Allow compilation of test programs when TEST is defined.
[libav.git] / libavutil / mathematics.c
1 /*
2 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
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 mathematics.c
23 * Miscellaneous math routines and tables.
24 */
25
26 #include "common.h"
27 #include "mathematics.h"
28
29 const uint8_t ff_sqrt_tab[128]={
30 0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5,
31 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
32 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
33 9, 9, 9, 9,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,11
34 };
35
36 const uint8_t ff_log2_tab[256]={
37 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
38 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
39 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
40 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
41 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
42 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
43 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
44 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
45 };
46
47 int64_t ff_gcd(int64_t a, int64_t b){
48 if(b) return ff_gcd(b, a%b);
49 else return a;
50 }
51
52 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd){
53 int64_t r=0;
54 assert(c > 0);
55 assert(b >=0);
56 assert(rnd >=0 && rnd<=5 && rnd!=4);
57
58 if(a<0 && a != INT64_MIN) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
59
60 if(rnd==AV_ROUND_NEAR_INF) r= c/2;
61 else if(rnd&1) r= c-1;
62
63 if(b<=INT_MAX && c<=INT_MAX){
64 if(a<=INT_MAX)
65 return (a * b + r)/c;
66 else
67 return a/c*b + (a%c*b + r)/c;
68 }else{
69 #if 1
70 uint64_t a0= a&0xFFFFFFFF;
71 uint64_t a1= a>>32;
72 uint64_t b0= b&0xFFFFFFFF;
73 uint64_t b1= b>>32;
74 uint64_t t1= a0*b1 + a1*b0;
75 uint64_t t1a= t1<<32;
76 int i;
77
78 a0 = a0*b0 + t1a;
79 a1 = a1*b1 + (t1>>32) + (a0<t1a);
80 a0 += r;
81 a1 += a0<r;
82
83 for(i=63; i>=0; i--){
84 // int o= a1 & 0x8000000000000000ULL;
85 a1+= a1 + ((a0>>i)&1);
86 t1+=t1;
87 if(/*o || */c <= a1){
88 a1 -= c;
89 t1++;
90 }
91 }
92 return t1;
93 }
94 #else
95 AVInteger ai;
96 ai= av_mul_i(av_int2i(a), av_int2i(b));
97 ai= av_add_i(ai, av_int2i(r));
98
99 return av_i2int(av_div_i(ai, av_int2i(c)));
100 }
101 #endif
102 }
103
104 int64_t av_rescale(int64_t a, int64_t b, int64_t c){
105 return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
106 }
107
108 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq){
109 int64_t b= bq.num * (int64_t)cq.den;
110 int64_t c= cq.num * (int64_t)bq.den;
111 return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
112 }
113
114 #ifdef TEST
115 #include "integer.h"
116 #undef printf
117 main(void){
118 int64_t a,b,c,d,e;
119
120 for(a=7; a<(1LL<<62); a+=a/3+1){
121 for(b=3; b<(1LL<<62); b+=b/4+1){
122 for(c=9; c<(1LL<<62); c+=(c*2)/5+3){
123 int64_t r= c/2;
124 AVInteger ai;
125 ai= av_mul_i(av_int2i(a), av_int2i(b));
126 ai= av_add_i(ai, av_int2i(r));
127
128 d= av_i2int(av_div_i(ai, av_int2i(c)));
129
130 e= av_rescale(a,b,c);
131
132 if((double)a * (double)b / (double)c > (1LL<<63))
133 continue;
134
135 if(d!=e) printf("%"PRId64"*%"PRId64"/%"PRId64"= %"PRId64"=%"PRId64"\n", a, b, c, d, e);
136 }
137 }
138 }
139 }
140 #endif