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pdf_parser.php
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pdf_parser.php
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<?php
/**
* This file is part of FPDI
*
* @package FPDI
* @copyright Copyright (c) 2015 Setasign - Jan Slabon (http://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License
* @version 1.6.1
*/
/**
* PLEASE NOTE THAT THIS FILE IS PROCESSED PROGRAMMATICALLY FOR THE itbz\fpdi
* RELEASE BUG REPORTS AND SUGGESTED CHANGES SHOULD BE DIRECTED TO SETASIGN
* DIRECTLY BUGS RELATED TO THIS CONVERSION CAN BE REPORTED AT
* https://github.com/hanneskod/fpdi/issues
*/
namespace fpdi {
class pdf_parser
{
const TYPE_NULL = 0;
const TYPE_NUMERIC = 1;
const TYPE_TOKEN = 2;
const TYPE_HEX = 3;
const TYPE_STRING = 4;
const TYPE_DICTIONARY = 5;
const TYPE_ARRAY = 6;
const TYPE_OBJDEC = 7;
const TYPE_OBJREF = 8;
const TYPE_OBJECT = 9;
const TYPE_STREAM = 10;
const TYPE_BOOLEAN = 11;
const TYPE_REAL = 12;
public static $searchForStartxrefLength = 5500;
public $filename;
protected $_f;
protected $_c;
protected $_xref;
protected $_root;
protected $_pdfVersion;
protected $_readPlain = true;
protected $_currentObj;
public function __construct($filename)
{
$this->filename = $filename;
$this->_f = @fopen($this->filename, 'rb');
if (!$this->_f) {
throw new \InvalidArgumentException(sprintf('Cannot open %s !', $filename));
}
$this->getPdfVersion();
if (!class_exists('pdf_context')) {
}
$this->_c = new \fpdi\pdf_context($this->_f);
$this->_xref = array();
$this->_readXref($this->_xref, $this->_findXref());
$this->getEncryption();
$this->_readRoot();
}
public function __destruct()
{
$this->closeFile();
}
public function closeFile()
{
if (isset($this->_f) && is_resource($this->_f)) {
fclose($this->_f);
unset($this->_f);
}
}
public function getEncryption()
{
if (isset($this->_xref['trailer'][1]['/Encrypt'])) {
throw new \Exception('File is encrypted!');
}
}
public function getPdfVersion()
{
if ($this->_pdfVersion === null) {
fseek($this->_f, 0);
preg_match('/\\d\\.\\d/', fread($this->_f, 16), $m);
if (isset($m[0])) {
$this->_pdfVersion = $m[0];
}
}
return $this->_pdfVersion;
}
protected function _readRoot()
{
if ($this->_xref['trailer'][1]['/Root'][0] != self::TYPE_OBJREF) {
throw new \Exception('Wrong Type of Root-Element! Must be an indirect reference');
}
$this->_root = $this->resolveObject($this->_xref['trailer'][1]['/Root']);
}
protected function _findXref()
{
$toRead = self::$searchForStartxrefLength;
$stat = fseek($this->_f, -$toRead, SEEK_END);
if ($stat === -1) {
fseek($this->_f, 0);
}
$data = fread($this->_f, $toRead);
$keywordPos = strpos(strrev($data), strrev('startxref'));
if (false === $keywordPos) {
$keywordPos = strpos(strrev($data), strrev('startref'));
}
if (false === $keywordPos) {
throw new \Exception('Unable to find "startxref" keyword.');
}
$pos = strlen($data) - $keywordPos;
$data = substr($data, $pos);
if (!preg_match('/\\s*(\\d+).*$/s', $data, $matches)) {
throw new \Exception('Unable to find pointer to xref table.');
}
return (int) $matches[1];
}
protected function _readXref(&$result, $offset)
{
$tempPos = $offset - min(20, $offset);
fseek($this->_f, $tempPos);
$data = fread($this->_f, 100);
$xrefPos = strrpos($data, 'xref');
if ($xrefPos === false) {
$this->_c->reset($offset);
$xrefStreamObjDec = $this->_readValue($this->_c);
if (is_array($xrefStreamObjDec) && isset($xrefStreamObjDec[0]) && $xrefStreamObjDec[0] == self::TYPE_OBJDEC) {
throw new \Exception(sprintf('This document (%s) probably uses a compression technique which is not supported by the ' . 'free parser shipped with FPDI. (See https://www.setasign.com/fpdi-pdf-parser for more details)', $this->filename));
} else {
throw new \Exception('Unable to find xref table.');
}
}
if (!isset($result['xrefLocation'])) {
$result['xrefLocation'] = $tempPos + $xrefPos;
$result['maxObject'] = 0;
}
$cycles = -1;
$bytesPerCycle = 100;
fseek($this->_f, $tempPos = $tempPos + $xrefPos + 4);
$data = fread($this->_f, $bytesPerCycle);
while (($trailerPos = strpos($data, 'trailer', max($bytesPerCycle * $cycles++, 0))) === false && !feof($this->_f)) {
$data .= fread($this->_f, $bytesPerCycle);
}
if ($trailerPos === false) {
throw new \Exception('Trailer keyword not found after xref table');
}
$data = ltrim(substr($data, 0, $trailerPos));
$found = preg_match_all('/(
|
|)/', substr($data, 0, 100), $m);
if ($found === 0) {
throw new \Exception('Xref table seems to be corrupted.');
}
$differentLineEndings = count(array_unique($m[0]));
if ($differentLineEndings > 1) {
$lines = preg_split('/(
|
|)/', $data, -1, PREG_SPLIT_NO_EMPTY);
} else {
$lines = explode($m[0][0], $data);
}
$data = $differentLineEndings = $m = null;
unset($data, $differentLineEndings, $m);
$linesCount = count($lines);
$start = 1;
for ($i = 0; $i < $linesCount; $i++) {
$line = trim($lines[$i]);
if ($line) {
$pieces = explode(' ', $line);
$c = count($pieces);
switch ($c) {
case 2:
$start = (int) $pieces[0];
$end = $start + (int) $pieces[1];
if ($end > $result['maxObject']) {
$result['maxObject'] = $end;
}
break;
case 3:
if (!isset($result['xref'][$start])) {
$result['xref'][$start] = array();
}
if (!array_key_exists($gen = (int) $pieces[1], $result['xref'][$start])) {
$result['xref'][$start][$gen] = $pieces[2] == 'n' ? (int) $pieces[0] : null;
}
$start++;
break;
default:
throw new \Exception('Unexpected data in xref table');
}
}
}
$lines = $pieces = $line = $start = $end = $gen = null;
unset($lines, $pieces, $line, $start, $end, $gen);
$this->_c->reset($tempPos + $trailerPos + 7);
$trailer = $this->_readValue($this->_c);
if (!isset($result['trailer'])) {
$result['trailer'] = $trailer;
}
if (isset($trailer[1]['/Prev'])) {
$this->_readXref($result, $trailer[1]['/Prev'][1]);
}
$trailer = null;
unset($trailer);
return true;
}
protected function _readValue(&$c, $token = null)
{
if (is_null($token)) {
$token = $this->_readToken($c);
}
if ($token === false) {
return false;
}
switch ($token) {
case '<':
$pos = $c->offset;
while (1) {
$match = strpos($c->buffer, '>', $pos);
if ($match === false) {
if (!$c->increaseLength()) {
return false;
} else {
continue;
}
}
$result = substr($c->buffer, $c->offset, $match - $c->offset);
$c->offset = $match + 1;
return array(self::TYPE_HEX, $result);
}
break;
case '<<':
$result = array();
while (($key = $this->_readToken($c)) !== '>>') {
if ($key === false) {
return false;
}
if (($value = $this->_readValue($c)) === false) {
return false;
}
if ($value[0] == self::TYPE_TOKEN && $value[1] == '>>') {
$result[$key] = array(self::TYPE_NULL);
break;
}
$result[$key] = $value;
}
return array(self::TYPE_DICTIONARY, $result);
case '[':
$result = array();
while (($token = $this->_readToken($c)) !== ']') {
if ($token === false) {
return false;
}
if (($value = $this->_readValue($c, $token)) === false) {
return false;
}
$result[] = $value;
}
return array(self::TYPE_ARRAY, $result);
case '(':
$pos = $c->offset;
$openBrackets = 1;
do {
for (; $openBrackets != 0 && $pos < $c->length; $pos++) {
switch (ord($c->buffer[$pos])) {
case 40:
$openBrackets++;
break;
case 41:
$openBrackets--;
break;
case 92:
$pos++;
}
}
} while ($openBrackets != 0 && $c->increaseLength());
$result = substr($c->buffer, $c->offset, $pos - $c->offset - 1);
$c->offset = $pos;
return array(self::TYPE_STRING, $result);
case 'stream':
$tempPos = $c->getPos() - strlen($c->buffer);
$tempOffset = $c->offset;
$c->reset($startPos = $tempPos + $tempOffset);
while ($c->buffer[0] !== chr(10) && $c->buffer[0] !== chr(13)) {
$c->reset(++$startPos);
if ($c->ensureContent() === false) {
throw new \Exception('Unable to parse stream data. No newline followed the stream keyword.');
}
}
$e = 0;
if ($c->buffer[0] == chr(10) || $c->buffer[0] == chr(13)) {
$e++;
}
if ($c->buffer[1] == chr(10) && $c->buffer[0] != chr(10)) {
$e++;
}
if ($this->_currentObj[1][1]['/Length'][0] == self::TYPE_OBJREF) {
$tmpLength = $this->resolveObject($this->_currentObj[1][1]['/Length']);
$length = $tmpLength[1][1];
} else {
$length = $this->_currentObj[1][1]['/Length'][1];
}
if ($length > 0) {
$c->reset($startPos + $e, $length);
$v = $c->buffer;
} else {
$v = '';
}
$c->reset($startPos + $e + $length);
$endstream = $this->_readToken($c);
if ($endstream != 'endstream') {
$c->reset($startPos + $e + $length + 9);
}
return array(self::TYPE_STREAM, $v);
default:
if (is_numeric($token)) {
if (($tok2 = $this->_readToken($c)) !== false) {
if (is_numeric($tok2)) {
if (($tok3 = $this->_readToken($c)) !== false) {
switch ($tok3) {
case 'obj':
return array(self::TYPE_OBJDEC, (int) $token, (int) $tok2);
case 'R':
return array(self::TYPE_OBJREF, (int) $token, (int) $tok2);
}
array_push($c->stack, $tok3);
}
}
array_push($c->stack, $tok2);
}
if ($token === (string) (int) $token) {
return array(self::TYPE_NUMERIC, (int) $token);
} else {
return array(self::TYPE_REAL, (double) $token);
}
} else {
if ($token == 'true' || $token == 'false') {
return array(self::TYPE_BOOLEAN, $token == 'true');
} else {
if ($token == 'null') {
return array(self::TYPE_NULL);
} else {
return array(self::TYPE_TOKEN, $token);
}
}
}
}
}
public function resolveObject($objSpec)
{
$c = $this->_c;
if (!is_array($objSpec)) {
return false;
}
if ($objSpec[0] == self::TYPE_OBJREF) {
if (isset($this->_xref['xref'][$objSpec[1]][$objSpec[2]])) {
$oldPos = $c->getPos();
$c->reset($this->_xref['xref'][$objSpec[1]][$objSpec[2]]);
$header = $this->_readValue($c);
if ($header[0] != self::TYPE_OBJDEC || $header[1] != $objSpec[1] || $header[2] != $objSpec[2]) {
$toSearchFor = $objSpec[1] . ' ' . $objSpec[2] . ' obj';
if (preg_match('/' . $toSearchFor . '/', $c->buffer)) {
$c->offset = strpos($c->buffer, $toSearchFor) + strlen($toSearchFor);
$c->stack = array();
} else {
throw new \Exception(sprintf('Unable to find object (%s, %s) at expected location.', $objSpec[1], $objSpec[2]));
}
}
$result = array(self::TYPE_OBJECT, 'obj' => $objSpec[1], 'gen' => $objSpec[2]);
$this->_currentObj =& $result;
while (true) {
$value = $this->_readValue($c);
if ($value === false || count($result) > 4) {
break;
}
if ($value[0] == self::TYPE_TOKEN && $value[1] === 'endobj') {
break;
}
$result[] = $value;
}
$c->reset($oldPos);
if (isset($result[2][0]) && $result[2][0] == self::TYPE_STREAM) {
$result[0] = self::TYPE_STREAM;
}
} else {
throw new \Exception(sprintf('Unable to find object (%s, %s) at expected location.', $objSpec[1], $objSpec[2]));
}
return $result;
} else {
return $objSpec;
}
}
protected function _readToken($c)
{
if (count($c->stack)) {
return array_pop($c->stack);
}
do {
if (!$c->ensureContent()) {
return false;
}
$c->offset += strspn($c->buffer, '
', $c->offset);
} while ($c->offset >= $c->length - 1);
$char = $c->buffer[$c->offset++];
switch ($char) {
case '[':
case ']':
case '(':
case ')':
return $char;
case '<':
case '>':
if ($c->buffer[$c->offset] == $char) {
if (!$c->ensureContent()) {
return false;
}
$c->offset++;
return $char . $char;
} else {
return $char;
}
case '%':
$pos = $c->offset;
while (1) {
$match = preg_match('/(
||
)/', $c->buffer, $m, PREG_OFFSET_CAPTURE, $pos);
if ($match === 0) {
if (!$c->increaseLength()) {
return false;
} else {
continue;
}
}
$c->offset = $m[0][1] + strlen($m[0][0]);
return $this->_readToken($c);
}
default:
if (!$c->ensureContent()) {
return false;
}
while (1) {
$pos = strcspn($c->buffer, ' %[]<>()/
', $c->offset);
if ($c->offset + $pos <= $c->length - 1) {
break;
} else {
$c->increaseLength();
}
}
$result = substr($c->buffer, $c->offset - 1, $pos + 1);
$c->offset += $pos;
return $result;
}
}
protected function _unFilterStream($obj)
{
$filters = array();
if (isset($obj[1][1]['/Filter'])) {
$filter = $obj[1][1]['/Filter'];
if ($filter[0] == \fpdi\pdf_parser::TYPE_OBJREF) {
$tmpFilter = $this->resolveObject($filter);
$filter = $tmpFilter[1];
}
if ($filter[0] == \fpdi\pdf_parser::TYPE_TOKEN) {
$filters[] = $filter;
} else {
if ($filter[0] == \fpdi\pdf_parser::TYPE_ARRAY) {
$filters = $filter[1];
}
}
}
$stream = $obj[2][1];
foreach ($filters as $filter) {
switch ($filter[1]) {
case '/FlateDecode':
case '/Fl':
if (function_exists('gzuncompress')) {
$oStream = $stream;
$stream = strlen($stream) > 0 ? @gzuncompress($stream) : '';
} else {
throw new \Exception(sprintf('To handle %s filter, please compile php with zlib support.', $filter[1]));
}
if ($stream === false) {
$tries = 0;
while ($tries < 8 && ($stream === false || strlen($stream) < strlen($oStream))) {
$oStream = substr($oStream, 1);
$stream = @gzinflate($oStream);
$tries++;
}
if ($stream === false) {
throw new \Exception('Error while decompressing stream.');
}
}
break;
case '/LZWDecode':
if (!class_exists('FilterLZW')) {
}
$decoder = new \fpdi\FilterLZW();
$stream = $decoder->decode($stream);
break;
case '/ASCII85Decode':
if (!class_exists('FilterASCII85')) {
}
$decoder = new \fpdi\FilterASCII85();
$stream = $decoder->decode($stream);
break;
case '/ASCIIHexDecode':
if (!class_exists('FilterASCIIHexDecode')) {
}
$decoder = new \fpdi\FilterASCIIHexDecode();
$stream = $decoder->decode($stream);
break;
case null:
break;
default:
throw new \Exception(sprintf('Unsupported Filter: %s', $filter[1]));
}
}
return $stream;
}
}
}