Rename ffmpeg-4.2-fit to ffmpeg-4-fit

trunk/3rdparty/ffmpeg-4-fit/libavutil/rational.c

@@ -0,0 +1,184 @@
+/*
+ * 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 numbers
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#include "avassert.h"
+#include <limits.h>
+
+#include "common.h"
+#include "mathematics.h"
+#include "rational.h"
+
+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 = (num < 0) ^ (den < 0);
+    int64_t gcd = av_gcd(FFABS(num), FFABS(den));
+
+    if (gcd) {
+        num = FFABS(num) / gcd;
+        den = FFABS(den) / gcd;
+    }
+    if (num <= max && den <= max) {
+        a1 = (AVRational) { num, den };
+        den = 0;
+    }
+
+    while (den) {
+        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;
+
+        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) > num * a1.den)
+                a1 = (AVRational) { x * a1.num + a0.num, x * a1.den + a0.den };
+            break;
+        }
+
+        a0  = a1;
+        a1  = (AVRational) { a2n, a2d };
+        num = den;
+        den = next_den;
+    }
+    av_assert2(av_gcd(a1.num, a1.den) <= 1U);
+    av_assert2(a1.num <= max && a1.den <= max);
+
+    *dst_num = 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;
+    int exponent;
+    int64_t den;
+    if (isnan(d))
+        return (AVRational) { 0,0 };
+    if (fabs(d) > INT_MAX + 3LL)
+        return (AVRational) { d < 0 ? -1 : 1, 0 };
+    frexp(d, &exponent);
+    exponent = FFMAX(exponent-1, 0);
+    den = 1LL << (61 - exponent);
+    // (int64_t)rint() and llrint() do not work with gcc on ia64 and sparc64,
+    // see Ticket2713 for affected gcc/glibc versions
+    av_reduce(&a.num, &a.den, floor(d * den + 0.5), den, max);
+    if ((!a.num || !a.den) && d && max>0 && max<INT_MAX)
+        av_reduce(&a.num, &a.den, floor(d * den + 0.5), den, 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;
+}
+
+uint32_t av_q2intfloat(AVRational q) {
+    int64_t n;
+    int shift;
+    int sign = 0;
+
+    if (q.den < 0) {
+        q.den *= -1;
+        q.num *= -1;
+    }
+    if (q.num < 0) {
+        q.num *= -1;
+        sign = 1;
+    }
+
+    if (!q.num && !q.den) return 0xFFC00000;
+    if (!q.num) return 0;
+    if (!q.den) return 0x7F800000 | (q.num & 0x80000000);
+
+    shift = 23 + av_log2(q.den) - av_log2(q.num);
+    if (shift >= 0) n = av_rescale(q.num, 1LL<<shift, q.den);
+    else            n = av_rescale(q.num, 1, ((int64_t)q.den) << -shift);
+
+    shift -= n >= (1<<24);
+    shift += n <  (1<<23);
+
+    if (shift >= 0) n = av_rescale(q.num, 1LL<<shift, q.den);
+    else            n = av_rescale(q.num, 1, ((int64_t)q.den) << -shift);
+
+    av_assert1(n <  (1<<24));
+    av_assert1(n >= (1<<23));
+
+    return sign<<31 | (150-shift)<<23 | (n - (1<<23));
+}