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96 lines
2.5 KiB
C
96 lines
2.5 KiB
C
/* ------------------------------------------------------------------------
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libcperm - A library for creating random permutations.
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Copyright (c) 2014, Lance Alt
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This file is part of libcperm.
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This library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this library. If not, see <http://www.gnu.org/licenses/>.
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------------------------------------------------------------------------
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include "cperm.h"
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#include "cperm-internal.h"
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#include "prefix.h"
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static int prefix_element_sort(const void* a, const void* b) {
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const struct prefix_element* ea = a;
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const struct prefix_element* eb = b;
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if(ea->ct < eb->ct) return -1;
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else return 1;
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}
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int perm_prefix_create(struct cperm_t* perm) {
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struct prefix_data_t* prefix_data = malloc(sizeof(*prefix_data));
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if(!prefix_data) {
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cperm_errno = PERM_ERROR_NOMEM;
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return PERM_ERROR_NOMEM;
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}
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struct prefix_element* vect = malloc(sizeof(struct prefix_element) * perm->range);
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if(!vect) {
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free(prefix_data);
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cperm_errno = PERM_ERROR_NOMEM;
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return PERM_ERROR_NOMEM;
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}
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for(uint32_t i = 0; i < perm->range; i++) {
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perm->cipher->enc(perm, i, &vect[i].ct);
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vect[i].pt = i;
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}
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qsort(vect, perm->range, sizeof(struct prefix_element), prefix_element_sort);
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prefix_data->vector = vect;
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prefix_data->next = 0;
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perm->mode_data = prefix_data;
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return 0;
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}
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int perm_prefix_get(struct cperm_t* perm, uint32_t pt, uint32_t* ct) {
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struct prefix_data_t* prefix_data = perm->mode_data;
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if(pt < perm->range) {
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*ct = prefix_data->vector[pt].pt;
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return 0;
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}
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cperm_errno = PERM_ERROR_RANGE;
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return PERM_ERROR_RANGE;
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}
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int perm_prefix_next(struct cperm_t* perm, uint32_t* ct) {
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struct prefix_data_t* prefix_data = perm->mode_data;
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if(prefix_data->next < perm->range) {
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*ct = prefix_data->vector[prefix_data->next++].pt;
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return 0;
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}
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cperm_errno = PERM_END;
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return PERM_END;
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}
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int perm_prefix_destroy(struct cperm_t* perm) {
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struct prefix_data_t* prefix_data = perm->mode_data;
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free(prefix_data->vector);
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free(prefix_data);
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return 0;
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}
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