clib package

packages/clib/maildrop/rfc2045/rfc2045_base64encode.c

@@ -0,0 +1,76 @@
+/*
+** Copyright 1998 - 1999 Double Precision, Inc.  See COPYING for
+** distribution information.
+*/
+
+/*
+** $Id$
+*/
+#include	"rfc2045.h"
+
+static unsigned char base64buf[57];
+		/* When encoded this becomes 76 characters */
+static int base64cnt;
+
+static void (*output_func)(const char *, size_t);
+
+void rfc2045_base64encode_start( void (*func)(const char *, size_t))
+{
+	output_func=func;
+	base64cnt=0;
+}
+
+void rfc2045_base64encode(const char *buf, size_t n)
+{
+	while (n)
+	{
+	size_t	i;
+
+		if (base64cnt == sizeof(base64buf))
+		{
+			rfc2045_base64encode_end();
+			base64cnt=0;
+		}
+		i=n;
+		if (i > sizeof(base64buf) - base64cnt)
+			i=sizeof(base64buf) - base64cnt;
+		memcpy(base64buf + base64cnt, buf, i);
+		base64cnt += i;
+		buf += i;
+		n -= i;
+	}
+}
+
+static const char base64tab[]=
+"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+void rfc2045_base64encode_end()
+{
+int	a=0,b=0,c=0;
+int	i, j;
+int	d, e, f, g;
+char	output_buf[ sizeof(base64buf) / 3 * 4+1];
+
+	if (base64cnt == 0)	return;
+
+	for (j=i=0; i<base64cnt; i += 3)
+	{
+		a=base64buf[i];
+		b= i+1 < base64cnt ? base64buf[i+1]:0;
+		c= i+2 < base64cnt ? base64buf[i+2]:0;
+
+		d=base64tab[ a >> 2 ];
+		e=base64tab[ ((a & 3 ) << 4) | (b >> 4)];
+		f=base64tab[ ((b & 15) << 2) | (c >> 6)];
+		g=base64tab[ c & 63 ];
+		if (i + 1 >= base64cnt)	f='=';
+		if (i + 2 >= base64cnt) g='=';
+		output_buf[j++]=d;
+		output_buf[j++]=e;
+		output_buf[j++]=f;
+		output_buf[j++]=g;
+	}
+
+	output_buf[j++]='\n';
+	(*output_func)(output_buf, j);
+}