FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavutil/rational.c
Date: 2026-10-20 22:17:59
Exec Total Coverage
Lines: 93 93 100.0%
Functions: 10 10 100.0%
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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
28 #include "avassert.h"
29 #include <limits.h>
30
31 #include "common.h"
32 #include "mathematics.h"
33 #include "rational.h"
34
35 21111421 int av_reduce(int *dst_num, int *dst_den,
36 int64_t num, int64_t den, int64_t max)
37 {
38 21111421 AVRational a0 = { 0, 1 }, a1 = { 1, 0 };
39 21111421 int sign = (num < 0) ^ (den < 0);
40 21111421 int64_t gcd = av_gcd(FFABS(num), FFABS(den));
41
42
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 21111421 if (gcd) {
43 21106756 num = FFABS(num) / gcd;
44 21106756 den = FFABS(den) / gcd;
45 }
46
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 21111421 if (num <= max && den <= max) {
47 21111048 a1 = (AVRational) { num, den };
48 21111048 den = 0;
49 }
50
51
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 21114023 while (den) {
52 2975 uint64_t x = num / den;
53 2975 int64_t next_den = num - den * x;
54 2975 int64_t a2n = x * a1.num + a0.num;
55 2975 int64_t a2d = x * a1.den + a0.den;
56
57
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 2975 if (a2n > max || a2d > max) {
58
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 373 if (a1.num) x = (max - a0.num) / a1.num;
59
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 373 if (a1.den) x = FFMIN(x, (max - a0.den) / a1.den);
60
61
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 373 if (den * (2 * x * a1.den + a0.den) > num * a1.den)
62 17 a1 = (AVRational) { x * a1.num + a0.num, x * a1.den + a0.den };
63 373 break;
64 }
65
66 2602 a0 = a1;
67 2602 a1 = (AVRational) { a2n, a2d };
68 2602 num = den;
69 2602 den = next_den;
70 }
71 av_assert2(av_gcd(a1.num, a1.den) <= 1U);
72 av_assert2(a1.num <= max && a1.den <= max);
73
74
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 21111421 *dst_num = sign ? -a1.num : a1.num;
75 21111421 *dst_den = a1.den;
76
77 21111421 return den == 0;
78 }
79
80 10587126 AVRational av_mul_q(AVRational b, AVRational c)
81 {
82 10587126 av_reduce(&b.num, &b.den,
83 10587126 b.num * (int64_t) c.num,
84 10587126 b.den * (int64_t) c.den, INT_MAX);
85 10587126 return b;
86 }
87
88 2586505 AVRational av_div_q(AVRational b, AVRational c)
89 {
90 2586505 return av_mul_q(b, (AVRational) { c.den, c.num });
91 }
92
93 10985 AVRational av_add_q(AVRational b, AVRational c) {
94 10985 av_reduce(&b.num, &b.den,
95 10985 b.num * (int64_t) c.den +
96 10985 c.num * (int64_t) b.den,
97 10985 b.den * (int64_t) c.den, INT_MAX);
98 10985 return b;
99 }
100
101 10085795 AVRational av_sub_q(AVRational b, AVRational c)
102 {
103 10085795 av_reduce(&b.num, &b.den,
104 10085795 b.num * (int64_t) c.den -
105 10085795 c.num * (int64_t) b.den,
106 10085795 b.den * (int64_t) c.den, INT_MAX);
107 10085795 return b;
108 }
109
110 226199 AVRational av_d2q(double d, int max)
111 {
112 AVRational a;
113 int exponent;
114 int64_t den;
115
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 226199 if (isnan(d))
116 50 return (AVRational) { 0,0 };
117
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 226149 if (fabs(d) > INT_MAX + 3LL)
118
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 8 return (AVRational) { d < 0 ? -1 : 1, 0 };
119 226141 frexp(d, &exponent);
120 226141 exponent = FFMAX(exponent-1, 0);
121 226141 den = 1LL << (62 - exponent);
122 // (int64_t)rint() and llrint() do not work with gcc on ia64 and sparc64,
123 // see Ticket2713 for affected gcc/glibc versions
124 226141 av_reduce(&a.num, &a.den, floor(d * den + 0.5), den, max);
125
126 226141 return a;
127 }
128
129 51194 int av_nearer_q(AVRational q, AVRational q1, AVRational q2)
130 {
131 /* n/d is q, a/b is the median between q1 and q2 */
132 51194 int64_t a = q1.num * (int64_t)q2.den + q2.num * (int64_t)q1.den;
133 51194 int64_t b = 2 * (int64_t)q1.den * q2.den;
134
135 /* rnd_up(a*d/b) > n => a*d/b > n */
136 51194 int64_t x_up = av_rescale_rnd(a, q.den, b, AV_ROUND_UP);
137
138 /* rnd_down(a*d/b) < n => a*d/b < n */
139 51194 int64_t x_down = av_rescale_rnd(a, q.den, b, AV_ROUND_DOWN);
140
141 51194 return ((x_up > q.num) - (x_down < q.num)) * av_cmp_q(q2, q1);
142 }
143
144 77 int av_find_nearest_q_idx(AVRational q, const AVRational* q_list)
145 {
146 77 int i, nearest_q_idx = 0;
147
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 4312 for (i = 0; q_list[i].den; i++)
148
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 4235 if (av_nearer_q(q, q_list[i], q_list[nearest_q_idx]) > 0)
149 878 nearest_q_idx = i;
150
151 77 return nearest_q_idx;
152 }
153
154 29558 uint32_t av_q2intfloat(AVRational q) {
155 29558 int64_t n, num = q.num, den = q.den;
156 int shift;
157 29558 uint32_t sign = 0;
158
159
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 29558 if (den < 0) {
160 8 den = -den;
161 8 num = -num;
162 }
163
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 29558 if (num < 0) {
164 27 num = -num;
165 27 sign = 1U << 31;
166 }
167
168
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 29558 if (!num && !den) return 0xFFC00000;
169
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 29557 if (!num) return 0;
170
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 29535 if (!den) return sign | 0x7F800000;
171
172 29532 shift = 23 + av_log2(den) - av_log2(num);
173
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 29532 if (shift >= 0) n = av_rescale(num, 1LL<<shift, den);
174 351 else n = av_rescale(num, 1, den << -shift);
175
176 29532 shift -= n >= (1<<24);
177 29532 shift += n < (1<<23);
178
179
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 29532 if (shift >= 0) n = av_rescale(num, 1LL<<shift, den);
180 310 else n = av_rescale(num, 1, den << -shift);
181
182 av_assert1(n < (1<<24));
183 av_assert1(n >= (1<<23));
184
185 29532 return sign | (150-shift)<<23 | (n - (1<<23));
186 }
187
188 500 AVRational av_gcd_q(AVRational a, AVRational b, int max_den, AVRational def)
189 {
190 int64_t gcd, lcm;
191
192 500 gcd = av_gcd(a.den, b.den);
193 500 lcm = (a.den / gcd) * b.den;
194
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 500 return lcm < max_den ? av_make_q(av_gcd(a.num, b.num), lcm) : def;
195 }
196