51 строка
1.9 KiB
C
51 строка
1.9 KiB
C
/*
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* librd - Rapid Development C library
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*
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* Copyright (c) 2012, Magnus Edenhill
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "rd.h"
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#include "rdrand.h"
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void rd_array_shuffle (void *base, size_t nmemb, size_t entry_size) {
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int i;
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void *tmp = alloca(entry_size);
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/* FIXME: Optimized version for word-sized entries. */
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for (i = nmemb - 1 ; i > 0 ; i--) {
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int j = rd_jitter(0, i);
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if (unlikely(i == j))
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continue;
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memcpy(tmp, (char *)base + (i*entry_size), entry_size);
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memcpy((char *)base+(i*entry_size),
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(char *)base+(j*entry_size), entry_size);
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memcpy((char *)base+(j*entry_size), tmp, entry_size);
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}
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}
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