hwcontext_vdpau: Remove duplicate definition of GET_CALLBACK

[ffmpeg] / libavutil / lfg.c

diff --git a/libavutil/lfg.c b/libavutil/lfg.c
index e876d18fefb6641f8a0e40de3c328b6efbaa23af..20900570a28dd348f3346647cda1253287e5da41 100644 (file)
--- a/libavutil/lfg.c
+++ b/libavutil/lfg.c
@@ -2,63 +2,59 @@
  * Lagged Fibonacci PRNG
  * Copyright (c) 2008 Michael Niedermayer
  *
- * This file is part of FFmpeg.
+ * This file is part of Libav.
  *
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <inttypes.h>
+#include <limits.h>
+#include <math.h>
 #include "lfg.h"
 #include "md5.h"
 #include "intreadwrite.h"
+#include "attributes.h"
 
-void av_cold av_lfg_init(AVLFG *c, unsigned int seed){
-    uint8_t tmp[16]={0};
+av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
+{
+    uint8_t tmp[16] = { 0 };
     int i;
 
-    for(i=8; i<64; i+=4){
-        AV_WL32(tmp, seed); tmp[4]=i;
-        av_md5_sum(tmp, tmp,  16);
-        c->state[i  ]= AV_RL32(tmp);
-        c->state[i+1]= AV_RL32(tmp+4);
-        c->state[i+2]= AV_RL32(tmp+8);
-        c->state[i+3]= AV_RL32(tmp+12);
+    for (i = 8; i < 64; i += 4) {
+        AV_WL32(tmp, seed);
+        tmp[4] = i;
+        av_md5_sum(tmp, tmp, 16);
+        c->state[i    ] = AV_RL32(tmp);
+        c->state[i + 1] = AV_RL32(tmp + 4);
+        c->state[i + 2] = AV_RL32(tmp + 8);
+        c->state[i + 3] = AV_RL32(tmp + 12);
     }
-    c->index=0;
+    c->index = 0;
 }
 
-#ifdef TEST
-#include "log.h"
-#include "common.h"
-
-int main(void)
+void av_bmg_get(AVLFG *lfg, double out[2])
 {
-    int x=0;
-    int i, j;
-    AVLFG state;
+    double x1, x2, w;
 
-    av_lfg_init(&state, 0xdeadbeef);
-    for (j = 0; j < 10000; j++) {
-        START_TIMER
-        for (i = 0; i < 624; i++) {
-//            av_log(NULL,AV_LOG_ERROR, "%X\n", av_lfg_get(&state));
-            x+=av_lfg_get(&state);
-        }
-        STOP_TIMER("624 calls of av_lfg_get");
-    }
-    av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x);
-    return 0;
+    do {
+        x1 = 2.0 / UINT_MAX * av_lfg_get(lfg) - 1.0;
+        x2 = 2.0 / UINT_MAX * av_lfg_get(lfg) - 1.0;
+        w  = x1 * x1 + x2 * x2;
+    } while (w >= 1.0);
+
+    w = sqrt((-2.0 * log(w)) / w);
+    out[0] = x1 * w;
+    out[1] = x2 * w;
 }
-#endif