Moved Base64-related functions to a separate file and added decode funtions.

1 files changed, 153 insertions, 0 deletions

diff --git a/lib/base64.c b/lib/base64.c
new file mode 100644
index 00000000..69069dae
--- /dev/null
+++ b/lib/base64.c
@@ -0,0 +1,153 @@
+/***************************************************************************\
+*                                                                           *
+*  BitlBee - An IRC to IM gateway                                           *
+*  Base64 handling functions. encode_real() is mostly based on the y64 en-  *
+*  coder from libyahoo2. Moving it to a new file because it's getting big.  *
+*                                                                           *
+*  Copyright 2006 Wilmer van der Gaast <wilmer@gaast.net>                   *
+*                                                                           *
+*  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 <glib.h>
+#include <string.h>
+#include "base64.h"
+
+static const char real_b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+
+char *tobase64(const char *text)
+{
+	return base64_encode(text, strlen(text));
+}
+
+char *base64_encode(const char *in, int len)
+{
+	char *out;
+	
+	out = g_malloc((len + 2)    /* the == padding */
+	                    / 3     /* every 3-byte block */
+	                    * 4     /* becomes a 4-byte one */
+	                    + 1);   /* and of course, ASCIIZ! */
+	
+	base64_encode_real((unsigned char*) in, len, (unsigned char*) out, real_b64);
+	
+	return out;
+}
+
+int base64_encode_real(const unsigned char *in, int inlen, unsigned char *out, const char *b64digits)
+{
+	int outlen = 0;
+	
+	for (; inlen >= 3; inlen -= 3)
+	{
+		out[outlen++] = b64digits[in[0] >> 2];
+		out[outlen++] = b64digits[((in[0]<<4) & 0x30) | (in[1]>>4)];
+		out[outlen++] = b64digits[((in[1]<<2) & 0x3c) | (in[2]>>6)];
+		out[outlen++] = b64digits[in[2] & 0x3f];
+		in += 3;
+	}
+	if (inlen > 0)
+	{
+		out[outlen++] = b64digits[in[0] >> 2];
+		if (inlen > 1)
+		{
+			out[outlen++] = b64digits[((in[0]<<4) & 0x30) | (in[1]>>4)];
+			out[outlen++] = b64digits[((in[1]<<2) & 0x3c)];
+		}
+		else
+		{
+			out[outlen++] = b64digits[((in[0]<<4) & 0x30)];
+			out[outlen++] = b64digits[64];
+		}
+		out[outlen++] = b64digits[64];
+	}
+	out[outlen] = 0;
+	
+	return outlen;
+}
+
+/* Just a simple wrapper, but usually not very convenient because of zero
+   termination. */
+char *frombase64(const char *in)
+{
+	unsigned char *out;
+	
+	base64_decode(in, &out);
+	
+	return (char*) out;
+}
+
+/* FIXME: Lookup table stuff is not threadsafe! (But for now BitlBee is not threaded.) */
+int base64_decode(const char *in, unsigned char **out)
+{
+	static char b64rev[256] = { 0 };
+	int len, i;
+	
+	/* Create a reverse-lookup for the Base64 sequence. */
+	if( b64rev[0] == 0 )
+	{
+		memset( b64rev, 0xff, 256 );
+		for( i = 0; i <= 64; i ++ )
+			b64rev[(int)real_b64[i]] = i;
+	}
+	
+	len = strlen( in );
+	*out = g_malloc( ( len + 6 ) / 4 * 3 );
+	len = base64_decode_real( (unsigned char*) in, *out, b64rev );
+	*out = g_realloc( *out, len + 1 );
+	out[0][len] = 0;	/* Zero termination can't hurt. */
+	
+	return len;
+}
+
+int base64_decode_real(const unsigned char *in, unsigned char *out, char *b64rev)
+{
+	int i, outlen = 0;
+	
+	for( i = 0; in[i]; i += 4 )
+	{
+		int sx;
+		
+		sx = b64rev[(int)in[i+0]];
+		if( sx >= 64 )
+			break;
+		out[outlen] = ( sx << 2 ) & 0xfc;
+		
+		sx = b64rev[(int)in[i+1]];
+		if( sx >= 64 )
+			break;
+		out[outlen] |= ( sx >> 4 ) & 0x03;
+		outlen ++;
+		out[outlen] = ( sx << 4 ) & 0xf0;
+		
+		sx = b64rev[(int)in[i+2]];
+		if( sx >= 64 )
+			break;
+		out[outlen] |= ( sx >> 2 ) & 0x0f;
+		outlen ++;
+		out[outlen] = ( sx << 6 ) & 0xc0;
+		
+		sx = b64rev[(int)in[i+3]];
+		if( sx >= 64 )
+			break;
+		out[outlen] |= sx;
+		outlen ++;
+	}
+	
+	/* If sx > 64 the base64 string was damaged. Should we ignore this? */
+	
+	return outlen;
+}