FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/cabac.c
Date: 2026-01-14 03:33:33
Exec Total Coverage
Lines: 12 13 92.3%
Functions: 1 1 100.0%
Branches: 3 4 75.0%
Line Branch Exec Source
1 /*
2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * Context Adaptive Binary Arithmetic Coder.
25 */
26
27 #include "libavutil/error.h"
28 #include "libavutil/mem_internal.h"
29
30 #include "cabac.h"
31
32 DECLARE_ASM_ALIGNED(1, const uint8_t, ff_h264_cabac_tables)[512 + 4*2*64 + 4*64 + 63] = {
33 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
34 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
35 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
36 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
37 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
38 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
39 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
40 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
41 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
42 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
43 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
44 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
45 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
46 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
47 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
48 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
49 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
50 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
51 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
52 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
53 // LPS range
54 -128, -128, -128, -128, -128, -128, 123, 123,
55 116, 116, 111, 111, 105, 105, 100, 100,
56 95, 95, 90, 90, 85, 85, 81, 81,
57 77, 77, 73, 73, 69, 69, 66, 66,
58 62, 62, 59, 59, 56, 56, 53, 53,
59 51, 51, 48, 48, 46, 46, 43, 43,
60 41, 41, 39, 39, 37, 37, 35, 35,
61 33, 33, 32, 32, 30, 30, 29, 29,
62 27, 27, 26, 26, 24, 24, 23, 23,
63 22, 22, 21, 21, 20, 20, 19, 19,
64 18, 18, 17, 17, 16, 16, 15, 15,
65 14, 14, 14, 14, 13, 13, 12, 12,
66 12, 12, 11, 11, 11, 11, 10, 10,
67 10, 10, 9, 9, 9, 9, 8, 8,
68 8, 8, 7, 7, 7, 7, 7, 7,
69 6, 6, 6, 6, 6, 6, 2, 2,
70 -80, -80, -89, -89, -98, -98, -106, -106,
71 -114, -114, -121, -121, -128, -128, 122, 122,
72 116, 116, 110, 110, 104, 104, 99, 99,
73 94, 94, 89, 89, 85, 85, 80, 80,
74 76, 76, 72, 72, 69, 69, 65, 65,
75 62, 62, 59, 59, 56, 56, 53, 53,
76 50, 50, 48, 48, 45, 45, 43, 43,
77 41, 41, 39, 39, 37, 37, 35, 35,
78 33, 33, 31, 31, 30, 30, 28, 28,
79 27, 27, 26, 26, 24, 24, 23, 23,
80 22, 22, 21, 21, 20, 20, 19, 19,
81 18, 18, 17, 17, 16, 16, 15, 15,
82 14, 14, 14, 14, 13, 13, 12, 12,
83 12, 12, 11, 11, 11, 11, 10, 10,
84 9, 9, 9, 9, 9, 9, 8, 8,
85 8, 8, 7, 7, 7, 7, 2, 2,
86 -48, -48, -59, -59, -69, -69, -78, -78,
87 -87, -87, -96, -96, -104, -104, -112, -112,
88 -119, -119, -126, -126, 123, 123, 117, 117,
89 111, 111, 105, 105, 100, 100, 95, 95,
90 90, 90, 86, 86, 81, 81, 77, 77,
91 73, 73, 69, 69, 66, 66, 63, 63,
92 59, 59, 56, 56, 54, 54, 51, 51,
93 48, 48, 46, 46, 43, 43, 41, 41,
94 39, 39, 37, 37, 35, 35, 33, 33,
95 32, 32, 30, 30, 29, 29, 27, 27,
96 26, 26, 25, 25, 23, 23, 22, 22,
97 21, 21, 20, 20, 19, 19, 18, 18,
98 17, 17, 16, 16, 15, 15, 15, 15,
99 14, 14, 13, 13, 12, 12, 12, 12,
100 11, 11, 11, 11, 10, 10, 10, 10,
101 9, 9, 9, 9, 8, 8, 2, 2,
102 -16, -16, -29, -29, -40, -40, -51, -51,
103 -61, -61, -71, -71, -81, -81, -90, -90,
104 -98, -98, -106, -106, -114, -114, -121, -121,
105 -128, -128, 122, 122, 116, 116, 110, 110,
106 104, 104, 99, 99, 94, 94, 89, 89,
107 85, 85, 80, 80, 76, 76, 72, 72,
108 69, 69, 65, 65, 62, 62, 59, 59,
109 56, 56, 53, 53, 50, 50, 48, 48,
110 45, 45, 43, 43, 41, 41, 39, 39,
111 37, 37, 35, 35, 33, 33, 31, 31,
112 30, 30, 28, 28, 27, 27, 25, 25,
113 24, 24, 23, 23, 22, 22, 21, 21,
114 20, 20, 19, 19, 18, 18, 17, 17,
115 16, 16, 15, 15, 14, 14, 14, 14,
116 13, 13, 12, 12, 12, 12, 11, 11,
117 11, 11, 10, 10, 9, 9, 2, 2,
118 // mlps state
119 127, 126, 77, 76, 77, 76, 75, 74,
120 75, 74, 75, 74, 73, 72, 73, 72,
121 73, 72, 71, 70, 71, 70, 71, 70,
122 69, 68, 69, 68, 67, 66, 67, 66,
123 67, 66, 65, 64, 65, 64, 63, 62,
124 61, 60, 61, 60, 61, 60, 59, 58,
125 59, 58, 57, 56, 55, 54, 55, 54,
126 53, 52, 53, 52, 51, 50, 49, 48,
127 49, 48, 47, 46, 45, 44, 45, 44,
128 43, 42, 43, 42, 39, 38, 39, 38,
129 37, 36, 37, 36, 33, 32, 33, 32,
130 31, 30, 31, 30, 27, 26, 27, 26,
131 25, 24, 23, 22, 23, 22, 19, 18,
132 19, 18, 17, 16, 15, 14, 13, 12,
133 11, 10, 9, 8, 9, 8, 5, 4,
134 5, 4, 3, 2, 1, 0, 0, 1,
135 2, 3, 4, 5, 6, 7, 8, 9,
136 10, 11, 12, 13, 14, 15, 16, 17,
137 18, 19, 20, 21, 22, 23, 24, 25,
138 26, 27, 28, 29, 30, 31, 32, 33,
139 34, 35, 36, 37, 38, 39, 40, 41,
140 42, 43, 44, 45, 46, 47, 48, 49,
141 50, 51, 52, 53, 54, 55, 56, 57,
142 58, 59, 60, 61, 62, 63, 64, 65,
143 66, 67, 68, 69, 70, 71, 72, 73,
144 74, 75, 76, 77, 78, 79, 80, 81,
145 82, 83, 84, 85, 86, 87, 88, 89,
146 90, 91, 92, 93, 94, 95, 96, 97,
147 98, 99, 100, 101, 102, 103, 104, 105,
148 106, 107, 108, 109, 110, 111, 112, 113,
149 114, 115, 116, 117, 118, 119, 120, 121,
150 122, 123, 124, 125, 124, 125, 126, 127,
151 // last_coeff_flag_offset_8x8
152 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
153 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
154 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
155 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
156 };
157
158 /**
159 *
160 * @param buf_size size of buf in bits
161 */
162 80125 int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
163 80125 c->bytestream_start=
164 80125 c->bytestream= buf;
165 80125 c->bytestream_end= buf + buf_size;
166
167 #if CABAC_BITS == 16
168 80125 c->low = (*c->bytestream++)<<18;
169 80125 c->low+= (*c->bytestream++)<<10;
170 // Keep our fetches on a 2-byte boundary as this should avoid ever having to
171 // do unaligned loads if the compiler (or asm) optimises the double byte
172 // load into a single instruction
173
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 80125 if(((uintptr_t)c->bytestream & 1) == 0) {
174 38942 c->low += (1 << 9);
175 }
176 else {
177 41183 c->low += ((*c->bytestream++) << 2) + 2;
178 }
179 #else
180 c->low = (*c->bytestream++)<<10;
181 c->low+= ((*c->bytestream++)<<2) + 2;
182 #endif
183 80125 c->range= 0x1FE;
184
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 80125 if ((c->range<<(CABAC_BITS+1)) < c->low)
185 ✗ return AVERROR_INVALIDDATA;
186 80125 return 0;
187 }
188