Passed
Push — fix/corrupted-pdf ( dfc539 )
by Jeremy
15:22 queued 06:51
created

RawDataParser::decodeXref()   C

Complexity

Conditions 15
Paths 134

Size

Total Lines 64
Code Lines 37

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 34
CRAP Score 15.0386

Importance

Changes 3
Bugs 1 Features 1
Metric Value
cc 15
eloc 37
c 3
b 1
f 1
nc 134
nop 3
dl 0
loc 64
ccs 34
cts 36
cp 0.9444
crap 15.0386
rs 5.6333

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 $cfg Configuration array, default is []
62
     */
63 18
    public function __construct($cfg = [])
64
    {
65
        // merge given array with default values
66 18
        $this->cfg = array_merge($this->cfg, $cfg);
67
68 18
        $this->filterHelper = new FilterHelper();
69 18
    }
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 $stream  Stream to decode
78
     *
79
     * @return array containing decoded stream data and remaining filters
80
     */
81 17
    protected function decodeStream($pdfData, $xref, $sdic, $stream)
82
    {
83
        // get stream length and filters
84 17
        $slength = \strlen($stream);
85 17
        if ($slength <= 0) {
86
            return ['', []];
87
        }
88 17
        $filters = [];
89 17
        foreach ($sdic as $k => $v) {
90 17
            if ('/' == $v[0]) {
91 17
                if (('Length' == $v[1]) and (isset($sdic[($k + 1)])) and ('numeric' == $sdic[($k + 1)][0])) {
92
                    // get declared stream length
93 17
                    $declength = (int) ($sdic[($k + 1)][1]);
94 17
                    if ($declength < $slength) {
95 17
                        $stream = substr($stream, 0, $declength);
96 17
                        $slength = $declength;
97
                    }
98 17
                } elseif (('Filter' == $v[1]) and (isset($sdic[($k + 1)]))) {
99
                    // resolve indirect object
100 17
                    $objval = $this->getObjectVal($pdfData, $xref, $sdic[($k + 1)]);
101 17
                    if ('/' == $objval[0]) {
102
                        // single filter
103 17
                        $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 17
        $remaining_filters = [];
118 17
        foreach ($filters as $filter) {
119 17
            if (\in_array($filter, $this->filterHelper->getAvailableFilters())) {
120
                try {
121 17
                    $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 17
                        throw new Exception($e->getMessage());
128
                    }
129
                }
130
            } else {
131
                // add missing filter to array
132 3
                $remaining_filters[] = $filter;
133
            }
134
        }
135
136 17
        return [$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  $xref      Previous xref array (if any)
145
     *
146
     * @return array containing xref and trailer data
147
     */
148 16
    protected function decodeXref($pdfData, $startxref, $xref = [])
149
    {
150 16
        $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 16
        $offset = $startxref + strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $startxref);
153
        // initialize object number
154 16
        $obj_num = 0;
155
        // search for cross-reference entries or subsection
156 16
        while (preg_match('/([0-9]+)[\x20]([0-9]+)[\x20]?([nf]?)(\r\n|[\x20]?[\r\n])/', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
157 16
            if ($matches[0][1] != $offset) {
158
                // we are on another section
159 3
                break;
160
            }
161 16
            $offset += \strlen($matches[0][0]);
162 16
            if ('n' == $matches[3][0]) {
163
                // create unique object index: [object number]_[generation number]
164 16
                $index = $obj_num.'_'.(int) ($matches[2][0]);
165
                // check if object already exist
166 16
                if (!isset($xref['xref'][$index])) {
167
                    // store object offset position
168 16
                    $xref['xref'][$index] = (int) ($matches[1][0]);
169
                }
170 16
                ++$obj_num;
171 16
            } elseif ('f' == $matches[3][0]) {
172 16
                ++$obj_num;
173
            } else {
174
                // object number (index)
175 16
                $obj_num = (int) ($matches[1][0]);
176
            }
177
        }
178
        // get trailer data
179 16
        if (preg_match('/trailer[\s]*<<(.*)>>/isU', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
180 16
            $trailer_data = $matches[1][0];
181 16
            if (!isset($xref['trailer']) or empty($xref['trailer'])) {
182
                // get only the last updated version
183 16
                $xref['trailer'] = [];
184
                // parse trailer_data
185 16
                if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
186 16
                    $xref['trailer']['size'] = (int) ($matches[1]);
187
                }
188 16
                if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
189 16
                    $xref['trailer']['root'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
190
                }
191 16
                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 16
                if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
195 16
                    $xref['trailer']['info'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
196
                }
197 16
                if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) {
198 15
                    $xref['trailer']['id'] = [];
199 15
                    $xref['trailer']['id'][0] = $matches[1];
200 15
                    $xref['trailer']['id'][1] = $matches[2];
201
                }
202
            }
203 16
            if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
204
                // get previous xref
205 16
                $xref = $this->getXrefData($pdfData, (int) ($matches[1]), $xref);
206
            }
207
        } else {
208
            throw new Exception('Unable to find trailer');
209
        }
210
211 16
        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  $xref      Previous xref array (if any)
220
     *
221
     * @return array containing xref and trailer data
222
     *
223
     * @throws Exception if unknown PNG predictor detected
224
     */
225 2
    protected function decodeXrefStream($pdfData, $startxref, $xref = [])
226
    {
227
        // try to read Cross-Reference Stream
228 2
        $xrefobj = $this->getRawObject($pdfData, $startxref);
229 2
        $xrefcrs = $this->getIndirectObject($pdfData, $xref, $xrefobj[1], $startxref, true);
230 2
        if (!isset($xref['trailer']) or empty($xref['trailer'])) {
231
            // get only the last updated version
232 2
            $xref['trailer'] = [];
233 2
            $filltrailer = true;
234
        } else {
235 2
            $filltrailer = false;
236
        }
237 2
        if (!isset($xref['xref'])) {
238 2
            $xref['xref'] = [];
239
        }
240 2
        $valid_crs = false;
241 2
        $columns = 0;
242 2
        $sarr = $xrefcrs[0][1];
243 2
        if (!\is_array($sarr)) {
244
            $sarr = [];
245
        }
246
247 2
        $wb = [];
248
249 2
        foreach ($sarr as $k => $v) {
250
            if (
251 2
                ('/' == $v[0])
252 2
                && ('Type' == $v[1])
253
                && (
254 2
                    isset($sarr[($k + 1)])
255 2
                    && '/' == $sarr[($k + 1)][0]
256 2
                    && 'XRef' == $sarr[($k + 1)][1]
257
                )
258
            ) {
259 2
                $valid_crs = true;
260 2
            } elseif (('/' == $v[0]) and ('Index' == $v[1]) and (isset($sarr[($k + 1)]))) {
261
                // first object number in the subsection
262 2
                $index_first = (int) ($sarr[($k + 1)][1][0][1]);
263 2
            } elseif (('/' == $v[0]) and ('Prev' == $v[1]) and (isset($sarr[($k + 1)]) and ('numeric' == $sarr[($k + 1)][0]))) {
264
                // get previous xref offset
265 2
                $prevxref = (int) ($sarr[($k + 1)][1]);
266 2
            } elseif (('/' == $v[0]) and ('W' == $v[1]) and (isset($sarr[($k + 1)]))) {
267
                // number of bytes (in the decoded stream) of the corresponding field
268 2
                $wb[0] = (int) ($sarr[($k + 1)][1][0][1]);
269 2
                $wb[1] = (int) ($sarr[($k + 1)][1][1][1]);
270 2
                $wb[2] = (int) ($sarr[($k + 1)][1][2][1]);
271 2
            } elseif (('/' == $v[0]) and ('DecodeParms' == $v[1]) and (isset($sarr[($k + 1)][1]))) {
272 2
                $decpar = $sarr[($k + 1)][1];
273 2
                foreach ($decpar as $kdc => $vdc) {
274
                    if (
275 2
                        '/' == $vdc[0]
276 2
                        && 'Columns' == $vdc[1]
277
                        && (
278 2
                            isset($decpar[($kdc + 1)])
279 2
                            && 'numeric' == $decpar[($kdc + 1)][0]
280
                        )
281
                    ) {
282 2
                        $columns = (int) ($decpar[($kdc + 1)][1]);
283
                    } elseif (
284 2
                        '/' == $vdc[0]
285 2
                        && 'Predictor' == $vdc[1]
286
                        && (
287 2
                            isset($decpar[($kdc + 1)])
288 2
                            && 'numeric' == $decpar[($kdc + 1)][0]
289
                        )
290
                    ) {
291 2
                        $predictor = (int) ($decpar[($kdc + 1)][1]);
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Unused Code introduced by
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292
                    }
293
                }
294 2
            } elseif ($filltrailer) {
295 2
                if (('/' == $v[0]) and ('Size' == $v[1]) and (isset($sarr[($k + 1)]) and ('numeric' == $sarr[($k + 1)][0]))) {
296 2
                    $xref['trailer']['size'] = $sarr[($k + 1)][1];
297 2
                } elseif (('/' == $v[0]) and ('Root' == $v[1]) and (isset($sarr[($k + 1)]) and ('objref' == $sarr[($k + 1)][0]))) {
298 2
                    $xref['trailer']['root'] = $sarr[($k + 1)][1];
299 2
                } elseif (('/' == $v[0]) and ('Info' == $v[1]) and (isset($sarr[($k + 1)]) and ('objref' == $sarr[($k + 1)][0]))) {
300 2
                    $xref['trailer']['info'] = $sarr[($k + 1)][1];
301 2
                } elseif (('/' == $v[0]) and ('Encrypt' == $v[1]) and (isset($sarr[($k + 1)]) and ('objref' == $sarr[($k + 1)][0]))) {
302
                    $xref['trailer']['encrypt'] = $sarr[($k + 1)][1];
303 2
                } elseif (('/' == $v[0]) and ('ID' == $v[1]) and (isset($sarr[($k + 1)]))) {
304 2
                    $xref['trailer']['id'] = [];
305 2
                    $xref['trailer']['id'][0] = $sarr[($k + 1)][1][0][1];
306 2
                    $xref['trailer']['id'][1] = $sarr[($k + 1)][1][1][1];
307
                }
308
            }
309
        }
310
311
        // decode data
312 2
        if ($valid_crs and isset($xrefcrs[1][3][0])) {
313
            // number of bytes in a row
314 2
            $rowlen = ($columns + 1);
315
            // convert the stream into an array of integers
316 2
            $sdata = unpack('C*', $xrefcrs[1][3][0]);
317
            // split the rows
318 2
            $sdata = array_chunk($sdata, $rowlen);
0 ignored issues
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Bug introduced by
It seems like $sdata can also be of type false; however, parameter $input of array_chunk() does only seem to accept array, 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

318
            $sdata = array_chunk(/** @scrutinizer ignore-type */ $sdata, $rowlen);
Loading history...
319
            // initialize decoded array
320 2
            $ddata = [];
321
            // initialize first row with zeros
322 2
            $prev_row = array_fill(0, $rowlen, 0);
323
            // for each row apply PNG unpredictor
324 2
            foreach ($sdata as $k => $row) {
325
                // initialize new row
326 2
                $ddata[$k] = [];
327
                // get PNG predictor value
328 2
                $predictor = (10 + $row[0]);
329
                // for each byte on the row
330 2
                for ($i = 1; $i <= $columns; ++$i) {
331
                    // new index
332 2
                    $j = ($i - 1);
333 2
                    $row_up = $prev_row[$j];
334 2
                    if (1 == $i) {
335 2
                        $row_left = 0;
336 2
                        $row_upleft = 0;
337
                    } else {
338 2
                        $row_left = $row[($i - 1)];
339 2
                        $row_upleft = $prev_row[($j - 1)];
340
                    }
341 2
                    switch ($predictor) {
342 2
                        case 10:  // PNG prediction (on encoding, PNG None on all rows)
343
                            $ddata[$k][$j] = $row[$i];
344
                            break;
345
346 2
                        case 11:  // PNG prediction (on encoding, PNG Sub on all rows)
347
                            $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
348
                            break;
349
350 2
                        case 12:  // PNG prediction (on encoding, PNG Up on all rows)
351 2
                            $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
352 2
                            break;
353
354
                        case 13:  // PNG prediction (on encoding, PNG Average on all rows)
355
                            $ddata[$k][$j] = (($row[$i] + (($row_left + $row_up) / 2)) & 0xff);
356
                            break;
357
358
                        case 14:  // PNG prediction (on encoding, PNG Paeth on all rows)
359
                            // initial estimate
360
                            $p = ($row_left + $row_up - $row_upleft);
361
                            // distances
362
                            $pa = abs($p - $row_left);
363
                            $pb = abs($p - $row_up);
364
                            $pc = abs($p - $row_upleft);
365
                            $pmin = min($pa, $pb, $pc);
366
                            // return minimum distance
367
                            switch ($pmin) {
368
                                case $pa:
369
                                    $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
370
                                    break;
371
372
                                case $pb:
373
                                    $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
374
                                    break;
375
376
                                case $pc:
377
                                    $ddata[$k][$j] = (($row[$i] + $row_upleft) & 0xff);
378
                                    break;
379
                            }
380
                            break;
381
382
                        default:  // PNG prediction (on encoding, PNG optimum)
383
                            throw new Exception('Unknown PNG predictor');
384
                    }
385
                }
386 2
                $prev_row = $ddata[$k];
387
            } // end for each row
388
            // complete decoding
389 2
            $sdata = [];
390
            // for every row
391 2
            foreach ($ddata as $k => $row) {
392
                // initialize new row
393 2
                $sdata[$k] = [0, 0, 0];
394 2
                if (0 == $wb[0]) {
395
                    // default type field
396
                    $sdata[$k][0] = 1;
397
                }
398 2
                $i = 0; // count bytes in the row
399
                // for every column
400 2
                for ($c = 0; $c < 3; ++$c) {
401
                    // for every byte on the column
402 2
                    for ($b = 0; $b < $wb[$c]; ++$b) {
403 2
                        if (isset($row[$i])) {
404 2
                            $sdata[$k][$c] += ($row[$i] << (($wb[$c] - 1 - $b) * 8));
405
                        }
406 2
                        ++$i;
407
                    }
408
                }
409
            }
410 2
            $ddata = [];
0 ignored issues
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Unused Code introduced by
The assignment to $ddata is dead and can be removed.
Loading history...
411
            // fill xref
412 2
            if (isset($index_first)) {
413 2
                $obj_num = $index_first;
414
            } else {
415 2
                $obj_num = 0;
416
            }
417 2
            foreach ($sdata as $k => $row) {
418 2
                switch ($row[0]) {
419 2
                    case 0:  // (f) linked list of free objects
420 2
                            break;
421
422 2
                    case 1:  // (n) objects that are in use but are not compressed
423
                            // create unique object index: [object number]_[generation number]
424 2
                            $index = $obj_num.'_'.$row[2];
425
                            // check if object already exist
426 2
                            if (!isset($xref['xref'][$index])) {
427
                                // store object offset position
428 2
                                $xref['xref'][$index] = $row[1];
429
                            }
430 2
                            break;
431
432 2
                    case 2:  // compressed objects
433
                            // $row[1] = object number of the object stream in which this object is stored
434
                            // $row[2] = index of this object within the object stream
435 2
                            $index = $row[1].'_0_'.$row[2];
436 2
                            $xref['xref'][$index] = -1;
437 2
                            break;
438
439
                    default:  // null objects
440
                            break;
441
                }
442 2
                ++$obj_num;
443
            }
444
        } // end decoding data
445 2
        if (isset($prevxref)) {
446
            // get previous xref
447 2
            $xref = $this->getXrefData($pdfData, $prevxref, $xref);
448
        }
449
450 2
        return $xref;
451
    }
452
453
    /**
454
     * Get content of indirect object.
455
     *
456
     * @param string $pdfData  PDF data
457
     * @param array  $xref
458
     * @param string $objRef   Object number and generation number separated by underscore character
459
     * @param int    $offset   Object offset
460
     * @param bool   $decoding If true decode streams
461
     *
462
     * @return array containing object data
463
     *
464
     * @throws Exception if invalid object reference found
465
     */
466 17
    protected function getIndirectObject($pdfData, $xref, $objRef, $offset = 0, $decoding = true)
467
    {
468
        /*
469
         * build indirect object header
470
         */
471
        // $objHeader = "[object number] [generation number] obj"
472 17
        $objRefArr = explode('_', $objRef);
473 17
        if (2 !== \count($objRefArr)) {
474
            throw new Exception('Invalid object reference for $obj.');
475
        }
476 17
        $objHeader = $objRefArr[0].' '.$objRefArr[1].' obj';
477
478
        /*
479
         * check if we are in position
480
         */
481
        // ignore whitespace characters at offset (NUL, HT, LF, FF, CR, SP)
482 17
        $offset += strspn($pdfData, "\0\t\n\f\r ", $offset);
483
        // ignore leading zeros for object number
484 17
        $offset += strspn($pdfData, '0', $offset);
485 17
        if (substr($pdfData, $offset, \strlen($objHeader)) !== $objHeader) {
486
            // an indirect reference to an undefined object shall be considered a reference to the null object
487
            return ['null', 'null', $offset];
488
        }
489
490
        /*
491
         * get content
492
         */
493
        // starting position of object content
494 17
        $offset += \strlen($objHeader);
495 17
        $objContentArr = [];
496 17
        $i = 0; // object main index
497
        do {
498 17
            $oldOffset = $offset;
499
            // get element
500 17
            $element = $this->getRawObject($pdfData, $offset);
501 17
            $offset = $element[2];
502
            // decode stream using stream's dictionary information
503 17
            if ($decoding && ('stream' === $element[0]) && (isset($objContentArr[($i - 1)][0])) && ('<<' === $objContentArr[($i - 1)][0])) {
504 17
                $element[3] = $this->decodeStream($pdfData, $xref, $objContentArr[($i - 1)][1], $element[1]);
505
            }
506 17
            $objContentArr[$i] = $element;
507 17
            ++$i;
508 17
        } while (('endobj' !== $element[0]) && ($offset !== $oldOffset));
509
        // remove closing delimiter
510 17
        array_pop($objContentArr);
511
512
        /*
513
         * return raw object content
514
         */
515 17
        return $objContentArr;
516
    }
517
518
    /**
519
     * Get the content of object, resolving indirect object reference if necessary.
520
     *
521
     * @param string $pdfData PDF data
522
     * @param array  $obj     Object value
523
     *
524
     * @return array containing object data
525
     *
526
     * @throws Exception
527
     */
528 17
    protected function getObjectVal($pdfData, $xref, $obj)
529
    {
530 17
        if ('objref' == $obj[0]) {
531
            // reference to indirect object
532
            if (isset($this->objects[$obj[1]])) {
533
                // this object has been already parsed
534
                return $this->objects[$obj[1]];
535
            } elseif (isset($xref[$obj[1]])) {
536
                // parse new object
537
                $this->objects[$obj[1]] = $this->getIndirectObject($pdfData, $xref, $obj[1], $xref[$obj[1]], false);
538
539
                return $this->objects[$obj[1]];
540
            }
541
        }
542
543 17
        return $obj;
544
    }
545
546
    /**
547
     * Get object type, raw value and offset to next object
548
     *
549
     * @param int $offset Object offset
550
     *
551
     * @return array containing object type, raw value and offset to next object
552
     */
553 17
    protected function getRawObject($pdfData, $offset = 0)
554
    {
555 17
        $objtype = ''; // object type to be returned
556 17
        $objval = ''; // object value to be returned
557
558
        /*
559
         * skip initial white space chars:
560
         *      \x00 null (NUL)
561
         *      \x09 horizontal tab (HT)
562
         *      \x0A line feed (LF)
563
         *      \x0C form feed (FF)
564
         *      \x0D carriage return (CR)
565
         *      \x20 space (SP)
566
         */
567 17
        $offset += strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $offset);
568
569
        // get first char
570 17
        $char = $pdfData[$offset];
571
        // get object type
572 17
        switch ($char) {
573 17
            case '%':  // \x25 PERCENT SIGN
574
                    // skip comment and search for next token
575
                    $next = strcspn($pdfData, "\r\n", $offset);
576
                    if ($next > 0) {
577
                        $offset += $next;
578
579
                        return $this->getRawObject($pdfData, $offset);
580
                    }
581
                    break;
582
583 17
            case '/':  // \x2F SOLIDUS
584
                    // name object
585 17
                    $objtype = $char;
586 17
                    ++$offset;
587 17
                    $pregResult = preg_match(
588 17
                        '/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/',
589 17
                        substr($pdfData, $offset, 256),
590
                        $matches
591
                    );
592 17
                    if (1 == $pregResult) {
593 17
                        $objval = $matches[1]; // unescaped value
594 17
                        $offset += \strlen($objval);
595
                    }
596 17
                    break;
597
598 17
            case '(':   // \x28 LEFT PARENTHESIS
599 17
            case ')':  // \x29 RIGHT PARENTHESIS
600
                    // literal string object
601 17
                    $objtype = $char;
602 17
                    ++$offset;
603 17
                    $strpos = $offset;
604 17
                    if ('(' == $char) {
605 17
                        $open_bracket = 1;
606 17
                        while ($open_bracket > 0) {
607 17
                            if (!isset($pdfData[$strpos])) {
608
                                break;
609
                            }
610 17
                            $ch = $pdfData[$strpos];
611 17
                            switch ($ch) {
612 17
                                case '\\':  // REVERSE SOLIDUS (5Ch) (Backslash)
613
                                        // skip next character
614 14
                                        ++$strpos;
615 14
                                        break;
616
617 17
                                case '(':  // LEFT PARENHESIS (28h)
618
                                        ++$open_bracket;
619
                                        break;
620
621 17
                                case ')':  // RIGHT PARENTHESIS (29h)
622 17
                                        --$open_bracket;
623 17
                                        break;
624
                            }
625 17
                            ++$strpos;
626
                        }
627 17
                        $objval = substr($pdfData, $offset, ($strpos - $offset - 1));
628 17
                        $offset = $strpos;
629
                    }
630 17
                    break;
631
632 17
            case '[':   // \x5B LEFT SQUARE BRACKET
633 17
            case ']':  // \x5D RIGHT SQUARE BRACKET
634
                    // array object
635 17
                    $objtype = $char;
636 17
                    ++$offset;
637 17
                    if ('[' == $char) {
638
                        // get array content
639 17
                        $objval = [];
640
                        do {
641
                            // get element
642 17
                            $element = $this->getRawObject($pdfData, $offset);
643 17
                            $offset = $element[2];
644 17
                            $objval[] = $element;
645 17
                        } while (']' != $element[0]);
646
                        // remove closing delimiter
647 17
                        array_pop($objval);
648
                    }
649 17
                    break;
650
651 17
            case '<':  // \x3C LESS-THAN SIGN
652 17
            case '>':  // \x3E GREATER-THAN SIGN
653 17
                    if (isset($pdfData[($offset + 1)]) and ($pdfData[($offset + 1)] == $char)) {
654
                        // dictionary object
655 17
                        $objtype = $char.$char;
656 17
                        $offset += 2;
657 17
                        if ('<' == $char) {
658
                            // get array content
659 17
                            $objval = [];
660
                            do {
661
                                // get element
662 17
                                $element = $this->getRawObject($pdfData, $offset);
663 17
                                $offset = $element[2];
664 17
                                $objval[] = $element;
665 17
                            } while ('>>' != $element[0]);
666
                            // remove closing delimiter
667 17
                            array_pop($objval);
668
                        }
669
                    } else {
670
                        // hexadecimal string object
671 4
                        $objtype = $char;
672 4
                        ++$offset;
673 4
                        $pregResult = preg_match(
674 4
                            '/^([0-9A-Fa-f\x09\x0a\x0c\x0d\x20]+)>/iU',
675 4
                            substr($pdfData, $offset),
676
                            $matches
677
                        );
678 4
                        if (('<' == $char) && 1 == $pregResult) {
679
                            // remove white space characters
680 4
                            $objval = strtr($matches[1], "\x09\x0a\x0c\x0d\x20", '');
681 4
                            $offset += \strlen($matches[0]);
682
                        } elseif (false !== ($endpos = strpos($pdfData, '>', $offset))) {
683
                            $offset = $endpos + 1;
684
                        }
685
                    }
686 17
                    break;
687
688
            default:
689 17
                    if ('endobj' == substr($pdfData, $offset, 6)) {
690
                        // indirect object
691 17
                        $objtype = 'endobj';
692 17
                        $offset += 6;
693 17
                    } elseif ('null' == substr($pdfData, $offset, 4)) {
694
                        // null object
695 2
                        $objtype = 'null';
696 2
                        $offset += 4;
697 2
                        $objval = 'null';
698 17
                    } elseif ('true' == substr($pdfData, $offset, 4)) {
699
                        // boolean true object
700 4
                        $objtype = 'boolean';
701 4
                        $offset += 4;
702 4
                        $objval = 'true';
703 17
                    } elseif ('false' == substr($pdfData, $offset, 5)) {
704
                        // boolean false object
705 1
                        $objtype = 'boolean';
706 1
                        $offset += 5;
707 1
                        $objval = 'false';
708 17
                    } elseif ('stream' == substr($pdfData, $offset, 6)) {
709
                        // start stream object
710 17
                        $objtype = 'stream';
711 17
                        $offset += 6;
712 17
                        if (1 == preg_match('/^([\r]?[\n])/isU', substr($pdfData, $offset), $matches)) {
713 17
                            $offset += \strlen($matches[0]);
714 17
                            $pregResult = preg_match(
715 17
                                '/(endstream)[\x09\x0a\x0c\x0d\x20]/isU',
716 17
                                substr($pdfData, $offset),
717
                                $matches,
718 17
                                PREG_OFFSET_CAPTURE
719
                            );
720 17
                            if (1 == $pregResult) {
721 17
                                $objval = substr($pdfData, $offset, $matches[0][1]);
722 17
                                $offset += $matches[1][1];
723
                            }
724
                        }
725 17
                    } elseif ('endstream' == substr($pdfData, $offset, 9)) {
726
                        // end stream object
727 17
                        $objtype = 'endstream';
728 17
                        $offset += 9;
729 17
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($pdfData, $offset, 33), $matches)) {
730
                        // indirect object reference
731 17
                        $objtype = 'objref';
732 17
                        $offset += \strlen($matches[0]);
733 17
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
734 17
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($pdfData, $offset, 33), $matches)) {
735
                        // object start
736 2
                        $objtype = 'obj';
737 2
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
738 2
                        $offset += \strlen($matches[0]);
739 17
                    } elseif (($numlen = strspn($pdfData, '+-.0123456789', $offset)) > 0) {
740
                        // numeric object
741 17
                        $objtype = 'numeric';
742 17
                        $objval = substr($pdfData, $offset, $numlen);
743 17
                        $offset += $numlen;
744
                    }
745 17
                    break;
746
        }
747
748 17
        return [$objtype, $objval, $offset];
749
    }
750
751
    /**
752
     * Get Cross-Reference (xref) table and trailer data from PDF document data.
753
     *
754
     * @param string $pdfData
755
     * @param int    $offset  xref offset (if know)
756
     * @param array  $xref    previous xref array (if any)
757
     *
758
     * @return array containing xref and trailer data
759
     *
760
     * @throws Exception if it was unable to find startxref
761
     * @throws Exception if it was unable to find xref
762
     */
763 18
    protected function getXrefData($pdfData, $offset = 0, $xref = [])
764
    {
765 18
        $startxrefPreg = preg_match(
766 18
            '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
767
            $pdfData,
768
            $matches,
769 18
            PREG_OFFSET_CAPTURE,
770
            $offset
771
        );
772
773 18
        if (0 == $offset) {
774
            // find last startxref
775 18
            $pregResult = preg_match_all(
776 18
                '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
777
                $pdfData, $matches,
778 18
                PREG_SET_ORDER,
779
                $offset
780
            );
781 18
            if (0 == $pregResult) {
782
                throw new Exception('Unable to find startxref');
783
            }
784 18
            $matches = array_pop($matches);
785 18
            $startxref = $matches[1];
786 4
        } elseif (strpos($pdfData, 'xref', $offset) == $offset) {
787
            // Already pointing at the xref table
788 3
            $startxref = $offset;
789 2
        } elseif (preg_match('/([0-9]+[\s][0-9]+[\s]obj)/i', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset)) {
790
            // Cross-Reference Stream object
791 2
            $startxref = $offset;
792
        } elseif ($startxrefPreg) {
793
            // startxref found
794
            $startxref = $matches[1][0];
795
        } else {
796
            throw new Exception('Unable to find startxref');
797
        }
798
799 18
        if ($startxref > \strlen($pdfData)) {
800 1
            throw new Exception('Unable to find xref (PDF corrupted?)');
801
        }
802
803
        // check xref position
804 17
        if (strpos($pdfData, 'xref', $startxref) == $startxref) {
805
            // Cross-Reference
806 16
            $xref = $this->decodeXref($pdfData, $startxref, $xref);
807
        } else {
808
            // Cross-Reference Stream
809 2
            $xref = $this->decodeXrefStream($pdfData, $startxref, $xref);
810
        }
811 17
        if (empty($xref)) {
812
            throw new Exception('Unable to find xref');
813
        }
814
815 17
        return $xref;
816
    }
817
818
    /**
819
     * Parses PDF data and returns extracted data as array.
820
     *
821
     * @param string $data PDF data to parse
822
     *
823
     * @return array array of parsed PDF document objects
824
     *
825
     * @throws Exception if empty PDF data given
826
     * @throws Exception if PDF data missing %PDF header
827
     */
828 18
    public function parseData($data)
829
    {
830 18
        if (empty($data)) {
831
            throw new Exception('Empty PDF data given.');
832
        }
833
        // find the pdf header starting position
834 18
        if (false === ($trimpos = strpos($data, '%PDF-'))) {
835
            throw new Exception('Invalid PDF data: missing %PDF header.');
836
        }
837
838
        // get PDF content string
839 18
        $pdfData = substr($data, $trimpos);
840
841
        // get xref and trailer data
842 18
        $xref = $this->getXrefData($pdfData);
843
844
        // parse all document objects
845 17
        $objects = [];
846 17
        foreach ($xref['xref'] as $obj => $offset) {
847 17
            if (!isset($objects[$obj]) and ($offset > 0)) {
848
                // decode objects with positive offset
849 17
                $objects[$obj] = $this->getIndirectObject($pdfData, $xref, $obj, $offset, true);
850
            }
851
        }
852
853 17
        return [$xref, $objects];
854
    }
855
}
856