857 lines
34 KiB
857 lines
34 KiB
<?php |
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/** |
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* This file is based on code of tecnickcom/TCPDF PDF library. |
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* |
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* Original author Nicola Asuni (info@tecnick.com) and |
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* contributors (https://github.com/tecnickcom/TCPDF/graphs/contributors). |
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* |
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* @see https://github.com/tecnickcom/TCPDF |
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* |
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* Original code was licensed on the terms of the LGPL v3. |
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* |
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* ------------------------------------------------------------------------------ |
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* |
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* @file This file is part of the PdfParser library. |
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* |
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* @author Konrad Abicht <k.abicht@gmail.com> |
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* @date 2020-01-06 |
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* |
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* @license LGPLv3 |
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* @url <https://github.com/smalot/pdfparser> |
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* |
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* PdfParser is a pdf library written in PHP, extraction oriented. |
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* Copyright (C) 2017 - Sébastien MALOT <sebastien@malot.fr> |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Lesser General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public License |
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* along with this program. |
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* If not, see <http://www.pdfparser.org/sites/default/LICENSE.txt>. |
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*/ |
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namespace Smalot\PdfParser\RawData; |
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use Exception; |
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class RawDataParser |
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{ |
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/** |
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* Configuration array. |
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*/ |
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protected $cfg = [ |
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// if `true` ignore filter decoding errors |
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'ignore_filter_decoding_errors' => true, |
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// if `true` ignore missing filter decoding errors |
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'ignore_missing_filter_decoders' => true, |
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]; |
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protected $filterHelper; |
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protected $objects; |
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/** |
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* @param array $cfg Configuration array, default is [] |
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*/ |
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public function __construct($cfg = []) |
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{ |
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// merge given array with default values |
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$this->cfg = array_merge($this->cfg, $cfg); |
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$this->filterHelper = new FilterHelper(); |
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} |
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/** |
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* Decode the specified stream. |
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* |
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* @param string $pdfData PDF data |
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* @param array $xref |
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* @param array $sdic Stream's dictionary array |
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* @param string $stream Stream to decode |
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* |
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* @return array containing decoded stream data and remaining filters |
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*/ |
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protected function decodeStream($pdfData, $xref, $sdic, $stream) |
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{ |
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// get stream length and filters |
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$slength = \strlen($stream); |
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if ($slength <= 0) { |
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return ['', []]; |
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} |
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$filters = []; |
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foreach ($sdic as $k => $v) { |
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if ('/' == $v[0]) { |
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if (('Length' == $v[1]) && (isset($sdic[($k + 1)])) && ('numeric' == $sdic[($k + 1)][0])) { |
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// get declared stream length |
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$declength = (int) ($sdic[($k + 1)][1]); |
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if ($declength < $slength) { |
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$stream = substr($stream, 0, $declength); |
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$slength = $declength; |
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} |
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} elseif (('Filter' == $v[1]) && (isset($sdic[($k + 1)]))) { |
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// resolve indirect object |
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$objval = $this->getObjectVal($pdfData, $xref, $sdic[($k + 1)]); |
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if ('/' == $objval[0]) { |
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// single filter |
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$filters[] = $objval[1]; |
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} elseif ('[' == $objval[0]) { |
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// array of filters |
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foreach ($objval[1] as $flt) { |
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if ('/' == $flt[0]) { |
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$filters[] = $flt[1]; |
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} |
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} |
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} |
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} |
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} |
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} |
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// decode the stream |
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$remaining_filters = []; |
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foreach ($filters as $filter) { |
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if (\in_array($filter, $this->filterHelper->getAvailableFilters())) { |
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try { |
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$stream = $this->filterHelper->decodeFilter($filter, $stream); |
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} catch (Exception $e) { |
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$emsg = $e->getMessage(); |
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if ((('~' == $emsg[0]) && !$this->cfg['ignore_missing_filter_decoders']) |
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|| (('~' != $emsg[0]) && !$this->cfg['ignore_filter_decoding_errors']) |
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) { |
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throw new Exception($e->getMessage()); |
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} |
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} |
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} else { |
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// add missing filter to array |
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$remaining_filters[] = $filter; |
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} |
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} |
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return [$stream, $remaining_filters]; |
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} |
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/** |
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* Decode the Cross-Reference section |
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* |
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* @param string $pdfData PDF data |
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* @param int $startxref Offset at which the xref section starts (position of the 'xref' keyword) |
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* @param array $xref Previous xref array (if any) |
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* |
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* @return array containing xref and trailer data |
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*/ |
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protected function decodeXref($pdfData, $startxref, $xref = []) |
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{ |
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$startxref += 4; // 4 is the length of the word 'xref' |
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// 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) |
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$offset = $startxref + strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $startxref); |
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// initialize object number |
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$obj_num = 0; |
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// search for cross-reference entries or subsection |
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while (preg_match('/([0-9]+)[\x20]([0-9]+)[\x20]?([nf]?)(\r\n|[\x20]?[\r\n])/', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { |
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if ($matches[0][1] != $offset) { |
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// we are on another section |
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break; |
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} |
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$offset += \strlen($matches[0][0]); |
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if ('n' == $matches[3][0]) { |
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// create unique object index: [object number]_[generation number] |
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$index = $obj_num.'_'.(int) ($matches[2][0]); |
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// check if object already exist |
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if (!isset($xref['xref'][$index])) { |
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// store object offset position |
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$xref['xref'][$index] = (int) ($matches[1][0]); |
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} |
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++$obj_num; |
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} elseif ('f' == $matches[3][0]) { |
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++$obj_num; |
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} else { |
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// object number (index) |
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$obj_num = (int) ($matches[1][0]); |
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} |
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} |
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// get trailer data |
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if (preg_match('/trailer[\s]*<<(.*)>>/isU', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { |
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$trailer_data = $matches[1][0]; |
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if (!isset($xref['trailer']) || empty($xref['trailer'])) { |
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// get only the last updated version |
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$xref['trailer'] = []; |
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// parse trailer_data |
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if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) { |
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$xref['trailer']['size'] = (int) ($matches[1]); |
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} |
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if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { |
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$xref['trailer']['root'] = (int) ($matches[1]).'_'.(int) ($matches[2]); |
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} |
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if (preg_match('/Encrypt[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { |
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$xref['trailer']['encrypt'] = (int) ($matches[1]).'_'.(int) ($matches[2]); |
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} |
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if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) { |
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$xref['trailer']['info'] = (int) ($matches[1]).'_'.(int) ($matches[2]); |
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} |
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if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) { |
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$xref['trailer']['id'] = []; |
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$xref['trailer']['id'][0] = $matches[1]; |
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$xref['trailer']['id'][1] = $matches[2]; |
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} |
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} |
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if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) { |
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// get previous xref |
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$xref = $this->getXrefData($pdfData, (int) ($matches[1]), $xref); |
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} |
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} else { |
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throw new Exception('Unable to find trailer'); |
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} |
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return $xref; |
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} |
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/** |
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* Decode the Cross-Reference Stream section |
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* |
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* @param string $pdfData PDF data |
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* @param int $startxref Offset at which the xref section starts |
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* @param array $xref Previous xref array (if any) |
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* |
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* @return array containing xref and trailer data |
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* |
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* @throws Exception if unknown PNG predictor detected |
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*/ |
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protected function decodeXrefStream($pdfData, $startxref, $xref = []) |
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{ |
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// try to read Cross-Reference Stream |
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$xrefobj = $this->getRawObject($pdfData, $startxref); |
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$xrefcrs = $this->getIndirectObject($pdfData, $xref, $xrefobj[1], $startxref, true); |
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if (!isset($xref['trailer']) || empty($xref['trailer'])) { |
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// get only the last updated version |
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$xref['trailer'] = []; |
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$filltrailer = true; |
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} else { |
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$filltrailer = false; |
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} |
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if (!isset($xref['xref'])) { |
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$xref['xref'] = []; |
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} |
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$valid_crs = false; |
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$columns = 0; |
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$sarr = $xrefcrs[0][1]; |
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if (!\is_array($sarr)) { |
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$sarr = []; |
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} |
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$wb = []; |
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foreach ($sarr as $k => $v) { |
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if ( |
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('/' == $v[0]) |
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&& ('Type' == $v[1]) |
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&& ( |
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isset($sarr[($k + 1)]) |
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&& '/' == $sarr[($k + 1)][0] |
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&& 'XRef' == $sarr[($k + 1)][1] |
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) |
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) { |
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$valid_crs = true; |
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} elseif (('/' == $v[0]) && ('Index' == $v[1]) && (isset($sarr[($k + 1)]))) { |
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// first object number in the subsection |
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$index_first = (int) ($sarr[($k + 1)][1][0][1]); |
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} elseif (('/' == $v[0]) && ('Prev' == $v[1]) && (isset($sarr[($k + 1)]) && ('numeric' == $sarr[($k + 1)][0]))) { |
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// get previous xref offset |
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$prevxref = (int) ($sarr[($k + 1)][1]); |
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} elseif (('/' == $v[0]) && ('W' == $v[1]) && (isset($sarr[($k + 1)]))) { |
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// number of bytes (in the decoded stream) of the corresponding field |
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$wb[0] = (int) ($sarr[($k + 1)][1][0][1]); |
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$wb[1] = (int) ($sarr[($k + 1)][1][1][1]); |
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$wb[2] = (int) ($sarr[($k + 1)][1][2][1]); |
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} elseif (('/' == $v[0]) && ('DecodeParms' == $v[1]) && (isset($sarr[($k + 1)][1]))) { |
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$decpar = $sarr[($k + 1)][1]; |
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foreach ($decpar as $kdc => $vdc) { |
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if ( |
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'/' == $vdc[0] |
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&& 'Columns' == $vdc[1] |
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&& ( |
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isset($decpar[($kdc + 1)]) |
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&& 'numeric' == $decpar[($kdc + 1)][0] |
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) |
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) { |
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$columns = (int) ($decpar[($kdc + 1)][1]); |
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} elseif ( |
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'/' == $vdc[0] |
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&& 'Predictor' == $vdc[1] |
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&& ( |
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isset($decpar[($kdc + 1)]) |
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&& 'numeric' == $decpar[($kdc + 1)][0] |
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) |
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) { |
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$predictor = (int) ($decpar[($kdc + 1)][1]); |
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} |
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} |
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} elseif ($filltrailer) { |
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if (('/' == $v[0]) && ('Size' == $v[1]) && (isset($sarr[($k + 1)]) && ('numeric' == $sarr[($k + 1)][0]))) { |
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$xref['trailer']['size'] = $sarr[($k + 1)][1]; |
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} elseif (('/' == $v[0]) && ('Root' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) { |
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$xref['trailer']['root'] = $sarr[($k + 1)][1]; |
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} elseif (('/' == $v[0]) && ('Info' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) { |
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$xref['trailer']['info'] = $sarr[($k + 1)][1]; |
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} elseif (('/' == $v[0]) && ('Encrypt' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) { |
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$xref['trailer']['encrypt'] = $sarr[($k + 1)][1]; |
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} elseif (('/' == $v[0]) && ('ID' == $v[1]) && (isset($sarr[($k + 1)]))) { |
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$xref['trailer']['id'] = []; |
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$xref['trailer']['id'][0] = $sarr[($k + 1)][1][0][1]; |
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$xref['trailer']['id'][1] = $sarr[($k + 1)][1][1][1]; |
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} |
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} |
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} |
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// decode data |
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if ($valid_crs && isset($xrefcrs[1][3][0])) { |
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// number of bytes in a row |
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$rowlen = ($columns + 1); |
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// convert the stream into an array of integers |
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$sdata = unpack('C*', $xrefcrs[1][3][0]); |
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// split the rows |
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$sdata = array_chunk($sdata, $rowlen); |
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// initialize decoded array |
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$ddata = []; |
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// initialize first row with zeros |
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$prev_row = array_fill(0, $rowlen, 0); |
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// for each row apply PNG unpredictor |
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foreach ($sdata as $k => $row) { |
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// initialize new row |
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$ddata[$k] = []; |
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// get PNG predictor value |
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$predictor = (10 + $row[0]); |
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// for each byte on the row |
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for ($i = 1; $i <= $columns; ++$i) { |
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// new index |
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$j = ($i - 1); |
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$row_up = $prev_row[$j]; |
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if (1 == $i) { |
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$row_left = 0; |
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$row_upleft = 0; |
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} else { |
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$row_left = $row[($i - 1)]; |
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$row_upleft = $prev_row[($j - 1)]; |
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} |
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switch ($predictor) { |
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case 10: // PNG prediction (on encoding, PNG None on all rows) |
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$ddata[$k][$j] = $row[$i]; |
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break; |
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case 11: // PNG prediction (on encoding, PNG Sub on all rows) |
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$ddata[$k][$j] = (($row[$i] + $row_left) & 0xff); |
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break; |
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case 12: // PNG prediction (on encoding, PNG Up on all rows) |
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$ddata[$k][$j] = (($row[$i] + $row_up) & 0xff); |
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break; |
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case 13: // PNG prediction (on encoding, PNG Average on all rows) |
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$ddata[$k][$j] = (($row[$i] + (($row_left + $row_up) / 2)) & 0xff); |
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break; |
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case 14: // PNG prediction (on encoding, PNG Paeth on all rows) |
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// initial estimate |
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$p = ($row_left + $row_up - $row_upleft); |
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// distances |
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$pa = abs($p - $row_left); |
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$pb = abs($p - $row_up); |
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$pc = abs($p - $row_upleft); |
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$pmin = min($pa, $pb, $pc); |
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// return minimum distance |
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switch ($pmin) { |
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case $pa: |
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$ddata[$k][$j] = (($row[$i] + $row_left) & 0xff); |
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break; |
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case $pb: |
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$ddata[$k][$j] = (($row[$i] + $row_up) & 0xff); |
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break; |
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case $pc: |
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$ddata[$k][$j] = (($row[$i] + $row_upleft) & 0xff); |
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break; |
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} |
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break; |
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default: // PNG prediction (on encoding, PNG optimum) |
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throw new Exception('Unknown PNG predictor'); |
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} |
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} |
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$prev_row = $ddata[$k]; |
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} // end for each row |
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// complete decoding |
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$sdata = []; |
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// for every row |
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foreach ($ddata as $k => $row) { |
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// initialize new row |
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$sdata[$k] = [0, 0, 0]; |
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if (0 == $wb[0]) { |
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// default type field |
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$sdata[$k][0] = 1; |
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} |
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$i = 0; // count bytes in the row |
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// for every column |
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for ($c = 0; $c < 3; ++$c) { |
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// for every byte on the column |
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for ($b = 0; $b < $wb[$c]; ++$b) { |
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if (isset($row[$i])) { |
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$sdata[$k][$c] += ($row[$i] << (($wb[$c] - 1 - $b) * 8)); |
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} |
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++$i; |
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} |
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} |
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} |
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$ddata = []; |
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// fill xref |
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if (isset($index_first)) { |
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$obj_num = $index_first; |
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} else { |
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$obj_num = 0; |
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} |
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foreach ($sdata as $k => $row) { |
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switch ($row[0]) { |
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case 0: // (f) linked list of free objects |
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break; |
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case 1: // (n) objects that are in use but are not compressed |
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// create unique object index: [object number]_[generation number] |
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$index = $obj_num.'_'.$row[2]; |
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// check if object already exist |
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if (!isset($xref['xref'][$index])) { |
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// store object offset position |
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$xref['xref'][$index] = $row[1]; |
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} |
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break; |
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case 2: // compressed objects |
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// $row[1] = object number of the object stream in which this object is stored |
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// $row[2] = index of this object within the object stream |
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$index = $row[1].'_0_'.$row[2]; |
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$xref['xref'][$index] = -1; |
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break; |
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default: // null objects |
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break; |
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} |
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++$obj_num; |
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} |
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} // end decoding data |
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if (isset($prevxref)) { |
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// get previous xref |
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$xref = $this->getXrefData($pdfData, $prevxref, $xref); |
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} |
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return $xref; |
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} |
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/** |
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* Get content of indirect object. |
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* |
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* @param string $pdfData PDF data |
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* @param array $xref |
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* @param string $objRef Object number and generation number separated by underscore character |
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* @param int $offset Object offset |
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* @param bool $decoding If true decode streams |
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* |
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* @return array containing object data |
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* |
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* @throws Exception if invalid object reference found |
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*/ |
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protected function getIndirectObject($pdfData, $xref, $objRef, $offset = 0, $decoding = true) |
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{ |
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/* |
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* build indirect object header |
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*/ |
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// $objHeader = "[object number] [generation number] obj" |
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$objRefArr = explode('_', $objRef); |
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if (2 !== \count($objRefArr)) { |
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throw new Exception('Invalid object reference for $obj.'); |
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} |
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$objHeader = $objRefArr[0].' '.$objRefArr[1].' obj'; |
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|
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/* |
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* check if we are in position |
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*/ |
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// ignore whitespace characters at offset (NUL, HT, LF, FF, CR, SP) |
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$offset += strspn($pdfData, "\0\t\n\f\r ", $offset); |
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// ignore leading zeros for object number |
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$offset += strspn($pdfData, '0', $offset); |
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if (substr($pdfData, $offset, \strlen($objHeader)) !== $objHeader) { |
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// an indirect reference to an undefined object shall be considered a reference to the null object |
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return ['null', 'null', $offset]; |
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} |
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|
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/* |
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* get content |
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*/ |
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// starting position of object content |
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$offset += \strlen($objHeader); |
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$objContentArr = []; |
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$i = 0; // object main index |
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do { |
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$oldOffset = $offset; |
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// get element |
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$element = $this->getRawObject($pdfData, $offset); |
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$offset = $element[2]; |
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// decode stream using stream's dictionary information |
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if ($decoding && ('stream' === $element[0]) && (isset($objContentArr[($i - 1)][0])) && ('<<' === $objContentArr[($i - 1)][0])) { |
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$element[3] = $this->decodeStream($pdfData, $xref, $objContentArr[($i - 1)][1], $element[1]); |
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} |
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$objContentArr[$i] = $element; |
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++$i; |
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} while (('endobj' !== $element[0]) && ($offset !== $oldOffset)); |
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// remove closing delimiter |
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array_pop($objContentArr); |
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/* |
|
* return raw object content |
|
*/ |
|
return $objContentArr; |
|
} |
|
|
|
/** |
|
* Get the content of object, resolving indirect object reference if necessary. |
|
* |
|
* @param string $pdfData PDF data |
|
* @param array $obj Object value |
|
* |
|
* @return array containing object data |
|
* |
|
* @throws Exception |
|
*/ |
|
protected function getObjectVal($pdfData, $xref, $obj) |
|
{ |
|
if ('objref' == $obj[0]) { |
|
// reference to indirect object |
|
if (isset($this->objects[$obj[1]])) { |
|
// this object has been already parsed |
|
return $this->objects[$obj[1]]; |
|
} elseif (isset($xref[$obj[1]])) { |
|
// parse new object |
|
$this->objects[$obj[1]] = $this->getIndirectObject($pdfData, $xref, $obj[1], $xref[$obj[1]], false); |
|
|
|
return $this->objects[$obj[1]]; |
|
} |
|
} |
|
|
|
return $obj; |
|
} |
|
|
|
/** |
|
* Get object type, raw value and offset to next object |
|
* |
|
* @param int $offset Object offset |
|
* |
|
* @return array containing object type, raw value and offset to next object |
|
*/ |
|
protected function getRawObject($pdfData, $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) |
|
*/ |
|
$offset += strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $offset); |
|
|
|
// get first char |
|
$char = $pdfData[$offset]; |
|
// get object type |
|
switch ($char) { |
|
case '%': // \x25 PERCENT SIGN |
|
// skip comment and search for next token |
|
$next = strcspn($pdfData, "\r\n", $offset); |
|
if ($next > 0) { |
|
$offset += $next; |
|
|
|
return $this->getRawObject($pdfData, $offset); |
|
} |
|
break; |
|
|
|
case '/': // \x2F SOLIDUS |
|
// name object |
|
$objtype = $char; |
|
++$offset; |
|
$pregResult = preg_match( |
|
'/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/', |
|
substr($pdfData, $offset, 256), |
|
$matches |
|
); |
|
if (1 == $pregResult) { |
|
$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($pdfData[$strpos])) { |
|
break; |
|
} |
|
$ch = $pdfData[$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; |
|
} |
|
$objval = substr($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 = []; |
|
do { |
|
$oldOffset = $offset; |
|
// get element |
|
$element = $this->getRawObject($pdfData, $offset); |
|
$offset = $element[2]; |
|
$objval[] = $element; |
|
} while ((']' != $element[0]) && ($offset != $oldOffset)); |
|
// remove closing delimiter |
|
array_pop($objval); |
|
} |
|
break; |
|
|
|
case '<': // \x3C LESS-THAN SIGN |
|
case '>': // \x3E GREATER-THAN SIGN |
|
if (isset($pdfData[($offset + 1)]) && ($pdfData[($offset + 1)] == $char)) { |
|
// dictionary object |
|
$objtype = $char.$char; |
|
$offset += 2; |
|
if ('<' == $char) { |
|
// get array content |
|
$objval = []; |
|
do { |
|
$oldOffset = $offset; |
|
// get element |
|
$element = $this->getRawObject($pdfData, $offset); |
|
$offset = $element[2]; |
|
$objval[] = $element; |
|
} while (('>>' != $element[0]) && ($offset != $oldOffset)); |
|
// remove closing delimiter |
|
array_pop($objval); |
|
} |
|
} else { |
|
// hexadecimal string object |
|
$objtype = $char; |
|
++$offset; |
|
$pregResult = preg_match( |
|
'/^([0-9A-Fa-f\x09\x0a\x0c\x0d\x20]+)>/iU', |
|
substr($pdfData, $offset), |
|
$matches |
|
); |
|
if (('<' == $char) && 1 == $pregResult) { |
|
// remove white space characters |
|
$objval = strtr($matches[1], "\x09\x0a\x0c\x0d\x20", ''); |
|
$offset += \strlen($matches[0]); |
|
} elseif (false !== ($endpos = strpos($pdfData, '>', $offset))) { |
|
$offset = $endpos + 1; |
|
} |
|
} |
|
break; |
|
|
|
default: |
|
if ('endobj' == substr($pdfData, $offset, 6)) { |
|
// indirect object |
|
$objtype = 'endobj'; |
|
$offset += 6; |
|
} elseif ('null' == substr($pdfData, $offset, 4)) { |
|
// null object |
|
$objtype = 'null'; |
|
$offset += 4; |
|
$objval = 'null'; |
|
} elseif ('true' == substr($pdfData, $offset, 4)) { |
|
// boolean true object |
|
$objtype = 'boolean'; |
|
$offset += 4; |
|
$objval = 'true'; |
|
} elseif ('false' == substr($pdfData, $offset, 5)) { |
|
// boolean false object |
|
$objtype = 'boolean'; |
|
$offset += 5; |
|
$objval = 'false'; |
|
} elseif ('stream' == substr($pdfData, $offset, 6)) { |
|
// start stream object |
|
$objtype = 'stream'; |
|
$offset += 6; |
|
if (1 == preg_match('/^([\r]?[\n])/isU', substr($pdfData, $offset), $matches)) { |
|
$offset += \strlen($matches[0]); |
|
$pregResult = preg_match( |
|
'/(endstream)[\x09\x0a\x0c\x0d\x20]/isU', |
|
substr($pdfData, $offset), |
|
$matches, |
|
PREG_OFFSET_CAPTURE |
|
); |
|
if (1 == $pregResult) { |
|
$objval = substr($pdfData, $offset, $matches[0][1]); |
|
$offset += $matches[1][1]; |
|
} |
|
} |
|
} elseif ('endstream' == substr($pdfData, $offset, 9)) { |
|
// end stream object |
|
$objtype = 'endstream'; |
|
$offset += 9; |
|
} elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($pdfData, $offset, 33), $matches)) { |
|
// indirect object reference |
|
$objtype = 'objref'; |
|
$offset += \strlen($matches[0]); |
|
$objval = (int) ($matches[1]).'_'.(int) ($matches[2]); |
|
} elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($pdfData, $offset, 33), $matches)) { |
|
// object start |
|
$objtype = 'obj'; |
|
$objval = (int) ($matches[1]).'_'.(int) ($matches[2]); |
|
$offset += \strlen($matches[0]); |
|
} elseif (($numlen = strspn($pdfData, '+-.0123456789', $offset)) > 0) { |
|
// numeric object |
|
$objtype = 'numeric'; |
|
$objval = substr($pdfData, $offset, $numlen); |
|
$offset += $numlen; |
|
} |
|
break; |
|
} |
|
|
|
return [$objtype, $objval, $offset]; |
|
} |
|
|
|
/** |
|
* Get Cross-Reference (xref) table and trailer data from PDF document data. |
|
* |
|
* @param string $pdfData |
|
* @param int $offset xref offset (if know) |
|
* @param array $xref previous xref array (if any) |
|
* |
|
* @return array containing xref and trailer data |
|
* |
|
* @throws Exception if it was unable to find startxref |
|
* @throws Exception if it was unable to find xref |
|
*/ |
|
protected function getXrefData($pdfData, $offset = 0, $xref = []) |
|
{ |
|
$startxrefPreg = preg_match( |
|
'/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i', |
|
$pdfData, |
|
$matches, |
|
PREG_OFFSET_CAPTURE, |
|
$offset |
|
); |
|
|
|
if (0 == $offset) { |
|
// find last startxref |
|
$pregResult = preg_match_all( |
|
'/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i', |
|
$pdfData, $matches, |
|
PREG_SET_ORDER, |
|
$offset |
|
); |
|
if (0 == $pregResult) { |
|
throw new Exception('Unable to find startxref'); |
|
} |
|
$matches = array_pop($matches); |
|
$startxref = $matches[1]; |
|
} elseif (strpos($pdfData, 'xref', $offset) == $offset) { |
|
// Already pointing at the xref table |
|
$startxref = $offset; |
|
} elseif (preg_match('/([0-9]+[\s][0-9]+[\s]obj)/i', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset)) { |
|
// Cross-Reference Stream object |
|
$startxref = $offset; |
|
} elseif ($startxrefPreg) { |
|
// startxref found |
|
$startxref = $matches[1][0]; |
|
} else { |
|
throw new Exception('Unable to find startxref'); |
|
} |
|
|
|
if ($startxref > \strlen($pdfData)) { |
|
throw new Exception('Unable to find xref (PDF corrupted?)'); |
|
} |
|
|
|
// check xref position |
|
if (strpos($pdfData, 'xref', $startxref) == $startxref) { |
|
// Cross-Reference |
|
$xref = $this->decodeXref($pdfData, $startxref, $xref); |
|
} else { |
|
// Cross-Reference Stream |
|
$xref = $this->decodeXrefStream($pdfData, $startxref, $xref); |
|
} |
|
if (empty($xref)) { |
|
throw new Exception('Unable to find xref'); |
|
} |
|
|
|
return $xref; |
|
} |
|
|
|
/** |
|
* Parses PDF data and returns extracted data as array. |
|
* |
|
* @param string $data PDF data to parse |
|
* |
|
* @return array array of parsed PDF document objects |
|
* |
|
* @throws Exception if empty PDF data given |
|
* @throws Exception if PDF data missing %PDF header |
|
*/ |
|
public function parseData($data) |
|
{ |
|
if (empty($data)) { |
|
throw new Exception('Empty PDF data given.'); |
|
} |
|
// find the pdf header starting position |
|
if (false === ($trimpos = strpos($data, '%PDF-'))) { |
|
throw new Exception('Invalid PDF data: missing %PDF header.'); |
|
} |
|
|
|
// get PDF content string |
|
$pdfData = substr($data, $trimpos); |
|
|
|
// get xref and trailer data |
|
$xref = $this->getXrefData($pdfData); |
|
|
|
// parse all document objects |
|
$objects = []; |
|
foreach ($xref['xref'] as $obj => $offset) { |
|
if (!isset($objects[$obj]) && ($offset > 0)) { |
|
// decode objects with positive offset |
|
$objects[$obj] = $this->getIndirectObject($pdfData, $xref, $obj, $offset, true); |
|
} |
|
} |
|
|
|
return [$xref, $objects]; |
|
} |
|
}
|
|
|