glibc/string/strfry.c

54 lines
1.4 KiB
C

/* Copyright (C) 1992, 1996, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <string.h>
#include <stdlib.h>
#include <time.h>
char *
strfry (char *string)
{
static int init;
static struct random_data rdata;
size_t len, i;
if (!init)
{
static char state[32];
rdata.state = NULL;
__initstate_r (time ((time_t *) NULL), state, sizeof (state), &rdata);
init = 1;
}
len = strlen (string);
for (i = 0; i < len; ++i)
{
int32_t j;
char c;
__random_r (&rdata, &j);
j %= len;
c = string[i];
string[i] = string[j];
string[j] = c;
}
return string;
}