                } elseif (preg_match('/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset)) {
                        // startxref found
                        $startxref = $matches[1][0];
                } else {
                        $this->Error('Unable to find startxref');
                }
                // check xref position
                if (strpos($this->pdfdata, 'xref', $startxref) == $startxref) {
                        // Cross-Reference
                        $xref = $this->decodeXref($startxref, $xref);
                } else {
                        // Cross-Reference Stream
                        $xref = $this->decodeXrefStream($startxref, $xref);
                }
                if (empty($xref)) {
                        $this->Error('Unable to find xref');
                }
                return $xref;
        }

        protected function decodeXref($startxref, $xref=array()) {
                $startxref += 4; // 4 is the length of the word 'xref'
                // 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 = $startxref + strspn($this->pdfdata, "\x00\x09\x0a\x0c\x0d\x20", $startxref);
                // initialize object number
                $obj_num = 0;
                // search for cross-reference entries or subsection
                while (preg_match('/([0-9]+)[\x20]([0-9]+)[\x20]?([nf]?)(\r\n|[\x20]?[\r\n])/', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
                        if ($matches[0][1] != $offset) {
                                // we are on another section
                                break;
                        }
                        $offset += strlen($matches[0][0]);
                        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;
                        } elseif ($matches[3][0] == 'f') {
                                ++$obj_num;
                        } else {
                                // object number (index)
                                $obj_num = intval($matches[1][0]);
                        }
                }
                // get trailer data
                if (preg_match('/trailer[\s]*<<(.*)>>/isU', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
                        $trailer_data = $matches[1][0];
                        if (!isset($xref['trailer']) OR empty($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 = $this->getXrefData(intval($matches[1]), $xref);
                        }
                } else {
                        $this->Error('Unable to find trailer');
                }
                return $xref;
        }

        protected function decodeXrefStream($startxref, $xref=array()) {
                // try to read Cross-Reference Stream
                $xrefobj = $this->getRawObject($startxref);
                $xrefcrs = $this->getIndirectObject($xrefobj[1], $startxref, true);
                if (!isset($xref['trailer']) OR empty($xref['trailer'])) {
                        // get only the last updated version
                        $xref['trailer'] = array();
                        $filltrailer = true;
                } else {
                        $filltrailer = false;
                }
                if (!isset($xref['xref'])) {
                        $xref['xref'] = array();
                }
                $valid_crs = false;
                $columns = 0;
                $sarr = $xrefcrs[0][1];
                if (!is_array($sarr)) {
                        $sarr = array();
                }
                foreach ($sarr as $k => $v) {
                        if (($v[0] == '/') AND ($v[1] == 'Type') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == '/') AND ($sarr[($k +1)][1] == 'XRef'))) {
                                $valid_crs = true;
                        } elseif (($v[0] == '/') AND ($v[1] == 'Index') AND (isset($sarr[($k +1)]))) {
                                // first object number in the subsection
                                $index_first = intval($sarr[($k +1)][1][0][1]);
                                // number of entries in the subsection
                                $index_entries = intval($sarr[($k +1)][1][1][1]);
                        } elseif (($v[0] == '/') AND ($v[1] == 'Prev') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == 'numeric'))) {
                                // get previous xref offset
                                $prevxref = intval($sarr[($k +1)][1]);
                        } elseif (($v[0] == '/') AND ($v[1] == 'W') AND (isset($sarr[($k +1)]))) {
                                // number of bytes (in the decoded stream) of the corresponding field
                                $wb = array();
                                $wb[0] = intval($sarr[($k +1)][1][0][1]);
                                $wb[1] = intval($sarr[($k +1)][1][1][1]);
                                $wb[2] = intval($sarr[($k +1)][1][2][1]);
                        } elseif (($v[0] == '/') AND ($v[1] == 'DecodeParms') AND (isset($sarr[($k +1)][1]))) {
                                $decpar = $sarr[($k +1)][1];
                                foreach ($decpar as $kdc => $vdc) {
                                        if (($vdc[0] == '/') AND ($vdc[1] == 'Columns') AND (isset($decpar[($kdc +1)]) AND ($decpar[($kdc +1)][0] == 'numeric'))) {
                                                $columns = intval($decpar[($kdc +1)][1]);
                                        } elseif (($vdc[0] == '/') AND ($vdc[1] == 'Predictor') AND (isset($decpar[($kdc +1)]) AND ($decpar[($kdc +1)][0] == 'numeric'))) {
                                                $predictor = intval($decpar[($kdc +1)][1]);
                                        }
                                }
                        } elseif ($filltrailer) {
                                if (($v[0] == '/') AND ($v[1] == 'Size') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == 'numeric'))) {
                                        $xref['trailer']['size'] = $sarr[($k +1)][1];
                                } elseif (($v[0] == '/') AND ($v[1] == 'Root') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == 'objref'))) {
                                        $xref['trailer']['root'] = $sarr[($k +1)][1];
                                } elseif (($v[0] == '/') AND ($v[1] == 'Info') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == 'objref'))) {
                                        $xref['trailer']['info'] = $sarr[($k +1)][1];
                                } elseif (($v[0] == '/') AND ($v[1] == 'Encrypt') AND (isset($sarr[($k +1)]) AND ($sarr[($k +1)][0] == 'objref'))) {
                                        $xref['trailer']['encrypt'] = $sarr[($k +1)][1];
                                } elseif (($v[0] == '/') AND ($v[1] == 'ID') AND (isset($sarr[($k +1)]))) {
                                        $xref['trailer']['id'] = array();
                                        $xref['trailer']['id'][0] = $sarr[($k +1)][1][0][1];
                                        $xref['trailer']['id'][1] = $sarr[($k +1)][1][1][1];
                                }
                        }
                }
                // decode data
                if ($valid_crs AND isset($xrefcrs[1][3][0])) {
                        // number of bytes in a row
                        $rowlen = ($columns + 1);
                        // convert the stream into an array of integers
                        $sdata = unpack('C*', $xrefcrs[1][3][0]);
                        // split the rows
                        $sdata = array_chunk($sdata, $rowlen);
                        // initialize decoded array
                        $ddata = array();
                        // initialize first row with zeros
                        $prev_row = array_fill (0, $rowlen, 0);
                        // for each row apply PNG unpredictor
                        foreach ($sdata as $k => $row) {
                                // initialize new row
                                $ddata[$k] = array();
                                // get PNG predictor value
                                $predictor = (10 + $row[0]);
                                // for each byte on the row
                                for ($i=1; $i<=$columns; ++$i) {
                                        // new index
                                        $j = ($i - 1);
                                        $row_up = $prev_row[$j];
                                        if ($i == 1) {
                                                $row_left = 0;
                                                $row_upleft = 0;
                                        } else {
                                                $row_left = $row[($i - 1)];
                                                $row_upleft = $prev_row[($j - 1)];
                                        }
                                        switch ($predictor) {
                                                case 10: { // PNG prediction (on encoding, PNG None on all rows)
                                                        $ddata[$k][$j] = $row[$i];
                                                        break;
                                                }
                                                case 11: { // PNG prediction (on encoding, PNG Sub on all rows)
                                                        $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
                                                        break;
                                                }
                                                case 12: { // PNG prediction (on encoding, PNG Up on all rows)
                                                        $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
                                                        break;
                                                }
                                                case 13: { // PNG prediction (on encoding, PNG Average on all rows)
                                                        $ddata[$k][$j] = (($row[$i] + (($row_left + $row_up) / 2)) & 0xff);
                                                        break;
                                                }
                                                case 14: { // PNG prediction (on encoding, PNG Paeth on all rows)
                                                        // initial estimate
                                                        $p = ($row_left + $row_up - $row_upleft);
                                                        // distances
                                                        $pa = abs($p - $row_left);
                                                        $pb = abs($p - $row_up);
                                                        $pc = abs($p - $row_upleft);
                                                        $pmin = min($pa, $pb, $pc);
                                                        // return minimum distance
                                                        switch ($pmin) {
                                                                case $pa: {
                                                                        $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
                                                                        break;
                                                                }
                                                                case $pb: {
                                                                        $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
                                                                        break;
                                                                }
                                                                case $pc: {
                                                                        $ddata[$k][$j] = (($row[$i] + $row_upleft) & 0xff);
                                                                        break;
                                                                }
                                                        }
                                                        break;
                                                }
                                                default: { // PNG prediction (on encoding, PNG optimum)
                                                        $this->Error('Unknown PNG predictor');
                                                        break;
                                                }
                                        }
                                }
                                $prev_row = $ddata[$k];
                        } // end for each row
                        // complete decoding
                        $sdata = array();
                        // for every row
                        foreach ($ddata as $k => $row) {
                                // initialize new row
                                $sdata[$k] = array(0, 0, 0);
                                if ($wb[0] == 0) {
                                        // default type field
                                        $sdata[$k][0] = 1;
                                }
                                $i = 0; // count bytes in the row
                                // for every column
                                for ($c = 0; $c < 3; ++$c) {
                                        // for every byte on the column
                                        for ($b = 0; $b < $wb[$c]; ++$b) {
                                                if (isset($row[$i])) {
                                                        $sdata[$k][$c] += ($row[$i] << (($wb[$c] - 1 - $b) * 8));
                                                }
                                                ++$i;
                                        }
                                }
                        }
                        $ddata = array();
                        // fill xref
                        if (isset($index_first)) {
                                $obj_num = $index_first;
                        } else {
                                $obj_num = 0;
                        }
                        foreach ($sdata as $k => $row) {
                                switch ($row[0]) {
                                        case 0: { // (f) linked list of free objects
                                                break;
                                        }
                                        case 1: { // (n) objects that are in use but are not compressed
                                                // create unique object index: [object number]_[generation number]
                                                $index = $obj_num.'_'.$row[2];
                                                // check if object already exist
                                                if (!isset($xref['xref'][$index])) {
                                                        // store object offset position
                                                        $xref['xref'][$index] = $row[1];
                                                }
                                                break;
                                        }
                                        case 2: { // compressed objects
                                                // $row[1] = object number of the object stream in which this object is stored
                                                // $row[2] = index of this object within the object stream
                                                $index = $row[1].'_0_'.$row[2];
                                                $xref['xref'][$index] = -1;
                                                break;
                                        }
                                        default: { // null objects
                                                break;
                                        }
                                }
                                ++$obj_num;
                        }
                } // end decoding data
                if (isset($prevxref)) {
                        // get previous xref
                        $xref = $this->getXrefData($prevxref, $xref);
                }
                return $xref;
        }

        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 $this->getRawObject($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 (($char == '<') AND (preg_match('/^([0-9A-Fa-f\x09\x0a\x0c\x0d\x20]+)>/iU', substr($this->pdfdata, $offset), $matches) == 1)) {
                                                // remove white space characters
                                                $objval = strtr($matches[1], "\x09\x0a\x0c\x0d\x20", '');
                                                $offset += strlen($matches[0]);
                                        } elseif (($endpos = strpos($this->pdfdata, '>', $offset)) !== FALSE) {
                                                $offset = $endpos + 1;
                    }
                                }
                                break;
                        }
                        default: {
                                if (substr($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';
                                        $offset += 6;
                                        if (preg_match('/^([\r]?[\n])/isU', substr($this->pdfdata, $offset), $matches) == 1) {
                                                $offset += strlen($matches[0]);
                                                if (preg_match('/(endstream)[\x09\x0a\x0c\x0d\x20]/isU', substr($this->pdfdata, $offset), $matches, PREG_OFFSET_CAPTURE) == 1) {
                                                        $objval = substr($this->pdfdata, $offset, $matches[0][1]);
                                                        $offset += $matches[1][1];
                                                }
                                        }
                                } elseif (substr($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 = 'objref';
                                        $offset += strlen($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 = 'obj';
                                        $objval = intval($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);
        }

        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';
                // ignore leading zeros
                $offset += strspn($this->pdfdata, '0', $offset);
                if (strpos($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 {
                        $oldoffset = $offset;
                        // 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 (($element[0] != 'endobj') AND ($offset != $oldoffset));
                // remove closing delimiter
                array_pop($objdata);
                // return raw object content
                return $objdata;
        }

        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;
        }

        protected function decodeStream($sdic, $stream) {
                // get stream length and filters
                $slength = strlen($stream);
                if ($slength <= 0) {
                        return array('', array());
                }
                $filters = array();
                foreach ($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 length
                                        $declength = intval($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, TCPDF_FILTERS::getAvailableFilters())) {
                                try {
                                        $stream = TCPDF_FILTERS::decodeFilter($filter, $stream);
                                } catch (Exception $e) {
                                        $emsg = $e->getMessage();
                                        if ((($emsg[0] == '~') AND !$this->cfg['ignore_missing_filter_decoders'])
                                                OR (($emsg[0] != '~') AND !$this->cfg['ignore_filter_decoding_errors'])) {
                                                $this->Error($e->getMessage());
                                        }
                                }
                        } else {
                                // add missing filter to array
                                $remaining_filters[] = $filter;
                        }
                }
                return array($stream, $remaining_filters);
        }

        public function Error($msg) {
                if ($this->cfg['die_for_errors']) {
                        die('<strong>TCPDF_PARSER ERROR: </strong>'.$msg);
                } else {
                        throw new Exception('TCPDF_PARSER ERROR: '.$msg);
                }
        }

} // END OF TCPDF_PARSER CLASS

//============================================================+
// END OF FILE
//============================================================+