/*
- * Rational numbers
+ * rational numbers
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
- * This library is free software; you can redistribute it and/or
+ * 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 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
*
- * This library 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 this library; 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 rational.h
- * Rational numbers.
+ * @file
+ * rational numbers
* @author Michael Niedermayer <michaelni@gmx.at>
*/
-#ifndef RATIONAL_H
-#define RATIONAL_H
+#ifndef AVUTIL_RATIONAL_H
+#define AVUTIL_RATIONAL_H
+
+#include <stdint.h>
+#include <limits.h>
+#include "attributes.h"
/**
- * Rational number num/den.
+ * @addtogroup lavu_math
+ * @{
+ */
+
+/**
+ * rational number numerator/denominator
*/
typedef struct AVRational{
int num; ///< numerator
} AVRational;
/**
- * returns 0 if a==b, 1 if a>b and -1 if a<b.
+ * 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>>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 the given AVRational to a double.
+ * 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 usefull for framerate calculations
- * @param max the maximum allowed for dst_nom & dst_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_nom, int *dst_den, int64_t nom, int64_t den, int64_t max);
+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;
-AVRational av_mul_q(AVRational b, AVRational c);
-AVRational av_div_q(AVRational b, AVRational c);
-AVRational av_add_q(AVRational b, AVRational c);
-AVRational av_sub_q(AVRational b, AVRational c);
-AVRational av_d2q(double d, int max);
+/**
+ * @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 // RATIONAL_H
+#endif /* AVUTIL_RATIONAL_H */
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