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/*
* Copyright (C) 2010-2011 Mamadou Diop.
*
* Contact: Mamadou Diop <diopmamadou(at)doubango[dot]org>
*
* This file is part of Open Source Doubango Framework.
*
* DOUBANGO 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.
*
* DOUBANGO 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 DOUBANGO.
*
*/
/**@file tsk_uuid.c
* @brief Universally Unique Identifier (UUID version 5) implementation (RFC 4122).
* This implementation is not fully conform to RFC 4122 but could be safely used to generate random UUIDs.
*
* @author Mamadou Diop <diopmamadou(at)doubango[dot]org>
*
*/
#include "tsk_uuid.h"
#include "tsk_sha1.h"
#include "tsk_string.h"
#include "tsk_time.h"
#include <stdlib.h>
#include <string.h>
/**@defgroup tsk_uuid_group niversally Unique Identifier (UUID version 5) implementation (RFC 4122).
*/
/**@ingroup tsk_uuid_group
*/
int tsk_uuidgenerate(tsk_uuidstring_t *result)
{
/* From wikipedia
* Version 5 UUIDs use a scheme with SHA-1 hashing, otherwise it is the same idea as in version 3.
* RFC 4122 states that version 5 is preferred over version 3 name based UUIDs.
* Note that the 160 bit SHA-1 hash is truncated to 128 bits to make the length work out.
*/
tsk_sha1string_t sha1result;
tsk_istr_t now;
unsigned i, k;
static char HEX[] = "0123456789abcdef";
tsk_itoa(tsk_time_now(), &now);
tsk_sha1compute(now, sizeof(now), &sha1result);
/* XOR the SHA-1 result with random numbers. */
for(i=0; i<(TSK_UUID_DIGEST_SIZE*2); i+=4) {
#if 0
*((uint32_t*)&sha1result[i]) ^= rand();
#else
k = rand();
sha1result[i] ^= k, sha1result[i + 1] ^= k,
sha1result[i + 2] ^= k, sha1result[i + 3] ^= k;
#endif
for(k=0; k<sizeof(uint32_t); k++) {
sha1result[i+k] = HEX[sha1result[i+k] & 0x0F]; /* To hexa. */
}
}
/* f47ac10b-58cc-4372-a567-0e02b2c3d479 */
memcpy(&(*result)[0], &sha1result[0], 8);
(*result)[8] = '-';
memcpy(&(*result)[9], &sha1result[8], 4);
(*result)[13] = '-';
memcpy(&(*result)[14], &sha1result[12], 4);
(*result)[18] = '-';
memcpy(&(*result)[19], &sha1result[16], 4);
(*result)[23] = '-';
memcpy(&(*result)[24], &sha1result[20], 12);
(*result)[36] = '\0';
return 0;
}
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