/*
* This file is part of DisOrder
* Copyright (C) 2005, 2007, 2008 Richard Kettlewell
*
* 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 3 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, see .
*/
/** @file lib/base64.c
* @brief Support for MIME base64
*/
#include "common.h"
#include "mem.h"
#include "base64.h"
#include "vector.h"
static const char mime_base64_table[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
/** @brief Convert MIME base64
* @param s base64 data
* @param nsp Where to store length of converted data
* @return Decoded data
*
* See RFC
* 2045 s6.8.
*/
char *mime_base64(const char *s, size_t *nsp) {
return generic_base64(s, nsp, mime_base64_table);
}
/** @brief Convert base64
* @param s base64 data
* @param nsp Where to store length of converted data
* @param table Table of characters to use
* @return Decoded data
*
* @p table should consist of 65 characters. The first 64 will be used to
* represents the 64 digits and the 65th will be used as padding at the end
* (i.e. the role of '=' in RFC2045 base64).
*/
char *generic_base64(const char *s, size_t *nsp, const char *table) {
struct dynstr d;
const char *t;
int b[4], n, c;
dynstr_init(&d);
n = 0;
while((c = (unsigned char)*s++)) {
if(c == table[64]) {
if(n >= 2) {
dynstr_append(&d, (b[0] << 2) + (b[1] >> 4));
if(n == 3)
dynstr_append(&d, (b[1] << 4) + (b[2] >> 2));
}
break;
} else if((t = strchr(table, c))) {
b[n++] = t - table;
if(n == 4) {
dynstr_append(&d, (b[0] << 2) + (b[1] >> 4));
dynstr_append(&d, (b[1] << 4) + (b[2] >> 2));
dynstr_append(&d, (b[2] << 6) + b[3]);
n = 0;
}
}
}
if(nsp)
*nsp = d.nvec;
dynstr_terminate(&d);
return d.vec;
}
/** @brief Convert a binary string to MIME base64
* @param s Bytes to convert
* @param ns Number of bytes to convert
* @return Encoded data
*
* This function does not attempt to split up lines.
*
* See RFC
* 2045 s6.8.
*/
char *mime_to_base64(const uint8_t *s, size_t ns) {
return generic_to_base64(s, ns, mime_base64_table);
}
/** @brief Convert a binary string to base64
* @param s Bytes to convert
* @param ns Number of bytes to convert
* @param table Table of characters to use
* @return Encoded data
*
* This function does not attempt to split up lines.
*
* @p table should consist of 65 characters. The first 64 will be used to
* represents the 64 digits and the 65th will be used as padding at the end
* (i.e. the role of '=' in RFC2045 base64).
*/
char *generic_to_base64(const uint8_t *s, size_t ns, const char *table) {
struct dynstr d[1];
dynstr_init(d);
while(ns >= 3) {
/* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */
/* Output bytes with input bits: 000000 001111 111122 222222 */
dynstr_append(d, table[s[0] >> 2]);
dynstr_append(d, table[((s[0] & 3) << 4)
+ (s[1] >> 4)]);
dynstr_append(d, table[((s[1] & 15) << 2)
+ (s[2] >> 6)]);
dynstr_append(d, table[s[2] & 63]);
ns -= 3;
s += 3;
}
if(ns > 0) {
dynstr_append(d, table[s[0] >> 2]);
switch(ns) {
case 1:
dynstr_append(d, table[(s[0] & 3) << 4]);
dynstr_append(d, table[64]);
dynstr_append(d, table[64]);
break;
case 2:
dynstr_append(d, table[((s[0] & 3) << 4)
+ (s[1] >> 4)]);
dynstr_append(d, table[(s[1] & 15) << 2]);
dynstr_append(d, table[64]);
break;
}
}
dynstr_terminate(d);
return d->vec;
}
/*
Local Variables:
c-basic-offset:2
comment-column:40
fill-column:79
End:
*/