X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Frational.h;h=a4871148bdde239b4c5ea9a26f0cbb466eb67f1a;hb=dc86ca1ab54c04f15214e6fc023d6dfc627aee34;hp=4d91f7baee8769dd54d308a41d9d07d41e4c4e79;hpb=ba87f0801d77c21eb1e4891ca1f846500bbb0939;p=ffmpeg

diff --git a/libavutil/rational.h b/libavutil/rational.h
index 4d91f7baee8..a4871148bdd 100644
--- a/libavutil/rational.h
+++ b/libavutil/rational.h
@@ -2,20 +2,20 @@
  * 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
  */
 
@@ -29,6 +29,7 @@
 #define AVUTIL_RATIONAL_H
 
 #include <stdint.h>
+#include <limits.h>
 #include "attributes.h"
 
 /**
@@ -40,20 +41,23 @@ typedef struct AVRational{
 } 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
  */
@@ -62,7 +66,7 @@ static inline double av_q2d(AVRational a){
 }
 
 /**
- * Reduces a fraction.
+ * Reduce a fraction.
  * This is useful for framerate calculations.
  * @param dst_num destination numerator
  * @param dst_den destination denominator
@@ -74,7 +78,7 @@ static inline double av_q2d(AVRational a){
 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
@@ -82,7 +86,7 @@ int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
 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
@@ -90,7 +94,7 @@ AVRational av_mul_q(AVRational b, AVRational c) av_const;
 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
@@ -98,7 +102,7 @@ AVRational av_div_q(AVRational b, AVRational c) av_const;
 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
@@ -106,7 +110,9 @@ AVRational av_add_q(AVRational b, AVRational c) av_const;
 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
@@ -120,7 +126,7 @@ AVRational av_d2q(double d, int max) av_const;
 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
  */