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/*
* This file is part of libESMTP, a library for submission of RFC 2822
* formatted electronic mail messages using the SMTP protocol described
* in RFC 2821.
*
* Copyright (C) 2001,2002 Brian Stafford <brian@stafford.uklinux.net>
*
* 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 2.1 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <assert.h>
/* Routines to encode and decode base64 text.
*/
#include <ctype.h>
#include <string.h>
#include "base64.h"
/* RFC 2045 section 6.8 */
static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789"
"+/";
static const char index_64[128] =
{
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
};
/* Decode srclen bytes of base64 data contained in src and put the result
in dst. Since the destination buffer may contain arbitrary binary
data and it is not necessarily a string, there is no \0 byte at the
end of the decoded data. */
int
b64_decode (void *dst, int dstlen, const char *src, int srclen)
{
const unsigned char *p, *q;
unsigned char *t;
int c1, c2;
assert (dst != NULL && dstlen > 0);
if (src == NULL)
return 0;
if (srclen < 0)
srclen = strlen (src);
/* Remove leading and trailing white space */
for (p = (const unsigned char *) src;
srclen > 0 && isspace (*p);
p++, srclen--)
;
for (q = p + srclen - 1; q >= p && isspace (*q); q--, srclen--)
;
/* Length MUST be a multiple of 4 */
if (srclen % 4 != 0)
return -1;
/* Destination buffer length must be sufficient */
if (srclen / 4 * 3 + 1 > dstlen)
return -1;
t = dst;
while (srclen > 0)
{
srclen -= 4;
if (*p >= 128 || (c1 = index_64[*p++]) == -1)
return -1;
if (*p >= 128 || (c2 = index_64[*p++]) == -1)
return -1;
*t++ = (c1 << 2) | ((c2 & 0x30) >> 4);
if (p[0] == '=' && p[1] == '=')
break;
if (*p >= 128 || (c1 = index_64[*p++]) == -1)
return -1;
*t++ = ((c2 & 0x0f) << 4) | ((c1 & 0x3c) >> 2);
if (p[0] == '=')
break;
if (*p >= 128 || (c2 = index_64[*p++]) == -1)
return -1;
*t++ = ((c1 & 0x03) << 6) | c2;
}
return t - (unsigned char *) dst;
}
/* Return a pointer to a base 64 encoded string. The input data is
arbitrary binary data, the output is a \0 terminated string.
src and dst may not share the same buffer. */
int
b64_encode (char *dst, int dstlen, const void *src, int srclen)
{
char *to = dst;
const unsigned char *from;
unsigned char c1, c2;
int dst_needed;
assert (dst != NULL && dstlen > 0 && srclen >= 0);
if (src == NULL)
return 0;
dst_needed = (srclen + 2) / 3;
dst_needed *= 4;
if (dstlen < dst_needed + 1)
return -1;
from = src;
while (srclen > 0)
{
c1 = *from++; srclen--;
*to++ = base64[c1 >> 2];
c1 = (c1 & 0x03) << 4;
if (srclen <= 0)
{
*to++ = base64[c1];
*to++ = '=';
*to++ = '=';
break;
}
c2 = *from++; srclen--;
c1 |= (c2 >> 4) & 0x0f;
*to++ = base64[c1];
c1 = (c2 & 0x0f) << 2;
if (srclen <= 0)
{
*to++ = base64[c1];
*to++ = '=';
break;
}
c2 = *from++; srclen--;
c1 |= (c2 >> 6) & 0x03;
*to++ = base64[c1];
*to++ = base64[c2 & 0x3f];
}
*to = '\0';
return to - dst;
}
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