mirror of https://git.ffmpeg.org/ffmpeg.git
131 lines
3.3 KiB
C
131 lines
3.3 KiB
C
/*
|
|
* Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* Libav is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* miscellaneous math routines and tables
|
|
*/
|
|
|
|
#include <stdint.h>
|
|
#include <limits.h>
|
|
|
|
#include "mathematics.h"
|
|
#include "version.h"
|
|
|
|
int64_t av_gcd(int64_t a, int64_t b)
|
|
{
|
|
if (b)
|
|
return av_gcd(b, a % b);
|
|
else
|
|
return a;
|
|
}
|
|
|
|
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd)
|
|
{
|
|
int64_t r = 0;
|
|
|
|
if (c <= 0 || b < 0 || rnd == 4 || rnd > 5)
|
|
return INT64_MIN;
|
|
|
|
if (a < 0 && a != INT64_MIN)
|
|
return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd >> 1) & 1));
|
|
|
|
if (rnd == AV_ROUND_NEAR_INF)
|
|
r = c / 2;
|
|
else if (rnd & 1)
|
|
r = c - 1;
|
|
|
|
if (b <= INT_MAX && c <= INT_MAX) {
|
|
if (a <= INT_MAX)
|
|
return (a * b + r) / c;
|
|
else
|
|
return a / c * b + (a % c * b + r) / c;
|
|
} else {
|
|
#if 1
|
|
uint64_t a0 = a & 0xFFFFFFFF;
|
|
uint64_t a1 = a >> 32;
|
|
uint64_t b0 = b & 0xFFFFFFFF;
|
|
uint64_t b1 = b >> 32;
|
|
uint64_t t1 = a0 * b1 + a1 * b0;
|
|
uint64_t t1a = t1 << 32;
|
|
int i;
|
|
|
|
a0 = a0 * b0 + t1a;
|
|
a1 = a1 * b1 + (t1 >> 32) + (a0 < t1a);
|
|
a0 += r;
|
|
a1 += a0 < r;
|
|
|
|
for (i = 63; i >= 0; i--) {
|
|
a1 += a1 + ((a0 >> i) & 1);
|
|
t1 += t1;
|
|
if (c <= a1) {
|
|
a1 -= c;
|
|
t1++;
|
|
}
|
|
}
|
|
return t1;
|
|
}
|
|
#else
|
|
AVInteger ai;
|
|
ai = av_mul_i(av_int2i(a), av_int2i(b));
|
|
ai = av_add_i(ai, av_int2i(r));
|
|
|
|
return av_i2int(av_div_i(ai, av_int2i(c)));
|
|
}
|
|
#endif
|
|
}
|
|
|
|
int64_t av_rescale(int64_t a, int64_t b, int64_t c)
|
|
{
|
|
return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
|
|
}
|
|
|
|
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
|
|
enum AVRounding rnd)
|
|
{
|
|
int64_t b = bq.num * (int64_t)cq.den;
|
|
int64_t c = cq.num * (int64_t)bq.den;
|
|
return av_rescale_rnd(a, b, c, rnd);
|
|
}
|
|
|
|
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
|
|
{
|
|
return av_rescale_q_rnd(a, bq, cq, AV_ROUND_NEAR_INF);
|
|
}
|
|
|
|
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
|
|
{
|
|
int64_t a = tb_a.num * (int64_t)tb_b.den;
|
|
int64_t b = tb_b.num * (int64_t)tb_a.den;
|
|
if (av_rescale_rnd(ts_a, a, b, AV_ROUND_DOWN) < ts_b)
|
|
return -1;
|
|
if (av_rescale_rnd(ts_b, b, a, AV_ROUND_DOWN) < ts_a)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod)
|
|
{
|
|
int64_t c = (a - b) & (mod - 1);
|
|
if (c > (mod >> 1))
|
|
c -= mod;
|
|
return c;
|
|
}
|