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1 | /* |
2 | * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> | |
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 | #ifndef AVUTIL_INTMATH_H | |
22 | #define AVUTIL_INTMATH_H | |
23 | ||
24 | #include <stdint.h> | |
25 | ||
26 | #include "config.h" | |
27 | #include "attributes.h" | |
28 | ||
29 | #if ARCH_ARM | |
30 | # include "arm/intmath.h" | |
31 | #endif | |
32 | ||
33 | /** | |
34 | * @addtogroup lavu_internal | |
35 | * @{ | |
36 | */ | |
37 | ||
38 | #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) | |
39 | ||
40 | #ifndef ff_log2 | |
41 | # define ff_log2(x) (31 - __builtin_clz((x)|1)) | |
42 | # ifndef ff_log2_16bit | |
43 | # define ff_log2_16bit av_log2 | |
44 | # endif | |
45 | #endif /* ff_log2 */ | |
46 | ||
47 | #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ | |
48 | ||
49 | extern const uint8_t ff_log2_tab[256]; | |
50 | ||
51 | #ifndef ff_log2 | |
52 | #define ff_log2 ff_log2_c | |
53 | static av_always_inline av_const int ff_log2_c(unsigned int v) | |
54 | { | |
55 | int n = 0; | |
56 | if (v & 0xffff0000) { | |
57 | v >>= 16; | |
58 | n += 16; | |
59 | } | |
60 | if (v & 0xff00) { | |
61 | v >>= 8; | |
62 | n += 8; | |
63 | } | |
64 | n += ff_log2_tab[v]; | |
65 | ||
66 | return n; | |
67 | } | |
68 | #endif | |
69 | ||
70 | #ifndef ff_log2_16bit | |
71 | #define ff_log2_16bit ff_log2_16bit_c | |
72 | static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) | |
73 | { | |
74 | int n = 0; | |
75 | if (v & 0xff00) { | |
76 | v >>= 8; | |
77 | n += 8; | |
78 | } | |
79 | n += ff_log2_tab[v]; | |
80 | ||
81 | return n; | |
82 | } | |
83 | #endif | |
84 | ||
85 | #define av_log2 ff_log2 | |
86 | #define av_log2_16bit ff_log2_16bit | |
87 | ||
88 | /** | |
89 | * @} | |
90 | */ | |
91 | ||
92 | /** | |
93 | * @addtogroup lavu_math | |
94 | * @{ | |
95 | */ | |
96 | ||
97 | #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) | |
98 | #ifndef ff_ctz | |
99 | #define ff_ctz(v) __builtin_ctz(v) | |
100 | #endif | |
101 | #endif | |
102 | ||
103 | #ifndef ff_ctz | |
104 | #define ff_ctz ff_ctz_c | |
105 | static av_always_inline av_const int ff_ctz_c(int v) | |
106 | { | |
107 | int c; | |
108 | ||
109 | if (v & 0x1) | |
110 | return 0; | |
111 | ||
112 | c = 1; | |
113 | if (!(v & 0xffff)) { | |
114 | v >>= 16; | |
115 | c += 16; | |
116 | } | |
117 | if (!(v & 0xff)) { | |
118 | v >>= 8; | |
119 | c += 8; | |
120 | } | |
121 | if (!(v & 0xf)) { | |
122 | v >>= 4; | |
123 | c += 4; | |
124 | } | |
125 | if (!(v & 0x3)) { | |
126 | v >>= 2; | |
127 | c += 2; | |
128 | } | |
129 | c -= v & 0x1; | |
130 | ||
131 | return c; | |
132 | } | |
133 | #endif | |
134 | ||
135 | /** | |
136 | * Trailing zero bit count. | |
137 | * | |
138 | * @param v input value. If v is 0, the result is undefined. | |
139 | * @return the number of trailing 0-bits | |
140 | */ | |
141 | int av_ctz(int v); | |
142 | ||
143 | /** | |
144 | * @} | |
145 | */ | |
146 | #endif /* AVUTIL_INTMATH_H */ |