* 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
*/
#define AVUTIL_RATIONAL_H
#include <stdint.h>
+#include <limits.h>
#include "attributes.h"
+/**
+ * @addtogroup lavu_math
+ * @{
+ */
+
/**
* rational number numerator/denominator
*/
* 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;
}
/**
*/
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
*/
int av_find_nearest_q_idx(AVRational q, const AVRational* q_list);
+/**
+ * @}
+ */
+
#endif /* AVUTIL_RATIONAL_H */