New class for zipping/unzipping gzip streams.

2004-05-10  Jeffrey Stedfast  <fejj@novell.com>

	* camel-mime-filter-gzip.[c,h]: New class for zipping/unzipping
	gzip streams.

	* camel-mime-filter-yenc.[c,h]: New class for encoding/decoding
	the crack known as YEncode.

svn path=/trunk/; revision=25847

7 files changed, 1236 insertions, 0 deletions

diff --git a/camel/ChangeLog b/camel/ChangeLog
index bcd209d453..7f2b12670b 100644
--- a/camel/ChangeLog
+++ b/camel/ChangeLog
@@ -1,3 +1,11 @@
+2004-05-10  Jeffrey Stedfast  <fejj@novell.com>
+
+	* camel-mime-filter-gzip.[c,h]: New class for zipping/unzipping
+	gzip streams.
+
+	* camel-mime-filter-yenc.[c,h]: New class for encoding/decoding
+	the crack known as YEncode.
+
 2004-05-07  Not Zed  <NotZed@Ximian.com>
 
 	* camel-folder-thread.c (thread_summary): properly set the parent
diff --git a/camel/Makefile.am b/camel/Makefile.am
index 4432d0e4a2..2811d95d56 100644
--- a/camel/Makefile.am
+++ b/camel/Makefile.am
@@ -58,12 +58,14 @@ libcamel_la_SOURCES = 				\
 	camel-mime-filter-crlf.c		\
 	camel-mime-filter-enriched.c		\
 	camel-mime-filter-from.c		\
+	camel-mime-filter-gzip.c		\
 	camel-mime-filter-html.c		\
 	camel-mime-filter-tohtml.c		\
 	camel-mime-filter-index.c		\
 	camel-mime-filter-linewrap.c		\
 	camel-mime-filter-save.c		\
 	camel-mime-filter-windows.c		\
+	camel-mime-filter-yenc.c		\
 	camel-mime-filter.c			\
 	camel-mime-message.c			\
 	camel-mime-parser.c			\
@@ -161,12 +163,14 @@ libcamelinclude_HEADERS =			\
 	camel-mime-filter-crlf.h		\
 	camel-mime-filter-enriched.h		\
 	camel-mime-filter-from.h		\
+	camel-mime-filter-gzip.h		\
 	camel-mime-filter-html.h		\
 	camel-mime-filter-tohtml.h		\
 	camel-mime-filter-index.h		\
 	camel-mime-filter-linewrap.h		\
 	camel-mime-filter-save.h		\
 	camel-mime-filter-windows.h		\
+	camel-mime-filter-yenc.h		\
 	camel-mime-filter.h			\
 	camel-mime-message.h			\
 	camel-mime-parser.h			\
diff --git a/camel/camel-mime-filter-gzip.c b/camel/camel-mime-filter-gzip.c
new file mode 100644
index 0000000000..f3c640240b
--- /dev/null
+++ b/camel/camel-mime-filter-gzip.c
@@ -0,0 +1,461 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ *  Authors: Jeffrey Stedfast <fejj@ximian.com>
+ *
+ *  Copyright 2001-2004 Ximian, Inc. (www.ximian.com)
+ *
+ *  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 Street #330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+
+#include <zlib.h>
+
+#include "camel-mime-filter-gzip.h"
+
+
+/* rfc1952 */
+
+enum {
+	GZIP_FLAG_FTEXT     = (1 << 0),
+	GZIP_FLAG_FHCRC     = (1 << 1),
+	GZIP_FLAG_FEXTRA    = (1 << 2),
+	GZIP_FLAG_FNAME     = (1 << 3),
+	GZIP_FLAG_FCOMMENT  = (1 << 4),
+	GZIP_FLAG_RESERVED0 = (1 << 5),
+	GZIP_FLAG_RESERVED1 = (1 << 6),
+	GZIP_FLAG_RESERVED2 = (1 << 7),
+};
+
+#define GZIP_FLAG_RESERVED (GZIP_FLAG_RESERVED0 | GZIP_FLAG_RESERVED1 | GZIP_FLAG_RESERVED2)
+
+typedef union {
+	unsigned char buf[10];
+	struct {
+		guint8 id1;
+		guint8 id2;
+		guint8 cm;
+		guint8 flg;
+		guint32 mtime;
+		guint8 xfl;
+		guint8 os;
+	} v;
+} gzip_hdr_t;
+
+typedef union {
+	struct {
+		guint16 xlen;
+		guint16 xlen_nread;
+		guint16 crc16;
+		
+		guint8 got_hdr:1;
+		guint8 is_valid:1;
+		guint8 got_xlen:1;
+		guint8 got_fname:1;
+		guint8 got_fcomment:1;
+		guint8 got_crc16:1;
+	} unzip;
+	struct {
+		guint32 wrote_hdr:1;
+	} zip;
+} gzip_state_t;
+
+struct _CamelMimeFilterGZipPrivate {
+	z_stream *stream;
+	
+	gzip_state_t state;
+	gzip_hdr_t hdr;
+	
+	guint32 crc32;
+	guint32 isize;
+};
+
+static void camel_mime_filter_gzip_class_init (CamelMimeFilterGZipClass *klass);
+static void camel_mime_filter_gzip_init (CamelMimeFilterGZip *filter, CamelMimeFilterGZipClass *klass);
+static void camel_mime_filter_gzip_finalize (CamelObject *object);
+
+static void filter_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+			   char **out, size_t *outlen, size_t *outprespace);
+static void filter_complete (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+			     char **out, size_t *outlen, size_t *outprespace);
+static void filter_reset (CamelMimeFilter *filter);
+
+
+static CamelMimeFilterClass *parent_class = NULL;
+
+
+CamelType
+camel_mime_filter_gzip_get_type (void)
+{
+	static CamelType type = CAMEL_INVALID_TYPE;
+	
+	if (type == CAMEL_INVALID_TYPE) {
+		type = camel_type_register (camel_mime_filter_get_type (),
+					    "CamelMimeFilterGZip",
+					    sizeof (CamelMimeFilterGZip),
+					    sizeof (CamelMimeFilterGZipClass),
+					    (CamelObjectClassInitFunc) camel_mime_filter_gzip_class_init,
+					    NULL,
+					    (CamelObjectInitFunc) camel_mime_filter_gzip_init,
+					    (CamelObjectFinalizeFunc) camel_mime_filter_gzip_finalize);
+	}
+	
+	return type;
+}
+
+
+static void
+camel_mime_filter_gzip_class_init (CamelMimeFilterGZipClass *klass)
+{
+	CamelMimeFilterClass *filter_class = (CamelMimeFilterClass *) klass;
+	
+	parent_class = CAMEL_MIME_FILTER_CLASS (camel_type_get_global_classfuncs (camel_mime_filter_get_type ()));
+	
+	filter_class->reset = filter_reset;
+	filter_class->filter = filter_filter;
+	filter_class->complete = filter_complete;
+}
+
+static void
+camel_mime_filter_gzip_init (CamelMimeFilterGZip *filter, CamelMimeFilterGZipClass *klass)
+{
+	filter->priv = g_new0 (struct _CamelMimeFilterGZipPrivate, 1);
+	filter->priv->stream = g_new0 (z_stream, 1);
+	filter->priv->crc32 = crc32 (0, Z_NULL, 0);
+}
+
+static void
+camel_mime_filter_gzip_finalize (CamelObject *object)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) object;
+	struct _CamelMimeFilterGZipPrivate *priv = gzip->priv;
+	
+	g_free (priv->stream);
+	g_free (priv);
+}
+
+
+static void
+gzip_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+	     char **out, size_t *outlen, size_t *outprespace, int flush)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) filter;
+	struct _CamelMimeFilterGZipPrivate *priv = gzip->priv;
+	int retval;
+	
+	if (!priv->state.zip.wrote_hdr) {
+		priv->hdr.v.id1 = 31;
+		priv->hdr.v.id2 = 139;
+		priv->hdr.v.cm = Z_DEFLATED;
+		priv->hdr.v.mtime = 0;
+		priv->hdr.v.flg = 0;
+		if (gzip->level == Z_BEST_COMPRESSION)
+			priv->hdr.v.xfl = 2;
+		else if (gzip->level == Z_BEST_SPEED)
+			priv->hdr.v.xfl = 4;
+		else
+			priv->hdr.v.xfl = 0;
+		priv->hdr.v.os = 255;
+		
+		camel_mime_filter_set_size (filter, (len * 2) + 22, FALSE);
+		
+		memcpy (filter->outbuf, priv->hdr.buf, 10);
+		
+		priv->stream->next_out = filter->outbuf + 10;
+		priv->stream->avail_out = filter->outsize - 10;
+		
+		priv->state.zip.wrote_hdr = TRUE;
+	} else {
+		camel_mime_filter_set_size (filter, (len * 2) + 12, FALSE);
+		
+		priv->stream->next_out = filter->outbuf;
+		priv->stream->avail_out = filter->outsize;
+	}
+	
+	priv->stream->next_in = in;
+	priv->stream->avail_in = len;
+	
+	do {
+		/* FIXME: handle error cases? */
+		if ((retval = deflate (priv->stream, flush)) != Z_OK)
+			fprintf (stderr, "gzip: %d: %s\n", retval, priv->stream->msg);
+		
+		if (flush == Z_FULL_FLUSH) {
+			size_t outlen;
+			
+			outlen = filter->outsize - priv->stream->avail_out;
+			camel_mime_filter_set_size (filter, outlen + (priv->stream->avail_in * 2) + 12, TRUE);
+			priv->stream->avail_out = filter->outsize - outlen;
+			priv->stream->next_out = filter->outbuf + outlen;
+			
+			if (priv->stream->avail_in == 0) {
+				guint32 val;
+				
+				val = GUINT32_TO_LE (priv->crc32);
+				memcpy (priv->stream->next_out, &val, 4);
+				priv->stream->avail_out -= 4;
+				priv->stream->next_out += 4;
+				
+				val = GUINT32_TO_LE (priv->isize);
+				memcpy (priv->stream->next_out, &val, 4);
+				priv->stream->avail_out -= 4;
+				priv->stream->next_out += 4;
+				
+				break;
+			}
+		} else {
+			if (priv->stream->avail_in > 0)
+				camel_mime_filter_backup (filter, priv->stream->next_in, priv->stream->avail_in);
+			
+			break;
+		}
+	} while (1);
+	
+	priv->crc32 = crc32 (priv->crc32, in, len - priv->stream->avail_in);
+	priv->isize += len - priv->stream->avail_in;
+	
+	*out = filter->outbuf;
+	*outlen = filter->outsize - priv->stream->avail_out;
+	*outprespace = filter->outpre;
+}
+
+static void
+gunzip_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+	       char **out, size_t *outlen, size_t *outprespace, int flush)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) filter;
+	struct _CamelMimeFilterGZipPrivate *priv = gzip->priv;
+	guint16 need, val;
+	int retval;
+	
+	if (!priv->state.unzip.got_hdr) {
+		if (len < 10) {
+			camel_mime_filter_backup (filter, in, len);
+			return;
+		}
+		
+		memcpy (priv->hdr.buf, in, 10);
+		priv->state.unzip.got_hdr = TRUE;
+		len -= 10;
+		in += 10;
+		
+		priv->state.unzip.is_valid = (priv->hdr.v.id1 == 31 &&
+					      priv->hdr.v.id2 == 139 &&
+					      priv->hdr.v.cm == Z_DEFLATED);
+	}
+	
+	if (!priv->state.unzip.is_valid)
+		return;
+	
+	if (priv->hdr.v.flg & GZIP_FLAG_FEXTRA) {
+		if (!priv->state.unzip.got_xlen) {
+			if (len < 2) {
+				camel_mime_filter_backup (filter, in, len);
+				return;
+			}
+			
+			memcpy (&val, in, 2);
+			priv->state.unzip.xlen = GUINT16_FROM_LE (val);
+			priv->state.unzip.got_xlen = TRUE;
+			len -= 2;
+			in += 2;
+		}
+		
+		if (priv->state.unzip.xlen_nread < priv->state.unzip.xlen) {
+			need = priv->state.unzip.xlen - priv->state.unzip.xlen_nread;
+			
+			if (need < len) {
+				priv->state.unzip.xlen_nread += need;
+				len -= need;
+				in += need;
+			} else {
+				priv->state.unzip.xlen_nread += len;
+				return;
+			}
+		}
+	}
+	
+	if ((priv->hdr.v.flg & GZIP_FLAG_FNAME) && !priv->state.unzip.got_fname) {
+		while (*in && len > 0) {
+			len--;
+			in++;
+		}
+		
+		if (*in == '\0' && len > 0) {
+			priv->state.unzip.got_fname = TRUE;
+			len--;
+			in++;
+		} else {
+			return;
+		}
+	}
+	
+	if ((priv->hdr.v.flg & GZIP_FLAG_FCOMMENT) && !priv->state.unzip.got_fcomment) {
+		while (*in && len > 0) {
+			len--;
+			in++;
+		}
+		
+		if (*in == '\0' && len > 0) {
+			priv->state.unzip.got_fcomment = TRUE;
+			len--;
+			in++;
+		} else {
+			return;
+		}
+	}
+	
+	if ((priv->hdr.v.flg & GZIP_FLAG_FHCRC) && !priv->state.unzip.got_crc16) {
+		if (len < 2) {
+			camel_mime_filter_backup (filter, in, len);
+			return;
+		}
+		
+		memcpy (&val, in, 2);
+		priv->state.unzip.crc16 = GUINT16_FROM_LE (val);
+		len -= 2;
+		in += 2;
+	}
+	
+	if (len == 0)
+		return;
+	
+	camel_mime_filter_set_size (filter, (len * 2) + 12, FALSE);
+	
+	priv->stream->next_in = in;
+	priv->stream->avail_in = len - 8;
+	
+	priv->stream->next_out = filter->outbuf;
+	priv->stream->avail_out = filter->outsize;
+	
+	do {
+		/* FIXME: handle error cases? */
+		if ((retval = inflate (priv->stream, flush)) != Z_OK)
+			fprintf (stderr, "gunzip: %d: %s\n", retval, priv->stream->msg);
+		
+		if (flush == Z_FULL_FLUSH) {
+			size_t outlen;
+			
+			if (priv->stream->avail_in == 0) {
+				/* FIXME: extract & compare calculated crc32 and isize values? */
+				break;
+			}
+			
+			outlen = filter->outsize - priv->stream->avail_out;
+			camel_mime_filter_set_size (filter, outlen + (priv->stream->avail_in * 2) + 12, TRUE);
+			priv->stream->avail_out = filter->outsize - outlen;
+			priv->stream->next_out = filter->outbuf + outlen;
+		} else {
+			priv->stream->avail_in += 8;
+			
+			if (priv->stream->avail_in > 0)
+				camel_mime_filter_backup (filter, priv->stream->next_in, priv->stream->avail_in);
+			
+			break;
+		}
+	} while (1);
+	
+	/* FIXME: if we keep this, we could check that the gzip'd
+	 * stream is sane, but how would we tell our consumer if it
+	 * was/wasn't? */
+	/*priv->crc32 = crc32 (priv->crc32, in, len - priv->stream->avail_in - 8);
+	  priv->isize += len - priv->stream->avail_in - 8;*/
+	
+	*out = filter->outbuf;
+	*outlen = filter->outsize - priv->stream->avail_out;
+	*outprespace = filter->outpre;
+}
+
+static void
+filter_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+	       char **out, size_t *outlen, size_t *outprespace)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) filter;
+	
+	if (gzip->mode == CAMEL_MIME_FILTER_GZIP_MODE_ZIP)
+		gzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_SYNC_FLUSH);
+	else
+		gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_SYNC_FLUSH);
+}
+
+static void
+filter_complete (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+		 char **out, size_t *outlen, size_t *outprespace)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) filter;
+	
+	if (gzip->mode == CAMEL_MIME_FILTER_GZIP_MODE_ZIP)
+		gzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_FULL_FLUSH);
+	else
+		gunzip_filter (filter, in, len, prespace, out, outlen, outprespace, Z_FULL_FLUSH);
+}
+
+/* should this 'flush' outstanding state/data bytes? */
+static void
+filter_reset (CamelMimeFilter *filter)
+{
+	CamelMimeFilterGZip *gzip = (CamelMimeFilterGZip *) filter;
+	struct _CamelMimeFilterGZipPrivate *priv = gzip->priv;
+	
+	memset (&priv->state, 0, sizeof (priv->state));
+	
+	if (gzip->mode == CAMEL_MIME_FILTER_GZIP_MODE_ZIP)
+		deflateReset (priv->stream);
+	else
+		inflateReset (priv->stream);
+	
+	priv->crc32 = crc32 (0, Z_NULL, 0);
+	priv->isize = 0;
+}
+
+
+/**
+ * camel_mime_filter_gzip_new:
+ * @mode: zip or unzip
+ * @level: compression level
+ *
+ * Creates a new gzip (or gunzip) filter.
+ *
+ * Returns a new gzip (or gunzip) filter.
+ **/
+CamelMimeFilter *
+camel_mime_filter_gzip_new (CamelMimeFilterGZipMode mode, int level)
+{
+	CamelMimeFilterGZip *new;
+	int retval;
+	
+	new = (CamelMimeFilterGZip *) camel_object_new (CAMEL_TYPE_MIME_FILTER_GZIP);
+	new->mode = mode;
+	new->level = level;
+	
+	if (mode == CAMEL_MIME_FILTER_GZIP_MODE_ZIP)
+		retval = deflateInit2 (new->priv->stream, level, Z_DEFLATED, -MAX_WBITS, MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+	else
+		retval = inflateInit2 (new->priv->stream, -MAX_WBITS);
+	
+	if (retval != Z_OK) {
+		camel_object_unref (new);
+		return NULL;
+	}
+	
+	return (CamelMimeFilter *) new;
+}
diff --git a/camel/camel-mime-filter-gzip.h b/camel/camel-mime-filter-gzip.h
new file mode 100644
index 0000000000..a8607b9174
--- /dev/null
+++ b/camel/camel-mime-filter-gzip.h
@@ -0,0 +1,72 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ *  Authors: Jeffrey Stedfast <fejj@ximian.com>
+ *
+ *  Copyright 2001-2004 Ximian, Inc. (www.ximian.com)
+ *
+ *  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 Street #330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+
+#ifndef __CAMEL_MIME_FILTER_GZIP_H__
+#define __CAMEL_MIME_FILTER_GZIP_H__
+
+#include <camel/camel-mime-filter.h>
+
+#ifdef __cplusplus
+extern "C" {
+#pragma }
+#endif /* __cplusplus */
+
+#define CAMEL_TYPE_MIME_FILTER_GZIP            (camel_mime_filter_gzip_get_type ())
+#define CAMEL_MIME_FILTER_GZIP(obj)            (CAMEL_CHECK_CAST ((obj), CAMEL_TYPE_MIME_FILTER_GZIP, CamelMimeFilterGZip))
+#define CAMEL_MIME_FILTER_GZIP_CLASS(klass)    (CAMEL_CHECK_CLASS_CAST ((klass), CAMEL_TYPE_MIME_FILTER_GZIP, CamelMimeFilterGZipClass))
+#define CAMEL_IS_MIME_FILTER_GZIP(obj)         (CAMEL_CHECK_TYPE ((obj), CAMEL_TYPE_MIME_FILTER_GZIP))
+#define CAMEL_IS_MIME_FILTER_GZIP_CLASS(klass) (CAMEL_CHECK_CLASS_TYPE ((klass), CAMEL_TYPE_MIME_FILTER_GZIP))
+#define CAMEL_MIME_FILTER_GZIP_GET_CLASS(obj)  (CAMEL_CHECK_GET_CLASS ((obj), CAMEL_TYPE_MIME_FILTER_GZIP, CamelMimeFilterGZipClass))
+
+typedef struct _CamelMimeFilterGZip CamelMimeFilterGZip;
+typedef struct _CamelMimeFilterGZipClass CamelMimeFilterGZipClass;
+
+typedef enum {
+	CAMEL_MIME_FILTER_GZIP_MODE_ZIP,
+	CAMEL_MIME_FILTER_GZIP_MODE_UNZIP
+} CamelMimeFilterGZipMode;
+
+struct _CamelMimeFilterGZip {
+	CamelMimeFilter parent_object;
+	
+	struct _CamelMimeFilterGZipPrivate *priv;
+	
+	CamelMimeFilterGZipMode mode;
+	int level;
+};
+
+struct _CamelMimeFilterGZipClass {
+	CamelMimeFilterClass parent_class;
+	
+};
+
+
+CamelType camel_mime_filter_gzip_get_type (void);
+
+CamelMimeFilter *camel_mime_filter_gzip_new (CamelMimeFilterGZipMode mode, int level);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __CAMEL_MIME_FILTER_GZIP_H__ */
diff --git a/camel/camel-mime-filter-yenc.c b/camel/camel-mime-filter-yenc.c
new file mode 100644
index 0000000000..b53486ca98
--- /dev/null
+++ b/camel/camel-mime-filter-yenc.c
@@ -0,0 +1,577 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ *  Authors: Jeffrey Stedfast <fejj@ximian.com>
+ *
+ *  Copyright 2002-2004 Ximian, Inc. (www.ximian.com)
+ *
+ *  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 Street #330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+
+#include "camel-mime-filter-yenc.h"
+
+static void camel_mime_filter_yenc_class_init (CamelMimeFilterYencClass *klass);
+static void camel_mime_filter_yenc_init (CamelMimeFilterYenc *filter, CamelMimeFilterYencClass *klass);
+
+static void filter_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+			   char **out, size_t *outlen, size_t *outprespace);
+static void filter_complete (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+			     char **out, size_t *outlen, size_t *outprespace);
+static void filter_reset (CamelMimeFilter *filter);
+
+
+static CamelMimeFilterClass *parent_class = NULL;
+
+
+CamelType
+camel_mime_filter_yenc_get_type (void)
+{
+	static CamelType type = CAMEL_INVALID_TYPE;
+	
+	if (type == CAMEL_INVALID_TYPE) {
+		type = camel_type_register (camel_mime_filter_get_type (),
+					    "CamelMimeFilterYenc",
+					    sizeof (CamelMimeFilterYenc),
+					    sizeof (CamelMimeFilterYencClass),
+					    (CamelObjectClassInitFunc) camel_mime_filter_yenc_class_init,
+					    NULL,
+					    (CamelObjectInitFunc) camel_mime_filter_yenc_init,
+					    NULL);
+	}
+	
+	return type;
+}
+
+
+static void
+camel_mime_filter_yenc_class_init (CamelMimeFilterYencClass *klass)
+{
+	CamelMimeFilterClass *filter_class = (CamelMimeFilterClass *) klass;
+	
+	parent_class = CAMEL_MIME_FILTER_CLASS (camel_type_get_global_classfuncs (camel_mime_filter_get_type ()));
+	
+	filter_class->reset = filter_reset;
+	filter_class->filter = filter_filter;
+	filter_class->complete = filter_complete;
+}
+
+static void
+camel_mime_filter_yenc_init (CamelMimeFilterYenc *filter, CamelMimeFilterYencClass *klass)
+{
+	filter->part = 0;
+	filter->pcrc = CAMEL_MIME_YENCODE_CRC_INIT;
+	filter->crc = CAMEL_MIME_YENCODE_CRC_INIT;
+}
+
+
+/* here we do all of the basic yEnc filtering */
+static void
+filter_filter (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+	       char **out, size_t *outlen, size_t *outprespace)
+{
+	CamelMimeFilterYenc *yenc = (CamelMimeFilterYenc *) filter;
+	size_t newlen = 0;
+	
+	switch (yenc->direction) {
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_ENCODE:
+		/* won't go to more than 2 * (x + 2) + 62 */
+		camel_mime_filter_set_size (filter, (len + 2) * 2 + 62, FALSE);
+		newlen = camel_yencode_step (in, len, filter->outbuf, &yenc->state,
+					     &yenc->pcrc, &yenc->crc);
+		g_assert (newlen <= (len + 2) * 2 + 62);
+		break;
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_DECODE:
+		if (!(yenc->state & CAMEL_MIME_YDECODE_STATE_DECODE)) {
+			register char *inptr, *inend;
+			size_t left;
+			
+			inptr = in;
+			inend = inptr + len;
+			
+			/* we cannot start decoding until we have found an =ybegin line */
+			if (!(yenc->state & CAMEL_MIME_YDECODE_STATE_BEGIN)) {
+				while (inptr < inend) {
+					left = inend - inptr;
+					if (left < 8) {
+						if (!strncmp (inptr, "=ybegin ", left))
+							camel_mime_filter_backup (filter, inptr, left);
+						break;
+					} else if (!strncmp (inptr, "=ybegin ", 8)) {
+						for (in = inptr; inptr < inend && *inptr != '\n'; inptr++);
+						if (inptr < inend) {
+							inptr++;
+							yenc->state |= CAMEL_MIME_YDECODE_STATE_BEGIN;
+							/* we can start ydecoding if the next line isn't
+							   a ypart... */
+							in = inptr;
+							len = inend - in;
+						} else {
+							/* we don't have enough... */
+							camel_mime_filter_backup (filter, in, left);
+						}
+						break;
+					}
+					
+					/* go to the next line */
+					while (inptr < inend && *inptr != '\n')
+						inptr++;
+					
+					if (inptr < inend)
+						inptr++;
+				}
+			}
+			
+			left = inend - inptr;
+			if ((yenc->state & CAMEL_MIME_YDECODE_STATE_BEGIN) && left > 0) {
+				/* we have found an '=ybegin' line but we may yet have an "=ypart" line to
+				   yield before decoding the content */
+				if (left < 7 && !strncmp (inptr, "=ypart ", left)) {
+					camel_mime_filter_backup (filter, inptr, left);
+				} else if (!strncmp (inptr, "=ypart ", 7)) {
+					for (in = inptr; inptr < inend && *inptr != '\n'; inptr++);
+					if (inptr < inend) {
+						inptr++;
+						yenc->state |= CAMEL_MIME_YDECODE_STATE_PART | CAMEL_MIME_YDECODE_STATE_DECODE;
+						in = inptr;
+						len = inend - in;
+					} else {
+						camel_mime_filter_backup (filter, in, left);
+					}
+				} else {
+					/* guess it doesn't have a =ypart line */
+					yenc->state |= CAMEL_MIME_YDECODE_STATE_DECODE;
+				}
+			}
+		}
+		
+		if ((yenc->state & CAMEL_MIME_YDECODE_STATE_DECODE) && !(yenc->state & CAMEL_MIME_YDECODE_STATE_END)) {
+			/* all yEnc headers have been found so we can now start decoding */
+			camel_mime_filter_set_size (filter, len + 3, FALSE);
+			newlen = camel_ydecode_step (in, len, filter->outbuf, &yenc->state, &yenc->pcrc, &yenc->crc);
+			g_assert (newlen <= len + 3);
+		} else {
+			newlen = 0;
+		}
+		break;
+	}
+	
+	*out = filter->outbuf;
+	*outlen = newlen;
+	*outprespace = filter->outpre;
+}
+
+static void
+filter_complete (CamelMimeFilter *filter, char *in, size_t len, size_t prespace,
+		 char **out, size_t *outlen, size_t *outprespace)
+{
+	CamelMimeFilterYenc *yenc = (CamelMimeFilterYenc *) filter;
+	size_t newlen = 0;
+	
+	switch (yenc->direction) {
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_ENCODE:
+		/* won't go to more than 2 * (x + 2) + 62 */
+		camel_mime_filter_set_size (filter, (len + 2) * 2 + 62, FALSE);
+		newlen = camel_yencode_close (in, len, filter->outbuf, &yenc->state,
+					       &yenc->pcrc, &yenc->crc);
+		g_assert (newlen <= (len + 2) * 2 + 62);
+		break;
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_DECODE:
+		if ((yenc->state & CAMEL_MIME_YDECODE_STATE_DECODE) && !(yenc->state & CAMEL_MIME_YDECODE_STATE_END)) {
+			/* all yEnc headers have been found so we can now start decoding */
+			camel_mime_filter_set_size (filter, len + 3, FALSE);
+			newlen = camel_ydecode_step (in, len, filter->outbuf, &yenc->state,
+						      &yenc->pcrc, &yenc->crc);
+			g_assert (newlen <= len + 3);
+		} else {
+			newlen = 0;
+		}
+		break;
+	}
+	
+	*out = filter->outbuf;
+	*outlen = newlen;
+	*outprespace = filter->outpre;
+}
+
+/* should this 'flush' outstanding state/data bytes? */
+static void
+filter_reset (CamelMimeFilter *filter)
+{
+	CamelMimeFilterYenc *yenc = (CamelMimeFilterYenc *) filter;
+	
+	switch (yenc->direction) {
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_ENCODE:
+		yenc->state = CAMEL_MIME_YENCODE_STATE_INIT;
+		break;
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_DECODE:
+		yenc->state = CAMEL_MIME_YDECODE_STATE_INIT;
+		break;
+	}
+	yenc->pcrc = CAMEL_MIME_YENCODE_CRC_INIT;
+	yenc->crc = CAMEL_MIME_YENCODE_CRC_INIT;
+}
+
+
+/**
+ * camel_mime_filter_yenc_new:
+ * @direction: encode direction
+ *
+ * Creates a new yEnc filter.
+ *
+ * Returns a new yEnc filter.
+ **/
+CamelMimeFilter *
+camel_mime_filter_yenc_new (CamelMimeFilterYencDirection direction)
+{
+	CamelMimeFilterYenc *new;
+	
+	new = (CamelMimeFilterYenc *) camel_object_new (CAMEL_TYPE_MIME_FILTER_YENC);
+	new->direction = direction;
+	
+	switch (direction) {
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_ENCODE:
+		new->state = CAMEL_MIME_YENCODE_STATE_INIT;
+		break;
+	case CAMEL_MIME_FILTER_YENC_DIRECTION_DECODE:
+		new->state = CAMEL_MIME_YDECODE_STATE_INIT;
+		break;
+	default:
+		g_assert_not_reached ();
+	}
+	
+	return (CamelMimeFilter *) new;
+}
+
+
+/**
+ * camel_mime_filter_yenc_set_state:
+ * @yenc: yEnc filter
+ * @state: encode/decode state
+ *
+ * Sets the current state of the yencoder/ydecoder
+ **/
+void
+camel_mime_filter_yenc_set_state (CamelMimeFilterYenc *yenc, int state)
+{
+	g_return_if_fail (CAMEL_IS_MIME_FILTER_YENC (yenc));
+	
+	yenc->state = state;
+}
+
+
+/**
+ * camel_mime_filter_yenc_set_crc:
+ * @yenc: yEnc filter
+ * @crc: crc32
+ *
+ * Sets the current crc32 value on the yEnc filter @yenc to @crc.
+ **/
+void
+camel_mime_filter_yenc_set_crc (CamelMimeFilterYenc *yenc, guint32 crc)
+{
+	g_return_if_fail (CAMEL_IS_MIME_FILTER_YENC (yenc));
+	
+	yenc->crc = crc;
+}
+
+
+#if 0
+/* FIXME: once we parse out the yenc part id, we can re-enable this interface */
+/**
+ * camel_mime_filter_yenc_get_part:
+ * @yenc: yEnc filter
+ *
+ * Gets the part id of the current decoded yEnc stream or -1 on fail.
+ *
+ * Returns the part id of the current decoded yEnc stream or -1 on
+ * fail.
+ **/
+int
+camel_mime_filter_yenc_get_part (CamelMimeFilterYenc *yenc)
+{
+	g_return_val_if_fail (CAMEL_IS_MIME_FILTER_YENC (yenc), -1);
+	
+	if (yenc->state & CAMEL_MIME_YDECODE_STATE_PART)
+		return yenc->part;
+	
+	return -1;
+}
+#endif
+
+/**
+ * camel_mime_filter_yenc_get_pcrc:
+ * @yenc: yEnc filter
+ *
+ * Get the computed part crc or (guint32) -1 on fail.
+ *
+ * Returns the computed part crc or (guint32) -1 on fail.
+ **/
+guint32
+camel_mime_filter_yenc_get_pcrc (CamelMimeFilterYenc *yenc)
+{
+	g_return_val_if_fail (CAMEL_IS_MIME_FILTER_YENC (yenc), -1);
+	
+	return CAMEL_MIME_YENCODE_CRC_FINAL (yenc->pcrc);
+}
+
+
+/**
+ * camel_mime_filter_yenc_get_crc:
+ * @yenc: yEnc filter
+ *
+ * Get the computed crc or (guint32) -1 on fail.
+ *
+ * Returns the computed crc or (guint32) -1 on fail.
+ **/
+guint32
+camel_mime_filter_yenc_get_crc (CamelMimeFilterYenc *yenc)
+{
+	g_return_val_if_fail (CAMEL_IS_MIME_FILTER_YENC (yenc), -1);
+	
+	return CAMEL_MIME_YENCODE_CRC_FINAL (yenc->crc);
+}
+
+
+static const int yenc_crc_table[256] = {
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+	0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+	0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+	0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+	0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+	0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+	0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+	0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+	0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+	0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+	0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+	0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+	0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+	0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+	0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+	0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+	0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+	0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+	0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+	0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+#define yenc_crc_add(crc, c) (yenc_crc_table[(((int) (crc)) ^ ((unsigned char) (c))) & 0xff] ^ ((((int) (crc)) >> 8) & 0x00ffffff))
+
+#define YENC_NEWLINE_ESCAPE (CAMEL_MIME_YDECODE_STATE_EOLN | CAMEL_MIME_YDECODE_STATE_ESCAPE)
+
+
+/**
+ * camel_ydecode_step:
+ * @in: input buffer
+ * @inlen: input buffer length
+ * @out: output buffer
+ * @state: ydecode state
+ * @pcrc: part crc state
+ * @crc: crc state
+ *
+ * Performs a 'decode step' on a chunk of yEncoded data of length
+ * @inlen pointed to by @in and writes to @out. Assumes the =ybegin
+ * and =ypart lines have already been stripped off.
+ *
+ * To get the crc32 value of the part, use CAMEL_MIME_YENCODE_CRC_FINAL
+ * (@pcrc). If there are more parts, you should reuse @crc without
+ * re-initializing. Once all parts have been decoded, you may get the
+ * combined crc32 value of all the parts using CAMEL_MIME_YENCODE_CRC_FINAL
+ * (@crc).
+ *
+ * Returns the number of bytes decoded.
+ **/
+size_t
+camel_ydecode_step (const unsigned char *in, size_t inlen, unsigned char *out,
+		    int *state, guint32 *pcrc, guint32 *crc)
+{
+	const register unsigned char *inptr;
+	register unsigned char *outptr;
+	const unsigned char *inend;
+	unsigned char ch;
+	int ystate;
+	
+	if (*state & CAMEL_MIME_YDECODE_STATE_END)
+		return 0;
+	
+	ystate = *state;
+	
+	inend = in + inlen;
+	outptr = out;
+	
+	inptr = in;
+	while (inptr < inend) {
+		ch = *inptr++;
+		
+		if ((ystate & YENC_NEWLINE_ESCAPE) == YENC_NEWLINE_ESCAPE) {
+			ystate &= ~CAMEL_MIME_YDECODE_STATE_EOLN;
+			
+			if (ch == 'y') {
+				/* we probably have a =yend here */
+				ystate |= CAMEL_MIME_YDECODE_STATE_END;
+				break;
+			}
+		}
+		
+		if (ch == '\n') {
+			ystate |= CAMEL_MIME_YDECODE_STATE_EOLN;
+			continue;
+		}
+		
+		if (ystate & CAMEL_MIME_YDECODE_STATE_ESCAPE) {
+			ystate &= ~CAMEL_MIME_YDECODE_STATE_ESCAPE;
+			ch -= 64;
+		} else if (ch == '=') {
+			ystate |= CAMEL_MIME_YDECODE_STATE_ESCAPE;
+			continue;
+		}
+		
+		ystate &= ~CAMEL_MIME_YDECODE_STATE_EOLN;
+		
+		*outptr++ = ch -= 42;
+		
+		*pcrc = yenc_crc_add (*pcrc, ch);
+		*crc = yenc_crc_add (*crc, ch);
+	}
+	
+	*state = ystate;
+	
+	return outptr - out;
+}
+
+
+/**
+ * camel_yencode_step:
+ * @in: input buffer
+ * @inlen: input buffer length
+ * @out: output buffer
+ * @state: yencode state
+ * @pcrc: part crc state
+ * @crc: crc state
+ *
+ * Performs an yEncode 'encode step' on a chunk of raw data of length
+ * @inlen pointed to by @in and writes to @out.
+ *
+ * @state should be initialized to CAMEL_MIME_YENCODE_STATE_INIT before
+ * beginning making the first call to this function. Subsequent calls
+ * should reuse @state.
+ *
+ * Along the same lines, @pcrc and @crc should be initialized to
+ * CAMEL_MIME_YENCODE_CRC_INIT before using.
+ *
+ * Returns the number of bytes encoded.
+ **/
+size_t
+camel_yencode_step (const unsigned char *in, size_t inlen, unsigned char *out,
+		    int *state, guint32 *pcrc, guint32 *crc)
+{
+	const register unsigned char *inptr;
+	register unsigned char *outptr;
+	const unsigned char *inend;
+	register int already;
+	unsigned char ch;
+	
+	inend = in + inlen;
+	outptr = out;
+	
+	already = *state;
+	
+	inptr = in;
+	while (inptr < inend) {
+		ch = (*inptr++);
+		
+		*pcrc = yenc_crc_add (*pcrc, ch);
+		*crc = yenc_crc_add (*crc, ch);
+		
+		ch += 42;
+		
+		if (ch == '\0' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '=') {
+			*outptr++ = '=';
+			*outptr++ = ch + 64;
+			already += 2;
+		} else {
+			*outptr++ = ch;
+			already++;
+		}
+		
+		if (already >= 128) {
+			*outptr++ = '\n';
+			already = 0;
+		}
+	}
+	
+	*state = already;
+	
+	return outptr - out;
+}
+
+
+/**
+ * camel_yencode_close:
+ * @in: input buffer
+ * @inlen: input buffer length
+ * @out: output buffer
+ * @state: yencode state
+ * @pcrc: part crc state
+ * @crc: crc state
+ *
+ * Call this function when finished encoding data with
+ * camel_yencode_step to flush off the remaining state.
+ *
+ * CAMEL_MIME_YENCODE_CRC_FINAL (@pcrc) will give you the crc32 of the
+ * encoded "part". If there are more "parts" to encode, you should
+ * re-use @crc when encoding the next "parts" and then use
+ * CAMEL_MIME_YENCODE_CRC_FINAL (@crc) to get the combined crc32 value of
+ * all the parts.
+ *
+ * Returns the number of bytes encoded.
+ **/
+size_t
+camel_yencode_close (const unsigned char *in, size_t inlen, unsigned char *out,
+		     int *state, guint32 *pcrc, guint32 *crc)
+{
+	register unsigned char *outptr;
+	
+	outptr = out;
+	
+	if (inlen)
+		outptr += camel_yencode_step (in, inlen, out, state, pcrc, crc);
+	
+	if (*state)
+		*outptr++ = '\n';
+	
+	*state = CAMEL_MIME_YENCODE_STATE_INIT;
+	
+	return outptr - out;
+}
diff --git a/camel/camel-mime-filter-yenc.h b/camel/camel-mime-filter-yenc.h
new file mode 100644
index 0000000000..8471fa5cb7
--- /dev/null
+++ b/camel/camel-mime-filter-yenc.h
@@ -0,0 +1,109 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ *  Authors: Jeffrey Stedfast <fejj@ximian.com>
+ *
+ *  Copyright 2002-2004 Ximian, Inc. (www.ximian.com)
+ *
+ *  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 Street #330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+
+#ifndef __CAMEL_MIME_FILTER_YENC_H__
+#define __CAMEL_MIME_FILTER_YENC_H__
+
+#include <camel/camel-mime-filter.h>
+
+#ifdef __cplusplus
+extern "C" {
+#pragma }
+#endif /* __cplusplus */
+
+#define CAMEL_TYPE_MIME_FILTER_YENC            (camel_mime_filter_yenc_get_type ())
+#define CAMEL_MIME_FILTER_YENC(obj)            (CAMEL_CHECK_CAST ((obj), CAMEL_TYPE_MIME_FILTER_YENC, CamelMimeFilterYenc))
+#define CAMEL_MIME_FILTER_YENC_CLASS(klass)    (CAMEL_CHECK_CLASS_CAST ((klass), CAMEL_TYPE_MIME_FILTER_YENC, CamelMimeFilterYencClass))
+#define CAMEL_IS_MIME_FILTER_YENC(obj)         (CAMEL_CHECK_TYPE ((obj), CAMEL_TYPE_MIME_FILTER_YENC))
+#define CAMEL_IS_MIME_FILTER_YENC_CLASS(klass) (CAMEL_CHECK_CLASS_TYPE ((klass), CAMEL_TYPE_MIME_FILTER_YENC))
+#define CAMEL_MIME_FILTER_YENC_GET_CLASS(obj)  (CAMEL_CHECK_GET_CLASS ((obj), CAMEL_TYPE_MIME_FILTER_YENC, CamelMimeFilterYencClass))
+
+typedef struct _CamelMimeFilterYenc CamelMimeFilterYenc;
+typedef struct _CamelMimeFilterYencClass CamelMimeFilterYencClass;
+
+typedef enum {
+	CAMEL_MIME_FILTER_YENC_DIRECTION_ENCODE,
+	CAMEL_MIME_FILTER_YENC_DIRECTION_DECODE
+} CamelMimeFilterYencDirection;
+
+#define CAMEL_MIME_YDECODE_STATE_INIT     (0)
+#define CAMEL_MIME_YENCODE_STATE_INIT     (0)
+
+/* first 8 bits are reserved for saving a byte */
+
+/* reserved for use only within camel_mime_ydecode_step */
+#define CAMEL_MIME_YDECODE_STATE_EOLN     (1 << 8)
+#define CAMEL_MIME_YDECODE_STATE_ESCAPE   (1 << 9)
+
+/* bits 10 and 11 reserved for later uses? */
+
+#define CAMEL_MIME_YDECODE_STATE_BEGIN    (1 << 12)
+#define CAMEL_MIME_YDECODE_STATE_PART     (1 << 13)
+#define CAMEL_MIME_YDECODE_STATE_DECODE   (1 << 14)
+#define CAMEL_MIME_YDECODE_STATE_END      (1 << 15)
+
+#define CAMEL_MIME_YENCODE_CRC_INIT       (~0)
+#define CAMEL_MIME_YENCODE_CRC_FINAL(crc) (~crc)
+
+struct _CamelMimeFilterYenc {
+	CamelMimeFilter parent_object;
+	
+	CamelMimeFilterYencDirection direction;
+	
+	int part;
+	
+	int state;
+	guint32 pcrc;
+	guint32 crc;
+};
+
+struct _CamelMimeFilterYencClass {
+	CamelMimeFilterClass parent_class;
+	
+};
+
+
+CamelType camel_mime_filter_yenc_get_type (void);
+
+CamelMimeFilter *camel_mime_filter_yenc_new (CamelMimeFilterYencDirection direction);
+
+void camel_mime_filter_yenc_set_state (CamelMimeFilterYenc *yenc, int state);
+void camel_mime_filter_yenc_set_crc (CamelMimeFilterYenc *yenc, guint32 crc);
+
+/*int     camel_mime_filter_yenc_get_part (CamelMimeFilterYenc *yenc);*/
+guint32 camel_mime_filter_yenc_get_pcrc (CamelMimeFilterYenc *yenc);
+guint32 camel_mime_filter_yenc_get_crc (CamelMimeFilterYenc *yenc);
+
+
+size_t camel_ydecode_step  (const unsigned char *in, size_t inlen, unsigned char *out,
+			    int *state, guint32 *pcrc, guint32 *crc);
+size_t camel_yencode_step  (const unsigned char *in, size_t inlen, unsigned char *out,
+			    int *state, guint32 *pcrc, guint32 *crc);
+size_t camel_yencode_close (const unsigned char *in, size_t inlen, unsigned char *out,
+			    int *state, guint32 *pcrc, guint32 *crc);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __CAMEL_MIME_FILTER_YENC_H__ */
diff --git a/camel/providers/imap4/camel-imap4-store.c b/camel/providers/imap4/camel-imap4-store.c
index aa8dfc0c0e..b7b4b4c358 100644
--- a/camel/providers/imap4/camel-imap4-store.c
+++ b/camel/providers/imap4/camel-imap4-store.c
@@ -999,6 +999,11 @@ imap4_get_folder_info (CamelStore *store, const char *top, guint32 flags, CamelE
 	char *pattern;
 	int id, i;
 	
+	if (engine == NULL) {
+		if (!camel_service_connect ((CamelService *) store, ex))
+			return NULL;
+	}
+	
 	if (flags & CAMEL_STORE_FOLDER_INFO_SUBSCRIBED)
 		cmd = "LSUB";
 	else