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/* base64.c
 * Base-64 conversion
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <string.h>
#include "base64.h"

/* Decode a base64 string in-place - simple and slow algorithm.
   Return length of result. Taken from rproxy/librsync/base64.c by
   Andrew Tridgell. */

size_t ws_base64_decode_inplace(char *s)
{
        static const char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\r\n";
        int bit_offset, byte_offset, idx, i;
        unsigned char *d = (unsigned char *)s;
        char *p;
        int  cr_idx;

        /* we will allow CR and LF - but ignore them */
        cr_idx = (int) (strchr(b64, '\r') - b64);

        i = 0;

        while (*s && (p=strchr(b64, *s))) {
                idx = (int)(p - b64);
                if(idx < cr_idx) {
                        byte_offset = (i*6)/8;
                        bit_offset = (i*6)%8;
                        d[byte_offset] &= ~((1<<(8-bit_offset))-1);
                        if (bit_offset < 3) {
                                d[byte_offset] |= (idx << (2-bit_offset));
                        } else {
                                d[byte_offset] |= (idx >> (bit_offset-2));
                                d[byte_offset+1] = 0;
                                d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
                        }
                        i++;
                }
                s++;
        }

        d[i*3/4] = 0;
        return i*3/4;
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */