* rational numbers
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file libavutil/rational.h
+ * @file
* rational numbers
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#define AVUTIL_RATIONAL_H
#include <stdint.h>
+#include <limits.h>
#include "attributes.h"
/**
} AVRational;
/**
- * Compares two rationals.
+ * Compare two rationals.
* @param a first rational
* @param b second rational
- * @return 0 if a==b, 1 if a>b and -1 if a<b
+ * @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>>63)|1;
- else return 0;
+ 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;
}
/**
- * Converts rational to double.
+ * Convert rational to double.
* @param a rational to convert
* @return (double) a
*/
}
/**
- * Reduces a fraction.
+ * Reduce a fraction.
* This is useful for framerate calculations.
* @param dst_num destination numerator
* @param dst_den destination denominator
int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max);
/**
- * Multiplies two rationals.
+ * Multiply two rationals.
* @param b first rational
* @param c second rational
* @return b*c
AVRational av_mul_q(AVRational b, AVRational c) av_const;
/**
- * Divides one rational by another.
+ * 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;
/**
- * Adds two rationals.
+ * Add two rationals.
* @param b first rational
* @param c second rational
* @return b+c
AVRational av_add_q(AVRational b, AVRational c) av_const;
/**
- * Subtracts one rational from another.
+ * 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;
/**
- * Converts a double precision floating point number to a rational.
+ * 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
int av_nearer_q(AVRational q, AVRational q1, AVRational q2);
/**
- * Finds the nearest value in q_list to q.
+ * 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
*/