Allow compilation of test programs when TEST is defined.
[libav.git] / libavutil / integer.c
1 /*
2 * arbitrary precision integers
3 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
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 integer.c
24 * arbitrary precision integers.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28 #include "common.h"
29 #include "integer.h"
30
31 AVInteger av_add_i(AVInteger a, AVInteger b){
32 int i, carry=0;
33
34 for(i=0; i<AV_INTEGER_SIZE; i++){
35 carry= (carry>>16) + a.v[i] + b.v[i];
36 a.v[i]= carry;
37 }
38 return a;
39 }
40
41 AVInteger av_sub_i(AVInteger a, AVInteger b){
42 int i, carry=0;
43
44 for(i=0; i<AV_INTEGER_SIZE; i++){
45 carry= (carry>>16) + a.v[i] - b.v[i];
46 a.v[i]= carry;
47 }
48 return a;
49 }
50
51 int av_log2_i(AVInteger a){
52 int i;
53
54 for(i=AV_INTEGER_SIZE-1; i>=0; i--){
55 if(a.v[i])
56 return av_log2_16bit(a.v[i]) + 16*i;
57 }
58 return -1;
59 }
60
61 AVInteger av_mul_i(AVInteger a, AVInteger b){
62 AVInteger out;
63 int i, j;
64 int na= (av_log2_i(a)+16) >> 4;
65 int nb= (av_log2_i(b)+16) >> 4;
66
67 memset(&out, 0, sizeof(out));
68
69 for(i=0; i<na; i++){
70 unsigned int carry=0;
71
72 if(a.v[i])
73 for(j=i; j<AV_INTEGER_SIZE && j-i<=nb; j++){
74 carry= (carry>>16) + out.v[j] + a.v[i]*b.v[j-i];
75 out.v[j]= carry;
76 }
77 }
78
79 return out;
80 }
81
82 int av_cmp_i(AVInteger a, AVInteger b){
83 int i;
84 int v= (int16_t)a.v[AV_INTEGER_SIZE-1] - (int16_t)b.v[AV_INTEGER_SIZE-1];
85 if(v) return (v>>16)|1;
86
87 for(i=AV_INTEGER_SIZE-2; i>=0; i--){
88 int v= a.v[i] - b.v[i];
89 if(v) return (v>>16)|1;
90 }
91 return 0;
92 }
93
94 AVInteger av_shr_i(AVInteger a, int s){
95 AVInteger out;
96 int i;
97
98 for(i=0; i<AV_INTEGER_SIZE; i++){
99 int index= i + (s>>4);
100 unsigned int v=0;
101 if(index+1<AV_INTEGER_SIZE && index+1>=0) v = a.v[index+1]<<16;
102 if(index <AV_INTEGER_SIZE && index >=0) v+= a.v[index ];
103 out.v[i]= v >> (s&15);
104 }
105 return out;
106 }
107
108 AVInteger av_mod_i(AVInteger *quot, AVInteger a, AVInteger b){
109 int i= av_log2_i(a) - av_log2_i(b);
110 AVInteger quot_temp;
111 if(!quot) quot = &quot_temp;
112
113 assert((int16_t)a[AV_INTEGER_SIZE-1] >= 0 && (int16_t)b[AV_INTEGER_SIZE-1] >= 0);
114 assert(av_log2(b)>=0);
115
116 if(i > 0)
117 b= av_shr_i(b, -i);
118
119 memset(quot, 0, sizeof(AVInteger));
120
121 while(i-- >= 0){
122 *quot= av_shr_i(*quot, -1);
123 if(av_cmp_i(a, b) >= 0){
124 a= av_sub_i(a, b);
125 quot->v[0] += 1;
126 }
127 b= av_shr_i(b, 1);
128 }
129 return a;
130 }
131
132 AVInteger av_div_i(AVInteger a, AVInteger b){
133 AVInteger quot;
134 av_mod_i(&quot, a, b);
135 return quot;
136 }
137
138 AVInteger av_int2i(int64_t a){
139 AVInteger out;
140 int i;
141
142 for(i=0; i<AV_INTEGER_SIZE; i++){
143 out.v[i]= a;
144 a>>=16;
145 }
146 return out;
147 }
148
149 int64_t av_i2int(AVInteger a){
150 int i;
151 int64_t out=(int8_t)a.v[AV_INTEGER_SIZE-1];
152
153 for(i= AV_INTEGER_SIZE-2; i>=0; i--){
154 out = (out<<16) + a.v[i];
155 }
156 return out;
157 }
158
159 #ifdef TEST
160 #undef NDEBUG
161 #include <assert.h>
162
163 const uint8_t ff_log2_tab[256]={
164 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,
165 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,
166 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,
167 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,
168 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,
169 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,
170 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,
171 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
172 };
173
174 main(void){
175 int64_t a,b;
176
177 for(a=7; a<256*256*256; a+=13215){
178 for(b=3; b<256*256*256; b+=27118){
179 AVInteger ai= av_int2i(a);
180 AVInteger bi= av_int2i(b);
181
182 assert(av_i2int(ai) == a);
183 assert(av_i2int(bi) == b);
184 assert(av_i2int(av_add_i(ai,bi)) == a+b);
185 assert(av_i2int(av_sub_i(ai,bi)) == a-b);
186 assert(av_i2int(av_mul_i(ai,bi)) == a*b);
187 assert(av_i2int(av_shr_i(ai, 9)) == a>>9);
188 assert(av_i2int(av_shr_i(ai,-9)) == a<<9);
189 assert(av_i2int(av_shr_i(ai, 17)) == a>>17);
190 assert(av_i2int(av_shr_i(ai,-17)) == a<<17);
191 assert(av_log2_i(ai) == av_log2(a));
192 assert(av_i2int(av_div_i(ai,bi)) == a/b);
193 }
194 }
195 }
196 #endif