From 4a6d9312cc1c9d62d66c4def71246d9faae29edb Mon Sep 17 00:00:00 2001
From: zhangmeng <775834166@qq.com>
Date: 星期三, 03 三月 2021 14:26:16 +0800
Subject: [PATCH] environment settings
---
module/VideoPlayer/lib/linux/ffmpeg/include/libavutil/lfg.h | 71 +++++++++++++++++++++++++++++++++++
1 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/module/VideoPlayer/lib/linux/ffmpeg/include/libavutil/lfg.h b/module/VideoPlayer/lib/linux/ffmpeg/include/libavutil/lfg.h
new file mode 100644
index 0000000..03f779a
--- /dev/null
+++ b/module/VideoPlayer/lib/linux/ffmpeg/include/libavutil/lfg.h
@@ -0,0 +1,71 @@
+/*
+ * Lagged Fibonacci PRNG
+ * Copyright (c) 2008 Michael Niedermayer
+ *
+ * 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
+ */
+
+#ifndef AVUTIL_LFG_H
+#define AVUTIL_LFG_H
+
+#include <stdint.h>
+
+typedef struct AVLFG {
+ unsigned int state[64];
+ int index;
+} AVLFG;
+
+void av_lfg_init(AVLFG *c, unsigned int seed);
+
+/**
+ * Seed the state of the ALFG using binary data.
+ *
+ * Return value: 0 on success, negative value (AVERROR) on failure.
+ */
+int av_lfg_init_from_data(AVLFG *c, const uint8_t *data, unsigned int length);
+
+/**
+ * Get the next random unsigned 32-bit number using an ALFG.
+ *
+ * Please also consider a simple LCG like state= state*1664525+1013904223,
+ * it may be good enough and faster for your specific use case.
+ */
+static inline unsigned int av_lfg_get(AVLFG *c){
+ c->state[c->index & 63] = c->state[(c->index-24) & 63] + c->state[(c->index-55) & 63];
+ return c->state[c->index++ & 63];
+}
+
+/**
+ * Get the next random unsigned 32-bit number using a MLFG.
+ *
+ * Please also consider av_lfg_get() above, it is faster.
+ */
+static inline unsigned int av_mlfg_get(AVLFG *c){
+ unsigned int a= c->state[(c->index-55) & 63];
+ unsigned int b= c->state[(c->index-24) & 63];
+ return c->state[c->index++ & 63] = 2*a*b+a+b;
+}
+
+/**
+ * Get the next two numbers generated by a Box-Muller Gaussian
+ * generator using the random numbers issued by lfg.
+ *
+ * @param out array where the two generated numbers are placed
+ */
+void av_bmg_get(AVLFG *lfg, double out[2]);
+
+#endif /* AVUTIL_LFG_H */
--
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