2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
6 * These libraries and programs are free software; you can
7 * redistribute them and/or modify them under the terms of the GNU
8 * Lesser General Public License as published by the Free Software
9 * Foundation; either version 2 of the License, or (at your option)
12 * These libraries and programs are distributed in the hope that
13 * they will be useful, but WITHOUT ANY WARRANTY; without even the
14 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
15 * PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with these librararies and programs; if not, write
20 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
21 * Floor, Boston, MA 02110-1301 USA
23 // $XConsortium: randomize.cc /main/3 1996/06/11 17:38:40 cde-hal $
25 #include "utility/randomize.h"
27 randomize::randomize(int sd) : rdn(sd)
31 void randomize::scramble(buffer& original)
33 int bytes = original.content_sz();
34 char* buf = original.get_base();
36 for ( int i=0; i<bytes-1; i++ )
37 char_swap(buf[i], buf[rdn.rand() % ( bytes - i ) + i]);
40 void randomize::restore(buffer& scrambled)
42 int bytes = scrambled.content_sz();
43 char* buf = scrambled.get_base();
45 int *pos = new int[bytes-1];
48 for ( i=0; i<bytes-1; i++ ) {
49 pos[i] = rdn.rand() % ( bytes - i ) + i;
52 for ( i=bytes-2; i>=0; i-- ) {
53 char_swap(buf[i], buf[pos[i]]);