1 files changed, 104 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavutil/rational.c b/contrib/ffmpeg/libavutil/rational.c
new file mode 100644
index 000000000..ac0c9d371
--- /dev/null
+++ b/contrib/ffmpeg/libavutil/rational.c
@@ -0,0 +1,104 @@
+/*
+ * Rational numbers
+ * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+/**
+ * @file rational.c
+ * Rational numbers
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+//#include <math.h>
+#include <limits.h>
+
+#include "common.h"
+#include "mathematics.h"
+#include "rational.h"
+
+int av_reduce(int *dst_nom, int *dst_den, int64_t nom, 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));
+
+    if(gcd){
+        nom = FFABS(nom)/gcd;
+        den = FFABS(den)/gcd;
+    }
+    if(nom<=max && den<=max){
+        a1= (AVRational){nom, den};
+        den=0;
+    }
+
+    while(den){
+        uint64_t x      = nom / den;
+        int64_t next_den= nom - den*x;
+        int64_t a2n= x*a1.num + a0.num;
+        int64_t a2d= x*a1.den + a0.den;
+
+        if(a2n > max || a2d > 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)
+                a1 = (AVRational){x*a1.num + a0.num, x*a1.den + a0.den};
+            break;
+        }
+
+        a0= a1;
+        a1= (AVRational){a2n, a2d};
+        nom= den;
+        den= next_den;
+    }
+    assert(ff_gcd(a1.num, a1.den) <= 1U);
+
+    *dst_nom = sign ? -a1.num : a1.num;
+    *dst_den = a1.den;
+
+    return den==0;
+}
+
+AVRational av_mul_q(AVRational b, AVRational c){
+    av_reduce(&b.num, &b.den, b.num * (int64_t)c.num, b.den * (int64_t)c.den, INT_MAX);
+    return b;
+}
+
+AVRational av_div_q(AVRational b, AVRational c){
+    return av_mul_q(b, (AVRational){c.den, c.num});
+}
+
+AVRational av_add_q(AVRational b, AVRational c){
+    av_reduce(&b.num, &b.den, b.num * (int64_t)c.den + c.num * (int64_t)b.den, b.den * (int64_t)c.den, INT_MAX);
+    return b;
+}
+
+AVRational av_sub_q(AVRational b, AVRational c){
+    return av_add_q(b, (AVRational){-c.num, c.den});
+}
+
+AVRational av_d2q(double d, int max){
+    AVRational a;
+#define LOG2  0.69314718055994530941723212145817656807550013436025
+    int exponent= FFMAX( (int)(log(fabs(d) + 1e-20)/LOG2), 0);
+    int64_t den= 1LL << (61 - exponent);
+    av_reduce(&a.num, &a.den, (int64_t)(d * den + 0.5), den, max);
+
+    return a;
+}