GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/bitstream.c Lines: 149 178 83.7 %
Date: 2021-04-20 04:37:23 Branches: 163 205 79.5 %

Line Branch Exec Source
1
/*
2
 * Common bit i/o utils
3
 * Copyright (c) 2000, 2001 Fabrice Bellard
4
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5
 * Copyright (c) 2010 Loren Merritt
6
 *
7
 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
8
 *
9
 * This file is part of FFmpeg.
10
 *
11
 * FFmpeg is free software; you can redistribute it and/or
12
 * modify it under the terms of the GNU Lesser General Public
13
 * License as published by the Free Software Foundation; either
14
 * version 2.1 of the License, or (at your option) any later version.
15
 *
16
 * FFmpeg is distributed in the hope that it will be useful,
17
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19
 * Lesser General Public License for more details.
20
 *
21
 * You should have received a copy of the GNU Lesser General Public
22
 * License along with FFmpeg; if not, write to the Free Software
23
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24
 */
25
26
/**
27
 * @file
28
 * bitstream api.
29
 */
30
31
#include "libavutil/avassert.h"
32
#include "libavutil/qsort.h"
33
#include "avcodec.h"
34
#include "internal.h"
35
#include "mathops.h"
36
#include "put_bits.h"
37
#include "vlc.h"
38
39
const uint8_t ff_log2_run[41]={
40
 0, 0, 0, 0, 1, 1, 1, 1,
41
 2, 2, 2, 2, 3, 3, 3, 3,
42
 4, 4, 5, 5, 6, 6, 7, 7,
43
 8, 9,10,11,12,13,14,15,
44
16,17,18,19,20,21,22,23,
45
24,
46
};
47
48
#if FF_API_AVPRIV_PUT_BITS
49
void avpriv_align_put_bits(PutBitContext *s)
50
{
51
    align_put_bits(s);
52
}
53
void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
54
{
55
    ff_copy_bits(pb, src, length);
56
}
57
#endif
58
59
1025
void ff_put_string(PutBitContext *pb, const char *string, int terminate_string)
60
{
61
6125
    while (*string) {
62
5100
        put_bits(pb, 8, *string);
63
5100
        string++;
64
    }
65
1025
    if (terminate_string)
66
365
        put_bits(pb, 8, 0);
67
1025
}
68
69
1232206
void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
70
{
71
1232206
    int words = length >> 4;
72
1232206
    int bits  = length & 15;
73
    int i;
74
75
1232206
    if (length == 0)
76
114010
        return;
77
78
1118196
    av_assert0(length <= put_bits_left(pb));
79
80

1118196
    if (CONFIG_SMALL || words < 16 || put_bits_count(pb) & 7) {
81
7767502
        for (i = 0; i < words; i++)
82
6664080
            put_bits(pb, 16, AV_RB16(src + 2 * i));
83
    } else {
84
35902
        for (i = 0; put_bits_count(pb) & 31; i++)
85
21128
            put_bits(pb, 8, src[i]);
86
14774
        flush_put_bits(pb);
87
14774
        memcpy(put_bits_ptr(pb), src + i, 2 * words - i);
88
14774
        skip_put_bytes(pb, 2 * words - i);
89
    }
90
91
1118196
    put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits));
92
}
93
94
/* VLC decoding */
95
96
#define GET_DATA(v, table, i, wrap, size)                   \
97
{                                                           \
98
    const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
99
    switch(size) {                                          \
100
    case 1:                                                 \
101
        v = *(const uint8_t *)ptr;                          \
102
        break;                                              \
103
    case 2:                                                 \
104
        v = *(const uint16_t *)ptr;                         \
105
        break;                                              \
106
    case 4:                                                 \
107
    default:                                                \
108
        av_assert1(size == 4);                              \
109
        v = *(const uint32_t *)ptr;                         \
110
        break;                                              \
111
    }                                                       \
112
}
113
114
115
434979
static int alloc_table(VLC *vlc, int size, int use_static)
116
{
117
434979
    int index = vlc->table_size;
118
119
434979
    vlc->table_size += size;
120
434979
    if (vlc->table_size > vlc->table_allocated) {
121
49653
        if (use_static)
122
            abort(); // cannot do anything, init_vlc() is used with too little memory
123
49653
        vlc->table_allocated += (1 << vlc->bits);
124
49653
        vlc->table = av_realloc_f(vlc->table, vlc->table_allocated, sizeof(VLC_TYPE) * 2);
125
49653
        if (!vlc->table) {
126
            vlc->table_allocated = 0;
127
            vlc->table_size = 0;
128
            return AVERROR(ENOMEM);
129
        }
130
49653
        memset(vlc->table + vlc->table_allocated - (1 << vlc->bits), 0, sizeof(VLC_TYPE) * 2 << vlc->bits);
131
    }
132
434979
    return index;
133
}
134
135
#define LOCALBUF_ELEMS 1500 // the maximum currently needed is 1296 by rv34
136
137
typedef struct VLCcode {
138
    uint8_t bits;
139
    VLC_TYPE symbol;
140
    /** codeword, with the first bit-to-be-read in the msb
141
     * (even if intended for a little-endian bitstream reader) */
142
    uint32_t code;
143
} VLCcode;
144
145
58257
static int vlc_common_init(VLC *vlc_arg, int nb_bits, int nb_codes,
146
                           VLC **vlc, VLC *localvlc, VLCcode **buf,
147
                           int flags)
148
{
149
58257
    *vlc = vlc_arg;
150
58257
    (*vlc)->bits = nb_bits;
151
58257
    if (flags & INIT_VLC_USE_NEW_STATIC) {
152
31464
        av_assert0(nb_codes <= LOCALBUF_ELEMS);
153
31464
        *localvlc = *vlc_arg;
154
31464
        *vlc = localvlc;
155
31464
        (*vlc)->table_size = 0;
156
    } else {
157
26793
        (*vlc)->table           = NULL;
158
26793
        (*vlc)->table_allocated = 0;
159
26793
        (*vlc)->table_size      = 0;
160
    }
161
58257
    if (nb_codes > LOCALBUF_ELEMS) {
162
120
        *buf = av_malloc_array(nb_codes, sizeof(VLCcode));
163
120
        if (!*buf)
164
            return AVERROR(ENOMEM);
165
    }
166
167
58257
    return 0;
168
}
169
170
20392081
static int compare_vlcspec(const void *a, const void *b)
171
{
172
20392081
    const VLCcode *sa = a, *sb = b;
173
20392081
    return (sa->code >> 1) - (sb->code >> 1);
174
}
175
/**
176
 * Build VLC decoding tables suitable for use with get_vlc().
177
 *
178
 * @param vlc            the context to be initialized
179
 *
180
 * @param table_nb_bits  max length of vlc codes to store directly in this table
181
 *                       (Longer codes are delegated to subtables.)
182
 *
183
 * @param nb_codes       number of elements in codes[]
184
 *
185
 * @param codes          descriptions of the vlc codes
186
 *                       These must be ordered such that codes going into the same subtable are contiguous.
187
 *                       Sorting by VLCcode.code is sufficient, though not necessary.
188
 */
189
434979
static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
190
                       VLCcode *codes, int flags)
191
{
192
    int table_size, table_index, index, code_prefix, symbol, subtable_bits;
193
    int i, j, k, n, nb, inc;
194
    uint32_t code;
195
    volatile VLC_TYPE (* volatile table)[2]; // the double volatile is needed to prevent an internal compiler error in gcc 4.2
196
197
434979
    if (table_nb_bits > 30)
198
       return AVERROR(EINVAL);
199
434979
    table_size = 1 << table_nb_bits;
200
434979
    table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
201
    ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size);
202
434979
    if (table_index < 0)
203
        return table_index;
204
434979
    table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
205
206
    /* first pass: map codes and compute auxiliary table sizes */
207
5377102
    for (i = 0; i < nb_codes; i++) {
208
4942123
        n      = codes[i].bits;
209
4942123
        code   = codes[i].code;
210
4942123
        symbol = codes[i].symbol;
211
        ff_dlog(NULL, "i=%d n=%d code=0x%"PRIx32"\n", i, n, code);
212
4942123
        if (n <= table_nb_bits) {
213
            /* no need to add another table */
214
4565401
            j = code >> (32 - table_nb_bits);
215
4565401
            nb = 1 << (table_nb_bits - n);
216
4565401
            inc = 1;
217
4565401
            if (flags & INIT_VLC_OUTPUT_LE) {
218
455435
                j = bitswap_32(code);
219
455435
                inc = 1 << n;
220
            }
221
44679710
            for (k = 0; k < nb; k++) {
222
40114309
                int bits = table[j][1];
223
40114309
                int oldsym  = table[j][0];
224
                ff_dlog(NULL, "%4x: code=%d n=%d\n", j, i, n);
225


40114309
                if ((bits || oldsym) && (bits != n || oldsym != symbol)) {
226
                    av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
227
                    return AVERROR_INVALIDDATA;
228
                }
229
40114309
                table[j][1] = n; //bits
230
40114309
                table[j][0] = symbol;
231
40114309
                j += inc;
232
            }
233
        } else {
234
            /* fill auxiliary table recursively */
235
376722
            n -= table_nb_bits;
236
376722
            code_prefix = code >> (32 - table_nb_bits);
237
376722
            subtable_bits = n;
238
376722
            codes[i].bits = n;
239
376722
            codes[i].code = code << table_nb_bits;
240
3453565
            for (k = i+1; k < nb_codes; k++) {
241
3441323
                n = codes[k].bits - table_nb_bits;
242
3441323
                if (n <= 0)
243
37283
                    break;
244
3404040
                code = codes[k].code;
245
3404040
                if (code >> (32 - table_nb_bits) != code_prefix)
246
327197
                    break;
247
3076843
                codes[k].bits = n;
248
3076843
                codes[k].code = code << table_nb_bits;
249
3076843
                subtable_bits = FFMAX(subtable_bits, n);
250
            }
251
376722
            subtable_bits = FFMIN(subtable_bits, table_nb_bits);
252
376722
            j = (flags & INIT_VLC_OUTPUT_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : code_prefix;
253
376722
            table[j][1] = -subtable_bits;
254
            ff_dlog(NULL, "%4x: n=%d (subtable)\n",
255
                    j, codes[i].bits + table_nb_bits);
256
376722
            index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
257
376722
            if (index < 0)
258
                return index;
259
            /* note: realloc has been done, so reload tables */
260
376722
            table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
261
376722
            table[j][0] = index; //code
262
376722
            if (table[j][0] != index) {
263
                avpriv_request_sample(NULL, "strange codes");
264
                return AVERROR_PATCHWELCOME;
265
            }
266
376722
            i = k-1;
267
        }
268
    }
269
270
41431845
    for (i = 0; i < table_size; i++) {
271
40996866
        if (table[i][1] == 0) //bits
272
505835
            table[i][0] = -1; //codes
273
    }
274
275
434979
    return table_index;
276
}
277
278
58257
static int vlc_common_end(VLC *vlc, int nb_bits, int nb_codes, VLCcode *codes,
279
                          int flags, VLC *vlc_arg, VLCcode localbuf[LOCALBUF_ELEMS])
280
{
281
58257
    int ret = build_table(vlc, nb_bits, nb_codes, codes, flags);
282
283
58257
    if (flags & INIT_VLC_USE_NEW_STATIC) {
284
31464
        if (vlc->table_size != vlc->table_allocated &&
285
6312
            !(flags & (INIT_VLC_STATIC_OVERLONG & ~INIT_VLC_USE_NEW_STATIC)))
286
            av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
287
31464
        av_assert0(ret >= 0);
288
31464
        *vlc_arg = *vlc;
289
    } else {
290
26793
        if (codes != localbuf)
291
120
            av_free(codes);
292
26793
        if (ret < 0) {
293
            av_freep(&vlc->table);
294
            return ret;
295
        }
296
    }
297
58257
    return 0;
298
}
299
300
/* Build VLC decoding tables suitable for use with get_vlc().
301
302
   'nb_bits' sets the decoding table size (2^nb_bits) entries. The
303
   bigger it is, the faster is the decoding. But it should not be too
304
   big to save memory and L1 cache. '9' is a good compromise.
305
306
   'nb_codes' : number of vlcs codes
307
308
   'bits' : table which gives the size (in bits) of each vlc code.
309
310
   'codes' : table which gives the bit pattern of of each vlc code.
311
312
   'symbols' : table which gives the values to be returned from get_vlc().
313
314
   'xxx_wrap' : give the number of bytes between each entry of the
315
   'bits' or 'codes' tables.
316
317
   'xxx_size' : gives the number of bytes of each entry of the 'bits'
318
   or 'codes' tables. Currently 1,2 and 4 are supported.
319
320
   'wrap' and 'size' make it possible to use any memory configuration and types
321
   (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
322
*/
323
36874
int ff_init_vlc_sparse(VLC *vlc_arg, int nb_bits, int nb_codes,
324
                       const void *bits, int bits_wrap, int bits_size,
325
                       const void *codes, int codes_wrap, int codes_size,
326
                       const void *symbols, int symbols_wrap, int symbols_size,
327
                       int flags)
328
{
329
36874
    VLCcode localbuf[LOCALBUF_ELEMS], *buf = localbuf;
330
    int i, j, ret;
331
    VLC localvlc, *vlc;
332
333
36874
    ret = vlc_common_init(vlc_arg, nb_bits, nb_codes, &vlc, &localvlc,
334
                          &buf, flags);
335
36874
    if (ret < 0)
336
        return ret;
337
338

36874
    av_assert0(symbols_size <= 2 || !symbols);
339
36874
    j = 0;
340
#define COPY(condition)\
341
    for (i = 0; i < nb_codes; i++) {                                        \
342
        unsigned len;                                                       \
343
        GET_DATA(len, bits, i, bits_wrap, bits_size);                       \
344
        if (!(condition))                                                   \
345
            continue;                                                       \
346
        if (len > 3*nb_bits || len > 32) {                                  \
347
            av_log(NULL, AV_LOG_ERROR, "Too long VLC (%u) in init_vlc\n", len);\
348
            if (buf != localbuf)                                            \
349
                av_free(buf);                                               \
350
            return AVERROR(EINVAL);                                         \
351
        }                                                                   \
352
        buf[j].bits = len;                                                  \
353
        GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size);            \
354
        if (buf[j].code >= (1LL<<buf[j].bits)) {                            \
355
            av_log(NULL, AV_LOG_ERROR, "Invalid code %"PRIx32" for %d in "  \
356
                   "init_vlc\n", buf[j].code, i);                           \
357
            if (buf != localbuf)                                            \
358
                av_free(buf);                                               \
359
            return AVERROR(EINVAL);                                         \
360
        }                                                                   \
361
        if (flags & INIT_VLC_INPUT_LE)                                      \
362
            buf[j].code = bitswap_32(buf[j].code);                          \
363
        else                                                                \
364
            buf[j].code <<= 32 - buf[j].bits;                               \
365
        if (symbols)                                                        \
366
            GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size) \
367
        else                                                                \
368
            buf[j].symbol = i;                                              \
369
        j++;                                                                \
370
    }
371






3287686
    COPY(len > nb_bits);
372
    // qsort is the slowest part of init_vlc, and could probably be improved or avoided
373











17164393
    AV_QSORT(buf, j, struct VLCcode, compare_vlcspec);
374







3287686
    COPY(len && len <= nb_bits);
375
36874
    nb_codes = j;
376
377
36874
    return vlc_common_end(vlc, nb_bits, nb_codes, buf,
378
                          flags, vlc_arg, localbuf);
379
}
380
381
21383
int ff_init_vlc_from_lengths(VLC *vlc_arg, int nb_bits, int nb_codes,
382
                             const int8_t *lens, int lens_wrap,
383
                             const void *symbols, int symbols_wrap, int symbols_size,
384
                             int offset, int flags, void *logctx)
385
{
386
21383
    VLCcode localbuf[LOCALBUF_ELEMS], *buf = localbuf;
387
    VLC localvlc, *vlc;
388
    uint64_t code;
389
21383
    int ret, j, len_max = FFMIN(32, 3 * nb_bits);
390
391
21383
    ret = vlc_common_init(vlc_arg, nb_bits, nb_codes, &vlc, &localvlc,
392
                          &buf, flags);
393
21383
    if (ret < 0)
394
        return ret;
395
396
21383
    j = code = 0;
397
1420488
    for (int i = 0; i < nb_codes; i++, lens += lens_wrap) {
398
1399105
        int len = *lens;
399
1399105
        if (len > 0) {
400
            unsigned sym;
401
402
1395533
            buf[j].bits = len;
403
1395533
            if (symbols)
404
1391496
                GET_DATA(sym, symbols, i, symbols_wrap, symbols_size)
405
            else
406
4037
                sym = i;
407
1395533
            buf[j].symbol = sym + offset;
408
1395533
            buf[j++].code = code;
409
3572
        } else if (len <  0) {
410
1504
            len = -len;
411
        } else
412
2068
            continue;
413

1397037
        if (len > len_max || code & ((1U << (32 - len)) - 1)) {
414
            av_log(logctx, AV_LOG_ERROR, "Invalid VLC (length %u)\n", len);
415
            goto fail;
416
        }
417
1397037
        code += 1U << (32 - len);
418
1397037
        if (code > UINT32_MAX + 1ULL) {
419
            av_log(logctx, AV_LOG_ERROR, "Overdetermined VLC tree\n");
420
            goto fail;
421
        }
422
    }
423
21383
    return vlc_common_end(vlc, nb_bits, j, buf,
424
                          flags, vlc_arg, localbuf);
425
fail:
426
    if (buf != localbuf)
427
        av_free(buf);
428
    return AVERROR_INVALIDDATA;
429
}
430
431
31075
void ff_free_vlc(VLC *vlc)
432
{
433
31075
    av_freep(&vlc->table);
434
31075
}