mathematics: remove asserts from av_rescale_rnd()
[libav.git] / libavutil / mathematics.c
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1/*
2 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
3 *
2912e87a 4 * This file is part of Libav.
b78e7197 5 *
2912e87a 6 * Libav is free software; you can redistribute it and/or
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7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
b78e7197 9 * version 2.1 of the License, or (at your option) any later version.
c11c2bc2 10 *
2912e87a 11 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 17 * License along with Libav; if not, write to the Free Software
5509bffa 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
c11c2bc2 19 */
115329f1 20
c11c2bc2 21/**
ba87f080 22 * @file
89c9ff50 23 * miscellaneous math routines and tables
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24 */
25
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26#include <stdint.h>
27#include <limits.h>
d5c62122 28
c11c2bc2 29#include "mathematics.h"
d5c62122 30#include "version.h"
c11c2bc2 31
d5c62122 32#if FF_API_AV_REVERSE
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33const uint8_t av_reverse[256]={
340x00,0x80,0x40,0xC0,0x20,0xA0,0x60,0xE0,0x10,0x90,0x50,0xD0,0x30,0xB0,0x70,0xF0,
350x08,0x88,0x48,0xC8,0x28,0xA8,0x68,0xE8,0x18,0x98,0x58,0xD8,0x38,0xB8,0x78,0xF8,
360x04,0x84,0x44,0xC4,0x24,0xA4,0x64,0xE4,0x14,0x94,0x54,0xD4,0x34,0xB4,0x74,0xF4,
370x0C,0x8C,0x4C,0xCC,0x2C,0xAC,0x6C,0xEC,0x1C,0x9C,0x5C,0xDC,0x3C,0xBC,0x7C,0xFC,
380x02,0x82,0x42,0xC2,0x22,0xA2,0x62,0xE2,0x12,0x92,0x52,0xD2,0x32,0xB2,0x72,0xF2,
390x0A,0x8A,0x4A,0xCA,0x2A,0xAA,0x6A,0xEA,0x1A,0x9A,0x5A,0xDA,0x3A,0xBA,0x7A,0xFA,
400x06,0x86,0x46,0xC6,0x26,0xA6,0x66,0xE6,0x16,0x96,0x56,0xD6,0x36,0xB6,0x76,0xF6,
410x0E,0x8E,0x4E,0xCE,0x2E,0xAE,0x6E,0xEE,0x1E,0x9E,0x5E,0xDE,0x3E,0xBE,0x7E,0xFE,
420x01,0x81,0x41,0xC1,0x21,0xA1,0x61,0xE1,0x11,0x91,0x51,0xD1,0x31,0xB1,0x71,0xF1,
430x09,0x89,0x49,0xC9,0x29,0xA9,0x69,0xE9,0x19,0x99,0x59,0xD9,0x39,0xB9,0x79,0xF9,
440x05,0x85,0x45,0xC5,0x25,0xA5,0x65,0xE5,0x15,0x95,0x55,0xD5,0x35,0xB5,0x75,0xF5,
450x0D,0x8D,0x4D,0xCD,0x2D,0xAD,0x6D,0xED,0x1D,0x9D,0x5D,0xDD,0x3D,0xBD,0x7D,0xFD,
460x03,0x83,0x43,0xC3,0x23,0xA3,0x63,0xE3,0x13,0x93,0x53,0xD3,0x33,0xB3,0x73,0xF3,
470x0B,0x8B,0x4B,0xCB,0x2B,0xAB,0x6B,0xEB,0x1B,0x9B,0x5B,0xDB,0x3B,0xBB,0x7B,0xFB,
480x07,0x87,0x47,0xC7,0x27,0xA7,0x67,0xE7,0x17,0x97,0x57,0xD7,0x37,0xB7,0x77,0xF7,
490x0F,0x8F,0x4F,0xCF,0x2F,0xAF,0x6F,0xEF,0x1F,0x9F,0x5F,0xDF,0x3F,0xBF,0x7F,0xFF,
50};
d5c62122 51#endif
91cc5d37 52
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53int64_t av_gcd(int64_t a, int64_t b){
54 if(b) return av_gcd(b, a%b);
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55 else return a;
56}
57
58int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd){
c11c2bc2 59 int64_t r=0;
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60
61 if (c <= 0 || b < 0 || rnd == 4 || rnd > 5)
62 return INT64_MIN;
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63
64 if(a<0 && a != INT64_MIN) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
65
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66 if(rnd==AV_ROUND_NEAR_INF) r= c/2;
67 else if(rnd&1) r= c-1;
68
69 if(b<=INT_MAX && c<=INT_MAX){
70 if(a<=INT_MAX)
71 return (a * b + r)/c;
72 else
73 return a/c*b + (a%c*b + r)/c;
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74 }else{
75#if 1
76 uint64_t a0= a&0xFFFFFFFF;
77 uint64_t a1= a>>32;
78 uint64_t b0= b&0xFFFFFFFF;
79 uint64_t b1= b>>32;
80 uint64_t t1= a0*b1 + a1*b0;
81 uint64_t t1a= t1<<32;
82 int i;
83
84 a0 = a0*b0 + t1a;
85 a1 = a1*b1 + (t1>>32) + (a0<t1a);
86 a0 += r;
87 a1 += a0<r;
115329f1 88
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89 for(i=63; i>=0; i--){
90// int o= a1 & 0x8000000000000000ULL;
91 a1+= a1 + ((a0>>i)&1);
92 t1+=t1;
5c1cb379 93 if(/*o || */c <= a1){
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94 a1 -= c;
95 t1++;
96 }
97 }
98 return t1;
99 }
100#else
101 AVInteger ai;
102 ai= av_mul_i(av_int2i(a), av_int2i(b));
103 ai= av_add_i(ai, av_int2i(r));
115329f1 104
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105 return av_i2int(av_div_i(ai, av_int2i(c)));
106 }
107#endif
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108}
109
110int64_t av_rescale(int64_t a, int64_t b, int64_t c){
111 return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
112}
113
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114int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
115 enum AVRounding rnd)
116{
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117 int64_t b= bq.num * (int64_t)cq.den;
118 int64_t c= cq.num * (int64_t)bq.den;
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119 return av_rescale_rnd(a, b, c, rnd);
120}
121
122int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
123{
124 return av_rescale_q_rnd(a, bq, cq, AV_ROUND_NEAR_INF);
c11c2bc2 125}
f0cb505a 126
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127int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b){
128 int64_t a= tb_a.num * (int64_t)tb_b.den;
129 int64_t b= tb_b.num * (int64_t)tb_a.den;
130 if (av_rescale_rnd(ts_a, a, b, AV_ROUND_DOWN) < ts_b) return -1;
131 if (av_rescale_rnd(ts_b, b, a, AV_ROUND_DOWN) < ts_a) return 1;
132 return 0;
133}
134
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135int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod){
136 int64_t c= (a-b) & (mod-1);
137 if(c > (mod>>1))
138 c-= mod;
139 return c;
140}