FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/vpx_rac.h
Date: 2022-10-02 18:56:10
Exec Total Coverage
Lines: 38 38 100.0%
Branches: 12 12 100.0%

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1 /*
2 * Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * Common VP5-VP9 range decoder stuff
24 */
25
26 #ifndef AVCODEC_VPX_RAC_H
27 #define AVCODEC_VPX_RAC_H
28
29 #include <stdint.h>
30
31 #include "config.h"
32 #include "libavutil/attributes.h"
33 #include "bytestream.h"
34
35 typedef struct VPXRangeCoder {
36 int high;
37 int bits; /* stored negated (i.e. negative "bits" is a positive number of
38 bits left) in order to eliminate a negate in cache refilling */
39 const uint8_t *buffer;
40 const uint8_t *end;
41 unsigned int code_word;
42 int end_reached;
43 } VPXRangeCoder;
44
45 extern const uint8_t ff_vpx_norm_shift[256];
46 int ff_vpx_init_range_decoder(VPXRangeCoder *c, const uint8_t *buf, int buf_size);
47
48 /**
49 * returns 1 if the end of the stream has been reached, 0 otherwise.
50 */
51 746247 static av_always_inline int vpx_rac_is_end(VPXRangeCoder *c)
52 {
53
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746247 if (c->end <= c->buffer && c->bits >= 0)
54 11 c->end_reached ++;
55 746247 return c->end_reached > 10;
56 }
57
58 97414603 static av_always_inline unsigned int vpx_rac_renorm(VPXRangeCoder *c)
59 {
60 97414603 int shift = ff_vpx_norm_shift[c->high];
61 97414603 int bits = c->bits;
62 97414603 unsigned int code_word = c->code_word;
63
64 97414603 c->high <<= shift;
65 97414603 code_word <<= shift;
66 97414603 bits += shift;
67
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97414603 if(bits >= 0 && c->buffer < c->end) {
68 4204777 code_word |= bytestream_get_be16(&c->buffer) << bits;
69 4204777 bits -= 16;
70 }
71 97414603 c->bits = bits;
72 97414603 return code_word;
73 }
74
75 #if ARCH_ARM
76 #include "arm/vpx_arith.h"
77 #elif ARCH_X86
78 #include "x86/vpx_arith.h"
79 #endif
80
81 #ifndef vpx_rac_get_prob
82 #define vpx_rac_get_prob vpx_rac_get_prob
83 static av_always_inline int vpx_rac_get_prob(VPXRangeCoder *c, uint8_t prob)
84 {
85 unsigned int code_word = vpx_rac_renorm(c);
86 unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
87 unsigned int low_shift = low << 16;
88 int bit = code_word >= low_shift;
89
90 c->high = bit ? c->high - low : low;
91 c->code_word = bit ? code_word - low_shift : code_word;
92
93 return bit;
94 }
95 #endif
96
97 #ifndef vpx_rac_get_prob_branchy
98 // branchy variant, to be used where there's a branch based on the bit decoded
99 66757341 static av_always_inline int vpx_rac_get_prob_branchy(VPXRangeCoder *c, int prob)
100 {
101 66757341 unsigned long code_word = vpx_rac_renorm(c);
102 66757341 unsigned low = 1 + (((c->high - 1) * prob) >> 8);
103 66757341 unsigned low_shift = low << 16;
104
105
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66757341 if (code_word >= low_shift) {
106 30859269 c->high -= low;
107 30859269 c->code_word = code_word - low_shift;
108 30859269 return 1;
109 }
110
111 35898072 c->high = low;
112 35898072 c->code_word = code_word;
113 35898072 return 0;
114 }
115 #endif
116
117 1303604 static av_always_inline int vpx_rac_get(VPXRangeCoder *c)
118 {
119 1303604 unsigned int code_word = vpx_rac_renorm(c);
120 /* equiprobable */
121 1303604 int low = (c->high + 1) >> 1;
122 1303604 unsigned int low_shift = low << 16;
123 1303604 int bit = code_word >= low_shift;
124
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1303604 if (bit) {
125 651693 c->high -= low;
126 651693 code_word -= low_shift;
127 } else {
128 651911 c->high = low;
129 }
130
131 1303604 c->code_word = code_word;
132 1303604 return bit;
133 }
134
135 #endif /* AVCODEC_VPX_RAC_H */
136