/* 

 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)

 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.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 2 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

 */

#include <pj/guid.h>

#include <pj/assert.h>

#include <pj/rand.h>

#include <pj/os.h>

#include <pj/string.h>

PJ_DEF_DATA(const unsigned) PJ_GUID_STRING_LENGTH=32;

static char guid_chars[64];

PJ_DEF(unsigned) pj_GUID_STRING_LENGTH()

{

    return PJ_GUID_STRING_LENGTH;

}

static void init_guid_chars(void)

{

    char *p = guid_chars;

    unsigned i;

    for (i=0; i<10; ++i)

        *p++ = '0'+i;

    for (i=0; i<26; ++i) {

        *p++ = 'a'+i;

        *p++ = 'A'+i;

    }

    *p++ = '-';

    *p++ = '.';

}

PJ_DEF(pj_str_t*) pj_generate_unique_string(pj_str_t *str)

{

    char *p, *end;

    PJ_CHECK_STACK();

    if (guid_chars[0] == '\0') {

        pj_enter_critical_section();

        if (guid_chars[0] == '\0') {

            init_guid_chars();

        }

        pj_leave_critical_section();

    }

    /* This would only work if PJ_GUID_STRING_LENGTH is multiple of 2 bytes */

    pj_assert(PJ_GUID_STRING_LENGTH % 2 == 0);

    for (p=str->ptr, end=p+PJ_GUID_STRING_LENGTH; p<end; ) {

        pj_uint32_t rand_val = pj_rand();

        pj_uint32_t rand_idx = RAND_MAX;

        for ( ; rand_idx>0 && p<end; rand_idx>>=8, rand_val>>=8, p++) {

            *p = guid_chars[(rand_val & 0xFF) & 63];

        }

    }

    str->slen = PJ_GUID_STRING_LENGTH;

    return str;

}