1/*
2 * librd - Rapid Development C library
3 *
4 * Copyright (c) 2012, Magnus Edenhill
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "rd.h"
30#include "rdrand.h"
31
32
33
34void rd_array_shuffle (void *base, size_t nmemb, size_t entry_size) {
35 int i;
36 void *tmp = rd_alloca(entry_size);
37
38 /* FIXME: Optimized version for word-sized entries. */
39
40 for (i = (int) nmemb - 1 ; i > 0 ; i--) {
41 int j = rd_jitter(0, i);
42 if (unlikely(i == j))
43 continue;
44
45 memcpy(tmp, (char *)base + (i*entry_size), entry_size);
46 memcpy((char *)base+(i*entry_size),
47 (char *)base+(j*entry_size), entry_size);
48 memcpy((char *)base+(j*entry_size), tmp, entry_size);
49 }
50}
51