aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/common/index.c
blob: f01206dec7b0ff02757d902a62e1c68d3c65d2f8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
///////////////////////////////////////////////////////////////////////////////
//
/// \file       index.c
/// \brief      Handling of Index
//
//  Copyright (C) 2007 Lasse Collin
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////

#include "index.h"


/// Number of Records to allocate at once.
#define INDEX_GROUP_SIZE 256


typedef struct lzma_index_group_s lzma_index_group;
struct lzma_index_group_s {
	/// Next group
	lzma_index_group *prev;

	/// Previous group
	lzma_index_group *next;

	/// Index of the last Record in this group
	size_t last;

	/// Total Size fields as cumulative sum relative to the beginning
	/// of the group. The total size of the group is total_sums[last].
	lzma_vli total_sums[INDEX_GROUP_SIZE];

	/// Uncompressed Size fields as cumulative sum relative to the
	/// beginning of the group. The uncompressed size of the group is
	/// uncompressed_sums[last].
	lzma_vli uncompressed_sums[INDEX_GROUP_SIZE];

	/// True if the Record is padding
	bool paddings[INDEX_GROUP_SIZE];
};


struct lzma_index_s {
	/// Total size of the Blocks and padding
	lzma_vli total_size;

	/// Uncompressed size of the Stream
	lzma_vli uncompressed_size;

	/// Number of non-padding records. This is needed by Index encoder.
	lzma_vli count;

	/// Size of the List of Records field; this is updated every time
	/// a new non-padding Record is added.
	lzma_vli index_list_size;

	/// This is zero if no Indexes have been combined with
	/// lzma_index_cat(). With combined Indexes, this contains the sizes
	/// of all but latest the Streams, including possible Stream Padding
	/// fields.
	lzma_vli padding_size;

	/// First group of Records
	lzma_index_group *head;

	/// Last group of Records
	lzma_index_group *tail;

	/// Tracking the read position
	struct {
		/// Group where the current read position is.
		lzma_index_group *group;

		/// The most recently read record in *group
		lzma_vli record;

		/// Uncompressed offset of the beginning of *group relative
		/// to the beginning of the Stream
		lzma_vli uncompressed_offset;

		/// Compressed offset of the beginning of *group relative
		/// to the beginning of the Stream
		lzma_vli stream_offset;
	} current;

	/// Information about earlier Indexes when multiple Indexes have
	/// been combined.
	struct {
		/// Sum of the Record counts of the all but the last Stream.
		lzma_vli count;

		/// Sum of the List of Records fields of all but the last
		/// Stream. This is needed when a new Index is concatenated
		/// to this lzma_index structure.
		lzma_vli index_list_size;
	} old;
};


static void
free_index_list(lzma_index *i, lzma_allocator *allocator)
{
	lzma_index_group *g = i->head;

	while (g != NULL) {
		lzma_index_group *tmp = g->next;
		lzma_free(g, allocator);
		g = tmp;
	}

	return;
}


extern LZMA_API lzma_index *
lzma_index_init(lzma_index *i, lzma_allocator *allocator)
{
	if (i == NULL) {
		i = lzma_alloc(sizeof(lzma_index), allocator);
		if (i == NULL)
			return NULL;
	} else {
		free_index_list(i, allocator);
	}

	i->total_size = 0;
	i->uncompressed_size = 0;
	i->count = 0;
	i->index_list_size = 0;
	i->padding_size = 0;
	i->head = NULL;
	i->tail = NULL;
	i->current.group = NULL;
	i->old.count = 0;
	i->old.index_list_size = 0;

	return i;
}


extern LZMA_API void
lzma_index_end(lzma_index *i, lzma_allocator *allocator)
{
	if (i != NULL) {
		free_index_list(i, allocator);
		lzma_free(i, allocator);
	}

	return;
}


extern LZMA_API lzma_vli
lzma_index_count(const lzma_index *i)
{
	return i->count;
}


extern LZMA_API lzma_vli
lzma_index_size(const lzma_index *i)
{
	return index_size(i->count, i->index_list_size);
}


extern LZMA_API lzma_vli
lzma_index_total_size(const lzma_index *i)
{
	return i->total_size;
}


extern LZMA_API lzma_vli
lzma_index_stream_size(const lzma_index *i)
{
	// Stream Header + Blocks + Index + Stream Footer
	return LZMA_STREAM_HEADER_SIZE + i->total_size
			+ index_size(i->count, i->index_list_size)
			+ LZMA_STREAM_HEADER_SIZE;
}


extern LZMA_API lzma_vli
lzma_index_file_size(const lzma_index *i)
{
	// If multiple Streams are concatenated, the Stream Header, Index,
	// and Stream Footer fields of all but the last Stream are already
	// included in padding_size. Thus, we need to calculate only the
	// size of the last Index, not all Indexes.
	return i->total_size + i->padding_size
			+ index_size(i->count - i->old.count,
				i->index_list_size - i->old.index_list_size)
			+ LZMA_STREAM_HEADER_SIZE * 2;
}


extern LZMA_API lzma_vli
lzma_index_uncompressed_size(const lzma_index *i)
{
	return i->uncompressed_size;
}


extern uint32_t
lzma_index_padding_size(const lzma_index *i)
{
	return (LZMA_VLI_C(4)
		- index_size_unpadded(i->count, i->index_list_size)) & 3;
}


/// Helper function for index_append()
static lzma_ret
index_append_real(lzma_index *i, lzma_allocator *allocator,
		lzma_vli total_size, lzma_vli uncompressed_size,
		bool is_padding)
{
	// Add the new record.
	if (i->tail == NULL || i->tail->last == INDEX_GROUP_SIZE - 1) {
		// Allocate a new group.
		lzma_index_group *g = lzma_alloc(sizeof(lzma_index_group),
				allocator);
		if (g == NULL)
			return LZMA_MEM_ERROR;

		// Initialize the group and set its first record.
		g->prev = i->tail;
		g->next = NULL;
		g->last = 0;
		g->total_sums[0] = total_size;
		g->uncompressed_sums[0] = uncompressed_size;
		g->paddings[0] = is_padding;

		// If this is the first group, make it the head.
		if (i->head == NULL)
			i->head = g;
		else
			i->tail->next = g;

		// Make it the new tail.
		i->tail = g;

	} else {
		// i->tail has space left for at least one record.
		i->tail->total_sums[i->tail->last + 1]
				= i->tail->total_sums[i->tail->last]
					+ total_size;
		i->tail->uncompressed_sums[i->tail->last + 1]
				= i->tail->uncompressed_sums[i->tail->last]
					+ uncompressed_size;
		i->tail->paddings[i->tail->last + 1] = is_padding;
		++i->tail->last;
	}

	return LZMA_OK;
}


static lzma_ret
index_append(lzma_index *i, lzma_allocator *allocator, lzma_vli total_size,
		lzma_vli uncompressed_size, bool is_padding)
{
	if (total_size > LZMA_VLI_VALUE_MAX
			|| uncompressed_size > LZMA_VLI_VALUE_MAX)
		return LZMA_DATA_ERROR;

	// This looks a bit ugly. We want to first validate that the Index
	// and Stream stay in valid limits after adding this Record. After
	// validating, we may need to allocate a new lzma_index_group (it's
	// slightly more correct to validate before allocating, YMMV).
	lzma_ret ret;

	if (is_padding) {
		assert(uncompressed_size == 0);

		// First update the info so we can validate it.
		i->padding_size += total_size;

		if (i->padding_size > LZMA_VLI_VALUE_MAX
				|| lzma_index_file_size(i)
					> LZMA_VLI_VALUE_MAX)
			ret = LZMA_DATA_ERROR; // Would grow past the limits.
		else
			ret = index_append_real(i, allocator,
					total_size, uncompressed_size, true);

		// If something went wrong, undo the updated value.
		if (ret != LZMA_OK)
			i->padding_size -= total_size;

	} else {
		// First update the overall info so we can validate it.
		const lzma_vli index_list_size_add
				= lzma_vli_size(total_size / 4 - 1)
				+ lzma_vli_size(uncompressed_size);

		i->total_size += total_size;
		i->uncompressed_size += uncompressed_size;
		++i->count;
		i->index_list_size += index_list_size_add;

		if (i->total_size > LZMA_VLI_VALUE_MAX
				|| i->uncompressed_size > LZMA_VLI_VALUE_MAX
				|| lzma_index_size(i) > LZMA_BACKWARD_SIZE_MAX
				|| lzma_index_file_size(i)
					> LZMA_VLI_VALUE_MAX)
			ret = LZMA_DATA_ERROR; // Would grow past the limits.
		else
			ret = index_append_real(i, allocator,
					total_size, uncompressed_size, false);

		if (ret != LZMA_OK) {
			// Something went wrong. Undo the updates.
			i->total_size -= total_size;
			i->uncompressed_size -= uncompressed_size;
			--i->count;
			i->index_list_size -= index_list_size_add;
		}
	}

	return ret;
}


extern LZMA_API lzma_ret
lzma_index_append(lzma_index *i, lzma_allocator *allocator,
		lzma_vli total_size, lzma_vli uncompressed_size)
{
	return index_append(i, allocator,
			total_size, uncompressed_size, false);
}


/// Initialize i->current to point to the first Record.
static bool
init_current(lzma_index *i)
{
	if (i->head == NULL) {
		assert(i->count == 0);
		return true;
	}

	assert(i->count > 0);

	i->current.group = i->head;
	i->current.record = 0;
	i->current.stream_offset = LZMA_STREAM_HEADER_SIZE;
	i->current.uncompressed_offset = 0;

	return false;
}


/// Go backward to the previous group.
static void
previous_group(lzma_index *i)
{
	assert(i->current.group->prev != NULL);

	// Go to the previous group first.
	i->current.group = i->current.group->prev;
	i->current.record = i->current.group->last;

	// Then update the offsets.
	i->current.stream_offset -= i->current.group
			->total_sums[i->current.group->last];
	i->current.uncompressed_offset -= i->current.group
			->uncompressed_sums[i->current.group->last];

	return;
}


/// Go forward to the next group.
static void
next_group(lzma_index *i)
{
	assert(i->current.group->next != NULL);

	// Update the offsets first.
	i->current.stream_offset += i->current.group
			->total_sums[i->current.group->last];
	i->current.uncompressed_offset += i->current.group
			->uncompressed_sums[i->current.group->last];

	// Then go to the next group.
	i->current.record = 0;
	i->current.group = i->current.group->next;

	return;
}


/// Set *info from i->current.
static void
set_info(const lzma_index *i, lzma_index_record *info)
{
	info->total_size = i->current.group->total_sums[i->current.record];
	info->uncompressed_size = i->current.group->uncompressed_sums[
			i->current.record];

	info->stream_offset = i->current.stream_offset;
	info->uncompressed_offset = i->current.uncompressed_offset;

	// If it's not the first Record in this group, we need to do some
	// adjustements.
	if (i->current.record > 0) {
		// _sums[] are cumulative, thus we need to substract the
		// _previous _sums[] to get the sizes of this Record.
		info->total_size -= i->current.group
				->total_sums[i->current.record - 1];
		info->uncompressed_size -= i->current.group
				->uncompressed_sums[i->current.record - 1];

		// i->current.{total,uncompressed}_offsets have the offset
		// of the beginning of the group, thus we need to add the
		// appropriate amount to get the offsetes of this Record.
		info->stream_offset += i->current.group
				->total_sums[i->current.record - 1];
		info->uncompressed_offset += i->current.group
				->uncompressed_sums[i->current.record - 1];
	}

	return;
}


extern LZMA_API lzma_bool
lzma_index_read(lzma_index *i, lzma_index_record *info)
{
	if (i->current.group == NULL) {
		// We are at the beginning of the Record list. Set up
		// i->current point at the first Record. Return if there
		// are no Records.
		if (init_current(i))
			return true;
	} else do {
		// Try to go the next Record.
		if (i->current.record < i->current.group->last)
			++i->current.record;
		else if (i->current.group->next == NULL)
			return true;
		else
			next_group(i);
	} while (i->current.group->paddings[i->current.record]);

	// We found a new Record. Set the information to *info.
	set_info(i, info);

	return false;
}


extern LZMA_API void
lzma_index_rewind(lzma_index *i)
{
	i->current.group = NULL;
	return;
}


extern LZMA_API lzma_bool
lzma_index_locate(lzma_index *i, lzma_index_record *info, lzma_vli target)
{
	// Check if it is possible to fullfill the request.
	if (target >= i->uncompressed_size)
		return true;

	// Now we know that we will have an answer. Initialize the current
	// read position if needed.
	if (i->current.group == NULL && init_current(i))
		return true;

	// Locate the group where the wanted Block is. First search forward.
	while (i->current.uncompressed_offset <= target) {
		// If the first uncompressed byte of the next group is past
		// the target offset, it has to be this or an earlier group.
		if (i->current.uncompressed_offset + i->current.group
				->uncompressed_sums[i->current.group->last]
				> target)
			break;

		// Go forward to the next group.
		next_group(i);
	}

	// Then search backward.
	while (i->current.uncompressed_offset > target)
		previous_group(i);

	// Now the target Block is somewhere in i->current.group. Offsets
	// in groups are relative to the beginning of the group, thus
	// we must adjust the target before starting the search loop.
	assert(target >= i->current.uncompressed_offset);
	target -= i->current.uncompressed_offset;

	// Use binary search to locate the exact Record. It is the first
	// Record whose uncompressed_sums[] value is greater than target.
	// This is because we want the rightmost Record that fullfills the
	// search criterion. It is possible that there are empty Blocks or
	// padding, we don't want to return them.
	size_t left = 0;
	size_t right = i->current.group->last;

	while (left < right) {
		const size_t pos = left + (right - left) / 2;
		if (i->current.group->uncompressed_sums[pos] <= target)
			left = pos + 1;
		else
			right = pos;
	}

	i->current.record = left;

#ifndef NDEBUG
	// The found Record must not be padding or have zero uncompressed size.
	assert(!i->current.group->paddings[i->current.record]);

	if (i->current.record == 0)
		assert(i->current.group->uncompressed_sums[0] > 0);
	else
		assert(i->current.group->uncompressed_sums[i->current.record]
				- i->current.group->uncompressed_sums[
					i->current.record - 1] > 0);
#endif

	set_info(i, info);

	return false;
}


extern LZMA_API lzma_ret
lzma_index_cat(lzma_index *restrict dest, lzma_index *restrict src,
		lzma_allocator *allocator, lzma_vli padding)
{
	if (dest == NULL || src == NULL || dest == src
			|| padding > LZMA_VLI_VALUE_MAX)
		return LZMA_PROG_ERROR;

	// Check that the combined size of the Indexes stays within limits.
	{
		const lzma_vli dest_size = lzma_index_file_size(dest);
		const lzma_vli src_size = lzma_index_file_size(src);
		if (dest_size + src_size > LZMA_VLI_VALUE_UNKNOWN
				|| dest_size + src_size + padding
					> LZMA_VLI_VALUE_UNKNOWN)
			return LZMA_DATA_ERROR;
	}

	// Add a padding Record to take into account the size of
	// Index + Stream Footer + Stream Padding + Stream Header.
	//
	// NOTE: This cannot overflow, because Index Size is always
	// far smaller than LZMA_VLI_VALUE_MAX, and adding two VLIs
	// (Index Size and padding) doesn't overflow. It may become
	// an invalid VLI if padding is huge, but that is caught by
	// index_append().
	padding += index_size(dest->count - dest->old.count,
				dest->index_list_size
					- dest->old.index_list_size)
			+ LZMA_STREAM_HEADER_SIZE * 2;

	// Add the padding Record.
	return_if_error(index_append(
			dest, allocator, padding, 0, true));

	// Avoid wasting lots of memory if src->head has only a few records
	// that fit into dest->tail. That is, combine two groups if possible.
	//
	// NOTE: We know that dest->tail != NULL since we just appended
	// a padding Record. But we don't know about src->head.
	if (src->head != NULL && src->head->last + 1
			<= INDEX_GROUP_SIZE - dest->tail->last - 1) {
		// Copy the first Record.
		dest->tail->total_sums[dest->tail->last + 1]
			= dest->tail->total_sums[dest->tail->last]
				+ src->head->total_sums[0];

		dest->tail->uncompressed_sums[dest->tail->last + 1]
			= dest->tail->uncompressed_sums[dest->tail->last]
				+ src->head->uncompressed_sums[0];

		dest->tail->paddings[dest->tail->last + 1]
				= src->head->paddings[0];

		++dest->tail->last;

		// Copy the rest.
		for (size_t i = 1; i < src->head->last; ++i) {
			dest->tail->total_sums[dest->tail->last + 1]
				= dest->tail->total_sums[dest->tail->last]
					+ src->head->total_sums[i + 1]
					- src->head->total_sums[i];

			dest->tail->uncompressed_sums[dest->tail->last + 1]
				= dest->tail->uncompressed_sums[
						dest->tail->last]
					+ src->head->uncompressed_sums[i + 1]
					- src->head->uncompressed_sums[i];

			dest->tail->paddings[dest->tail->last + 1]
				= src->head->paddings[i + 1];

			++dest->tail->last;
		}

		// Free the head group of *src. Don't bother updating prev
		// pointers since those won't be used for anything before
		// we deallocate the whole *src structure.
		lzma_index_group *tmp = src->head;
		src->head = src->head->next;
		lzma_free(tmp, allocator);
	}

	// If there are groups left in *src, join them as is. Note that if we
	// are combining already combined Indexes, src->head can be non-NULL
	// even if we just combined the old src->head to dest->tail.
	if (src->head != NULL) {
		src->head->prev = dest->tail;
		dest->tail->next = src->head;
		dest->tail = src->tail;
	}

	// Update information about earlier Indexes. Only the last Index
	// from *src won't be counted in dest->old. The last Index is left
	// open and can be even appended with lzma_index_append().
	dest->old.count = dest->count + src->old.count;
	dest->old.index_list_size
			= dest->index_list_size + src->old.index_list_size;

	// Update overall information.
	dest->total_size += src->total_size;
	dest->uncompressed_size += src->uncompressed_size;
	dest->count += src->count;
	dest->index_list_size += src->index_list_size;
	dest->padding_size += src->padding_size;

	// *src has nothing left but the base structure.
	lzma_free(src, allocator);

	return LZMA_OK;
}


extern LZMA_API lzma_index *
lzma_index_dup(const lzma_index *src, lzma_allocator *allocator)
{
	lzma_index *dest = lzma_alloc(sizeof(lzma_index), allocator);
	if (dest == NULL)
		return NULL;

	// Copy the base structure except the pointers.
	*dest = *src;
	dest->head = NULL;
	dest->tail = NULL;
	dest->current.group = NULL;

	// Copy the Records.
	const lzma_index_group *src_group = src->head;
	while (src_group != NULL) {
		// Allocate a new group.
		lzma_index_group *dest_group = lzma_alloc(
				sizeof(lzma_index_group), allocator);
		if (dest_group == NULL) {
			lzma_index_end(dest, allocator);
			return NULL;
		}

		// Set the pointers.
		dest_group->prev = dest->tail;
		dest_group->next = NULL;

		if (dest->head == NULL)
			dest->head = dest_group;
		else
			dest->tail->next = dest_group;

		dest->tail = dest_group;

		dest_group->last = src_group->last;

		// Copy the arrays so that we don't read uninitialized memory.
		const size_t count = src_group->last + 1;
		memcpy(dest_group->total_sums, src_group->total_sums,
				sizeof(lzma_vli) * count);
		memcpy(dest_group->uncompressed_sums,
				src_group->uncompressed_sums,
				sizeof(lzma_vli) * count);
		memcpy(dest_group->paddings, src_group->paddings,
				sizeof(bool) * count);

		// Copy also the read position.
		if (src_group == src->current.group)
			dest->current.group = dest->tail;

		src_group = src_group->next;
	}

	return dest;
}


extern LZMA_API lzma_bool
lzma_index_equal(const lzma_index *a, const lzma_index *b)
{
	// No point to compare more if the pointers are the same.
	if (a == b)
		return true;

	// Compare the basic properties.
	if (a->total_size != b->total_size
			|| a->uncompressed_size != b->uncompressed_size
			|| a->index_list_size != b->index_list_size
			|| a->count != b->count)
		return false;

	// Compare the Records.
	const lzma_index_group *ag = a->head;
	const lzma_index_group *bg = b->head;
	while (ag != NULL && bg != NULL) {
		const size_t count = ag->last + 1;
		if (ag->last != bg->last
				|| memcmp(ag->total_sums,
					bg->total_sums,
					sizeof(lzma_vli) * count) != 0
				|| memcmp(ag->uncompressed_sums,
					bg->uncompressed_sums,
					sizeof(lzma_vli) * count) != 0
				|| memcmp(ag->paddings, bg->paddings,
					sizeof(bool) * count) != 0)
			return false;

		ag = ag->next;
		bg = bg->next;
	}

	return ag == NULL && bg == NULL;
}