summaryrefslogtreecommitdiff
path: root/archival/libunarchive/decompress_unlzma.c
blob: 33e5cd65d40c58d8d9029000789b5bed444d806e (plain)
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
/* vi: set sw=4 ts=4: */
/*
 * Small lzma deflate implementation.
 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
 *
 * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
 * Copyright (C) 1999-2005  Igor Pavlov
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include "unarchive.h"

#if ENABLE_FEATURE_LZMA_FAST
#  define speed_inline ALWAYS_INLINE
#else
#  define speed_inline
#endif


typedef struct {
	int fd;
	uint8_t *ptr;

/* Was keeping rc on stack in unlzma and separately allocating buffer,
 * but with "buffer 'attached to' allocated rc" code is smaller: */
	/* uint8_t *buffer; */
#define RC_BUFFER ((uint8_t*)(rc+1))

	uint8_t *buffer_end;

/* Had provisions for variable buffer, but we don't need it here */
	/* int buffer_size; */
#define RC_BUFFER_SIZE 0x10000

	uint32_t code;
	uint32_t range;
	uint32_t bound;
} rc_t;

#define RC_TOP_BITS 24
#define RC_MOVE_BITS 5
#define RC_MODEL_TOTAL_BITS 11


/* Called twice: once at startup and once in rc_normalize() */
static void rc_read(rc_t *rc)
{
	int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE);
	if (buffer_size <= 0)
		bb_error_msg_and_die("unexpected EOF");
	rc->ptr = RC_BUFFER;
	rc->buffer_end = RC_BUFFER + buffer_size;
}

/* Called once */
static rc_t* rc_init(int fd) /*, int buffer_size) */
{
	int i;
	rc_t *rc;

	rc = xmalloc(sizeof(*rc) + RC_BUFFER_SIZE);

	rc->fd = fd;
	/* rc->buffer_size = buffer_size; */
	rc->buffer_end = RC_BUFFER + RC_BUFFER_SIZE;
	rc->ptr = rc->buffer_end;

	rc->code = 0;
	rc->range = 0xFFFFFFFF;
	for (i = 0; i < 5; i++) {
		if (rc->ptr >= rc->buffer_end)
			rc_read(rc);
		rc->code = (rc->code << 8) | *rc->ptr++;
	}
	return rc;
}

/* Called once  */
static ALWAYS_INLINE void rc_free(rc_t *rc)
{
	free(rc);
}

/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */
static void rc_do_normalize(rc_t *rc)
{
	if (rc->ptr >= rc->buffer_end)
		rc_read(rc);
	rc->range <<= 8;
	rc->code = (rc->code << 8) | *rc->ptr++;
}
static ALWAYS_INLINE void rc_normalize(rc_t *rc)
{
	if (rc->range < (1 << RC_TOP_BITS)) {
		rc_do_normalize(rc);
	}
}

/* rc_is_bit_0 is called 9 times */
/* Why rc_is_bit_0_helper exists?
 * Because we want to always expose (rc->code < rc->bound) to optimizer.
 * Thus rc_is_bit_0 is always inlined, and rc_is_bit_0_helper is inlined
 * only if we compile for speed.
 */
static speed_inline uint32_t rc_is_bit_0_helper(rc_t *rc, uint16_t *p)
{
	rc_normalize(rc);
	rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
	return rc->bound;
}
static ALWAYS_INLINE int rc_is_bit_0(rc_t *rc, uint16_t *p)
{
	uint32_t t = rc_is_bit_0_helper(rc, p);
	return rc->code < t;
}

/* Called ~10 times, but very small, thus inlined */
static speed_inline void rc_update_bit_0(rc_t *rc, uint16_t *p)
{
	rc->range = rc->bound;
	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
}
static speed_inline void rc_update_bit_1(rc_t *rc, uint16_t *p)
{
	rc->range -= rc->bound;
	rc->code -= rc->bound;
	*p -= *p >> RC_MOVE_BITS;
}

/* Called 4 times in unlzma loop */
static int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
{
	if (rc_is_bit_0(rc, p)) {
		rc_update_bit_0(rc, p);
		*symbol *= 2;
		return 0;
	} else {
		rc_update_bit_1(rc, p);
		*symbol = *symbol * 2 + 1;
		return 1;
	}
}

/* Called once */
static ALWAYS_INLINE int rc_direct_bit(rc_t *rc)
{
	rc_normalize(rc);
	rc->range >>= 1;
	if (rc->code >= rc->range) {
		rc->code -= rc->range;
		return 1;
	}
	return 0;
}

/* Called twice */
static speed_inline void
rc_bit_tree_decode(rc_t *rc, uint16_t *p, int num_levels, int *symbol)
{
	int i = num_levels;

	*symbol = 1;
	while (i--)
		rc_get_bit(rc, p + *symbol, symbol);
	*symbol -= 1 << num_levels;
}


typedef struct {
	uint8_t pos;
	uint32_t dict_size;
	uint64_t dst_size;
} __attribute__ ((packed)) lzma_header_t;


/* #defines will force compiler to compute/optimize each one with each usage.
 * Have heart and use enum instead. */
enum {
	LZMA_BASE_SIZE = 1846,
	LZMA_LIT_SIZE  = 768,

	LZMA_NUM_POS_BITS_MAX = 4,

	LZMA_LEN_NUM_LOW_BITS  = 3,
	LZMA_LEN_NUM_MID_BITS  = 3,
	LZMA_LEN_NUM_HIGH_BITS = 8,

	LZMA_LEN_CHOICE     = 0,
	LZMA_LEN_CHOICE_2   = (LZMA_LEN_CHOICE + 1),
	LZMA_LEN_LOW        = (LZMA_LEN_CHOICE_2 + 1),
	LZMA_LEN_MID        = (LZMA_LEN_LOW \
	                      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS))),
	LZMA_LEN_HIGH       = (LZMA_LEN_MID \
	                      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS))),
	LZMA_NUM_LEN_PROBS  = (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS)),

	LZMA_NUM_STATES     = 12,
	LZMA_NUM_LIT_STATES = 7,

	LZMA_START_POS_MODEL_INDEX = 4,
	LZMA_END_POS_MODEL_INDEX   = 14,
	LZMA_NUM_FULL_DISTANCES    = (1 << (LZMA_END_POS_MODEL_INDEX >> 1)),

	LZMA_NUM_POS_SLOT_BITS = 6,
	LZMA_NUM_LEN_TO_POS_STATES = 4,

	LZMA_NUM_ALIGN_BITS = 4,

	LZMA_MATCH_MIN_LEN  = 2,

	LZMA_IS_MATCH       = 0,
	LZMA_IS_REP         = (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX)),
	LZMA_IS_REP_G0      = (LZMA_IS_REP + LZMA_NUM_STATES),
	LZMA_IS_REP_G1      = (LZMA_IS_REP_G0 + LZMA_NUM_STATES),
	LZMA_IS_REP_G2      = (LZMA_IS_REP_G1 + LZMA_NUM_STATES),
	LZMA_IS_REP_0_LONG  = (LZMA_IS_REP_G2 + LZMA_NUM_STATES),
	LZMA_POS_SLOT       = (LZMA_IS_REP_0_LONG \
	                      + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX)),
	LZMA_SPEC_POS       = (LZMA_POS_SLOT \
	                      + (LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS)),
	LZMA_ALIGN          = (LZMA_SPEC_POS \
	                      + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX),
	LZMA_LEN_CODER      = (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS)),
	LZMA_REP_LEN_CODER  = (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS),
	LZMA_LITERAL        = (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS),
};


IF_DESKTOP(long long) int FAST_FUNC
unpack_lzma_stream(int src_fd, int dst_fd)
{
	IF_DESKTOP(long long total_written = 0;)
	lzma_header_t header;
	int lc, pb, lp;
	uint32_t pos_state_mask;
	uint32_t literal_pos_mask;
	uint32_t pos;
	uint16_t *p;
	uint16_t *prob;
	uint16_t *prob_lit;
	int num_bits;
	int num_probs;
	rc_t *rc;
	int i, mi;
	uint8_t *buffer;
	uint8_t previous_byte = 0;
	size_t buffer_pos = 0, global_pos = 0;
	int len = 0;
	int state = 0;
	uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;

	xread(src_fd, &header, sizeof(header));

	if (header.pos >= (9 * 5 * 5))
		bb_error_msg_and_die("bad header");
	mi = header.pos / 9;
	lc = header.pos % 9;
	pb = mi / 5;
	lp = mi % 5;
	pos_state_mask = (1 << pb) - 1;
	literal_pos_mask = (1 << lp) - 1;

	header.dict_size = SWAP_LE32(header.dict_size);
	header.dst_size = SWAP_LE64(header.dst_size);

	if (header.dict_size == 0)
		header.dict_size = 1;

	buffer = xmalloc(MIN(header.dst_size, header.dict_size));

	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
	p = xmalloc(num_probs * sizeof(*p));
	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
	for (i = 0; i < num_probs; i++)
		p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;

	rc = rc_init(src_fd); /*, RC_BUFFER_SIZE); */

	while (global_pos + buffer_pos < header.dst_size) {
		int pos_state = (buffer_pos + global_pos) & pos_state_mask;

		prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
		if (rc_is_bit_0(rc, prob)) {
			mi = 1;
			rc_update_bit_0(rc, prob);
			prob = (p + LZMA_LITERAL
			        + (LZMA_LIT_SIZE * ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
			                            + (previous_byte >> (8 - lc))
			                           )
			          )
			);

			if (state >= LZMA_NUM_LIT_STATES) {
				int match_byte;

				pos = buffer_pos - rep0;
				while (pos >= header.dict_size)
					pos += header.dict_size;
				match_byte = buffer[pos];
				do {
					int bit;

					match_byte <<= 1;
					bit = match_byte & 0x100;
					prob_lit = prob + 0x100 + bit + mi;
					bit ^= (rc_get_bit(rc, prob_lit, &mi) << 8); /* 0x100 or 0 */
					if (bit)
						break;
				} while (mi < 0x100);
			}
			while (mi < 0x100) {
				prob_lit = prob + mi;
				rc_get_bit(rc, prob_lit, &mi);
			}

			state -= 3;
			if (state < 4-3)
				state = 0;
			if (state >= 10-3)
				state -= 6-3;

			previous_byte = (uint8_t) mi;
#if ENABLE_FEATURE_LZMA_FAST
 one_byte1:
			buffer[buffer_pos++] = previous_byte;
			if (buffer_pos == header.dict_size) {
				buffer_pos = 0;
				global_pos += header.dict_size;
				if (full_write(dst_fd, buffer, header.dict_size) != (ssize_t)header.dict_size)
					goto bad;
				IF_DESKTOP(total_written += header.dict_size;)
			}
#else
			len = 1;
			goto one_byte2;
#endif
		} else {
			int offset;
			uint16_t *prob_len;

			rc_update_bit_1(rc, prob);
			prob = p + LZMA_IS_REP + state;
			if (rc_is_bit_0(rc, prob)) {
				rc_update_bit_0(rc, prob);
				rep3 = rep2;
				rep2 = rep1;
				rep1 = rep0;
				state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
				prob = p + LZMA_LEN_CODER;
			} else {
				rc_update_bit_1(rc, prob);
				prob = p + LZMA_IS_REP_G0 + state;
				if (rc_is_bit_0(rc, prob)) {
					rc_update_bit_0(rc, prob);
					prob = (p + LZMA_IS_REP_0_LONG
					        + (state << LZMA_NUM_POS_BITS_MAX)
					        + pos_state
					);
					if (rc_is_bit_0(rc, prob)) {
						rc_update_bit_0(rc, prob);

						state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
#if ENABLE_FEATURE_LZMA_FAST
						pos = buffer_pos - rep0;
						while (pos >= header.dict_size)
							pos += header.dict_size;
						previous_byte = buffer[pos];
						goto one_byte1;
#else
						len = 1;
						goto string;
#endif
					} else {
						rc_update_bit_1(rc, prob);
					}
				} else {
					uint32_t distance;

					rc_update_bit_1(rc, prob);
					prob = p + LZMA_IS_REP_G1 + state;
					if (rc_is_bit_0(rc, prob)) {
						rc_update_bit_0(rc, prob);
						distance = rep1;
					} else {
						rc_update_bit_1(rc, prob);
						prob = p + LZMA_IS_REP_G2 + state;
						if (rc_is_bit_0(rc, prob)) {
							rc_update_bit_0(rc, prob);
							distance = rep2;
						} else {
							rc_update_bit_1(rc, prob);
							distance = rep3;
							rep3 = rep2;
						}
						rep2 = rep1;
					}
					rep1 = rep0;
					rep0 = distance;
				}
				state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
				prob = p + LZMA_REP_LEN_CODER;
			}

			prob_len = prob + LZMA_LEN_CHOICE;
			if (rc_is_bit_0(rc, prob_len)) {
				rc_update_bit_0(rc, prob_len);
				prob_len = (prob + LZMA_LEN_LOW
				            + (pos_state << LZMA_LEN_NUM_LOW_BITS));
				offset = 0;
				num_bits = LZMA_LEN_NUM_LOW_BITS;
			} else {
				rc_update_bit_1(rc, prob_len);
				prob_len = prob + LZMA_LEN_CHOICE_2;
				if (rc_is_bit_0(rc, prob_len)) {
					rc_update_bit_0(rc, prob_len);
					prob_len = (prob + LZMA_LEN_MID
					            + (pos_state << LZMA_LEN_NUM_MID_BITS));
					offset = 1 << LZMA_LEN_NUM_LOW_BITS;
					num_bits = LZMA_LEN_NUM_MID_BITS;
				} else {
					rc_update_bit_1(rc, prob_len);
					prob_len = prob + LZMA_LEN_HIGH;
					offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
					          + (1 << LZMA_LEN_NUM_MID_BITS));
					num_bits = LZMA_LEN_NUM_HIGH_BITS;
				}
			}
			rc_bit_tree_decode(rc, prob_len, num_bits, &len);
			len += offset;

			if (state < 4) {
				int pos_slot;

				state += LZMA_NUM_LIT_STATES;
				prob = p + LZMA_POS_SLOT +
				       ((len < LZMA_NUM_LEN_TO_POS_STATES ? len :
				         LZMA_NUM_LEN_TO_POS_STATES - 1)
				         << LZMA_NUM_POS_SLOT_BITS);
				rc_bit_tree_decode(rc, prob, LZMA_NUM_POS_SLOT_BITS,
								   &pos_slot);
				if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
					num_bits = (pos_slot >> 1) - 1;
					rep0 = 2 | (pos_slot & 1);
					if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
						rep0 <<= num_bits;
						prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
					} else {
						num_bits -= LZMA_NUM_ALIGN_BITS;
						while (num_bits--)
							rep0 = (rep0 << 1) | rc_direct_bit(rc);
						prob = p + LZMA_ALIGN;
						rep0 <<= LZMA_NUM_ALIGN_BITS;
						num_bits = LZMA_NUM_ALIGN_BITS;
					}
					i = 1;
					mi = 1;
					while (num_bits--) {
						if (rc_get_bit(rc, prob + mi, &mi))
							rep0 |= i;
						i <<= 1;
					}
				} else
					rep0 = pos_slot;
				if (++rep0 == 0)
					break;
			}

			len += LZMA_MATCH_MIN_LEN;
 IF_NOT_FEATURE_LZMA_FAST(string:)
			do {
				pos = buffer_pos - rep0;
				while (pos >= header.dict_size)
					pos += header.dict_size;
				previous_byte = buffer[pos];
 IF_NOT_FEATURE_LZMA_FAST(one_byte2:)
				buffer[buffer_pos++] = previous_byte;
				if (buffer_pos == header.dict_size) {
					buffer_pos = 0;
					global_pos += header.dict_size;
					if (full_write(dst_fd, buffer, header.dict_size) != (ssize_t)header.dict_size)
						goto bad;
					IF_DESKTOP(total_written += header.dict_size;)
				}
				len--;
			} while (len != 0 && buffer_pos < header.dst_size);
		}
	}

	{
		IF_NOT_DESKTOP(int total_written = 0; /* success */)
		IF_DESKTOP(total_written += buffer_pos;)
		if (full_write(dst_fd, buffer, buffer_pos) != (ssize_t)buffer_pos) {
 bad:
			total_written = -1; /* failure */
		}
		rc_free(rc);
		free(p);
		free(buffer);
		return total_written;
	}
}