Passed
Pull Request — master (#400)
by Sebastien
04:40 queued 02:27
created

RawDataParser::decodeXrefStream()   F

Complexity

Conditions 79
Paths 1536

Size

Total Lines 238
Code Lines 153

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 113
CRAP Score 127.8868

Importance

Changes 3
Bugs 1 Features 1
Metric Value
cc 79
eloc 153
c 3
b 1
f 1
nc 1536
nop 3
dl 0
loc 238
ccs 113
cts 141
cp 0.8014
crap 127.8868
rs 0

How to fix   Long Method    Complexity   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

1
<?php
2
3
/**
4
 * This file is based on code of tecnickcom/TCPDF PDF library.
5
 *
6
 * Original author Nicola Asuni ([email protected]) and
7
 * contributors (https://github.com/tecnickcom/TCPDF/graphs/contributors).
8
 *
9
 * @see https://github.com/tecnickcom/TCPDF
10
 *
11
 * Original code was licensed on the terms of the LGPL v3.
12
 *
13
 * ------------------------------------------------------------------------------
14
 *
15
 * @file This file is part of the PdfParser library.
16
 *
17
 * @author  Konrad Abicht <[email protected]>
18
 * @date    2020-01-06
19
 *
20
 * @license LGPLv3
21
 * @url     <https://github.com/smalot/pdfparser>
22
 *
23
 *  PdfParser is a pdf library written in PHP, extraction oriented.
24
 *  Copyright (C) 2017 - Sébastien MALOT <[email protected]>
25
 *
26
 *  This program is free software: you can redistribute it and/or modify
27
 *  it under the terms of the GNU Lesser General Public License as published by
28
 *  the Free Software Foundation, either version 3 of the License, or
29
 *  (at your option) any later version.
30
 *
31
 *  This program is distributed in the hope that it will be useful,
32
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
33
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
34
 *  GNU Lesser General Public License for more details.
35
 *
36
 *  You should have received a copy of the GNU Lesser General Public License
37
 *  along with this program.
38
 *  If not, see <http://www.pdfparser.org/sites/default/LICENSE.txt>.
39
 */
40
41
namespace Smalot\PdfParser\RawData;
42
43
use Exception;
44
45
class RawDataParser
46
{
47
    /**
48
     * Configuration array.
49
     */
50
    protected $cfg = [
51
        // if `true` ignore filter decoding errors
52
        'ignore_filter_decoding_errors' => true,
53
        // if `true` ignore missing filter decoding errors
54
        'ignore_missing_filter_decoders' => true,
55
    ];
56
57
    protected $filterHelper;
58
    protected $objects;
59
60
    /**
61
     * @param array $cfg Configuration array, default is []
62
     */
63 31
    public function __construct($cfg = [])
64
    {
65
        // merge given array with default values
66 31
        $this->cfg = array_merge($this->cfg, $cfg);
67
68 31
        $this->filterHelper = new FilterHelper();
69 31
    }
70
71
    /**
72
     * Decode the specified stream.
73
     *
74
     * @param string $pdfData PDF data
75
     * @param array  $xref
76
     * @param array  $sdic    Stream's dictionary array
77
     * @param string $stream  Stream to decode
78
     *
79
     * @return array containing decoded stream data and remaining filters
80
     */
81 27
    protected function decodeStream($pdfData, $xref, $sdic, $stream)
82
    {
83
        // get stream length and filters
84 27
        $slength = \strlen($stream);
85 27
        if ($slength <= 0) {
86
            return ['', []];
87
        }
88 27
        $filters = [];
89 27
        foreach ($sdic as $k => $v) {
90 27
            if ('/' == $v[0]) {
91 27
                if (('Length' == $v[1]) && (isset($sdic[($k + 1)])) && ('numeric' == $sdic[($k + 1)][0])) {
92
                    // get declared stream length
93 26
                    $declength = (int) ($sdic[($k + 1)][1]);
94 26
                    if ($declength < $slength) {
95 26
                        $stream = substr($stream, 0, $declength);
96 26
                        $slength = $declength;
97
                    }
98 27
                } elseif (('Filter' == $v[1]) && (isset($sdic[($k + 1)]))) {
99
                    // resolve indirect object
100 27
                    $objval = $this->getObjectVal($pdfData, $xref, $sdic[($k + 1)]);
101 27
                    if ('/' == $objval[0]) {
102
                        // single filter
103 27
                        $filters[] = $objval[1];
104 1
                    } elseif ('[' == $objval[0]) {
105
                        // array of filters
106 1
                        foreach ($objval[1] as $flt) {
107 1
                            if ('/' == $flt[0]) {
108 1
                                $filters[] = $flt[1];
109
                            }
110
                        }
111
                    }
112
                }
113
            }
114
        }
115
116
        // decode the stream
117 27
        $remaining_filters = [];
118 27
        foreach ($filters as $filter) {
119 27
            if (\in_array($filter, $this->filterHelper->getAvailableFilters())) {
120
                try {
121 27
                    $stream = $this->filterHelper->decodeFilter($filter, $stream);
122 1
                } catch (Exception $e) {
123 1
                    $emsg = $e->getMessage();
124 1
                    if ((('~' == $emsg[0]) && !$this->cfg['ignore_missing_filter_decoders'])
125 1
                        || (('~' != $emsg[0]) && !$this->cfg['ignore_filter_decoding_errors'])
126
                    ) {
127 27
                        throw new Exception($e->getMessage());
128
                    }
129
                }
130
            } else {
131
                // add missing filter to array
132 4
                $remaining_filters[] = $filter;
133
            }
134
        }
135
136 27
        return [$stream, $remaining_filters];
137
    }
138
139
    /**
140
     * Decode the Cross-Reference section
141
     *
142
     * @param string $pdfData   PDF data
143
     * @param int    $startxref Offset at which the xref section starts (position of the 'xref' keyword)
144
     * @param array  $xref      Previous xref array (if any)
145
     *
146
     * @return array containing xref and trailer data
147
     */
148 22
    protected function decodeXref($pdfData, $startxref, $xref = [])
149
    {
150 22
        $startxref += 4; // 4 is the length of the word 'xref'
151
        // 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)
152 22
        $offset = $startxref + strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $startxref);
153
        // initialize object number
154 22
        $obj_num = 0;
155
        // search for cross-reference entries or subsection
156 22
        while (preg_match('/([0-9]+)[\x20]([0-9]+)[\x20]?([nf]?)(\r\n|[\x20]?[\r\n])/', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset) > 0) {
157 22
            if ($matches[0][1] != $offset) {
158
                // we are on another section
159 5
                break;
160
            }
161 22
            $offset += \strlen($matches[0][0]);
162 22
            if ('n' == $matches[3][0]) {
163
                // create unique object index: [object number]_[generation number]
164 22
                $index = $obj_num.'_'.(int) ($matches[2][0]);
165
                // check if object already exist
166 22
                if (!isset($xref['xref'][$index])) {
167
                    // store object offset position
168 22
                    $xref['xref'][$index] = (int) ($matches[1][0]);
169
                }
170 22
                ++$obj_num;
171 22
            } elseif ('f' == $matches[3][0]) {
172 22
                ++$obj_num;
173
            } else {
174
                // object number (index)
175 22
                $obj_num = (int) ($matches[1][0]);
176
            }
177
        }
178
        // get trailer data
179 22
        if (preg_match('/trailer[\s]*<<(.*)>>/isU', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset) > 0) {
180 22
            $trailer_data = $matches[1][0];
181 22
            if (!isset($xref['trailer']) || empty($xref['trailer'])) {
182
                // get only the last updated version
183 22
                $xref['trailer'] = [];
184
                // parse trailer_data
185 22
                if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
186 22
                    $xref['trailer']['size'] = (int) ($matches[1]);
187
                }
188 22
                if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
189 22
                    $xref['trailer']['root'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
190
                }
191 22
                if (preg_match('/Encrypt[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
192
                    $xref['trailer']['encrypt'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
193
                }
194 22
                if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
195 22
                    $xref['trailer']['info'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
196
                }
197 22
                if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) {
198 21
                    $xref['trailer']['id'] = [];
199 21
                    $xref['trailer']['id'][0] = $matches[1];
200 21
                    $xref['trailer']['id'][1] = $matches[2];
201
                }
202
            }
203 22
            if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
204
                // get previous xref
205 22
                $xref = $this->getXrefData($pdfData, (int) ($matches[1]), $xref);
206
            }
207
        } else {
208
            throw new Exception('Unable to find trailer');
209
        }
210
211 22
        return $xref;
212
    }
213
214
    /**
215
     * Decode the Cross-Reference Stream section
216
     *
217
     * @param string $pdfData   PDF data
218
     * @param int    $startxref Offset at which the xref section starts
219
     * @param array  $xref      Previous xref array (if any)
220
     *
221
     * @return array containing xref and trailer data
222
     *
223
     * @throws Exception if unknown PNG predictor detected
224
     */
225 6
    protected function decodeXrefStream($pdfData, $startxref, $xref = [])
226
    {
227
        // try to read Cross-Reference Stream
228 6
        $xrefobj = $this->getRawObject($pdfData, $startxref);
229 6
        $xrefcrs = $this->getIndirectObject($pdfData, $xref, $xrefobj[1], $startxref, true);
230 6
        if (!isset($xref['trailer']) || empty($xref['trailer'])) {
231
            // get only the last updated version
232 6
            $xref['trailer'] = [];
233 6
            $filltrailer = true;
234
        } else {
235 4
            $filltrailer = false;
236
        }
237 6
        if (!isset($xref['xref'])) {
238 6
            $xref['xref'] = [];
239
        }
240 6
        $valid_crs = false;
241 6
        $columns = 0;
242 6
        $sarr = $xrefcrs[0][1];
243 6
        if (!\is_array($sarr)) {
244
            $sarr = [];
245
        }
246
247 6
        $wb = [];
248
249 6
        foreach ($sarr as $k => $v) {
250
            if (
251 6
                ('/' == $v[0])
252 6
                && ('Type' == $v[1])
253
                && (
254 6
                    isset($sarr[($k + 1)])
255 6
                    && '/' == $sarr[($k + 1)][0]
256 6
                    && 'XRef' == $sarr[($k + 1)][1]
257
                )
258
            ) {
259 6
                $valid_crs = true;
260 6
            } elseif (('/' == $v[0]) && ('Index' == $v[1]) && (isset($sarr[($k + 1)]))) {
261
                // first object number in the subsection
262 4
                $index_first = (int) ($sarr[($k + 1)][1][0][1]);
263 6
            } elseif (('/' == $v[0]) && ('Prev' == $v[1]) && (isset($sarr[($k + 1)]) && ('numeric' == $sarr[($k + 1)][0]))) {
264
                // get previous xref offset
265 4
                $prevxref = (int) ($sarr[($k + 1)][1]);
266 6
            } elseif (('/' == $v[0]) && ('W' == $v[1]) && (isset($sarr[($k + 1)]))) {
267
                // number of bytes (in the decoded stream) of the corresponding field
268 6
                $wb[0] = (int) ($sarr[($k + 1)][1][0][1]);
269 6
                $wb[1] = (int) ($sarr[($k + 1)][1][1][1]);
270 6
                $wb[2] = (int) ($sarr[($k + 1)][1][2][1]);
271 6
            } elseif (('/' == $v[0]) && ('DecodeParms' == $v[1]) && (isset($sarr[($k + 1)][1]))) {
272 5
                $decpar = $sarr[($k + 1)][1];
273 5
                foreach ($decpar as $kdc => $vdc) {
274
                    if (
275 5
                        '/' == $vdc[0]
276 5
                        && 'Columns' == $vdc[1]
277
                        && (
278 5
                            isset($decpar[($kdc + 1)])
279 5
                            && 'numeric' == $decpar[($kdc + 1)][0]
280
                        )
281
                    ) {
282 5
                        $columns = (int) ($decpar[($kdc + 1)][1]);
283
                    } elseif (
284 5
                        '/' == $vdc[0]
285 5
                        && 'Predictor' == $vdc[1]
286
                        && (
287 5
                            isset($decpar[($kdc + 1)])
288 5
                            && 'numeric' == $decpar[($kdc + 1)][0]
289
                        )
290
                    ) {
291 5
                        $predictor = (int) ($decpar[($kdc + 1)][1]);
292
                    }
293
                }
294 6
            } elseif ($filltrailer) {
295 6
                if (('/' == $v[0]) && ('Size' == $v[1]) && (isset($sarr[($k + 1)]) && ('numeric' == $sarr[($k + 1)][0]))) {
296 6
                    $xref['trailer']['size'] = $sarr[($k + 1)][1];
297 6
                } elseif (('/' == $v[0]) && ('Root' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) {
298 6
                    $xref['trailer']['root'] = $sarr[($k + 1)][1];
299 6
                } elseif (('/' == $v[0]) && ('Info' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) {
300 6
                    $xref['trailer']['info'] = $sarr[($k + 1)][1];
301 6
                } elseif (('/' == $v[0]) && ('Encrypt' == $v[1]) && (isset($sarr[($k + 1)]) && ('objref' == $sarr[($k + 1)][0]))) {
302
                    $xref['trailer']['encrypt'] = $sarr[($k + 1)][1];
303 6
                } elseif (('/' == $v[0]) && ('ID' == $v[1]) && (isset($sarr[($k + 1)]))) {
304 6
                    $xref['trailer']['id'] = [];
305 6
                    $xref['trailer']['id'][0] = $sarr[($k + 1)][1][0][1];
306 6
                    $xref['trailer']['id'][1] = $sarr[($k + 1)][1][1][1];
307
                }
308
            }
309
        }
310
311
        // decode data
312 6
        if ($valid_crs && isset($xrefcrs[1][3][0])) {
313 6
            if (isset($predictor)) {
314
                // number of bytes in a row
315 5
                $rowlen = ($columns + 1);
316
                // convert the stream into an array of integers
317 5
                $sdata = unpack('C*', $xrefcrs[1][3][0]);
318
                // split the rows
319 5
                $sdata = array_chunk($sdata, $rowlen);
320
321
                // initialize decoded array
322 5
                $ddata = [];
323
                // initialize first row with zeros
324 5
                $prev_row = array_fill(0, $rowlen, 0);
325
                // for each row apply PNG unpredictor
326 5
                foreach ($sdata as $k => $row) {
327
                    // initialize new row
328 5
                    $ddata[$k] = [];
329
                    // get PNG predictor value
330 5
                    $predictor = (10 + $row[0]);
331
                    // for each byte on the row
332 5
                    for ($i = 1; $i <= $columns; ++$i) {
333
                        // new index
334 5
                        $j = ($i - 1);
335 5
                        $row_up = $prev_row[$j];
336 5
                        if (1 == $i) {
337 5
                            $row_left = 0;
338 5
                            $row_upleft = 0;
339
                        } else {
340 5
                            $row_left = $row[($i - 1)];
341 5
                            $row_upleft = $prev_row[($j - 1)];
342
                        }
343 5
                        switch ($predictor) {
344 5
                            case 10:  // PNG prediction (on encoding, PNG None on all rows)
345
                                $ddata[$k][$j] = $row[$i];
346
                                break;
347
348 5
                            case 11:  // PNG prediction (on encoding, PNG Sub on all rows)
349
                                $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
350
                                break;
351
352 5
                            case 12:  // PNG prediction (on encoding, PNG Up on all rows)
353 5
                                $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
354 5
                                break;
355
356
                            case 13:  // PNG prediction (on encoding, PNG Average on all rows)
357
                                $ddata[$k][$j] = (($row[$i] + (($row_left + $row_up) / 2)) & 0xff);
358
                                break;
359
360
                            case 14:  // PNG prediction (on encoding, PNG Paeth on all rows)
361
                                // initial estimate
362
                                $p = ($row_left + $row_up - $row_upleft);
363
                                // distances
364
                                $pa = abs($p - $row_left);
365
                                $pb = abs($p - $row_up);
366
                                $pc = abs($p - $row_upleft);
367
                                $pmin = min($pa, $pb, $pc);
368
                                // return minimum distance
369
                                switch ($pmin) {
370
                                    case $pa:
371
                                        $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
372
                                        break;
373
374
                                    case $pb:
375
                                        $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
376
                                        break;
377
378
                                    case $pc:
379
                                        $ddata[$k][$j] = (($row[$i] + $row_upleft) & 0xff);
380
                                        break;
381
                                }
382
                                break;
383
384
                            default:  // PNG prediction (on encoding, PNG optimum)
385
                                throw new Exception('Unknown PNG predictor: '.$predictor);
386
                        }
387
                    }
388 5
                    $prev_row = $ddata[$k];
389
                } // end for each row
390
                // complete decoding
391
            } else {
392
                // number of bytes in a row
393 2
                $rowlen = array_sum($wb);
394
                // convert the stream into an array of integers
395 2
                $sdata = unpack('C*', $xrefcrs[1][3][0]);
396
                // split the rows
397 2
                $ddata = array_chunk($sdata, $rowlen);
0 ignored issues
show
Bug introduced by
It seems like $rowlen can also be of type double; however, parameter $length of array_chunk() does only seem to accept integer, maybe add an additional type check? ( Ignorable by Annotation )

If this is a false-positive, you can also ignore this issue in your code via the ignore-type  annotation

397
                $ddata = array_chunk($sdata, /** @scrutinizer ignore-type */ $rowlen);
Loading history...
398
            }
399
400 6
            $sdata = [];
401
402
            // for every row
403 6
            foreach ($ddata as $k => $row) {
404
                // initialize new row
405 6
                $sdata[$k] = [0, 0, 0];
406 6
                if (0 == $wb[0]) {
407
                    // default type field
408
                    $sdata[$k][0] = 1;
409
                }
410 6
                $i = 0; // count bytes in the row
411
                // for every column
412 6
                for ($c = 0; $c < 3; ++$c) {
413
                    // for every byte on the column
414 6
                    for ($b = 0; $b < $wb[$c]; ++$b) {
415 6
                        if (isset($row[$i])) {
416 6
                            $sdata[$k][$c] += ($row[$i] << (($wb[$c] - 1 - $b) * 8));
417
                        }
418 6
                        ++$i;
419
                    }
420
                }
421
            }
422 6
            $ddata = [];
0 ignored issues
show
Unused Code introduced by
The assignment to $ddata is dead and can be removed.
Loading history...
423
            // fill xref
424 6
            if (isset($index_first)) {
425 4
                $obj_num = $index_first;
426
            } else {
427 6
                $obj_num = 0;
428
            }
429 6
            foreach ($sdata as $k => $row) {
430 6
                switch ($row[0]) {
431 6
                    case 0:  // (f) linked list of free objects
432 6
                            break;
433
434 6
                    case 1:  // (n) objects that are in use but are not compressed
435
                            // create unique object index: [object number]_[generation number]
436 6
                            $index = $obj_num.'_'.$row[2];
437
                            // check if object already exist
438 6
                            if (!isset($xref['xref'][$index])) {
439
                                // store object offset position
440 6
                                $xref['xref'][$index] = $row[1];
441
                            }
442 6
                            break;
443
444 6
                    case 2:  // compressed objects
445
                            // $row[1] = object number of the object stream in which this object is stored
446
                            // $row[2] = index of this object within the object stream
447 6
                            $index = $row[1].'_0_'.$row[2];
448 6
                            $xref['xref'][$index] = -1;
449 6
                            break;
450
451
                    default:  // null objects
452
                            break;
453
                }
454 6
                ++$obj_num;
455
            }
456
        } // end decoding data
457 6
        if (isset($prevxref)) {
458
            // get previous xref
459 4
            $xref = $this->getXrefData($pdfData, $prevxref, $xref);
460
        }
461
462 6
        return $xref;
463
    }
464
465
    /**
466
     * Get content of indirect object.
467
     *
468
     * @param string $pdfData  PDF data
469
     * @param array  $xref
470
     * @param string $objRef   Object number and generation number separated by underscore character
471
     * @param int    $offset   Object offset
472
     * @param bool   $decoding If true decode streams
473
     *
474
     * @return array containing object data
475
     *
476
     * @throws Exception if invalid object reference found
477
     */
478 27
    protected function getIndirectObject($pdfData, $xref, $objRef, $offset = 0, $decoding = true)
479
    {
480
        /*
481
         * build indirect object header
482
         */
483
        // $objHeader = "[object number] [generation number] obj"
484 27
        $objRefArr = explode('_', $objRef);
485 27
        if (2 !== \count($objRefArr)) {
486
            throw new Exception('Invalid object reference for $obj.');
487
        }
488 27
        $objHeader = $objRefArr[0].' '.$objRefArr[1].' obj';
489
490
        /*
491
         * check if we are in position
492
         */
493
        // ignore whitespace characters at offset (NUL, HT, LF, FF, CR, SP)
494 27
        $offset += strspn($pdfData, "\0\t\n\f\r ", $offset);
495
        // ignore leading zeros for object number
496 27
        $offset += strspn($pdfData, '0', $offset);
497 27
        if (substr($pdfData, $offset, \strlen($objHeader)) !== $objHeader) {
498
            // an indirect reference to an undefined object shall be considered a reference to the null object
499 2
            return ['null', 'null', $offset];
500
        }
501
502
        /*
503
         * get content
504
         */
505
        // starting position of object content
506 27
        $offset += \strlen($objHeader);
507 27
        $objContentArr = [];
508 27
        $i = 0; // object main index
509
        do {
510 27
            $oldOffset = $offset;
511
            // get element
512 27
            $element = $this->getRawObject($pdfData, $offset);
513 27
            $offset = $element[2];
514
            // decode stream using stream's dictionary information
515 27
            if ($decoding && ('stream' === $element[0]) && (isset($objContentArr[($i - 1)][0])) && ('<<' === $objContentArr[($i - 1)][0])) {
516 27
                $element[3] = $this->decodeStream($pdfData, $xref, $objContentArr[($i - 1)][1], $element[1]);
517
            }
518 27
            $objContentArr[$i] = $element;
519 27
            ++$i;
520 27
        } while (('endobj' !== $element[0]) && ($offset !== $oldOffset));
521
        // remove closing delimiter
522 27
        array_pop($objContentArr);
523
524
        /*
525
         * return raw object content
526
         */
527 27
        return $objContentArr;
528
    }
529
530
    /**
531
     * Get the content of object, resolving indirect object reference if necessary.
532
     *
533
     * @param string $pdfData PDF data
534
     * @param array  $obj     Object value
535
     *
536
     * @return array containing object data
537
     *
538
     * @throws Exception
539
     */
540 27
    protected function getObjectVal($pdfData, $xref, $obj)
541
    {
542 27
        if ('objref' == $obj[0]) {
543
            // reference to indirect object
544
            if (isset($this->objects[$obj[1]])) {
545
                // this object has been already parsed
546
                return $this->objects[$obj[1]];
547
            } elseif (isset($xref[$obj[1]])) {
548
                // parse new object
549
                $this->objects[$obj[1]] = $this->getIndirectObject($pdfData, $xref, $obj[1], $xref[$obj[1]], false);
550
551
                return $this->objects[$obj[1]];
552
            }
553
        }
554
555 27
        return $obj;
556
    }
557
558
    /**
559
     * Get object type, raw value and offset to next object
560
     *
561
     * @param int $offset Object offset
562
     *
563
     * @return array containing object type, raw value and offset to next object
564
     */
565 28
    protected function getRawObject($pdfData, $offset = 0)
566
    {
567 28
        $objtype = ''; // object type to be returned
568 28
        $objval = ''; // object value to be returned
569
570
        /*
571
         * skip initial white space chars:
572
         *      \x00 null (NUL)
573
         *      \x09 horizontal tab (HT)
574
         *      \x0A line feed (LF)
575
         *      \x0C form feed (FF)
576
         *      \x0D carriage return (CR)
577
         *      \x20 space (SP)
578
         */
579 28
        $offset += strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $offset);
580
581
        // get first char
582 28
        $char = $pdfData[$offset];
583
        // get object type
584 28
        switch ($char) {
585 28
            case '%':  // \x25 PERCENT SIGN
586
                    // skip comment and search for next token
587
                    $next = strcspn($pdfData, "\r\n", $offset);
588
                    if ($next > 0) {
589
                        $offset += $next;
590
591
                        return $this->getRawObject($pdfData, $offset);
592
                    }
593
                    break;
594
595 28
            case '/':  // \x2F SOLIDUS
596
                    // name object
597 28
                    $objtype = $char;
598 28
                    ++$offset;
599 28
                    $pregResult = preg_match(
600 28
                        '/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/',
601 28
                        substr($pdfData, $offset, 256),
602
                        $matches
603
                    );
604 28
                    if (1 == $pregResult) {
605 28
                        $objval = $matches[1]; // unescaped value
606 28
                        $offset += \strlen($objval);
607
                    }
608 28
                    break;
609
610 28
            case '(':   // \x28 LEFT PARENTHESIS
611 28
            case ')':  // \x29 RIGHT PARENTHESIS
612
                    // literal string object
613 25
                    $objtype = $char;
614 25
                    ++$offset;
615 25
                    $strpos = $offset;
616 25
                    if ('(' == $char) {
617 25
                        $open_bracket = 1;
618 25
                        while ($open_bracket > 0) {
619 25
                            if (!isset($pdfData[$strpos])) {
620
                                break;
621
                            }
622 25
                            $ch = $pdfData[$strpos];
623 25
                            switch ($ch) {
624 25
                                case '\\':  // REVERSE SOLIDUS (5Ch) (Backslash)
625
                                        // skip next character
626 15
                                        ++$strpos;
627 15
                                        break;
628
629 25
                                case '(':  // LEFT PARENHESIS (28h)
630
                                        ++$open_bracket;
631
                                        break;
632
633 25
                                case ')':  // RIGHT PARENTHESIS (29h)
634 25
                                        --$open_bracket;
635 25
                                        break;
636
                            }
637 25
                            ++$strpos;
638
                        }
639 25
                        $objval = substr($pdfData, $offset, ($strpos - $offset - 1));
640 25
                        $offset = $strpos;
641
                    }
642 25
                    break;
643
644 28
            case '[':   // \x5B LEFT SQUARE BRACKET
645 28
            case ']':  // \x5D RIGHT SQUARE BRACKET
646
                // array object
647 27
                $objtype = $char;
648 27
                ++$offset;
649 27
                if ('[' == $char) {
650
                    // get array content
651 27
                    $objval = [];
652
                    do {
653 27
                        $oldOffset = $offset;
654
                        // get element
655 27
                        $element = $this->getRawObject($pdfData, $offset);
656 27
                        $offset = $element[2];
657 27
                        $objval[] = $element;
658 27
                    } while ((']' != $element[0]) && ($offset != $oldOffset));
659
                    // remove closing delimiter
660 27
                    array_pop($objval);
661
                }
662 27
                break;
663
664 28
            case '<':  // \x3C LESS-THAN SIGN
665 28
            case '>':  // \x3E GREATER-THAN SIGN
666 28
                if (isset($pdfData[($offset + 1)]) && ($pdfData[($offset + 1)] == $char)) {
667
                    // dictionary object
668 28
                    $objtype = $char.$char;
669 28
                    $offset += 2;
670 28
                    if ('<' == $char) {
671
                        // get array content
672 28
                        $objval = [];
673
                        do {
674 28
                            $oldOffset = $offset;
675
                            // get element
676 28
                            $element = $this->getRawObject($pdfData, $offset);
677 28
                            $offset = $element[2];
678 28
                            $objval[] = $element;
679 28
                        } while (('>>' != $element[0]) && ($offset != $oldOffset));
680
                        // remove closing delimiter
681 28
                        array_pop($objval);
682
                    }
683
                } else {
684
                    // hexadecimal string object
685 10
                    $objtype = $char;
686 10
                    ++$offset;
687 10
                    $pregResult = preg_match(
688 10
                            '/^([0-9A-Fa-f\x09\x0a\x0c\x0d\x20]+)>/iU',
689 10
                            substr($pdfData, $offset),
690
                            $matches
691
                        );
692 10
                    if (('<' == $char) && 1 == $pregResult) {
693
                        // remove white space characters
694 10
                        $objval = strtr($matches[1], "\x09\x0a\x0c\x0d\x20", '');
695 10
                        $offset += \strlen($matches[0]);
696
                    } elseif (false !== ($endpos = strpos($pdfData, '>', $offset))) {
697
                        $offset = $endpos + 1;
698
                    }
699
                }
700 28
                    break;
701
702
            default:
703 28
                    if ('endobj' == substr($pdfData, $offset, 6)) {
704
                        // indirect object
705 27
                        $objtype = 'endobj';
706 27
                        $offset += 6;
707 28
                    } elseif ('null' == substr($pdfData, $offset, 4)) {
708
                        // null object
709 3
                        $objtype = 'null';
710 3
                        $offset += 4;
711 3
                        $objval = 'null';
712 28
                    } elseif ('true' == substr($pdfData, $offset, 4)) {
713
                        // boolean true object
714 8
                        $objtype = 'boolean';
715 8
                        $offset += 4;
716 8
                        $objval = 'true';
717 28
                    } elseif ('false' == substr($pdfData, $offset, 5)) {
718
                        // boolean false object
719 2
                        $objtype = 'boolean';
720 2
                        $offset += 5;
721 2
                        $objval = 'false';
722 28
                    } elseif ('stream' == substr($pdfData, $offset, 6)) {
723
                        // start stream object
724 27
                        $objtype = 'stream';
725 27
                        $offset += 6;
726 27
                        if (1 == preg_match('/^([\r]?[\n])/isU', substr($pdfData, $offset), $matches)) {
727 27
                            $offset += \strlen($matches[0]);
728 27
                            $pregResult = preg_match(
729 27
                                '/(endstream)[\x09\x0a\x0c\x0d\x20]/isU',
730 27
                                substr($pdfData, $offset),
731
                                $matches,
732 27
                                \PREG_OFFSET_CAPTURE
733
                            );
734 27
                            if (1 == $pregResult) {
735 27
                                $objval = substr($pdfData, $offset, $matches[0][1]);
736 27
                                $offset += $matches[1][1];
737
                            }
738
                        }
739 28
                    } elseif ('endstream' == substr($pdfData, $offset, 9)) {
740
                        // end stream object
741 27
                        $objtype = 'endstream';
742 27
                        $offset += 9;
743 28
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($pdfData, $offset, 33), $matches)) {
744
                        // indirect object reference
745 27
                        $objtype = 'objref';
746 27
                        $offset += \strlen($matches[0]);
747 27
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
748 28
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($pdfData, $offset, 33), $matches)) {
749
                        // object start
750 6
                        $objtype = 'obj';
751 6
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
752 6
                        $offset += \strlen($matches[0]);
753 28
                    } elseif (($numlen = strspn($pdfData, '+-.0123456789', $offset)) > 0) {
754
                        // numeric object
755 27
                        $objtype = 'numeric';
756 27
                        $objval = substr($pdfData, $offset, $numlen);
757 27
                        $offset += $numlen;
758
                    }
759 28
                    break;
760
        }
761
762 28
        return [$objtype, $objval, $offset];
763
    }
764
765
    /**
766
     * Get Cross-Reference (xref) table and trailer data from PDF document data.
767
     *
768
     * @param string $pdfData
769
     * @param int    $offset  xref offset (if know)
770
     * @param array  $xref    previous xref array (if any)
771
     *
772
     * @return array containing xref and trailer data
773
     *
774
     * @throws Exception if it was unable to find startxref
775
     * @throws Exception if it was unable to find xref
776
     */
777 28
    protected function getXrefData($pdfData, $offset = 0, $xref = [])
778
    {
779 28
        $startxrefPreg = preg_match(
780 28
            '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
781
            $pdfData,
782
            $matches,
783 28
            \PREG_OFFSET_CAPTURE,
784
            $offset
785
        );
786
787 28
        if (0 == $offset) {
788
            // find last startxref
789 28
            $pregResult = preg_match_all(
790 28
                '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
791
                $pdfData, $matches,
792 28
                \PREG_SET_ORDER,
793
                $offset
794
            );
795 28
            if (0 == $pregResult) {
796
                throw new Exception('Unable to find startxref');
797
            }
798 28
            $matches = array_pop($matches);
799 28
            $startxref = $matches[1];
800 8
        } elseif (strpos($pdfData, 'xref', $offset) == $offset) {
801
            // Already pointing at the xref table
802 5
            $startxref = $offset;
803 4
        } elseif (preg_match('/([0-9]+[\s][0-9]+[\s]obj)/i', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset)) {
804
            // Cross-Reference Stream object
805 4
            $startxref = $offset;
806
        } elseif ($startxrefPreg) {
807
            // startxref found
808
            $startxref = $matches[1][0];
809
        } else {
810
            throw new Exception('Unable to find startxref');
811
        }
812
813 28
        if ($startxref > \strlen($pdfData)) {
814 1
            throw new Exception('Unable to find xref (PDF corrupted?)');
815
        }
816
817
        // check xref position
818 27
        if (strpos($pdfData, 'xref', $startxref) == $startxref) {
819
            // Cross-Reference
820 22
            $xref = $this->decodeXref($pdfData, $startxref, $xref);
821
        } else {
822
            // Cross-Reference Stream
823 6
            $xref = $this->decodeXrefStream($pdfData, $startxref, $xref);
824
        }
825 27
        if (empty($xref)) {
826
            throw new Exception('Unable to find xref');
827
        }
828
829 27
        return $xref;
830
    }
831
832
    /**
833
     * Parses PDF data and returns extracted data as array.
834
     *
835
     * @param string $data PDF data to parse
836
     *
837
     * @return array array of parsed PDF document objects
838
     *
839
     * @throws Exception if empty PDF data given
840
     * @throws Exception if PDF data missing %PDF header
841
     */
842 28
    public function parseData($data)
843
    {
844 28
        if (empty($data)) {
845
            throw new Exception('Empty PDF data given.');
846
        }
847
        // find the pdf header starting position
848 28
        if (false === ($trimpos = strpos($data, '%PDF-'))) {
849
            throw new Exception('Invalid PDF data: missing %PDF header.');
850
        }
851
852
        // get PDF content string
853 28
        $pdfData = substr($data, $trimpos);
854
855
        // get xref and trailer data
856 28
        $xref = $this->getXrefData($pdfData);
857
858
        // parse all document objects
859 27
        $objects = [];
860 27
        foreach ($xref['xref'] as $obj => $offset) {
861 27
            if (!isset($objects[$obj]) && ($offset > 0)) {
862
                // decode objects with positive offset
863 27
                $objects[$obj] = $this->getIndirectObject($pdfData, $xref, $obj, $offset, true);
864
            }
865
        }
866
867 27
        return [$xref, $objects];
868
    }
869
}
870