FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/dirac_arith.c
Date: 2021-09-16 08:47:15
Exec Total Coverage
Lines: 24 24 100.0%
Branches: 9 10 90.0%

Line Branch Exec Source
1 /*
2 * Copyright (C) 2007 Marco Gerards <marco@gnu.org>
3 * Copyright (C) 2009 David Conrad
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 * Arithmetic decoder for Dirac
25 * @author Marco Gerards <marco@gnu.org>
26 */
27
28 #include "dirac_arith.h"
29
30
31 static const uint16_t dirac_prob[256] = {
32 0, 2, 5, 8, 11, 15, 20, 24,
33 29, 35, 41, 47, 53, 60, 67, 74,
34 82, 89, 97, 106, 114, 123, 132, 141,
35 150, 160, 170, 180, 190, 201, 211, 222,
36 233, 244, 256, 267, 279, 291, 303, 315,
37 327, 340, 353, 366, 379, 392, 405, 419,
38 433, 447, 461, 475, 489, 504, 518, 533,
39 548, 563, 578, 593, 609, 624, 640, 656,
40 672, 688, 705, 721, 738, 754, 771, 788,
41 805, 822, 840, 857, 875, 892, 910, 928,
42 946, 964, 983, 1001, 1020, 1038, 1057, 1076,
43 1095, 1114, 1133, 1153, 1172, 1192, 1211, 1231,
44 1251, 1271, 1291, 1311, 1332, 1352, 1373, 1393,
45 1414, 1435, 1456, 1477, 1498, 1520, 1541, 1562,
46 1584, 1606, 1628, 1649, 1671, 1694, 1716, 1738,
47 1760, 1783, 1806, 1828, 1851, 1874, 1897, 1920,
48 1935, 1942, 1949, 1955, 1961, 1968, 1974, 1980,
49 1985, 1991, 1996, 2001, 2006, 2011, 2016, 2021,
50 2025, 2029, 2033, 2037, 2040, 2044, 2047, 2050,
51 2053, 2056, 2058, 2061, 2063, 2065, 2066, 2068,
52 2069, 2070, 2071, 2072, 2072, 2072, 2072, 2072,
53 2072, 2071, 2070, 2069, 2068, 2066, 2065, 2063,
54 2060, 2058, 2055, 2052, 2049, 2045, 2042, 2038,
55 2033, 2029, 2024, 2019, 2013, 2008, 2002, 1996,
56 1989, 1982, 1975, 1968, 1960, 1952, 1943, 1934,
57 1925, 1916, 1906, 1896, 1885, 1874, 1863, 1851,
58 1839, 1827, 1814, 1800, 1786, 1772, 1757, 1742,
59 1727, 1710, 1694, 1676, 1659, 1640, 1622, 1602,
60 1582, 1561, 1540, 1518, 1495, 1471, 1447, 1422,
61 1396, 1369, 1341, 1312, 1282, 1251, 1219, 1186,
62 1151, 1114, 1077, 1037, 995, 952, 906, 857,
63 805, 750, 690, 625, 553, 471, 376, 255
64 };
65
66 const uint8_t ff_dirac_next_ctx[DIRAC_CTX_COUNT] = {
67 [CTX_ZPZN_F1] = CTX_ZP_F2,
68 [CTX_ZPNN_F1] = CTX_ZP_F2,
69 [CTX_ZP_F2] = CTX_ZP_F3,
70 [CTX_ZP_F3] = CTX_ZP_F4,
71 [CTX_ZP_F4] = CTX_ZP_F5,
72 [CTX_ZP_F5] = CTX_ZP_F6,
73 [CTX_ZP_F6] = CTX_ZP_F6,
74 [CTX_NPZN_F1] = CTX_NP_F2,
75 [CTX_NPNN_F1] = CTX_NP_F2,
76 [CTX_NP_F2] = CTX_NP_F3,
77 [CTX_NP_F3] = CTX_NP_F4,
78 [CTX_NP_F4] = CTX_NP_F5,
79 [CTX_NP_F5] = CTX_NP_F6,
80 [CTX_NP_F6] = CTX_NP_F6,
81 [CTX_DELTA_Q_F] = CTX_DELTA_Q_F,
82 };
83
84 int16_t ff_dirac_prob_branchless[256][2];
85
86 35 av_cold void ff_dirac_init_arith_tables(void)
87 {
88 int i;
89
90
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8995 for (i = 0; i < 256; i++) {
91 8960 ff_dirac_prob_branchless[i][0] = dirac_prob[255-i];
92 8960 ff_dirac_prob_branchless[i][1] = -dirac_prob[i];
93 }
94 35 }
95
96 926 void ff_dirac_init_arith_decoder(DiracArith *c, GetBitContext *gb, int length)
97 {
98 int i;
99 926 align_get_bits(gb);
100
101
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926 length = FFMIN(length, get_bits_left(gb)/8);
102
103 926 c->bytestream = gb->buffer + get_bits_count(gb)/8;
104 926 c->bytestream_end = c->bytestream + length;
105 926 skip_bits_long(gb, length*8);
106
107 926 c->low = 0;
108
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4630 for (i = 0; i < 4; i++) {
109 3704 c->low <<= 8;
110
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3704 if (c->bytestream < c->bytestream_end)
111 3694 c->low |= *c->bytestream++;
112 else
113 10 c->low |= 0xff;
114 }
115
116 926 c->counter = -16;
117 926 c->range = 0xffff;
118 926 c->error = 0;
119 926 c->overread= 0;
120
121
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21298 for (i = 0; i < DIRAC_CTX_COUNT; i++)
122 20372 c->contexts[i] = 0x8000;
123 926 }
124