X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Frational.h;h=5d7dab7fd0d2d5081ced7f19f8277537ba6e8dff;hb=e036bb7899d0faca9159206be9bf5552e76e7633;hp=f53f2786197ea1089b7b08737cdbaa4808f7352a;hpb=5b21bdabe43611385d1d55a21d5b1f607b133d29;p=ffmpeg

diff --git a/libavutil/rational.h b/libavutil/rational.h
index f53f2786197..5d7dab7fd0d 100644
--- a/libavutil/rational.h
+++ b/libavutil/rational.h
@@ -1,37 +1,44 @@
 /*
- * Rational numbers
+ * 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 rational.h
- * Rational numbers.
+ * @file
+ * rational numbers
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 
-#ifndef FFMPEG_RATIONAL_H
-#define FFMPEG_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
@@ -42,17 +49,20 @@ typedef struct AVRational{
  * 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;
 }
 
 /**
- * Rational to double conversion.
+ * Convert rational to double.
  * @param a rational to convert
  * @return (double) a
  */
@@ -63,53 +73,83 @@ static inline double av_q2d(AVRational a){
 /**
  * Reduce a fraction.
  * This is useful for framerate calculations.
- * @param dst_nom destination numerator
+ * @param dst_num destination numerator
  * @param dst_den destination denominator
- * @param nom source numerator
+ * @param num source numerator
  * @param den source denominator
- * @param max the maximum allowed for dst_nom & dst_den
+ * @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);
 
 /**
- * Multiplies two rationals.
- * @param b first rational.
- * @param c second rational.
- * @return b*c.
+ * Multiply two rationals.
+ * @param b first rational
+ * @param c second rational
+ * @return b*c
  */
-AVRational av_mul_q(AVRational b, AVRational c);
+AVRational av_mul_q(AVRational b, AVRational c) av_const;
 
 /**
- * Divides one rational by another.
- * @param b first rational.
- * @param c second rational.
- * @return b/c.
+ * Divide one rational by another.
+ * @param b first rational
+ * @param c second rational
+ * @return b/c
  */
-AVRational av_div_q(AVRational b, AVRational c);
+AVRational av_div_q(AVRational b, AVRational c) av_const;
 
 /**
- * Adds two rationals.
- * @param b first rational.
- * @param c second rational.
- * @return b+c.
+ * Add two rationals.
+ * @param b first rational
+ * @param c second rational
+ * @return b+c
  */
-AVRational av_add_q(AVRational b, AVRational c);
+AVRational av_add_q(AVRational b, AVRational c) av_const;
 
 /**
- * Subtracts one rational from another.
- * @param b first rational.
- * @param c second rational.
- * @return b-c.
+ * Subtract one rational from another.
+ * @param b first rational
+ * @param c second rational
+ * @return b-c
  */
-AVRational av_sub_q(AVRational b, AVRational c);
+AVRational av_sub_q(AVRational b, AVRational c) av_const;
 
 /**
- * Converts a double precision floating point number to a rational.
+ * 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.
+ * @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);
+
+/**
+ * @}
  */
-AVRational av_d2q(double d, int max);
 
-#endif /* FFMPEG_RATIONAL_H */
+#endif /* AVUTIL_RATIONAL_H */