Make sure that values generated for ff_vorbis_len2vlc in

[ffmpeg] / libavutil / rational.c

diff --git a/libavutil/rational.c b/libavutil/rational.c
index 96a4c5462ef31749b33d2baf5ba0171c323bb3ec..097519ccbe03af858e0d9ee8a416ddec038fd184 100644 (file)
--- a/libavutil/rational.c
+++ b/libavutil/rational.c
@@ -1,5 +1,5 @@
 /*
- * Rational numbers
+ * rational numbers
  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
@@ -20,11 +20,12 @@
  */
 
 /**
- * @file rational.c
- * Rational numbers
+ * @file libavutil/rational.c
+ * rational numbers
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 
+#include <assert.h>
 //#include <math.h>
 #include <limits.h>
 
@@ -32,23 +33,23 @@
 #include "mathematics.h"
 #include "rational.h"
 
-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){
     AVRational a0={0,1}, a1={1,0};
-    int sign= (nom<0) ^ (den<0);
-    int64_t gcd= ff_gcd(FFABS(nom), FFABS(den));
+    int sign= (num<0) ^ (den<0);
+    int64_t gcd= av_gcd(FFABS(num), FFABS(den));
 
     if(gcd){
-        nom = FFABS(nom)/gcd;
+        num = FFABS(num)/gcd;
         den = FFABS(den)/gcd;
     }
-    if(nom<=max && den<=max){
-        a1= (AVRational){nom, den};
+    if(num<=max && den<=max){
+        a1= (AVRational){num, den};
         den=0;
     }
 
     while(den){
-        uint64_t x      = nom / den;
-        int64_t next_den= nom - den*x;
+        uint64_t x      = num / den;
+        int64_t next_den= num - den*x;
         int64_t a2n= x*a1.num + a0.num;
         int64_t a2d= x*a1.den + a0.den;
 
@@ -56,19 +57,19 @@ int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max)
             if(a1.num) x= (max - a0.num) / a1.num;
             if(a1.den) x= FFMIN(x, (max - a0.den) / a1.den);
 
-            if (den*(2*x*a1.den + a0.den) > nom*a1.den)
+            if (den*(2*x*a1.den + a0.den) > num*a1.den)
                 a1 = (AVRational){x*a1.num + a0.num, x*a1.den + a0.den};
             break;
         }
 
         a0= a1;
         a1= (AVRational){a2n, a2d};
-        nom= den;
+        num= den;
         den= next_den;
     }
-    assert(ff_gcd(a1.num, a1.den) <= 1U);
+    assert(av_gcd(a1.num, a1.den) <= 1U);
 
-    *dst_nom = sign ? -a1.num : a1.num;
+    *dst_num = sign ? -a1.num : a1.num;
     *dst_den = a1.den;
 
     return den==0;
@@ -101,3 +102,28 @@ AVRational av_d2q(double d, int max){
 
     return a;
 }
+
+int av_nearer_q(AVRational q, AVRational q1, AVRational q2)
+{
+    /* n/d is q, a/b is the median between q1 and q2 */
+    int64_t a = q1.num * (int64_t)q2.den + q2.num * (int64_t)q1.den;
+    int64_t b = 2 * (int64_t)q1.den * q2.den;
+
+    /* rnd_up(a*d/b) > n => a*d/b > n */
+    int64_t x_up = av_rescale_rnd(a, q.den, b, AV_ROUND_UP);
+
+    /* rnd_down(a*d/b) < n => a*d/b < n */
+    int64_t x_down = av_rescale_rnd(a, q.den, b, AV_ROUND_DOWN);
+
+    return ((x_up > q.num) - (x_down < q.num)) * av_cmp_q(q2, q1);
+}
+
+int av_find_nearest_q_idx(AVRational q, const AVRational* q_list)
+{
+    int i, nearest_q_idx = 0;
+    for(i=0; q_list[i].den; i++)
+        if (av_nearer_q(q, q_list[i], q_list[nearest_q_idx]) > 0)
+            nearest_q_idx = i;
+
+    return nearest_q_idx;
+}