Completed
Push — master ( 72a877...c9c2be )
by Konrad
08:04
created

RawDataParser::decodeStream()   D

Complexity

Conditions 21
Paths 51

Size

Total Lines 56
Code Lines 32

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 30
CRAP Score 21.0148

Importance

Changes 2
Bugs 1 Features 1
Metric Value
cc 21
eloc 32
c 2
b 1
f 1
nc 51
nop 4
dl 0
loc 56
ccs 30
cts 31
cp 0.9677
crap 21.0148
rs 4.1666

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 $cfg Configuration array, default is []
62
     */
63 25
    public function __construct($cfg = [])
64
    {
65
        // merge given array with default values
66 25
        $this->cfg = array_merge($this->cfg, $cfg);
67
68 25
        $this->filterHelper = new FilterHelper();
69 25
    }
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 $stream  Stream to decode
78
     *
79
     * @return array containing decoded stream data and remaining filters
80
     */
81 23
    protected function decodeStream($pdfData, $xref, $sdic, $stream)
82
    {
83
        // get stream length and filters
84 23
        $slength = \strlen($stream);
85 23
        if ($slength <= 0) {
86
            return ['', []];
87
        }
88 23
        $filters = [];
89 23
        foreach ($sdic as $k => $v) {
90 23
            if ('/' == $v[0]) {
91 23
                if (('Length' == $v[1]) and (isset($sdic[($k + 1)])) and ('numeric' == $sdic[($k + 1)][0])) {
92
                    // get declared stream length
93 23
                    $declength = (int) ($sdic[($k + 1)][1]);
94 23
                    if ($declength < $slength) {
95 23
                        $stream = substr($stream, 0, $declength);
96 23
                        $slength = $declength;
97
                    }
98 23
                } elseif (('Filter' == $v[1]) and (isset($sdic[($k + 1)]))) {
99
                    // resolve indirect object
100 23
                    $objval = $this->getObjectVal($pdfData, $xref, $sdic[($k + 1)]);
101 23
                    if ('/' == $objval[0]) {
102
                        // single filter
103 23
                        $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 23
        $remaining_filters = [];
118 23
        foreach ($filters as $filter) {
119 23
            if (\in_array($filter, $this->filterHelper->getAvailableFilters())) {
120
                try {
121 23
                    $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 23
                        throw new Exception($e->getMessage());
128
                    }
129
                }
130
            } else {
131
                // add missing filter to array
132 3
                $remaining_filters[] = $filter;
133
            }
134
        }
135
136 23
        return [$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  $xref      Previous xref array (if any)
145
     *
146
     * @return array containing xref and trailer data
147
     */
148 19
    protected function decodeXref($pdfData, $startxref, $xref = [])
149
    {
150 19
        $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 19
        $offset = $startxref + strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $startxref);
153
        // initialize object number
154 19
        $obj_num = 0;
155
        // search for cross-reference entries or subsection
156 19
        while (preg_match('/([0-9]+)[\x20]([0-9]+)[\x20]?([nf]?)(\r\n|[\x20]?[\r\n])/', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
157 19
            if ($matches[0][1] != $offset) {
158
                // we are on another section
159 5
                break;
160
            }
161 19
            $offset += \strlen($matches[0][0]);
162 19
            if ('n' == $matches[3][0]) {
163
                // create unique object index: [object number]_[generation number]
164 19
                $index = $obj_num.'_'.(int) ($matches[2][0]);
165
                // check if object already exist
166 19
                if (!isset($xref['xref'][$index])) {
167
                    // store object offset position
168 19
                    $xref['xref'][$index] = (int) ($matches[1][0]);
169
                }
170 19
                ++$obj_num;
171 19
            } elseif ('f' == $matches[3][0]) {
172 19
                ++$obj_num;
173
            } else {
174
                // object number (index)
175 19
                $obj_num = (int) ($matches[1][0]);
176
            }
177
        }
178
        // get trailer data
179 19
        if (preg_match('/trailer[\s]*<<(.*)>>/isU', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
180 19
            $trailer_data = $matches[1][0];
181 19
            if (!isset($xref['trailer']) or empty($xref['trailer'])) {
182
                // get only the last updated version
183 19
                $xref['trailer'] = [];
184
                // parse trailer_data
185 19
                if (preg_match('/Size[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
186 19
                    $xref['trailer']['size'] = (int) ($matches[1]);
187
                }
188 19
                if (preg_match('/Root[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
189 19
                    $xref['trailer']['root'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
190
                }
191 19
                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 19
                if (preg_match('/Info[\s]+([0-9]+)[\s]+([0-9]+)[\s]+R/i', $trailer_data, $matches) > 0) {
195 19
                    $xref['trailer']['info'] = (int) ($matches[1]).'_'.(int) ($matches[2]);
196
                }
197 19
                if (preg_match('/ID[\s]*[\[][\s]*[<]([^>]*)[>][\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) {
198 18
                    $xref['trailer']['id'] = [];
199 18
                    $xref['trailer']['id'][0] = $matches[1];
200 18
                    $xref['trailer']['id'][1] = $matches[2];
201
                }
202
            }
203 19
            if (preg_match('/Prev[\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
204
                // get previous xref
205 19
                $xref = $this->getXrefData($pdfData, (int) ($matches[1]), $xref);
206
            }
207
        } else {
208
            throw new Exception('Unable to find trailer');
209
        }
210
211 19
        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  $xref      Previous xref array (if any)
220
     *
221
     * @return array containing xref and trailer data
222
     *
223
     * @throws Exception if unknown PNG predictor detected
224
     */
225 5
    protected function decodeXrefStream($pdfData, $startxref, $xref = [])
226
    {
227
        // try to read Cross-Reference Stream
228 5
        $xrefobj = $this->getRawObject($pdfData, $startxref);
229 5
        $xrefcrs = $this->getIndirectObject($pdfData, $xref, $xrefobj[1], $startxref, true);
230 5
        if (!isset($xref['trailer']) or empty($xref['trailer'])) {
231
            // get only the last updated version
232 5
            $xref['trailer'] = [];
233 5
            $filltrailer = true;
234
        } else {
235 4
            $filltrailer = false;
236
        }
237 5
        if (!isset($xref['xref'])) {
238 5
            $xref['xref'] = [];
239
        }
240 5
        $valid_crs = false;
241 5
        $columns = 0;
242 5
        $sarr = $xrefcrs[0][1];
243 5
        if (!\is_array($sarr)) {
244
            $sarr = [];
245
        }
246
247 5
        $wb = [];
248
249 5
        foreach ($sarr as $k => $v) {
250
            if (
251 5
                ('/' == $v[0])
252 5
                && ('Type' == $v[1])
253
                && (
254 5
                    isset($sarr[($k + 1)])
255 5
                    && '/' == $sarr[($k + 1)][0]
256 5
                    && 'XRef' == $sarr[($k + 1)][1]
257
                )
258
            ) {
259 5
                $valid_crs = true;
260 5
            } elseif (('/' == $v[0]) and ('Index' == $v[1]) and (isset($sarr[($k + 1)]))) {
261
                // first object number in the subsection
262 4
                $index_first = (int) ($sarr[($k + 1)][1][0][1]);
263 5
            } elseif (('/' == $v[0]) and ('Prev' == $v[1]) and (isset($sarr[($k + 1)]) and ('numeric' == $sarr[($k + 1)][0]))) {
264
                // get previous xref offset
265 4
                $prevxref = (int) ($sarr[($k + 1)][1]);
266 5
            } 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 5
                $wb[0] = (int) ($sarr[($k + 1)][1][0][1]);
269 5
                $wb[1] = (int) ($sarr[($k + 1)][1][1][1]);
270 5
                $wb[2] = (int) ($sarr[($k + 1)][1][2][1]);
271 5
            } elseif (('/' == $v[0]) and ('DecodeParms' == $v[1]) and (isset($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[($kdc + 1)][1]);
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Unused Code introduced by
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292
                    }
293
                }
294 5
            } elseif ($filltrailer) {
295 5
                if (('/' == $v[0]) and ('Size' == $v[1]) and (isset($sarr[($k + 1)]) and ('numeric' == $sarr[($k + 1)][0]))) {
296 5
                    $xref['trailer']['size'] = $sarr[($k + 1)][1];
297 5
                } elseif (('/' == $v[0]) and ('Root' == $v[1]) and (isset($sarr[($k + 1)]) and ('objref' == $sarr[($k + 1)][0]))) {
298 5
                    $xref['trailer']['root'] = $sarr[($k + 1)][1];
299 5
                } elseif (('/' == $v[0]) and ('Info' == $v[1]) and (isset($sarr[($k + 1)]) and ('objref' == $sarr[($k + 1)][0]))) {
300 5
                    $xref['trailer']['info'] = $sarr[($k + 1)][1];
301 5
                } 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 5
                } elseif (('/' == $v[0]) and ('ID' == $v[1]) and (isset($sarr[($k + 1)]))) {
304 5
                    $xref['trailer']['id'] = [];
305 5
                    $xref['trailer']['id'][0] = $sarr[($k + 1)][1][0][1];
306 5
                    $xref['trailer']['id'][1] = $sarr[($k + 1)][1][1][1];
307
                }
308
            }
309
        }
310
311
        // decode data
312 5
        if ($valid_crs and isset($xrefcrs[1][3][0])) {
313
            // number of bytes in a row
314 5
            $rowlen = ($columns + 1);
315
            // convert the stream into an array of integers
316 5
            $sdata = unpack('C*', $xrefcrs[1][3][0]);
317
            // split the rows
318 5
            $sdata = array_chunk($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);
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319
            // initialize decoded array
320 5
            $ddata = [];
321
            // initialize first row with zeros
322 5
            $prev_row = array_fill(0, $rowlen, 0);
323
            // for each row apply PNG unpredictor
324 5
            foreach ($sdata as $k => $row) {
325
                // initialize new row
326 5
                $ddata[$k] = [];
327
                // get PNG predictor value
328 5
                $predictor = (10 + $row[0]);
329
                // for each byte on the row
330 5
                for ($i = 1; $i <= $columns; ++$i) {
331
                    // new index
332 5
                    $j = ($i - 1);
333 5
                    $row_up = $prev_row[$j];
334 5
                    if (1 == $i) {
335 5
                        $row_left = 0;
336 5
                        $row_upleft = 0;
337
                    } else {
338 5
                        $row_left = $row[($i - 1)];
339 5
                        $row_upleft = $prev_row[($j - 1)];
340
                    }
341 5
                    switch ($predictor) {
342 5
                        case 10:  // PNG prediction (on encoding, PNG None on all rows)
343
                            $ddata[$k][$j] = $row[$i];
344
                            break;
345
346 5
                        case 11:  // PNG prediction (on encoding, PNG Sub on all rows)
347
                            $ddata[$k][$j] = (($row[$i] + $row_left) & 0xff);
348
                            break;
349
350 5
                        case 12:  // PNG prediction (on encoding, PNG Up on all rows)
351 5
                            $ddata[$k][$j] = (($row[$i] + $row_up) & 0xff);
352 5
                            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 5
                $prev_row = $ddata[$k];
387
            } // end for each row
388
            // complete decoding
389 5
            $sdata = [];
390
            // for every row
391 5
            foreach ($ddata as $k => $row) {
392
                // initialize new row
393 5
                $sdata[$k] = [0, 0, 0];
394 5
                if (0 == $wb[0]) {
395
                    // default type field
396
                    $sdata[$k][0] = 1;
397
                }
398 5
                $i = 0; // count bytes in the row
399
                // for every column
400 5
                for ($c = 0; $c < 3; ++$c) {
401
                    // for every byte on the column
402 5
                    for ($b = 0; $b < $wb[$c]; ++$b) {
403 5
                        if (isset($row[$i])) {
404 5
                            $sdata[$k][$c] += ($row[$i] << (($wb[$c] - 1 - $b) * 8));
405
                        }
406 5
                        ++$i;
407
                    }
408
                }
409
            }
410 5
            $ddata = [];
0 ignored issues
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Unused Code introduced by
The assignment to $ddata is dead and can be removed.
Loading history...
411
            // fill xref
412 5
            if (isset($index_first)) {
413 4
                $obj_num = $index_first;
414
            } else {
415 5
                $obj_num = 0;
416
            }
417 5
            foreach ($sdata as $k => $row) {
418 5
                switch ($row[0]) {
419 5
                    case 0:  // (f) linked list of free objects
420 5
                            break;
421
422 5
                    case 1:  // (n) objects that are in use but are not compressed
423
                            // create unique object index: [object number]_[generation number]
424 5
                            $index = $obj_num.'_'.$row[2];
425
                            // check if object already exist
426 5
                            if (!isset($xref['xref'][$index])) {
427
                                // store object offset position
428 5
                                $xref['xref'][$index] = $row[1];
429
                            }
430 5
                            break;
431
432 5
                    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 5
                            $index = $row[1].'_0_'.$row[2];
436 5
                            $xref['xref'][$index] = -1;
437 5
                            break;
438
439
                    default:  // null objects
440
                            break;
441
                }
442 5
                ++$obj_num;
443
            }
444
        } // end decoding data
445 5
        if (isset($prevxref)) {
446
            // get previous xref
447 4
            $xref = $this->getXrefData($pdfData, $prevxref, $xref);
448
        }
449
450 5
        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   $decoding If true decode streams
461
     *
462
     * @return array containing object data
463
     *
464
     * @throws Exception if invalid object reference found
465
     */
466 23
    protected function getIndirectObject($pdfData, $xref, $objRef, $offset = 0, $decoding = true)
467
    {
468
        /*
469
         * build indirect object header
470
         */
471
        // $objHeader = "[object number] [generation number] obj"
472 23
        $objRefArr = explode('_', $objRef);
473 23
        if (2 !== \count($objRefArr)) {
474
            throw new Exception('Invalid object reference for $obj.');
475
        }
476 23
        $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 23
        $offset += strspn($pdfData, "\0\t\n\f\r ", $offset);
483
        // ignore leading zeros for object number
484 23
        $offset += strspn($pdfData, '0', $offset);
485 23
        if (substr($pdfData, $offset, \strlen($objHeader)) !== $objHeader) {
486
            // an indirect reference to an undefined object shall be considered a reference to the null object
487 2
            return ['null', 'null', $offset];
488
        }
489
490
        /*
491
         * get content
492
         */
493
        // starting position of object content
494 23
        $offset += \strlen($objHeader);
495 23
        $objContentArr = [];
496 23
        $i = 0; // object main index
497
        do {
498 23
            $oldOffset = $offset;
499
            // get element
500 23
            $element = $this->getRawObject($pdfData, $offset);
501 23
            $offset = $element[2];
502
            // decode stream using stream's dictionary information
503 23
            if ($decoding && ('stream' === $element[0]) && (isset($objContentArr[($i - 1)][0])) && ('<<' === $objContentArr[($i - 1)][0])) {
504 23
                $element[3] = $this->decodeStream($pdfData, $xref, $objContentArr[($i - 1)][1], $element[1]);
505
            }
506 23
            $objContentArr[$i] = $element;
507 23
            ++$i;
508 23
        } while (('endobj' !== $element[0]) && ($offset !== $oldOffset));
509
        // remove closing delimiter
510 23
        array_pop($objContentArr);
511
512
        /*
513
         * return raw object content
514
         */
515 23
        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  $obj     Object value
523
     *
524
     * @return array containing object data
525
     *
526
     * @throws Exception
527
     */
528 23
    protected function getObjectVal($pdfData, $xref, $obj)
529
    {
530 23
        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 23
        return $obj;
544
    }
545
546
    /**
547
     * Get object type, raw value and offset to next object
548
     *
549
     * @param int $offset Object offset
550
     *
551
     * @return array containing object type, raw value and offset to next object
552
     */
553 23
    protected function getRawObject($pdfData, $offset = 0)
554
    {
555 23
        $objtype = ''; // object type to be returned
556 23
        $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 23
        $offset += strspn($pdfData, "\x00\x09\x0a\x0c\x0d\x20", $offset);
568
569
        // get first char
570 23
        $char = $pdfData[$offset];
571
        // get object type
572 23
        switch ($char) {
573 23
            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 23
            case '/':  // \x2F SOLIDUS
584
                    // name object
585 23
                    $objtype = $char;
586 23
                    ++$offset;
587 23
                    $pregResult = preg_match(
588 23
                        '/^([^\x00\x09\x0a\x0c\x0d\x20\s\x28\x29\x3c\x3e\x5b\x5d\x7b\x7d\x2f\x25]+)/',
589 23
                        substr($pdfData, $offset, 256),
590
                        $matches
591
                    );
592 23
                    if (1 == $pregResult) {
593 23
                        $objval = $matches[1]; // unescaped value
594 23
                        $offset += \strlen($objval);
595
                    }
596 23
                    break;
597
598 23
            case '(':   // \x28 LEFT PARENTHESIS
599 23
            case ')':  // \x29 RIGHT PARENTHESIS
600
                    // literal string object
601 21
                    $objtype = $char;
602 21
                    ++$offset;
603 21
                    $strpos = $offset;
604 21
                    if ('(' == $char) {
605 21
                        $open_bracket = 1;
606 21
                        while ($open_bracket > 0) {
607 21
                            if (!isset($pdfData[$strpos])) {
608
                                break;
609
                            }
610 21
                            $ch = $pdfData[$strpos];
611 21
                            switch ($ch) {
612 21
                                case '\\':  // REVERSE SOLIDUS (5Ch) (Backslash)
613
                                        // skip next character
614 15
                                        ++$strpos;
615 15
                                        break;
616
617 21
                                case '(':  // LEFT PARENHESIS (28h)
618
                                        ++$open_bracket;
619
                                        break;
620
621 21
                                case ')':  // RIGHT PARENTHESIS (29h)
622 21
                                        --$open_bracket;
623 21
                                        break;
624
                            }
625 21
                            ++$strpos;
626
                        }
627 21
                        $objval = substr($pdfData, $offset, ($strpos - $offset - 1));
628 21
                        $offset = $strpos;
629
                    }
630 21
                    break;
631
632 23
            case '[':   // \x5B LEFT SQUARE BRACKET
633 23
            case ']':  // \x5D RIGHT SQUARE BRACKET
634
                    // array object
635 23
                    $objtype = $char;
636 23
                    ++$offset;
637 23
                    if ('[' == $char) {
638
                        // get array content
639 23
                        $objval = [];
640
                        do {
641
                            // get element
642 23
                            $element = $this->getRawObject($pdfData, $offset);
643 23
                            $offset = $element[2];
644 23
                            $objval[] = $element;
645 23
                        } while (']' != $element[0]);
646
                        // remove closing delimiter
647 23
                        array_pop($objval);
648
                    }
649 23
                    break;
650
651 23
            case '<':  // \x3C LESS-THAN SIGN
652 23
            case '>':  // \x3E GREATER-THAN SIGN
653 23
                    if (isset($pdfData[($offset + 1)]) and ($pdfData[($offset + 1)] == $char)) {
654
                        // dictionary object
655 23
                        $objtype = $char.$char;
656 23
                        $offset += 2;
657 23
                        if ('<' == $char) {
658
                            // get array content
659 23
                            $objval = [];
660
                            do {
661
                                // get element
662 23
                                $element = $this->getRawObject($pdfData, $offset);
663 23
                                $offset = $element[2];
664 23
                                $objval[] = $element;
665 23
                            } while ('>>' != $element[0]);
666
                            // remove closing delimiter
667 23
                            array_pop($objval);
668
                        }
669
                    } else {
670
                        // hexadecimal string object
671 8
                        $objtype = $char;
672 8
                        ++$offset;
673 8
                        $pregResult = preg_match(
674 8
                            '/^([0-9A-Fa-f\x09\x0a\x0c\x0d\x20]+)>/iU',
675 8
                            substr($pdfData, $offset),
676
                            $matches
677
                        );
678 8
                        if (('<' == $char) && 1 == $pregResult) {
679
                            // remove white space characters
680 8
                            $objval = strtr($matches[1], "\x09\x0a\x0c\x0d\x20", '');
681 8
                            $offset += \strlen($matches[0]);
682
                        } elseif (false !== ($endpos = strpos($pdfData, '>', $offset))) {
683
                            $offset = $endpos + 1;
684
                        }
685
                    }
686 23
                    break;
687
688
            default:
689 23
                    if ('endobj' == substr($pdfData, $offset, 6)) {
690
                        // indirect object
691 23
                        $objtype = 'endobj';
692 23
                        $offset += 6;
693 23
                    } elseif ('null' == substr($pdfData, $offset, 4)) {
694
                        // null object
695 3
                        $objtype = 'null';
696 3
                        $offset += 4;
697 3
                        $objval = 'null';
698 23
                    } elseif ('true' == substr($pdfData, $offset, 4)) {
699
                        // boolean true object
700 7
                        $objtype = 'boolean';
701 7
                        $offset += 4;
702 7
                        $objval = 'true';
703 23
                    } elseif ('false' == substr($pdfData, $offset, 5)) {
704
                        // boolean false object
705 2
                        $objtype = 'boolean';
706 2
                        $offset += 5;
707 2
                        $objval = 'false';
708 23
                    } elseif ('stream' == substr($pdfData, $offset, 6)) {
709
                        // start stream object
710 23
                        $objtype = 'stream';
711 23
                        $offset += 6;
712 23
                        if (1 == preg_match('/^([\r]?[\n])/isU', substr($pdfData, $offset), $matches)) {
713 23
                            $offset += \strlen($matches[0]);
714 23
                            $pregResult = preg_match(
715 23
                                '/(endstream)[\x09\x0a\x0c\x0d\x20]/isU',
716 23
                                substr($pdfData, $offset),
717
                                $matches,
718 23
                                PREG_OFFSET_CAPTURE
719
                            );
720 23
                            if (1 == $pregResult) {
721 23
                                $objval = substr($pdfData, $offset, $matches[0][1]);
722 23
                                $offset += $matches[1][1];
723
                            }
724
                        }
725 23
                    } elseif ('endstream' == substr($pdfData, $offset, 9)) {
726
                        // end stream object
727 23
                        $objtype = 'endstream';
728 23
                        $offset += 9;
729 23
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+R/iU', substr($pdfData, $offset, 33), $matches)) {
730
                        // indirect object reference
731 23
                        $objtype = 'objref';
732 23
                        $offset += \strlen($matches[0]);
733 23
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
734 23
                    } elseif (1 == preg_match('/^([0-9]+)[\s]+([0-9]+)[\s]+obj/iU', substr($pdfData, $offset, 33), $matches)) {
735
                        // object start
736 5
                        $objtype = 'obj';
737 5
                        $objval = (int) ($matches[1]).'_'.(int) ($matches[2]);
738 5
                        $offset += \strlen($matches[0]);
739 23
                    } elseif (($numlen = strspn($pdfData, '+-.0123456789', $offset)) > 0) {
740
                        // numeric object
741 23
                        $objtype = 'numeric';
742 23
                        $objval = substr($pdfData, $offset, $numlen);
743 23
                        $offset += $numlen;
744
                    }
745 23
                    break;
746
        }
747
748 23
        return [$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  $xref    previous xref array (if any)
757
     *
758
     * @return array containing xref and trailer data
759
     *
760
     * @throws Exception if it was unable to find startxref
761
     * @throws Exception if it was unable to find xref
762
     */
763 24
    protected function getXrefData($pdfData, $offset = 0, $xref = [])
764
    {
765 24
        $startxrefPreg = preg_match(
766 24
            '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
767
            $pdfData,
768
            $matches,
769 24
            PREG_OFFSET_CAPTURE,
770
            $offset
771
        );
772
773 24
        if (0 == $offset) {
774
            // find last startxref
775 24
            $pregResult = preg_match_all(
776 24
                '/[\r\n]startxref[\s]*[\r\n]+([0-9]+)[\s]*[\r\n]+%%EOF/i',
777
                $pdfData, $matches,
778 24
                PREG_SET_ORDER,
779
                $offset
780
            );
781 24
            if (0 == $pregResult) {
782
                throw new Exception('Unable to find startxref');
783
            }
784 24
            $matches = array_pop($matches);
785 24
            $startxref = $matches[1];
786 8
        } elseif (strpos($pdfData, 'xref', $offset) == $offset) {
787
            // Already pointing at the xref table
788 5
            $startxref = $offset;
789 4
        } elseif (preg_match('/([0-9]+[\s][0-9]+[\s]obj)/i', $pdfData, $matches, PREG_OFFSET_CAPTURE, $offset)) {
790
            // Cross-Reference Stream object
791 4
            $startxref = $offset;
792
        } elseif ($startxrefPreg) {
793
            // startxref found
794
            $startxref = $matches[1][0];
795
        } else {
796
            throw new Exception('Unable to find startxref');
797
        }
798
799 24
        if ($startxref > \strlen($pdfData)) {
800 1
            throw new Exception('Unable to find xref (PDF corrupted?)');
801
        }
802
803
        // check xref position
804 23
        if (strpos($pdfData, 'xref', $startxref) == $startxref) {
805
            // Cross-Reference
806 19
            $xref = $this->decodeXref($pdfData, $startxref, $xref);
807
        } else {
808
            // Cross-Reference Stream
809 5
            $xref = $this->decodeXrefStream($pdfData, $startxref, $xref);
810
        }
811 23
        if (empty($xref)) {
812
            throw new Exception('Unable to find xref');
813
        }
814
815 23
        return $xref;
816
    }
817
818
    /**
819
     * Parses PDF data and returns extracted data as array.
820
     *
821
     * @param string $data PDF data to parse
822
     *
823
     * @return array array of parsed PDF document objects
824
     *
825
     * @throws Exception if empty PDF data given
826
     * @throws Exception if PDF data missing %PDF header
827
     */
828 24
    public function parseData($data)
829
    {
830 24
        if (empty($data)) {
831
            throw new Exception('Empty PDF data given.');
832
        }
833
        // find the pdf header starting position
834 24
        if (false === ($trimpos = strpos($data, '%PDF-'))) {
835
            throw new Exception('Invalid PDF data: missing %PDF header.');
836
        }
837
838
        // get PDF content string
839 24
        $pdfData = substr($data, $trimpos);
840
841
        // get xref and trailer data
842 24
        $xref = $this->getXrefData($pdfData);
843
844
        // parse all document objects
845 23
        $objects = [];
846 23
        foreach ($xref['xref'] as $obj => $offset) {
847 23
            if (!isset($objects[$obj]) and ($offset > 0)) {
848
                // decode objects with positive offset
849 23
                $objects[$obj] = $this->getIndirectObject($pdfData, $xref, $obj, $offset, true);
850
            }
851
        }
852
853 23
        return [$xref, $objects];
854
    }
855
}
856