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/* base64.c
Copyright (c) 2010 Matthias Kramm <kramm@quiss.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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "base64.h"
static const char base64[65]=
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
void write_base64(FILE*fi, const char* s)
{
const unsigned char*b = (const unsigned char*)s;
const unsigned char*end = b + strlen(b);
const unsigned char*end_minus_3 = end - 3;
while(b <= end_minus_3) {
char data[4];
data[0] = base64[(b[0]>>2)&63 ];
data[1] = base64[(b[0]<<4|b[1]>>4)&63];
data[2] = base64[(b[1]<<2|b[2]>>6)&63];
data[3] = base64[(b[2])&63 ];
fwrite(data, 4, 1, fi);
b += 3;
}
unsigned char data[4];
switch(end - b) {
case 0:
return; //done
case 1:
data[0] = base64[(b[0]>>2)&63];
data[1] = base64[(b[0]<<4)&63];
data[2] = '=';
data[3] = '=';
break;
case 2:
data[0] = base64[(b[0]>>2)&63];
data[1] = base64[(b[0]<<4|b[1]>>4)&63];
data[2] = base64[(b[1]<<2)&63];
data[3] = '=';
break;
default:
fprintf(stderr, "internal error in base64 implementation (%d)\n", end-b);
break;
}
fwrite(data, 4, 1, fi);
}
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