X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Frational.h;h=5d7dab7fd0d2d5081ced7f19f8277537ba6e8dff;hb=7081620aca36e616ea96f71fd71d2703e3abae09;hp=2dd0c2c5948e5480877bb13ca6421e7a31428794;hpb=49bd8e4b843d9a92fdb8ef4361a551a1e019c65d;p=ffmpeg

diff --git a/libavutil/rational.h b/libavutil/rational.h
index 2dd0c2c5948..5d7dab7fd0d 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
  */
 
@@ -29,8 +29,14 @@
 #define AVUTIL_RATIONAL_H
 
 #include <stdint.h>
+#include <limits.h>
 #include "attributes.h"
 
+/**
+ * @addtogroup lavu_math
+ * @{
+ */
+
 /**
  * rational number numerator/denominator
  */
@@ -43,13 +49,16 @@ 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;
 }
 
 /**
@@ -105,8 +114,21 @@ AVRational av_add_q(AVRational b, AVRational c) av_const;
  */
 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
@@ -126,4 +148,8 @@ int av_nearer_q(AVRational q, AVRational q1, AVRational q2);
  */
 int av_find_nearest_q_idx(AVRational q, const AVRational* q_list);
 
+/**
+ * @}
+ */
+
 #endif /* AVUTIL_RATIONAL_H */