58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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// $XConsortium: randomize.cc /main/3 1996/06/11 17:38:40 cde-hal $
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#include "utility/randomize.h"
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randomize::randomize(int sd) : rdn(sd)
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{
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}
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void randomize::scramble(buffer& original)
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{
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int bytes = original.content_sz();
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char* buf = original.get_base();
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for ( int i=0; i<bytes-1; i++ )
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char_swap(buf[i], buf[rdn.rand() % ( bytes - i ) + i]);
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}
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void randomize::restore(buffer& scrambled)
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{
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int bytes = scrambled.content_sz();
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char* buf = scrambled.get_base();
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int *pos = new int[bytes-1];
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int i;
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for ( i=0; i<bytes-1; i++ ) {
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pos[i] = rdn.rand() % ( bytes - i ) + i;
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}
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for ( i=bytes-2; i>=0; i-- ) {
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char_swap(buf[i], buf[pos[i]]);
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}
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delete [] pos;
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}
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