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

RawDataParser::decodeXrefStream()   F

Complexity

Conditions 78
Paths 1024

Size

Total Lines 226
Code Lines 148

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 109
CRAP Score 129.9555

Importance

Changes 3
Bugs 1 Features 1
Metric Value
cc 78
eloc 148
c 3
b 1
f 1
nc 1024
nop 3
dl 0
loc 226
ccs 109
cts 137
cp 0.7956
crap 129.9555
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 $cfg Configuration array, default is []
62
     */
63 18
    public function __construct($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]);
0 ignored issues
show
Unused Code introduced by
The assignment to $predictor is dead and can be removed.
Loading history...
292
                    }
293
                }
294 2
            } elseif ($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
show
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
show
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