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

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

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ *
+ * 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
+ */
+
+#include "config.h"
+
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_IO_H
+#include <io.h>
+#endif
+#if HAVE_BCRYPT
+#include <windows.h>
+#include <bcrypt.h>
+#endif
+#include <fcntl.h>
+#include <math.h>
+#include <time.h>
+#include <string.h>
+#include "avassert.h"
+#include "internal.h"
+#include "intreadwrite.h"
+#include "timer.h"
+#include "random_seed.h"
+#include "sha.h"
+
+#ifndef TEST
+#define TEST 0
+#endif
+
+static int read_random(uint32_t *dst, const char *file)
+{
+#if HAVE_UNISTD_H
+    int fd = avpriv_open(file, O_RDONLY);
+    int err = -1;
+
+    if (fd == -1)
+        return -1;
+    err = read(fd, dst, sizeof(*dst));
+    close(fd);
+
+    return err;
+#else
+    return -1;
+#endif
+}
+
+static uint32_t get_generic_seed(void)
+{
+    uint64_t tmp[120/8];
+    struct AVSHA *sha = (void*)tmp;
+    clock_t last_t  = 0;
+    clock_t last_td = 0;
+    clock_t init_t = 0;
+    static uint64_t i = 0;
+    static uint32_t buffer[512] = { 0 };
+    unsigned char digest[20];
+    uint64_t last_i = i;
+
+    av_assert0(sizeof(tmp) >= av_sha_size);
+
+    if(TEST){
+        memset(buffer, 0, sizeof(buffer));
+        last_i = i = 0;
+    }else{
+#ifdef AV_READ_TIME
+        buffer[13] ^= AV_READ_TIME();
+        buffer[41] ^= AV_READ_TIME()>>32;
+#endif
+    }
+
+    for (;;) {
+        clock_t t = clock();
+        if (last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t) {
+            last_td = t - last_t;
+            buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U);
+        } else {
+            last_td = t - last_t;
+            buffer[++i & 511] += last_td % 3294638521U;
+            if ((t - init_t) >= CLOCKS_PER_SEC>>5)
+                if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8)
+                    break;
+        }
+        last_t = t;
+        if (!init_t)
+            init_t = t;
+    }
+
+    if(TEST) {
+        buffer[0] = buffer[1] = 0;
+    } else {
+#ifdef AV_READ_TIME
+        buffer[111] += AV_READ_TIME();
+#endif
+    }
+
+    av_sha_init(sha, 160);
+    av_sha_update(sha, (const uint8_t *)buffer, sizeof(buffer));
+    av_sha_final(sha, digest);
+    return AV_RB32(digest) + AV_RB32(digest + 16);
+}
+
+uint32_t av_get_random_seed(void)
+{
+    uint32_t seed;
+
+#if HAVE_BCRYPT
+    BCRYPT_ALG_HANDLE algo_handle;
+    NTSTATUS ret = BCryptOpenAlgorithmProvider(&algo_handle, BCRYPT_RNG_ALGORITHM,
+                                               MS_PRIMITIVE_PROVIDER, 0);
+    if (BCRYPT_SUCCESS(ret)) {
+        NTSTATUS ret = BCryptGenRandom(algo_handle, (UCHAR*)&seed, sizeof(seed), 0);
+        BCryptCloseAlgorithmProvider(algo_handle, 0);
+        if (BCRYPT_SUCCESS(ret))
+            return seed;
+    }
+#endif
+
+#if HAVE_ARC4RANDOM
+    return arc4random();
+#endif
+
+    if (read_random(&seed, "/dev/urandom") == sizeof(seed))
+        return seed;
+    if (read_random(&seed, "/dev/random")  == sizeof(seed))
+        return seed;
+    return get_generic_seed();
+}