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/**
* slibc — Yet another C library
* Copyright © 2015, 2016 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include <stdlib.h>
/* Durstenfeld's algorithm. */
/**
* Shuffles all bytes in a string.
*
* This is a GNU joke extension.
*
* @param anagram An anagram of the output, will be modified.
* @retrun The string, which will `== anagram`.
*
* @since Always.
*/
char* strfry(char* anagram)
{
size_t i, j, n;
int r;
char t;
if (anagram == NULL)
return NULL;
n = strlen(anagram);
for (i = n - 1; n && i; i--)
{
r = rand();
j = (size_t)((double)r / ((double)RAND_MAX + 1) * (double)i); /* TODO This is not uniformally random. */
t = anagram[i], anagram[i] = anagram[j], anagram[j] = t;
}
return anagram;
}
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