/*

 * rational numbers

 * Copyright (c) 2003 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

 * 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 ((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 */