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tcpdf/tcpdf_parser.php
nicolaasuni 542c27f159 5.9.160
2012-05-03 22:57:49 +01:00

511 lines
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<?php
//============================================================+
// File name : tcpdf_parser.php
// Version : 1.0.001
// Begin : 2011-05-23
// Last Update : 2012-05-03
// Author : Nicola Asuni - Tecnick.com LTD - Manor Coach House, Church Hill, Aldershot, Hants, GU12 4RQ, UK - www.tecnick.com - info@tecnick.com
// License : http://www.tecnick.com/pagefiles/tcpdf/LICENSE.TXT GNU-LGPLv3
// -------------------------------------------------------------------
// Copyright (C) 2011-2012 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.
//
//============================================================+
/**
* @file
* This is a PHP class for parsing PDF documents.<br>
* @package com.tecnick.tcpdf
* @author Nicola Asuni
* @version 1.0.001
*/
// include class for decoding filters
require_once(dirname(__FILE__).'/tcpdf_filters.php');
/**
* @class TCPDF_PARSER
* This is a PHP class for parsing PDF documents.<br>
* @package com.tecnick.tcpdf
* @brief This is a PHP class for parsing PDF documents..
* @version 1.0.001
* @author Nicola Asuni - info@tecnick.com
*/
class TCPDF_PARSER {
/**
* Raw content of the PDF document.
* @private
*/
private $pdfdata = '';
/**
* XREF data.
* @protected
*/
protected $xref = array();
/**
* Array of PDF objects.
* @protected
*/
protected $objects = array();
/**
* Class object for decoding filters.
* @private
*/
private $FilterDecoders;
// -----------------------------------------------------------------------------
/**
* Parse a PDF document an return an array of objects.
* @param $data (string) PDF data to parse.
* @public
* @since 1.0.000 (2011-05-24)
*/
public function __construct($data) {
if (empty($data)) {
$this->Error('Empty PDF data.');
}
$this->pdfdata = $data;
// get length
$pdflen = strlen($this->pdfdata);
// initialize class for decoding filters
$this->FilterDecoders = new TCPDF_FILTERS();
// get xref and trailer data
$this->xref = $this->getXrefData();
// parse all document objects
$this->objects = array();
foreach ($this->xref['xref'] as $obj => $offset) {
if (!isset($this->objects[$obj])) {
$this->objects[$obj] = $this->getIndirectObject($obj, $offset, true);
}
}
// release some memory
unset($this->pdfdata);
$this->pdfdata = '';
}
/**
* Return an array of parsed PDF document objects.
* @return (array) Array of parsed PDF document objects.
* @public
* @since 1.0.000 (2011-06-26)
*/
public function getParsedData() {
return array($this->xref, $this->objects);
}
/**
* Get xref (cross-reference table) and trailer data from PDF document data.
* @param $offset (int) xref offset (if know).
* @param $xref (array) previous xref array (if any).
* @return Array containing xref and trailer data.
* @protected
* @since 1.0.000 (2011-05-24)
*/
protected function getXrefData($offset=0, $xref=array()) {
if ($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];
} else {
// get the first xref at the specified offset
if (preg_match('/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) == 0) {
$this->Error('Unable to find startxref');
}
$startxref = $matches[1][0];
}
// check xref position
if (strpos($this->pdfdata, 'xref', $startxref) != $startxref) {
$this->Error('Unable to find xref');
}
// extract xref data (object indexes and offsets)
$xoffset = $startxref + 5;
// initialize object number
$obj_num = 0;
$offset = $xoffset;
while (preg_match('/^([0-9]+)[\s]([0-9]+)[\s]?([nf]?)/im', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
$offset = (strlen($matches[0][0]) + $matches[0][1]);
if ($matches[3][0] == 'n') {
// create unique object index: [object number]_[generation number]
$index = $obj_num.'_'.intval($matches[2][0]);
// check if object already exist
if (!isset($xref['xref'][$index])) {
// store object offset position
$xref['xref'][$index] = intval($matches[1][0]);
}
++$obj_num;
$offset += 2;
} elseif ($matches[3][0] == 'f') {
++$obj_num;
$offset += 2;
} else {
// object number (index)
$obj_num = intval($matches[1][0]);
}
}
// get trailer data
if (preg_match('/trailer[\s]*<<(.*)>>[\s]*[\r\n]+startxref[\s]*[\r\n]+/isU', $this->pdfdata, $matches, PREG_OFFSET_CAPTURE, $xoffset) > 0) {
$trailer_data = $matches[1][0];
if (!isset($xref['trailer'])) {
// get only the last updated version
$xref['trailer'] = array();
// parse trailer_data
if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
$xref['trailer']['size'] = intval($matches[1]);
}
if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
$xref['trailer']['root'] = intval($matches[1]).'_'.intval($matches[2]);
}
if (preg_match('/Encrypt[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
$xref['trailer']['encrypt'] = intval($matches[1]).'_'.intval($matches[2]);
}
if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
$xref['trailer']['info'] = intval($matches[1]).'_'.intval($matches[2]);
}
if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) {
$xref['trailer']['id'] = array();
$xref['trailer']['id'][0] = $matches[1];
$xref['trailer']['id'][1] = $matches[2];
}
}
if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
// get previous xref
$xref = $this->getXrefData(intval($matches[1]), $xref);
}
} else {
$this->Error('Unable to find trailer');
}
return $xref;
}
/**
* Get object type, raw value and offset to next object
* @param $offset (int) Object offset.
* @return array containing object type, raw value and offset to next object
* @protected
* @since 1.0.000 (2011-06-20)
*/
protected function getRawObject($offset=0) {
$objtype = ''; // object type to be returned
$objval = ''; // object value to be returned
// skip initial white space chars: \x00 null (NUL), \x09 horizontal tab (HT), \x0A line feed (LF), \x0C form feed (FF), \x0D carriage return (CR), \x20 space (SP)
$offset += strspn($this->pdfdata, "\x00\x09\x0a\x0c\x0d\x20", $offset);
// get first char
$char = $this->pdfdata{$offset};
// get object type
switch ($char) {
case '%': { // \x25 PERCENT SIGN
// skip comment and search for next token
$next = strcspn($this->pdfdata, "\r\n", $offset);
if ($next > 0) {
$offset += $next;
return $this->getRawObject($this->pdfdata, $offset);
}
break;
}
case '/': { // \x2F SOLIDUS
// name object
$objtype = $char;
++$offset;
if (preg_match('/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/', substr($this->pdfdata, $offset, 256), $matches) == 1) {
$objval = $matches[1]; // unescaped value
$offset += strlen($objval);
}
break;
}
case '(': // \x28 LEFT PARENTHESIS
case ')': { // \x29 RIGHT PARENTHESIS
// literal string object
$objtype = $char;
++$offset;
$strpos = $offset;
if ($char == '(') {
$open_bracket = 1;
while ($open_bracket > 0) {
if (!isset($this->pdfdata{$strpos})) {
break;
}
$ch = $this->pdfdata{$strpos};
switch ($ch) {
case '\\': { // REVERSE SOLIDUS (5Ch) (Backslash)
// skip next character
++$strpos;
break;
}
case '(': { // LEFT PARENHESIS (28h)
++$open_bracket;
break;
}
case ')': { // RIGHT PARENTHESIS (29h)
--$open_bracket;
break;
}
}
++$strpos;
}
$objval = substr($this->pdfdata, $offset, ($strpos - $offset - 1));
$offset = $strpos;
}
break;
}
case '[': // \x5B LEFT SQUARE BRACKET
case ']': { // \x5D RIGHT SQUARE BRACKET
// array object
$objtype = $char;
++$offset;
if ($char == '[') {
// get array content
$objval = array();
do {
// get element
$element = $this->getRawObject($offset);
$offset = $element[2];
$objval[] = $element;
} while ($element[0] != ']');
// remove closing delimiter
array_pop($objval);
}
break;
}
case '<': // \x3C LESS-THAN SIGN
case '>': { // \x3E GREATER-THAN SIGN
if (isset($this->pdfdata{($offset + 1)}) AND ($this->pdfdata{($offset + 1)} == $char)) {
// dictionary object
$objtype = $char.$char;
$offset += 2;
if ($char == '<') {
// get array content
$objval = array();
do {
// get element
$element = $this->getRawObject($offset);
$offset = $element[2];
$objval[] = $element;
} while ($element[0] != '>>');
// remove closing delimiter
array_pop($objval);
}
} else {
// hexadecimal string object
$objtype = $char;
++$offset;
if (($char == '<') AND (preg_match('/^([0-9A-Fa-f]+)[>]/iU', substr($this->pdfdata, $offset), $matches) == 1)) {
$objval = $matches[1];
$offset += strlen($matches[0]);
}
}
break;
}
default: {
if (substr($this->pdfdata, $offset, 6) == 'endobj') {
// indirect object
$objtype = 'endobj';
$offset += 6;
} elseif (substr($this->pdfdata, $offset, 4) == 'null') {
// null object
$objtype = 'null';
$offset += 4;
$objval = 'null';
} elseif (substr($this->pdfdata, $offset, 4) == 'true') {
// boolean true object
$objtype = 'boolean';
$offset += 4;
$objval = 'true';
} elseif (substr($this->pdfdata, $offset, 5) == 'false') {
// boolean false object
$objtype = 'boolean';
$offset += 5;
$objval = 'false';
} elseif (substr($this->pdfdata, $offset, 6) == 'stream') {
// start stream object
$objtype = 'stream';
$offset += 6;
if (preg_match('/^[\r\n]+(.*)[\r\n]*endstream/isU', substr($this->pdfdata, $offset), $matches) == 1) {
$objval = $matches[1];
$offset += strlen($matches[0]);
}
} elseif (substr($this->pdfdata, $offset, 9) == 'endstream') {
// end stream object
$objtype = 'endstream';
$offset += 9;
} elseif (preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($this->pdfdata, $offset, 33), $matches) == 1) {
// indirect object reference
$objtype = 'ojbref';
$offset += strlen($matches[0]);
$objval = intval($matches[1]).'_'.intval($matches[2]);
} elseif (preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($this->pdfdata, $offset, 33), $matches) == 1) {
// object start
$objtype = 'ojb';
$objval = intval($matches[1]).'_'.intval($matches[2]);
$offset += strlen ($matches[0]);
} elseif (($numlen = strspn($this->pdfdata, '+-.0123456789', $offset)) > 0) {
// numeric object
$objtype = 'numeric';
$objval = substr($this->pdfdata, $offset, $numlen);
$offset += $numlen;
}
break;
}
}
return array($objtype, $objval, $offset);
}
/**
* Get content of indirect object.
* @param $obj_ref (string) Object number and generation number separated by underscore character.
* @param $offset (int) Object offset.
* @param $decoding (boolean) If true decode streams.
* @return array containing object data.
* @protected
* @since 1.0.000 (2011-05-24)
*/
protected function getIndirectObject($obj_ref, $offset=0, $decoding=true) {
$obj = explode('_', $obj_ref);
if (($obj === false) OR (count($obj) != 2)) {
$this->Error('Invalid object reference: '.$obj);
return;
}
$objref = $obj[0].' '.$obj[1].' obj';
if (strpos($this->pdfdata, $objref, $offset) != $offset) {
// an indirect reference to an undefined object shall be considered a reference to the null object
return array('null', 'null', $offset);
}
// starting position of object content
$offset += strlen($objref);
// get array of object content
$objdata = array();
$i = 0; // object main index
do {
// get element
$element = $this->getRawObject($offset);
$offset = $element[2];
// decode stream using stream's dictionary information
if ($decoding AND ($element[0] == 'stream') AND (isset($objdata[($i - 1)][0])) AND ($objdata[($i - 1)][0] == '<<')) {
$element[3] = $this->decodeStream($objdata[($i - 1)][1], substr($element[1], 1));
}
$objdata[$i] = $element;
++$i;
} while ($element[0] != 'endobj');
// remove closing delimiter
array_pop($objdata);
// return raw object content
return $objdata;
}
/**
* Get the content of object, resolving indect object reference if necessary.
* @param $obj (string) Object value.
* @return array containing object data.
* @protected
* @since 1.0.000 (2011-06-26)
*/
protected function getObjectVal($obj) {
if ($obj[0] == 'objref') {
// reference to indirect object
if (isset($this->objects[$obj[1]])) {
// this object has been already parsed
return $this->objects[$obj[1]];
} elseif (isset($this->xref[$obj[1]])) {
// parse new object
$this->objects[$obj[1]] = $this->getIndirectObject($obj[1], $this->xref[$obj[1]], false);
return $this->objects[$obj[1]];
}
}
return $obj;
}
/**
* Decode the specified stream.
* @param $sdic (array) Stream's dictionary array.
* @param $stream (string) Stream to decode.
* @return array containing decoded stream data and remaining filters.
* @protected
* @since 1.0.000 (2011-06-22)
*/
protected function decodeStream($sdic, $stream) {
// get stream lenght and filters
$slength = strlen($stream);
$filters = array();
foreach ($sdic as $k => $v) {
if ($v[0] == '/') {
if (($v[1] == 'Length') AND (isset($sdic[($k + 1)])) AND ($sdic[($k + 1)][0] == 'numeric')) {
// get declared stream lenght
$declength = intval($sdic[($k + 1)][1]);
if ($declength < $slength) {
$stream = substr($stream, 0, $declength);
$slength = $declength;
}
} elseif (($v[1] == 'Filter') AND (isset($sdic[($k + 1)]))) {
// resolve indirect object
$objval = $this->getObjectVal($sdic[($k + 1)]);
if ($objval[0] == '/') {
// single filter
$filters[] = $objval[1];
} elseif ($objval[0] == '[') {
// array of filters
foreach ($objval[1] as $flt) {
if ($flt[0] == '/') {
$filters[] = $flt[1];
}
}
}
}
}
}
// decode the stream
$remaining_filters = array();
foreach ($filters as $filter) {
if (in_array($filter, $this->FilterDecoders->getAvailableFilters())) {
$stream = $this->FilterDecoders->decodeFilter($filter, $stream);
} else {
// add missing filter to array
$remaining_filters[] = $filter;
}
}
return array($stream, $remaining_filters);
}
/**
* This method is automatically called in case of fatal error; it simply outputs the message and halts the execution.
* @param $msg (string) The error message
* @public
* @since 1.0.000 (2011-05-23)
*/
public function Error($msg) {
// exit program and print error
die('<strong>TCPDF_PARSER ERROR: </strong>'.$msg);
}
} // END OF TCPDF_PARSER CLASS
//============================================================+
// END OF FILE
//============================================================+
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