1 /*
2 * rational numbers
3 * Copyright (c) 2003 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
24 * rational numbers
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
30
34
37 {
39 int sign = (num < 0) ^ (den < 0);
41
42 if (gcd) {
43 num =
FFABS(num) / gcd;
44 den =
FFABS(den) / gcd;
45 }
46 if (num <=
max && den <=
max) {
48 den = 0;
49 }
50
51 while (den) {
52 uint64_t x = num / den;
53 int64_t next_den = num - den * x;
56
57 if (a2n >
max || a2d >
max) {
60
61 if (den * (2 * x *
a1.den +
a0.den) > num *
a1.den)
63 break;
64 }
65
68 num = den;
69 den = next_den;
70 }
73
74 *dst_num = sign ? -
a1.num :
a1.num;
76
77 return den == 0;
78 }
79
81 {
86 }
87
89 {
91 }
92
99 }
100
102 {
104 }
105
107 {
109 int exponent;
113 if (
fabs(d) > INT_MAX + 3LL)
115 frexp(d, &exponent);
116 exponent =
FFMAX(exponent-1, 0);
117 den = 1LL << (62 - exponent);
118 // (int64_t)rint() and llrint() do not work with gcc on ia64 and sparc64,
119 // see Ticket2713 for affected gcc/glibc versions
121
123 }
124
126 {
127 /* n/d is q, a/b is the median between q1 and q2 */
130
131 /* rnd_up(a*d/b) > n => a*d/b > n */
133
134 /* rnd_down(a*d/b) < n => a*d/b < n */
136
138 }
139
141 {
142 int i, nearest_q_idx = 0;
143 for (
i = 0; q_list[
i].
den;
i++)
144 if (
av_nearer_q(q, q_list[
i], q_list[nearest_q_idx]) > 0)
146
147 return nearest_q_idx;
148 }
149
153 int sign = 0;
154
158 }
161 sign = 1;
162 }
163
164 if (!q.
num && !q.
den)
return 0xFFC00000;
165 if (!q.
num)
return 0;
166 if (!q.
den)
return 0x7F800000 | (q.
num & 0x80000000);
167
171
172 shift -= n >= (1<<24);
173 shift += n < (1<<23);
174
177
180
181 return sign<<31 | (150-
shift)<<23 | (n - (1<<23));
182 }
183
185 {
187
189 lcm = (
a.den / gcd) *
b.den;
191 }