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73 lines
2.2 KiB
73 lines
2.2 KiB
/*
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Copyright (c) 2012 Martin Sustrik All rights reserved.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom
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the Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included
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in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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IN THE SOFTWARE.
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*/
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#include "random.h"
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#include "clock.h"
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#include "fast.h"
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#ifdef NN_HAVE_WINDOWS
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#include "win.h"
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#else
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#include <sys/types.h>
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#include <unistd.h>
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#endif
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#include <string.h>
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static uint64_t nn_random_state;
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void nn_random_seed ()
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{
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uint64_t pid;
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#ifdef NN_HAVE_WINDOWS
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pid = (uint64_t) GetCurrentProcessId ();
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#else
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pid = (uint64_t) getpid ();
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#endif
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/* The initial state for pseudo-random number generator is computed from
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the exact timestamp and process ID. */
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memcpy (&nn_random_state, "\xfa\x9b\x23\xe3\x07\xcc\x61\x1f", 8);
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nn_random_state ^= pid + nn_clock_timestamp ();
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}
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void nn_random_generate (void *buf, size_t len)
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{
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uint8_t *pos;
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pos = (uint8_t*) buf;
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while (1) {
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/* Generate a pseudo-random integer. */
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nn_random_state = nn_random_state * 1103515245 + 12345;
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/* Move the bytes to the output buffer. */
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memcpy (pos, &nn_random_state, len > 8 ? 8 : len);
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if (nn_fast (len <= 8))
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return;
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len -= 8;
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pos += 8;
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}
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}
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