Update to 2.0.0 tree from current Fremantle build

[opencv] / 3rdparty / include / ffmpeg_ / random.h

diff --git a/3rdparty/include/ffmpeg_/random.h b/3rdparty/include/ffmpeg_/random.h
new file mode 100644 (file)
index 0000000..4d16eb9
--- /dev/null
+++ b/3rdparty/include/ffmpeg_/random.h
@@ -0,0 +1,79 @@
+/*
+ * Mersenne Twister PRNG algorithm
+ * Copyright (c) 2006 Ryan Martell
+ * Based on a C program for MT19937, with initialization improved 2002/1/26.
+ * Coded by Takuji Nishimura and Makoto Matsumoto.
+ *
+ * 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_RANDOM_H
+#define AVUTIL_RANDOM_H
+
+#define AV_RANDOM_N 624
+
+#include "avutil.h"
+#include "common.h"
+
+typedef struct {
+    unsigned int mt[AV_RANDOM_N]; ///< the array for the state vector
+    int index; ///< Current untempered value we use as the base.
+} AVRandomState;
+
+
+#if LIBAVUTIL_VERSION_MAJOR < 50
+attribute_deprecated void av_init_random(unsigned int seed, AVRandomState *state);
+#endif
+void av_random_init(AVRandomState *state, unsigned int seed); ///< To be inlined, the struct must be visible. So it does not make sense to try and keep it opaque with malloc/free-like calls.
+void av_random_generate_untempered_numbers(AVRandomState *state); ///< Regenerate the untempered numbers (must be done every 624 iterations, or it will loop).
+
+/**
+ * Generates a random number from the interval [0,0xffffffff].
+ *
+ * Please do NOT use the Mersenne Twister, it is slow. Use the random number
+ * generator from lfg.c/h or a simple LCG like state = state*1664525+1013904223.
+ * If you still choose to use MT, expect that you will have to provide
+ * some evidence that it makes a difference for the case where you use it.
+ */
+static inline unsigned int av_random(AVRandomState *state)
+{
+    unsigned int y;
+
+    // Regenerate the untempered numbers if we should...
+    if (state->index >= AV_RANDOM_N)
+        av_random_generate_untempered_numbers(state);
+
+    // Grab one...
+    y = state->mt[state->index++];
+
+    /* Now temper (Mersenne Twister coefficients). The coefficients for MT19937 are.. */
+    y ^= (y >> 11);
+    y ^= (y << 7) & 0x9d2c5680;
+    y ^= (y << 15) & 0xefc60000;
+    y ^= (y >> 18);
+
+    return y;
+}
+
+/** Returns a random number in the range [0-1] as double. */
+static inline double av_random_real1(AVRandomState *state)
+{
+    /* divided by 2^32-1 */
+    return av_random(state) * (1.0 / 4294967296.0);
+}
+
+#endif /* AVUTIL_RANDOM_H */