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/** @file nanohttp-base64.c Base64 data encoding/decoding */
/******************************************************************
* $Id: nanohttp-base64.c,v 1.5 2007/11/03 22:40:10 m0gg Exp $
*
* CSOAP Project: A http client/server library in C
* Copyright (C) 2003 Ferhat Ayaz
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library 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.
*
* Email: hero@persua.de
******************************************************************/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "nanohttp-base64.h"
static const char cb64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char cd64[] = "|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
/**
*
* encode 3 8-bit binary bytes as 4 '6-bit' characters
*
*/
static void _encodeblock(unsigned char in[3], unsigned char out[4], int len)
{
out[0] = cb64[in[0] >> 2];
out[1] = cb64[((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4)];
out[2] = (unsigned char)(len > 1 ? cb64[((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6)] : '=');
out[3] = (unsigned char)(len > 2 ? cb64[in[2] & 0x3f] : '=');
return;
}
void base64_encode_string(const unsigned char *instr, unsigned char *outstr)
{
unsigned char in[3], out[4];
int i, len;
while (*instr)
{
len = 0;
for (i = 0; i < 3; i++)
{
if ((in[i] = (unsigned char)*instr))
{
len++;
instr++;
}
}
if (len)
{
_encodeblock(in, out, len);
for (i = 0; i < 4; i++)
*outstr++ = out[i];
}
}
}
/**
*
* decode 4 '6-bit' characters into 3 8-bit binary bytes
*
*/
static void _decodeblock(unsigned char in[4], unsigned char out[3])
{
out[0] = (unsigned char)(in[0] << 2 | in[1] >> 4);
out[1] = (unsigned char)(in[1] << 4 | in[2] >> 2);
out[2] = (unsigned char)(((in[2] << 6) & 0xc0) | in[3]);
return;
}
/**
*
* decode a base64 encoded string (maybe broken...)
*
*/
void base64_decode_string(const unsigned char *instr, unsigned char *outstr)
{
unsigned char in[4], out[3], v;
int i, len;
while (*instr)
{
for (len = 0, i = 0; i < 4 && *instr; i++)
{
v = 0;
while (*instr && v == 0)
{
v = *instr++;
v = (unsigned char)((v < 43 || v > 122) ? 0 : cd64[v - 43]);
if (v)
v = (unsigned char)((v == '$') ? 0 : v - 61);
}
if (*instr)
{
len++;
if (v)
in[i] = (unsigned char)(v - 1);
}
else
{
in[i] = 0;
}
}
if (len)
{
_decodeblock(in, out);
for (i = 0; i < len - 1; i++)
*outstr++ = out[i];
}
}
}
#ifdef BASE64_TEST_CASE_FROM_RFC2617
#include <stdio.h>
#include <strings.h>
int main(int argc, char **argv) {
unsigned char *instr = "QWxhZGRpbjpvcGVuIHNlc2FtZQ==";
unsigned char *result = "Aladdin:open sesame";
unsigned char instr2[80];
unsigned char outstr[80];
bzero(outstr, 80);
base64_decode_string(instr, outstr);
printf("\"%s\" => \"%s\"\n", instr, outstr);
if (strcmp(outstr, result))
printf("base64_decode failed\n");
strcpy(instr2, outstr);
bzero(outstr, 80);
base64_encode_string(instr2, outstr);
printf("\"%s\" => \"%s\"\n", instr2, outstr);
if (strcmp(outstr, instr))
printf("base64_encode failed\n");
return 0;
}
#endif
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