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+/*
+ * Copyright (c) 2005-2012 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
+ * miscellaneous math routines and tables
+ */
+
+#include <stdint.h>
+#include <limits.h>
+
+#include "avutil.h"
+#include "mathematics.h"
+#include "libavutil/intmath.h"
+#include "libavutil/common.h"
+#include "avassert.h"
+
+/* Stein's binary GCD algorithm:
+ * https://en.wikipedia.org/wiki/Binary_GCD_algorithm */
+int64_t av_gcd(int64_t a, int64_t b) {
+ int za, zb, k;
+ int64_t u, v;
+ if (a == 0)
+ return b;
+ if (b == 0)
+ return a;
+ za = ff_ctzll(a);
+ zb = ff_ctzll(b);
+ k = FFMIN(za, zb);
+ u = llabs(a >> za);
+ v = llabs(b >> zb);
+ while (u != v) {
+ if (u > v)
+ FFSWAP(int64_t, v, u);
+ v -= u;
+ v >>= ff_ctzll(v);
+ }
+ return (uint64_t)u << k;
+}
+
+int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd)
+{
+ int64_t r = 0;
+ av_assert2(c > 0);
+ av_assert2(b >=0);
+ av_assert2((unsigned)(rnd&~AV_ROUND_PASS_MINMAX)<=5 && (rnd&~AV_ROUND_PASS_MINMAX)!=4);
+
+ if (c <= 0 || b < 0 || !((unsigned)(rnd&~AV_ROUND_PASS_MINMAX)<=5 && (rnd&~AV_ROUND_PASS_MINMAX)!=4))
+ return INT64_MIN;
+
+ if (rnd & AV_ROUND_PASS_MINMAX) {
+ if (a == INT64_MIN || a == INT64_MAX)
+ return a;
+ rnd -= AV_ROUND_PASS_MINMAX;
+ }
+
+ if (a < 0)
+ return -(uint64_t)av_rescale_rnd(-FFMAX(a, -INT64_MAX), b, c, rnd ^ ((rnd >> 1) & 1));
+
+ if (rnd == AV_ROUND_NEAR_INF)
+ r = c / 2;
+ else if (rnd & 1)
+ r = c - 1;
+
+ if (b <= INT_MAX && c <= INT_MAX) {
+ if (a <= INT_MAX)
+ return (a * b + r) / c;
+ else {
+ int64_t ad = a / c;
+ int64_t a2 = (a % c * b + r) / c;
+ if (ad >= INT32_MAX && b && ad > (INT64_MAX - a2) / b)
+ return INT64_MIN;
+ return ad * b + a2;
+ }
+ } else {
+#if 1
+ uint64_t a0 = a & 0xFFFFFFFF;
+ uint64_t a1 = a >> 32;
+ uint64_t b0 = b & 0xFFFFFFFF;
+ uint64_t b1 = b >> 32;
+ uint64_t t1 = a0 * b1 + a1 * b0;
+ uint64_t t1a = t1 << 32;
+ int i;
+
+ a0 = a0 * b0 + t1a;
+ a1 = a1 * b1 + (t1 >> 32) + (a0 < t1a);
+ a0 += r;
+ a1 += a0 < r;
+
+ for (i = 63; i >= 0; i--) {
+ a1 += a1 + ((a0 >> i) & 1);
+ t1 += t1;
+ if (c <= a1) {
+ a1 -= c;
+ t1++;
+ }
+ }
+ if (t1 > INT64_MAX)
+ return INT64_MIN;
+ return t1;
+#else
+ /* reference code doing (a*b + r) / c, requires libavutil/integer.h */
+ AVInteger ai;
+ ai = av_mul_i(av_int2i(a), av_int2i(b));
+ ai = av_add_i(ai, av_int2i(r));
+
+ return av_i2int(av_div_i(ai, av_int2i(c)));
+#endif
+ }
+}
+
+int64_t av_rescale(int64_t a, int64_t b, int64_t c)
+{
+ return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
+}
+
+int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
+ enum AVRounding rnd)
+{
+ int64_t b = bq.num * (int64_t)cq.den;
+ int64_t c = cq.num * (int64_t)bq.den;
+ return av_rescale_rnd(a, b, c, rnd);
+}
+
+int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
+{
+ return av_rescale_q_rnd(a, bq, cq, AV_ROUND_NEAR_INF);
+}
+
+int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
+{
+ int64_t a = tb_a.num * (int64_t)tb_b.den;
+ int64_t b = tb_b.num * (int64_t)tb_a.den;
+ if ((FFABS64U(ts_a)|a|FFABS64U(ts_b)|b) <= INT_MAX)
+ return (ts_a*a > ts_b*b) - (ts_a*a < ts_b*b);
+ if (av_rescale_rnd(ts_a, a, b, AV_ROUND_DOWN) < ts_b)
+ return -1;
+ if (av_rescale_rnd(ts_b, b, a, AV_ROUND_DOWN) < ts_a)
+ return 1;
+ return 0;
+}
+
+int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod)
+{
+ int64_t c = (a - b) & (mod - 1);
+ if (c > (mod >> 1))
+ c -= mod;
+ return c;
+}
+
+int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb){
+ int64_t a, b, this;
+
+ av_assert0(in_ts != AV_NOPTS_VALUE);
+ av_assert0(duration >= 0);
+
+ if (*last == AV_NOPTS_VALUE || !duration || in_tb.num*(int64_t)out_tb.den <= out_tb.num*(int64_t)in_tb.den) {
+simple_round:
+ *last = av_rescale_q(in_ts, in_tb, fs_tb) + duration;
+ return av_rescale_q(in_ts, in_tb, out_tb);
+ }
+
+ a = av_rescale_q_rnd(2*in_ts-1, in_tb, fs_tb, AV_ROUND_DOWN) >>1;
+ b = (av_rescale_q_rnd(2*in_ts+1, in_tb, fs_tb, AV_ROUND_UP )+1)>>1;
+ if (*last < 2*a - b || *last > 2*b - a)
+ goto simple_round;
+
+ this = av_clip64(*last, a, b);
+ *last = this + duration;
+
+ return av_rescale_q(this, fs_tb, out_tb);
+}
+
+int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc)
+{
+ int64_t m, d;
+
+ if (inc != 1)
+ inc_tb = av_mul_q(inc_tb, (AVRational) {inc, 1});
+
+ m = inc_tb.num * (int64_t)ts_tb.den;
+ d = inc_tb.den * (int64_t)ts_tb.num;
+
+ if (m % d == 0 && ts <= INT64_MAX - m / d)
+ return ts + m / d;
+ if (m < d)
+ return ts;
+
+ {
+ int64_t old = av_rescale_q(ts, ts_tb, inc_tb);
+ int64_t old_ts = av_rescale_q(old, inc_tb, ts_tb);
+
+ if (old == INT64_MAX || old == AV_NOPTS_VALUE || old_ts == AV_NOPTS_VALUE)
+ return ts;
+
+ return av_sat_add64(av_rescale_q(old + 1, inc_tb, ts_tb), ts - old_ts);
+ }
+}
+
+static inline double eval_poly(const double *coeff, int size, double x) {
+ double sum = coeff[size-1];
+ int i;
+ for (i = size-2; i >= 0; --i) {
+ sum *= x;
+ sum += coeff[i];
+ }
+ return sum;
+}
+
+/**
+ * 0th order modified bessel function of the first kind.
+ * Algorithm taken from the Boost project, source:
+ * https://searchcode.com/codesearch/view/14918379/
+ * Use, modification and distribution are subject to the
+ * Boost Software License, Version 1.0 (see notice below).
+ * Boost Software License - Version 1.0 - August 17th, 2003
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+ */
+
+double av_bessel_i0(double x) {
+// Modified Bessel function of the first kind of order zero
+// minimax rational approximations on intervals, see
+// Blair and Edwards, Chalk River Report AECL-4928, 1974
+ static const double p1[] = {
+ -2.2335582639474375249e+15,
+ -5.5050369673018427753e+14,
+ -3.2940087627407749166e+13,
+ -8.4925101247114157499e+11,
+ -1.1912746104985237192e+10,
+ -1.0313066708737980747e+08,
+ -5.9545626019847898221e+05,
+ -2.4125195876041896775e+03,
+ -7.0935347449210549190e+00,
+ -1.5453977791786851041e-02,
+ -2.5172644670688975051e-05,
+ -3.0517226450451067446e-08,
+ -2.6843448573468483278e-11,
+ -1.5982226675653184646e-14,
+ -5.2487866627945699800e-18,
+ };
+ static const double q1[] = {
+ -2.2335582639474375245e+15,
+ 7.8858692566751002988e+12,
+ -1.2207067397808979846e+10,
+ 1.0377081058062166144e+07,
+ -4.8527560179962773045e+03,
+ 1.0,
+ };
+ static const double p2[] = {
+ -2.2210262233306573296e-04,
+ 1.3067392038106924055e-02,
+ -4.4700805721174453923e-01,
+ 5.5674518371240761397e+00,
+ -2.3517945679239481621e+01,
+ 3.1611322818701131207e+01,
+ -9.6090021968656180000e+00,
+ };
+ static const double q2[] = {
+ -5.5194330231005480228e-04,
+ 3.2547697594819615062e-02,
+ -1.1151759188741312645e+00,
+ 1.3982595353892851542e+01,
+ -6.0228002066743340583e+01,
+ 8.5539563258012929600e+01,
+ -3.1446690275135491500e+01,
+ 1.0,
+ };
+ double y, r, factor;
+ if (x == 0)
+ return 1.0;
+ x = fabs(x);
+ if (x <= 15) {
+ y = x * x;
+ return eval_poly(p1, FF_ARRAY_ELEMS(p1), y) / eval_poly(q1, FF_ARRAY_ELEMS(q1), y);
+ }
+ else {
+ y = 1 / x - 1.0 / 15;
+ r = eval_poly(p2, FF_ARRAY_ELEMS(p2), y) / eval_poly(q2, FF_ARRAY_ELEMS(q2), y);
+ factor = exp(x) / sqrt(x);
+ return factor * r;
+ }
+}