clib package

packages/clib/maildrop/rfc2045/rfc2045cdecode.c

@@ -0,0 +1,201 @@
+/*
+** Copyright 1998 - 1999 Double Precision, Inc.  See COPYING for
+** distribution information.
+*/
+
+#include	"rfc2045.h"
+#include	<ctype.h>
+#include	<string.h>
+
+/* $Id$ */
+
+extern void rfc2045_add_buf( char **, size_t *, size_t *,
+		const char *, size_t);
+extern void rfc2045_add_workbuf(struct rfc2045 *, const char *, size_t);
+extern void rfc2045_add_workbufch(struct rfc2045 *, int);
+
+static int decode_raw(struct rfc2045 *p, const char *s, size_t l)
+{
+	if (s && l)	return ((*p->udecode_func)(s,l,p->misc_decode_ptr));
+	return (0);
+}
+
+static const char xdigit[]="0123456789ABCDEF";
+
+static int do_decode_qp(struct rfc2045 *p)
+{
+char	*a, *b, *c, *end;
+int	d;
+
+	end=p->workbuf + p->workbuflen;
+	for (a=b=p->workbuf; a < end; )
+	{
+		if (*a != '=')
+		{
+			*b++ = *a++;
+			continue;
+		}
+		++a;
+		if (!*a || a >= end || isspace((int)(unsigned char)*a))
+			break;
+
+		if ((c=strchr(xdigit, *a)) == 0) continue;
+		d= (c-xdigit)*16;
+		++a;
+		if (!*a || a >= end)
+			break;
+		if ((c=strchr(xdigit, *a)) == 0) continue;
+		d += c-xdigit;
+		++a;
+		*b++=d;
+	}
+	p->workbuflen= b-p->workbuf;
+	d=(*p->udecode_func)(p->workbuf, p->workbuflen, p->misc_decode_ptr);
+	p->workbuflen=0;
+	return (d);
+}
+
+static unsigned char decode64tab[256];
+static int decode64tab_init=0;
+
+/* When we have enough base64-encoded data in the buffer, decode it. */
+
+static int do_decode_base64(struct rfc2045 *p)
+{
+size_t	i, j;
+char	a,b,c;
+size_t	k;
+int	rc;
+
+	if (!decode64tab_init)
+	{
+		for (i=0; i<256; i++)	decode64tab[i]=100;
+		for (i=0; i<64; i++)
+			decode64tab[ (int)
+				("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[i])				]=i;
+		decode64tab[ (int)'=' ] = 99;
+	}
+
+	/* Remove everything except base64encoded data */
+
+	for (i=j=0; i<p->workbuflen; i++)
+		if (decode64tab[(int)(unsigned char)p->workbuf[i]] < 100)
+			p->workbuf[j++]=p->workbuf[i];
+
+
+	p->workbuflen=j;
+
+	/* Decode the data, in 4-byte pieces */
+
+	i=j / 4;
+	i=i*4;
+	k=0;
+	for (j=0; j<i; j += 4)
+	{
+	int	w=decode64tab[(int)(unsigned char)p->workbuf[j]];
+	int	x=decode64tab[(int)(unsigned char)p->workbuf[j+1]];
+	int	y=decode64tab[(int)(unsigned char)p->workbuf[j+2]];
+	int	z=decode64tab[(int)(unsigned char)p->workbuf[j+3]];
+
+		a= (w << 2) | (x >> 4);
+		b= (x << 4) | (y >> 2);
+		c= (y << 6) | z;
+		p->workbuf[k++]=a;
+		if ( p->workbuf[j+2] != '=')
+			p->workbuf[k++]=b;
+		if ( p->workbuf[j+3] != '=')
+			p->workbuf[k++]=c;
+	}
+	rc=(*p->udecode_func)(p->workbuf, k, p->misc_decode_ptr);
+
+	/* Anything left?  Move it to the start of the buffer */
+
+	k=0;
+	while (j < p->workbuflen)
+		p->workbuf[k++]=p->workbuf[j++];
+	p->workbuflen=k;
+	return (0);
+}
+
+static int decode_qp(struct rfc2045 *p, const char *s, size_t l)
+{
+size_t	start,i;
+int	rc;
+
+	if (!s)
+		return (do_decode_qp(p));
+
+	for (start=0; start<l; )
+	{
+		for (i=start; i<l; i++)
+		{
+			if (s[i] != '\n') continue;
+			rfc2045_add_workbuf(p, s+start, i-start);
+			rfc2045_add_workbufch(p, '\n');
+			if ((rc=do_decode_qp(p)) != 0)	return (rc);
+			start= ++i;
+			break;
+		}
+		rfc2045_add_workbuf(p, s+start, i-start);
+		if (p->workbuflen > 1024)
+		{
+		char	buf[10];
+		int	i;
+
+			for (i=p->workbuflen - 5; i<p->workbuflen; i++)
+				if (p->workbuf[i] == '=')	break;
+			if (i < p->workbuflen)
+			{
+			int j=p->workbuflen-i;
+
+				memcpy(buf, p->workbuf+i, j);
+				buf[j]=0;
+				p->workbuflen=i;
+			}
+			else	buf[0]=0;
+			if ((rc=do_decode_qp(p)) != 0)	return (rc);
+			rfc2045_add_workbuf(p, buf, strlen(buf));
+		}
+		start=i;
+	}
+	return (0);
+}
+
+static int decode_base64(struct rfc2045 *p, const char *s, size_t l)
+{
+	if (!s)
+		return (do_decode_base64(p));
+
+	rfc2045_add_workbuf(p, s, l);
+	if (p->workbuflen > 256)
+		return (do_decode_base64(p));
+	return (0);
+}
+
+void rfc2045_cdecode_start(struct rfc2045 *p,
+	int (*u)(const char *, size_t, void *), void *miscptr)
+{
+	p->misc_decode_ptr=miscptr;
+	p->udecode_func=u;
+	p->decode_func= &decode_raw;
+	p->workbuflen=0;
+	if (p->content_transfer_encoding)
+	{
+		if (strcmp(p->content_transfer_encoding,
+				"quoted-printable") == 0)
+			p->decode_func= &decode_qp;
+		else if (strcmp(p->content_transfer_encoding, "base64") == 0)
+			p->decode_func= &decode_base64;
+	}
+}
+
+int rfc2045_cdecode_end(struct rfc2045 *p)
+{
+	return ((*p->decode_func)(p, NULL, 0));
+}
+
+int rfc2045_cdecode(struct rfc2045 *p, const char *s, size_t l)
+{
+	if (s && l)	return ((*p->decode_func)(p, s, l));
+	return (0);
+}