GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/bitstream.c Lines: 121 136 89.0 %
Date: 2019-11-22 03:34:36 Branches: 142 182 78.0 %

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
703171
void avpriv_align_put_bits(PutBitContext *s)
49
{
50
703171
    put_bits(s, s->bit_left & 7, 0);
51
703171
}
52
53
1025
void avpriv_put_string(PutBitContext *pb, const char *string,
54
                       int terminate_string)
55
{
56
6125
    while (*string) {
57
5100
        put_bits(pb, 8, *string);
58
5100
        string++;
59
    }
60
1025
    if (terminate_string)
61
365
        put_bits(pb, 8, 0);
62
1025
}
63
64
1232579
void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
65
{
66
1232579
    int words = length >> 4;
67
1232579
    int bits  = length & 15;
68
    int i;
69
70
1232579
    if (length == 0)
71
114010
        return;
72
73
1118569
    av_assert0(length <= put_bits_left(pb));
74
75

1118569
    if (CONFIG_SMALL || words < 16 || put_bits_count(pb) & 7) {
76
7800573
        for (i = 0; i < words; i++)
77
6696778
            put_bits(pb, 16, AV_RB16(src + 2 * i));
78
    } else {
79
35902
        for (i = 0; put_bits_count(pb) & 31; i++)
80
21128
            put_bits(pb, 8, src[i]);
81
14774
        flush_put_bits(pb);
82
14774
        memcpy(put_bits_ptr(pb), src + i, 2 * words - i);
83
14774
        skip_put_bytes(pb, 2 * words - i);
84
    }
85
86
1118569
    put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits));
87
}
88
89
/* VLC decoding */
90
91
#define GET_DATA(v, table, i, wrap, size)                   \
92
{                                                           \
93
    const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
94
    switch(size) {                                          \
95
    case 1:                                                 \
96
        v = *(const uint8_t *)ptr;                          \
97
        break;                                              \
98
    case 2:                                                 \
99
        v = *(const uint16_t *)ptr;                         \
100
        break;                                              \
101
    case 4:                                                 \
102
        v = *(const uint32_t *)ptr;                         \
103
        break;                                              \
104
    default:                                                \
105
        av_assert1(0);                                      \
106
    }                                                       \
107
}
108
109
110
440743
static int alloc_table(VLC *vlc, int size, int use_static)
111
{
112
440743
    int index = vlc->table_size;
113
114
440743
    vlc->table_size += size;
115
440743
    if (vlc->table_size > vlc->table_allocated) {
116
53153
        if (use_static)
117
            abort(); // cannot do anything, init_vlc() is used with too little memory
118
53153
        vlc->table_allocated += (1 << vlc->bits);
119
53153
        vlc->table = av_realloc_f(vlc->table, vlc->table_allocated, sizeof(VLC_TYPE) * 2);
120
53153
        if (!vlc->table) {
121
            vlc->table_allocated = 0;
122
            vlc->table_size = 0;
123
            return AVERROR(ENOMEM);
124
        }
125
53153
        memset(vlc->table + vlc->table_allocated - (1 << vlc->bits), 0, sizeof(VLC_TYPE) * 2 << vlc->bits);
126
    }
127
440743
    return index;
128
}
129
130
typedef struct VLCcode {
131
    uint8_t bits;
132
    uint16_t symbol;
133
    /** codeword, with the first bit-to-be-read in the msb
134
     * (even if intended for a little-endian bitstream reader) */
135
    uint32_t code;
136
} VLCcode;
137
138
26009692
static int compare_vlcspec(const void *a, const void *b)
139
{
140
26009692
    const VLCcode *sa = a, *sb = b;
141
26009692
    return (sa->code >> 1) - (sb->code >> 1);
142
}
143
/**
144
 * Build VLC decoding tables suitable for use with get_vlc().
145
 *
146
 * @param vlc            the context to be initialized
147
 *
148
 * @param table_nb_bits  max length of vlc codes to store directly in this table
149
 *                       (Longer codes are delegated to subtables.)
150
 *
151
 * @param nb_codes       number of elements in codes[]
152
 *
153
 * @param codes          descriptions of the vlc codes
154
 *                       These must be ordered such that codes going into the same subtable are contiguous.
155
 *                       Sorting by VLCcode.code is sufficient, though not necessary.
156
 */
157
440743
static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
158
                       VLCcode *codes, int flags)
159
{
160
    int table_size, table_index, index, code_prefix, symbol, subtable_bits;
161
    int i, j, k, n, nb, inc;
162
    uint32_t code;
163
    volatile VLC_TYPE (* volatile table)[2]; // the double volatile is needed to prevent an internal compiler error in gcc 4.2
164
165
440743
    table_size = 1 << table_nb_bits;
166
440743
    if (table_nb_bits > 30)
167
       return AVERROR(EINVAL);
168
440743
    table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
169
    ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size);
170
440743
    if (table_index < 0)
171
        return table_index;
172
440743
    table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
173
174
    /* first pass: map codes and compute auxiliary table sizes */
175
5463308
    for (i = 0; i < nb_codes; i++) {
176
5022565
        n      = codes[i].bits;
177
5022565
        code   = codes[i].code;
178
5022565
        symbol = codes[i].symbol;
179
        ff_dlog(NULL, "i=%d n=%d code=0x%"PRIx32"\n", i, n, code);
180
5022565
        if (n <= table_nb_bits) {
181
            /* no need to add another table */
182
4642412
            j = code >> (32 - table_nb_bits);
183
4642412
            nb = 1 << (table_nb_bits - n);
184
4642412
            inc = 1;
185
4642412
            if (flags & INIT_VLC_LE) {
186
431226
                j = bitswap_32(code);
187
431226
                inc = 1 << n;
188
            }
189
46632487
            for (k = 0; k < nb; k++) {
190
41990075
                int bits = table[j][1];
191
41990075
                int oldsym  = table[j][0];
192
                ff_dlog(NULL, "%4x: code=%d n=%d\n", j, i, n);
193


41990075
                if ((bits || oldsym) && (bits != n || oldsym != symbol)) {
194
                    av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
195
                    return AVERROR_INVALIDDATA;
196
                }
197
41990075
                table[j][1] = n; //bits
198
41990075
                table[j][0] = symbol;
199
41990075
                j += inc;
200
            }
201
        } else {
202
            /* fill auxiliary table recursively */
203
380153
            n -= table_nb_bits;
204
380153
            code_prefix = code >> (32 - table_nb_bits);
205
380153
            subtable_bits = n;
206
380153
            codes[i].bits = n;
207
380153
            codes[i].code = code << table_nb_bits;
208
3452447
            for (k = i+1; k < nb_codes; k++) {
209
3451048
                n = codes[k].bits - table_nb_bits;
210
3451048
                if (n <= 0)
211
44291
                    break;
212
3406757
                code = codes[k].code;
213
3406757
                if (code >> (32 - table_nb_bits) != code_prefix)
214
334463
                    break;
215
3072294
                codes[k].bits = n;
216
3072294
                codes[k].code = code << table_nb_bits;
217
3072294
                subtable_bits = FFMAX(subtable_bits, n);
218
            }
219
380153
            subtable_bits = FFMIN(subtable_bits, table_nb_bits);
220
380153
            j = (flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : code_prefix;
221
380153
            table[j][1] = -subtable_bits;
222
            ff_dlog(NULL, "%4x: n=%d (subtable)\n",
223
                    j, codes[i].bits + table_nb_bits);
224
380153
            index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
225
380153
            if (index < 0)
226
                return index;
227
            /* note: realloc has been done, so reload tables */
228
380153
            table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
229
380153
            table[j][0] = index; //code
230
380153
            if (table[j][0] != index) {
231
                avpriv_request_sample(NULL, "strange codes");
232
                return AVERROR_PATCHWELCOME;
233
            }
234
380153
            i = k-1;
235
        }
236
    }
237
238
43330321
    for (i = 0; i < table_size; i++) {
239
42889578
        if (table[i][1] == 0) //bits
240
519350
            table[i][0] = -1; //codes
241
    }
242
243
440743
    return table_index;
244
}
245
246
247
/* Build VLC decoding tables suitable for use with get_vlc().
248
249
   'nb_bits' sets the decoding table size (2^nb_bits) entries. The
250
   bigger it is, the faster is the decoding. But it should not be too
251
   big to save memory and L1 cache. '9' is a good compromise.
252
253
   'nb_codes' : number of vlcs codes
254
255
   'bits' : table which gives the size (in bits) of each vlc code.
256
257
   'codes' : table which gives the bit pattern of of each vlc code.
258
259
   'symbols' : table which gives the values to be returned from get_vlc().
260
261
   'xxx_wrap' : give the number of bytes between each entry of the
262
   'bits' or 'codes' tables.
263
264
   'xxx_size' : gives the number of bytes of each entry of the 'bits'
265
   or 'codes' tables. Currently 1,2 and 4 are supported.
266
267
   'wrap' and 'size' make it possible to use any memory configuration and types
268
   (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
269
270
   'use_static' should be set to 1 for tables, which should be freed
271
   with av_free_static(), 0 if ff_free_vlc() will be used.
272
*/
273
60590
int ff_init_vlc_sparse(VLC *vlc_arg, int nb_bits, int nb_codes,
274
                       const void *bits, int bits_wrap, int bits_size,
275
                       const void *codes, int codes_wrap, int codes_size,
276
                       const void *symbols, int symbols_wrap, int symbols_size,
277
                       int flags)
278
{
279
    VLCcode *buf;
280
    int i, j, ret;
281
    VLCcode localbuf[1500]; // the maximum currently needed is 1296 by rv34
282
    VLC localvlc, *vlc;
283
284
60590
    vlc = vlc_arg;
285
60590
    vlc->bits = nb_bits;
286
60590
    if (flags & INIT_VLC_USE_NEW_STATIC) {
287
31878
        av_assert0(nb_codes + 1 <= FF_ARRAY_ELEMS(localbuf));
288
31878
        buf = localbuf;
289
31878
        localvlc = *vlc_arg;
290
31878
        vlc = &localvlc;
291
31878
        vlc->table_size = 0;
292
    } else {
293
28712
        vlc->table           = NULL;
294
28712
        vlc->table_allocated = 0;
295
28712
        vlc->table_size      = 0;
296
297
28712
        buf = av_malloc_array((nb_codes + 1), sizeof(VLCcode));
298
28712
        if (!buf)
299
            return AVERROR(ENOMEM);
300
    }
301
302
303

60590
    av_assert0(symbols_size <= 2 || !symbols);
304
60590
    j = 0;
305
#define COPY(condition)\
306
    for (i = 0; i < nb_codes; i++) {                                        \
307
        GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size);               \
308
        if (!(condition))                                                   \
309
            continue;                                                       \
310
        if (buf[j].bits > 3*nb_bits || buf[j].bits>32) {                    \
311
            av_log(NULL, AV_LOG_ERROR, "Too long VLC (%d) in init_vlc\n", buf[j].bits);\
312
            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
313
                av_free(buf);                                               \
314
            return AVERROR(EINVAL);                                         \
315
        }                                                                   \
316
        GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size);            \
317
        if (buf[j].code >= (1LL<<buf[j].bits)) {                            \
318
            av_log(NULL, AV_LOG_ERROR, "Invalid code %"PRIx32" for %d in "  \
319
                   "init_vlc\n", buf[j].code, i);                           \
320
            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
321
                av_free(buf);                                               \
322
            return AVERROR(EINVAL);                                         \
323
        }                                                                   \
324
        if (flags & INIT_VLC_LE)                                            \
325
            buf[j].code = bitswap_32(buf[j].code);                          \
326
        else                                                                \
327
            buf[j].code <<= 32 - buf[j].bits;                               \
328
        if (symbols)                                                        \
329
            GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size) \
330
        else                                                                \
331
            buf[j].symbol = i;                                              \
332
        j++;                                                                \
333
    }
334







6757865
    COPY(buf[j].bits > nb_bits);
335
    // qsort is the slowest part of init_vlc, and could probably be improved or avoided
336











21725775
    AV_QSORT(buf, j, struct VLCcode, compare_vlcspec);
337








6757865
    COPY(buf[j].bits && buf[j].bits <= nb_bits);
338
60590
    nb_codes = j;
339
340
60590
    ret = build_table(vlc, nb_bits, nb_codes, buf, flags);
341
342
60590
    if (flags & INIT_VLC_USE_NEW_STATIC) {
343
31878
        if(vlc->table_size != vlc->table_allocated)
344
            av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
345
346
31878
        av_assert0(ret >= 0);
347
31878
        *vlc_arg = *vlc;
348
    } else {
349
28712
        av_free(buf);
350
28712
        if (ret < 0) {
351
            av_freep(&vlc->table);
352
            return ret;
353
        }
354
    }
355
60590
    return 0;
356
}
357
358
359
31526
void ff_free_vlc(VLC *vlc)
360
{
361
31526
    av_freep(&vlc->table);
362
31526
}