/*

  * 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;
 

 /**

  * Create a rational.
  * Useful for compilers that do not support compound literals.
  * @note  The return value is not reduced.
  */
 static inline AVRational av_make_q(int num, int den)
 {
     AVRational r = { num, den };
     return r;
 }
 
 /**

  * 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 */