0,0 → 1,155 |
/* |
* rational numbers |
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> |
* |
* This file is part of FFmpeg. |
* |
* FFmpeg 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. |
* |
* FFmpeg 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 FFmpeg; if not, write to the Free Software |
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
*/ |
|
/** |
* @file |
* rational numbers |
* @author Michael Niedermayer <michaelni@gmx.at> |
*/ |
|
#ifndef AVUTIL_RATIONAL_H |
#define AVUTIL_RATIONAL_H |
|
#include <stdint.h> |
#include <limits.h> |
#include "attributes.h" |
|
/** |
* @addtogroup lavu_math |
* @{ |
*/ |
|
/** |
* rational number numerator/denominator |
*/ |
typedef struct AVRational{ |
int num; ///< numerator |
int den; ///< denominator |
} AVRational; |
|
/** |
* Compare two rationals. |
* @param a first rational |
* @param b second rational |
* @return 0 if a==b, 1 if a>b, -1 if a<b, and INT_MIN if one of the |
* values is of the form 0/0 |
*/ |
static inline int av_cmp_q(AVRational a, AVRational b){ |
const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den; |
|
if(tmp) return (int)((tmp ^ a.den ^ b.den)>>63)|1; |
else if(b.den && a.den) return 0; |
else if(a.num && b.num) return (a.num>>31) - (b.num>>31); |
else return INT_MIN; |
} |
|
/** |
* Convert rational to double. |
* @param a rational to convert |
* @return (double) a |
*/ |
static inline double av_q2d(AVRational a){ |
return a.num / (double) a.den; |
} |
|
/** |
* Reduce a fraction. |
* This is useful for framerate calculations. |
* @param dst_num destination numerator |
* @param dst_den destination denominator |
* @param num source numerator |
* @param den source denominator |
* @param max the maximum allowed for dst_num & dst_den |
* @return 1 if exact, 0 otherwise |
*/ |
int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max); |
|
/** |
* Multiply two rationals. |
* @param b first rational |
* @param c second rational |
* @return b*c |
*/ |
AVRational av_mul_q(AVRational b, AVRational c) av_const; |
|
/** |
* Divide one rational by another. |
* @param b first rational |
* @param c second rational |
* @return b/c |
*/ |
AVRational av_div_q(AVRational b, AVRational c) av_const; |
|
/** |
* Add two rationals. |
* @param b first rational |
* @param c second rational |
* @return b+c |
*/ |
AVRational av_add_q(AVRational b, AVRational c) av_const; |
|
/** |
* Subtract one rational from another. |
* @param b first rational |
* @param c second rational |
* @return b-c |
*/ |
AVRational av_sub_q(AVRational b, AVRational c) av_const; |
|
/** |
* Invert a rational. |
* @param q value |
* @return 1 / q |
*/ |
static av_always_inline AVRational av_inv_q(AVRational q) |
{ |
AVRational r = { q.den, q.num }; |
return r; |
} |
|
/** |
* Convert a double precision floating point number to a rational. |
* inf is expressed as {1,0} or {-1,0} depending on the sign. |
* |
* @param d double to convert |
* @param max the maximum allowed numerator and denominator |
* @return (AVRational) d |
*/ |
AVRational av_d2q(double d, int max) av_const; |
|
/** |
* @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer |
* than q1, 0 if they have the same distance. |
*/ |
int av_nearer_q(AVRational q, AVRational q1, AVRational q2); |
|
/** |
* Find the nearest value in q_list to q. |
* @param q_list an array of rationals terminated by {0, 0} |
* @return the index of the nearest value found in the array |
*/ |
int av_find_nearest_q_idx(AVRational q, const AVRational* q_list); |
|
/** |
* @} |
*/ |
|
#endif /* AVUTIL_RATIONAL_H */ |