1
0
mirror of https://github.com/cmand/yarrp.git synced 2024-05-11 05:55:06 +00:00
Files
cmand-yarrp/libcperm/prefix.c
2019-11-17 09:13:49 -08:00

96 lines
2.5 KiB
C

/* ------------------------------------------------------------------------
libcperm - A library for creating random permutations.
Copyright (c) 2014, Lance Alt
This file is part of libcperm.
This library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this library. If not, see <http://www.gnu.org/licenses/>.
------------------------------------------------------------------------
*/
#include <stdint.h>
#include <stdlib.h>
#include "cperm.h"
#include "cperm-internal.h"
#include "prefix.h"
static int prefix_element_sort(const void* a, const void* b) {
const struct prefix_element* ea = a;
const struct prefix_element* eb = b;
if(ea->ct < eb->ct) return -1;
else return 1;
}
int perm_prefix_create(struct cperm_t* perm) {
struct prefix_data_t* prefix_data = malloc(sizeof(*prefix_data));
if(!prefix_data) {
cperm_errno = PERM_ERROR_NOMEM;
return PERM_ERROR_NOMEM;
}
struct prefix_element* vect = malloc(sizeof(struct prefix_element) * perm->range);
if(!vect) {
free(prefix_data);
cperm_errno = PERM_ERROR_NOMEM;
return PERM_ERROR_NOMEM;
}
for(uint32_t i = 0; i < perm->range; i++) {
perm->cipher->enc(perm, i, &vect[i].ct);
vect[i].pt = i;
}
qsort(vect, perm->range, sizeof(struct prefix_element), prefix_element_sort);
prefix_data->vector = vect;
prefix_data->next = 0;
perm->mode_data = prefix_data;
return 0;
}
int perm_prefix_get(struct cperm_t* perm, uint32_t pt, uint32_t* ct) {
struct prefix_data_t* prefix_data = perm->mode_data;
if(pt < perm->range) {
*ct = prefix_data->vector[pt].pt;
return 0;
}
cperm_errno = PERM_ERROR_RANGE;
return PERM_ERROR_RANGE;
}
int perm_prefix_next(struct cperm_t* perm, uint32_t* ct) {
struct prefix_data_t* prefix_data = perm->mode_data;
if(prefix_data->next < perm->range) {
*ct = prefix_data->vector[prefix_data->next++].pt;
return 0;
}
cperm_errno = PERM_END;
return PERM_END;
}
int perm_prefix_destroy(struct cperm_t* perm) {
struct prefix_data_t* prefix_data = perm->mode_data;
free(prefix_data->vector);
free(prefix_data);
return 0;
}