Functions for formatting RFC-2231-compliant mail headers fields.

* include/mailutils/cctype.h (MU_CTYPE_TSPEC): New class.  Represents
tspecials as per RFC 2045, section 5.1.
(mu_istspec): New define.
* libmailutils/string/muctype.c (mu_c_tab): Mark tspecials

* include/mailutils/assoc.h (mu_assoc_mark)
(mu_assoc_sweep): New protos.
* libmailutils/base/assoc.c (_mu_assoc_elem): New field: mark
(mu_assoc_mark,mu_assoc_sweep): New functions.

* libmailutils/filter/Makefile.am (libfilter_la_SOURCES): Add dq.c
and percent.c.
* libmailutils/filter/dq.c: New file.
* libmailutils/filter/percent.c: New file.
* include/mailutils/filter.h (mu_percent_filter)
(mu_dq_filter): New externs.
* libmailutils/filter/filter.c (mu_filter_get_list): Register
mu_percent_filter and mu_dq_filter.

* include/mailutils/mime.h (mu_mime_header_set)
(mu_mime_header_set_w): New protos.
* libmailutils/mime/Makefile.am (libmime_la_SOURCES): Add mimehdrset.c
* libmailutils/mime/mimehdrset.c: New file.
* libmailutils/mime/mime.c (_mime_set_content_type): For multipart/alternative,
remove also all parameters except charset from the Content-Type header.
* mail/send.c (saveatt): Remove the now unneeded conditionals.
* libmailutils/tests/mimehdr.at: Test formatting functions.

* include/mailutils/stream.h (MU_IOCTL_FILTER_SET_OUTBUF_SIZE): New ioctl.
* include/mailutils/sys/filter.h (_MU_FILTER_DISABLED)
(_MU_FILTER_EOF): Remove.  Use bitfields instead.
(_mu_filter_stream): Remove fltflag.  New fields: flag_disabled,
flag_eof, outbuf_size.
* libmailutils/stream/fltstream.c (MFB_BASE)
(MFB_CURPTR, MFB_ENDPTR, MFB_SIZE, MFB_LEVEL)
(MFB_POS, MFB_RDBYTES, MFB_FREESIZE)
(MBF_CLEAR, MBF_FREE): Replace with inline functions.
(init_iobuf): Use the outbuf_size field (unless 0) to
set the output buffer size.
(filter_read): Stop if on success if outbuf_size is set,
without trying to fill the entire buffer.
(filter_ctl): Handle MU_IOCTL_FILTER_SET_OUTBUF_SIZE.

* libmailutils/tests/mimehdr.c: New option -width: format and
print the value assuming given line width.

19 files changed, 1069 insertions, 129 deletions

diff --git a/include/mailutils/assoc.h b/include/mailutils/assoc.h
index 23ae7cda4..a8f9845e1 100644
--- a/include/mailutils/assoc.h
+++ b/include/mailutils/assoc.h
@@ -53,6 +53,10 @@ typedef int (*mu_assoc_comparator_t) (const char *, const void *,
 
 int mu_assoc_sort_r (mu_assoc_t assoc, mu_assoc_comparator_t cmp, void *data);
   
+int mu_assoc_mark (mu_assoc_t asc, int (*cond) (char const *, void *, void *),
+		   void *data);
+int mu_assoc_sweep (mu_assoc_t asc);
+
   
 #ifdef __cplusplus
 }
diff --git a/include/mailutils/cctype.h b/include/mailutils/cctype.h
index ecd9c4007..bed749b96 100644
--- a/include/mailutils/cctype.h
+++ b/include/mailutils/cctype.h
@@ -24,18 +24,19 @@
 extern "C" {
 #endif
 
-#define MU_CTYPE_ALPHA   0x001
-#define MU_CTYPE_DIGIT   0x002
-#define MU_CTYPE_BLANK   0x004
-#define MU_CTYPE_CNTRL   0x008
-#define MU_CTYPE_GRAPH   0x010
-#define MU_CTYPE_LOWER   0x020
-#define MU_CTYPE_UPPER   0x040
-#define MU_CTYPE_PRINT   0x080
-#define MU_CTYPE_PUNCT   0x100
-#define MU_CTYPE_SPACE   0x200
-#define MU_CTYPE_XLETR   0x400
-#define MU_CTYPE_ENDLN   0x800
+#define MU_CTYPE_ALPHA   0x0001
+#define MU_CTYPE_DIGIT   0x0002
+#define MU_CTYPE_BLANK   0x0004
+#define MU_CTYPE_CNTRL   0x0008
+#define MU_CTYPE_GRAPH   0x0010
+#define MU_CTYPE_LOWER   0x0020
+#define MU_CTYPE_UPPER   0x0040
+#define MU_CTYPE_PRINT   0x0080
+#define MU_CTYPE_PUNCT   0x0100
+#define MU_CTYPE_SPACE   0x0200
+#define MU_CTYPE_XLETR   0x0400
+#define MU_CTYPE_ENDLN   0x0800
+#define MU_CTYPE_TSPEC   0x1000  /* tspecials: RFC 2045, section 5.1. */
 
 #define MU_C_TAB_MAX     128
 
@@ -58,7 +59,8 @@ extern int mu_c_tab[MU_C_TAB_MAX];
 #define mu_isascii(c) (((unsigned)c) < MU_C_TAB_MAX)
 #define mu_isblank(c) mu_c_is_class (c, MU_CTYPE_BLANK)
 #define mu_isendln(c) mu_c_is_class (c, MU_CTYPE_ENDLN)
-
+#define mu_istspec(c) mu_c_is_class (c, MU_CTYPE_TSPEC)
+  
 #define mu_tolower(c)					\
   ({ int __c = (c);					\
     (__c >= 'A' && __c <= 'Z' ? __c - 'A' + 'a' : __c); \
diff --git a/include/mailutils/filter.h b/include/mailutils/filter.h
index 8bd107100..c8bddd40b 100644
--- a/include/mailutils/filter.h
+++ b/include/mailutils/filter.h
@@ -126,7 +126,9 @@ extern mu_filter_record_t mu_iconv_filter;
 extern mu_filter_record_t mu_c_escape_filter;
 extern mu_filter_record_t mu_htmlent_filter;
 extern mu_filter_record_t mu_xml_filter;
-  
+extern mu_filter_record_t mu_percent_filter;
+extern mu_filter_record_t mu_dq_filter;
+
 enum mu_iconv_fallback_mode
   {
     mu_fallback_none,
diff --git a/include/mailutils/mime.h b/include/mailutils/mime.h
index 786f96f2b..503ebe399 100644
--- a/include/mailutils/mime.h
+++ b/include/mailutils/mime.h
@@ -75,6 +75,13 @@ int mu_mime_header_parse (const char *text, const char *charset, char **pvalue,
 int mu_mime_header_parse_subset (const char *text, const char *charset,
 				 char **pvalue,
 				 mu_assoc_t assoc);
+
+int mu_mime_header_set_w (mu_header_t hdr, const char *name,
+			  const char *value, mu_assoc_t params,
+			  size_t line_width);
+int mu_mime_header_set (mu_header_t hdr, const char *name,
+			const char *value, mu_assoc_t params);
+
   
 #ifdef __cplusplus
 }
diff --git a/include/mailutils/stream.h b/include/mailutils/stream.h
index 2e7b86cb5..f7f58ba8a 100644
--- a/include/mailutils/stream.h
+++ b/include/mailutils/stream.h
@@ -195,6 +195,12 @@ enum mu_buffer_type
 #define MU_IOCTL_FILTER_GET_DISABLED 0
 #define MU_IOCTL_FILTER_SET_DISABLED 1  
 
+  /* Set transcoder output buffer size.
+     Arg: size_t*
+     Has effect only if the stream is unbuffered
+   */
+#define MU_IOCTL_FILTER_SET_OUTBUF_SIZE  2
+  
   /* TLS transport streams */
   /* Get cipher info.
      Arg: mu_property_t *
diff --git a/include/mailutils/sys/filter.h b/include/mailutils/sys/filter.h
index 1ee0b1942..23b5affcd 100644
--- a/include/mailutils/sys/filter.h
+++ b/include/mailutils/sys/filter.h
@@ -36,16 +36,14 @@ struct _mu_filter_buffer
   size_t pos;
 };
 
-#define _MU_FILTER_DISABLED 0x01
-#define _MU_FILTER_EOF      0x02  
-  
 struct _mu_filter_stream
 {
   struct _mu_stream stream;
   mu_stream_t transport;
   int mode;
-  int fltflag;
-  
+  unsigned flag_disabled:1;
+  unsigned flag_eof:1;
+  size_t outbuf_size;
   struct _mu_filter_buffer inbuf, outbuf;
   mu_filter_xcode_t xcode;
   void *xdata;
diff --git a/libmailutils/base/assoc.c b/libmailutils/base/assoc.c
index 4e31b499a..b0e353d32 100644
--- a/libmailutils/base/assoc.c
+++ b/libmailutils/base/assoc.c
@@ -47,6 +47,7 @@ struct _mu_assoc_elem
 {
   char *name;
   struct _mu_assoc_elem *next, *prev;
+  int mark:1;
   char *data;
 };
 
@@ -793,4 +794,34 @@ mu_assoc_sort_r (mu_assoc_t assoc, mu_assoc_comparator_t cmp, void *data)
 
   return 0;
 }
+
+int
+mu_assoc_mark (mu_assoc_t asc, int (*cond) (char const *, void *, void *),
+	       void *data)
+{
+  struct _mu_assoc_elem *elt;
+
+  if (!asc)
+    return EINVAL;
+  for (elt = asc->head; elt; elt = elt->next)
+    elt->mark = !!cond (elt->name, elt->data, data);
+  return 0;
+}
+
+int
+mu_assoc_sweep (mu_assoc_t asc)
+{
+  unsigned i;
+  
+  if (!asc)
+    return EINVAL;
+
+  for (i = hash_size[asc->hash_num]; i > 0; i--)
+    {
+      if (asc->tab[i-1] && asc->tab[i-1]->mark)
+	assoc_remove (asc, i-1);
+    }
   
+  return 0;
+}
+
diff --git a/libmailutils/filter/Makefile.am b/libmailutils/filter/Makefile.am
index b735bf772..5daedacae 100644
--- a/libmailutils/filter/Makefile.am
+++ b/libmailutils/filter/Makefile.am
@@ -25,6 +25,7 @@ libfilter_la_SOURCES =\
  crlfflt.c\
  decode.c\
  dot.c\
+ dq.c\
  filter.c\
  fltchain.c\
  fromflt.c\
@@ -34,6 +35,7 @@ libfilter_la_SOURCES =\
  inline-comment.c\
  linecon.c\
  linelenflt.c\
+ percent.c\
  qpflt.c\
  xml.c
 
diff --git a/libmailutils/filter/dq.c b/libmailutils/filter/dq.c
new file mode 100644
index 000000000..d3bb18523
--- /dev/null
+++ b/libmailutils/filter/dq.c
@@ -0,0 +1,143 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011-2012, 2014-2017 Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+/* Doble-quote escaping filter.
+   In encode mode, escapes each occurrence of double-quote and backslash
+   by prefixing it with backslash.
+   In decode mode, removes backslash prefixes.
+*/
+   
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <mailutils/errno.h>
+#include <mailutils/filter.h>
+#include <mailutils/wordsplit.h>
+#include <mailutils/cctype.h>
+
+/* Move min(isize,osize) bytes from iptr to optr, replacing each
+   escapable control character with its escape sequence. */
+static enum mu_filter_result
+_dq_encoder (void *xd MU_ARG_UNUSED,
+	     enum mu_filter_command cmd,
+	     struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+  
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; i++)
+    {
+      unsigned char c = *iptr++;
+
+      if (strchr ("\\\"", c))
+	{
+	  if (j + 1 == osize)
+	    {
+	      if (i == 0)
+		{
+		  iobuf->osize = 2;
+		  return mu_filter_moreoutput;
+		}
+	      break;
+	    }
+	  else
+	    {
+	      optr[j++] = '\\';
+	      optr[j++] = c;
+	    }
+	}
+      else
+	optr[j++] = c;
+    }
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+/* Move min(isize,osize) bytes from iptr to optr, replacing each escape
+   sequence with its ASCII code. */
+static enum mu_filter_result
+_dq_decoder (void *xd MU_ARG_UNUSED,
+	     enum mu_filter_command cmd,
+	     struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+  
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; i++)
+    {
+      unsigned char c = *iptr++;
+      if (c == '\\')
+	{
+	  if (i + 1 == isize)
+	    break;
+	  optr[j++] = *iptr++;
+	}
+      else
+	optr[j++] = c;
+    }
+
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+static struct _mu_filter_record _dq_filter = {
+  "dq",
+  NULL,
+  _dq_encoder,
+  _dq_decoder,
+};
+
+mu_filter_record_t mu_dq_filter = &_dq_filter;
+
diff --git a/libmailutils/filter/filter.c b/libmailutils/filter/filter.c
index 0717425fc..00bc50fa2 100644
--- a/libmailutils/filter/filter.c
+++ b/libmailutils/filter/filter.c
@@ -86,6 +86,8 @@ mu_filter_get_list (mu_list_t *plist)
       mu_list_append (filter_list, mu_c_escape_filter);
       mu_list_append (filter_list, mu_htmlent_filter);
       mu_list_append (filter_list, mu_xml_filter);
+      mu_list_append (filter_list, mu_percent_filter);
+      mu_list_append (filter_list, mu_dq_filter);
       /* FIXME: add the default encodings?  */
     }
   *plist = filter_list;
diff --git a/libmailutils/filter/percent.c b/libmailutils/filter/percent.c
new file mode 100644
index 000000000..62d248d88
--- /dev/null
+++ b/libmailutils/filter/percent.c
@@ -0,0 +1,186 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011-2012, 2014-2017 Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <mailutils/errno.h>
+#include <mailutils/filter.h>
+#include <mailutils/cctype.h>
+
+static char xchar[] = "0123456789ABCDEF";
+
+static enum mu_filter_result
+percent_encoder (void *xd,
+		 enum mu_filter_command cmd,
+		 struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  char *escape_chars = xd;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; i++)
+    {
+      unsigned char c = iptr[i];
+
+      if (c == 0 || strchr (escape_chars, c))
+	{
+	  if (j + 3 >= osize)
+	    {
+	      if (i == 0)
+		{
+		  iobuf->osize = 3;
+		  return mu_filter_moreoutput;
+		}
+	      break;
+	    }
+	  optr[j++] = '%';
+	  optr[j++] = xchar[((c >> 4) & 0xf)];
+	  optr[j++] = xchar[c & 0xf];
+	}
+      else
+	optr[j++] = c;
+    }
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+static enum mu_filter_result
+percent_decoder (void *xd MU_ARG_UNUSED,
+		 enum mu_filter_command cmd,
+		 struct mu_filter_io *iobuf)
+{
+  size_t i, j;
+  const unsigned char *iptr;
+  size_t isize;
+  char *optr;
+  size_t osize;
+  
+  switch (cmd)
+    {
+    case mu_filter_init:
+    case mu_filter_done:
+      return mu_filter_ok;
+    default:
+      break;
+    }
+  
+  iptr = (const unsigned char *) iobuf->input;
+  isize = iobuf->isize;
+  optr = iobuf->output;
+  osize = iobuf->osize;
+
+  for (i = j = 0; i < isize && j < osize; j++)
+    {
+      unsigned char c = iptr[i++];
+      if (c == '%')
+	{
+	  char *phi, *plo;
+	  
+	  if (i + 2 >= isize)
+	    break;
+	  phi = strchr (xchar, mu_toupper (iptr[i]));
+	  plo = strchr (xchar, mu_toupper (iptr[i+1]));
+	  if (phi && plo)
+	    {
+	      optr[j] = ((phi - xchar) << 4) + (plo - xchar);
+	      i += 2;
+	    }
+	  else
+	    optr[j] = c;
+	}
+      else
+	optr[j] = c;
+    }
+  iobuf->isize = i;
+  iobuf->osize = j;
+  return mu_filter_ok;
+}
+
+static int
+percent_alloc (void **pret, int mode, int argc, const char **argv)
+{
+  if (mode == MU_FILTER_ENCODE)
+    {
+      char *s;
+      if (argc > 1)
+	{
+	  int i;
+	  size_t len = 0;
+
+	  for (i = 1; i < argc; i++)
+	    len += strlen (argv[i]);
+	  s = malloc (len + 1);
+	  if (!s)
+	    return ENOMEM;
+	  *pret = s;
+	  *s = 0;
+	  for (i = 1; i < argc; i++)
+	    strcat (s, argv[i]);
+	}
+      else
+	{
+	  int i;
+	  
+	  s = malloc (UCHAR_MAX);
+	  if (!s)
+	    return ENOMEM;
+	  *pret = s;
+	  for (i = 1; i <= UCHAR_MAX; i++)
+	    {
+	      if (i == '%' || i == '"' || !mu_isgraph (i))
+		*s++ = i;
+	    }
+	  *s = 0;
+	}
+    }
+  else
+    *pret = NULL;
+  return 0;
+}
+
+static struct _mu_filter_record _percent_filter = {
+  "percent",
+  percent_alloc,
+  percent_encoder,
+  percent_decoder
+};
+
+mu_filter_record_t mu_percent_filter = &_percent_filter;
+
+  
diff --git a/libmailutils/mime/Makefile.am b/libmailutils/mime/Makefile.am
index 98895cfd7..3edb9fdfa 100644
--- a/libmailutils/mime/Makefile.am
+++ b/libmailutils/mime/Makefile.am
@@ -20,6 +20,7 @@ noinst_LTLIBRARIES = libmime.la
 libmime_la_SOURCES = \
  attachment.c\
  mime.c\
- mimehdr.c
+ mimehdr.c\
+ mimehdrset.c
 
 AM_CPPFLAGS = @MU_LIB_COMMON_INCLUDES@ -I/libmailutils
diff --git a/libmailutils/mime/mime.c b/libmailutils/mime/mime.c
index 9c3879769..e4463d307 100644
--- a/libmailutils/mime/mime.c
+++ b/libmailutils/mime/mime.c
@@ -38,6 +38,8 @@
 #include <mailutils/header.h>
 #include <mailutils/errno.h>
 #include <mailutils/util.h>
+#include <mailutils/assoc.h>
+#include <mailutils/io.h>
 
 #include <mailutils/sys/mime.h>
 #include <mailutils/sys/message.h>
@@ -445,6 +447,13 @@ _mimepart_body_lines (mu_body_t body, size_t *plines)
 
 /*------ Mime message/header functions for CREATING multipart message -----*/
 static int
+retain_charset (char const *name, void *value MU_ARG_UNUSED,
+		void *data MU_ARG_UNUSED)
+{
+  return strcmp (name, "charset") != 0;
+}
+		 
+static int
 _mime_set_content_type (mu_mime_t mime)
 {
   const char  *content_type;
@@ -473,9 +482,36 @@ _mime_set_content_type (mu_mime_t mime)
 	  for (i = 0; i < mime->nmtp_parts; i++)
 	    {
 	      mu_header_t hdr;
+	      char *val;
+	      int rc;
 	      
 	      mu_message_get_header (mime->mtp_parts[i]->msg, &hdr);
 	      mu_header_remove (hdr, MU_HEADER_CONTENT_DISPOSITION, 1);
+
+	      rc = mu_header_aget_value_unfold (hdr, MU_HEADER_CONTENT_TYPE,
+						&val);
+	      if (rc == 0)
+		{
+		  mu_content_type_t ct;
+		  rc = mu_content_type_parse (val, NULL, &ct);
+		  if (rc == 0)
+		    {
+		      char *type;
+		      
+		      mu_assoc_mark (ct->param, retain_charset, NULL);
+		      mu_assoc_sweep (ct->param);
+
+		      rc = mu_asprintf (&type, "%s/%s", ct->type, ct->subtype);
+		      if (rc == 0)
+			{
+			  mu_mime_header_set (hdr,
+					      MU_HEADER_CONTENT_TYPE, type,
+					      ct->param);
+			  free (type);
+			}
+		      mu_content_type_destroy (&ct);
+		    }
+		}
 	    }
 	  
 	  content_type = "multipart/alternative; boundary=";
diff --git a/libmailutils/mime/mimehdrset.c b/libmailutils/mime/mimehdrset.c
new file mode 100644
index 000000000..7c127caee
--- /dev/null
+++ b/libmailutils/mime/mimehdrset.c
@@ -0,0 +1,314 @@
+/* Functions for formatting RFC-2231-compliant mail headers fields.
+   GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999-2001, 2004-2005, 2007, 2009-2012, 2014-2017 Free
+   Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not,
+   see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <mailutils/mime.h>
+#include <mailutils/cctype.h>
+#include <mailutils/cstr.h>
+#include <mailutils/header.h>
+#include <mailutils/stream.h>
+#include <mailutils/filter.h>
+#include <mailutils/assoc.h>
+#include <mailutils/errno.h>
+
+struct header_buffer
+{
+  mu_stream_t str;     /* Output stream */
+  size_t line_len;     /* Length of current line */
+  size_t line_max;     /* Max. line length */
+};
+
+static int
+mime_store_parameter (char const *name, void *value, void *data)
+{
+  struct mu_mime_param *p = value;
+  struct header_buffer *hbuf = data;
+  size_t nlen;   /* Length of parameter name
+		    (eq. sign, eventual seqence no. and language info mark
+		    included) */
+  size_t vlen;   /* Length of lang'charset' part */
+  int langinfo;  /* True if language info is available */ 
+  int quote = 0; /* 2 if the value should be quoted, 0 otherwise */
+  int segment = -1; /* Segment sequence number */
+  mu_stream_t valstr;  /* Value stream (properly encoded) */
+  mu_off_t valsize;    /* Number of octets left in valstr */
+  char const *filter_name = NULL; /* Name of the filter for the value */
+  int rc;
+    
+  rc = mu_static_memory_stream_create (&valstr, p->value, strlen (p->value));
+  if (rc)
+    return rc;
+  
+  nlen = strlen (name);
+  if (p->lang || p->cset)
+    {
+      vlen = 2;
+      if (p->lang)
+	vlen += strlen (p->lang);
+      if (p->cset)
+	vlen += strlen (p->cset);
+      langinfo = 1;
+      filter_name = "percent";
+    }
+  else
+    {
+      if (*mu_str_skip_class_comp (p->value, MU_CTYPE_TSPEC|MU_CTYPE_BLANK))
+	{
+	  /* Must be in quoted-string, to use within parameter values */
+	  quote = 2;
+	  filter_name = "dq";
+	}
+      else
+	quote = 0;
+      vlen = 0;
+      langinfo = 0;
+    }
+
+  if (filter_name)
+    {
+      mu_stream_t tmp;
+      
+      rc = mu_filter_create (&tmp, valstr, filter_name, MU_FILTER_ENCODE,
+			     MU_STREAM_READ | MU_STREAM_SEEK);
+      if (rc)
+	goto err;
+      mu_stream_unref (valstr);
+      valstr = tmp;
+      rc = mu_memory_stream_create (&tmp, MU_STREAM_RDWR);
+      if (rc == 0)
+	{
+	  rc = mu_stream_copy (tmp, valstr, 0, &valsize);
+	  mu_stream_destroy (&tmp);
+	}
+    }
+  else
+    rc = mu_stream_size (valstr, &valsize);
+
+  if (rc)
+    goto err;
+
+  nlen += langinfo;
+  
+  rc = mu_stream_seek (valstr, 0, MU_SEEK_SET, NULL);
+
+  if (hbuf->line_max == 0)
+    {
+      /* No line wrapping requested.  Store the value as it is */
+      mu_stream_printf (hbuf->str, "%s", name);
+      if (langinfo)
+	mu_stream_write (hbuf->str, "*", 1, NULL);
+      mu_stream_write (hbuf->str, "=", 1, NULL);
+      if (vlen)
+	{
+	  mu_stream_printf (hbuf->str, "%s'%s'",
+			    p->lang ? p->lang : "",
+			    p->cset ? p->cset : "");
+	  vlen = 0;
+	}
+      else if (quote)
+	mu_stream_write (hbuf->str, "\"", 1, NULL);
+      mu_stream_copy (hbuf->str, valstr, 0, NULL);
+      if (quote)
+	mu_stream_write (hbuf->str, "\"", 1, NULL);
+      if (mu_stream_err (hbuf->str))
+	rc = mu_stream_last_error (hbuf->str);
+    }
+  else
+    {
+      /* Split the value into sequentially indexed segments, each one no
+	 wider than the requested line width.
+
+	 Without special precautions, an encoded character occurring at
+	 the end of a segment can be split between this and the following
+	 segment to satisfy line width requirements.  To avoid this, the
+	 following approach is used:
+
+	 1. The value stream is put to unbuffered mode.
+	 2. Before each write, the size of the transcoder output buffer
+	    in valstr is set to the number of bytes left in the current
+	    line.
+
+	 This way the transcoder will write as many bytes as possible
+	 without breaking the encoded constructs while the unbuffered mode
+	 will ensure that it will not be called again to fill up the stream
+	 buffer.
+
+	 If the line width is insufficient, MU_ERR_BUFSPACE will be returned.
+      */
+      char *iobuf;
+
+      iobuf = malloc (hbuf->line_max + 1);
+      if (!iobuf)
+	{
+	  rc = errno;
+	  goto err;
+	}
+      
+      mu_stream_set_buffer (valstr, mu_buffer_none, 0);
+
+      while (rc == 0 && valsize)
+	{
+	  mu_off_t start, nr; /* Start and end positions in stream */
+	  size_t sz, n;
+      
+	  mu_stream_write (hbuf->str, ";", 1, NULL);
+	  mu_stream_seek (hbuf->str, 0, MU_SEEK_CUR, &start);
+      
+	  if (segment >= 0)
+	    {
+	      mu_stream_write (hbuf->str, "\n", 1, NULL);
+	      hbuf->line_len = 0;
+	      segment++;
+	    }
+	  else if (hbuf->line_len + valsize + quote + vlen + nlen + 1 >
+		   hbuf->line_max)
+	    {
+	      mu_stream_write (hbuf->str, "\n", 1, NULL);
+	      hbuf->line_len = 0;
+	      if (hbuf->line_len + valsize + quote + vlen + nlen + 1 >
+		   hbuf->line_max)
+		segment++;
+	    }
+	  
+	  mu_stream_write (hbuf->str, " ", 1, NULL);
+	  
+	  if (segment >= 0)
+	    mu_stream_printf (hbuf->str, "%s*%d", name, segment);
+	  else
+	    mu_stream_printf (hbuf->str, "%s", name);
+	  if (langinfo)
+	    mu_stream_write (hbuf->str, "*", 1, NULL);
+	  mu_stream_write (hbuf->str, "=", 1, NULL);
+	  mu_stream_seek (hbuf->str, 0, MU_SEEK_CUR, &nr);
+	  nlen = nr - start;
+	  hbuf->line_len += nlen;
+	  start = nr;
+
+	  /* Compute the number of octets to put into the current line.
+	     If the requested line width is not enough to accomodate
+	     the line, signal the error */
+	  if (hbuf->line_max <= (hbuf->line_len + quote + vlen))
+	    {
+	      rc = MU_ERR_BUFSPACE;
+	      break;
+	    }
+
+	  sz = hbuf->line_max - (hbuf->line_len + quote + vlen);
+	  mu_stream_ioctl (valstr, MU_IOCTL_FILTER,
+			   MU_IOCTL_FILTER_SET_OUTBUF_SIZE, &sz);
+	  
+	  rc = mu_stream_read (valstr, iobuf, sz, &n);
+	  if (rc || n == 0)
+	    break;
+	  
+	  if (vlen)
+	    {
+	      mu_stream_printf (hbuf->str, "%s'%s'",
+				p->lang ? p->lang : "",
+				p->cset ? p->cset : "");
+	      vlen = 0;
+	    }
+	  else if (quote)
+	    mu_stream_write (hbuf->str, "\"", 1, NULL);
+
+	  mu_stream_write (hbuf->str, iobuf, n, NULL);
+	  
+	  if (quote)
+	    mu_stream_write (hbuf->str, "\"", 1, NULL);
+	  mu_stream_seek (hbuf->str, 0, MU_SEEK_CUR, &nr);
+	  nr -= start;
+	  hbuf->line_len += nr;
+	  valsize -= n;
+	  
+	  if (mu_stream_err (hbuf->str))
+	    rc = mu_stream_last_error (hbuf->str);
+	}
+      free (iobuf);
+    }
+ err:
+  mu_stream_destroy (&valstr);
+
+  return rc;
+}
+
+static int
+mime_header_format (const char *value, mu_assoc_t params,
+		    struct header_buffer *hbuf)
+{
+  size_t l = strlen (value);
+  
+  mu_stream_write (hbuf->str, value, l, NULL);
+  hbuf->line_len += l;
+  return mu_assoc_foreach (params, mime_store_parameter, hbuf);
+}
+
+/* Store a header in accordance with RFC 2231, Section 3,
+   "Parameter Value Continuations"
+
+   HDR    -  Message header object
+   NAME   -  Header name
+   VALUE  -  Header value part
+   PARAMS -  Named parameters (assoc of struct mu_mime_param *)
+   LINE_WIDTH - Maximum line width.
+*/
+
+int
+mu_mime_header_set_w (mu_header_t hdr, const char *name,
+		      const char *value, mu_assoc_t params, size_t line_width)
+{
+  struct header_buffer hbuf;
+  int rc;
+  
+  rc = mu_memory_stream_create (&hbuf.str, MU_STREAM_RDWR);
+  if (rc)
+    return rc;
+  hbuf.line_len = strlen (name) + 2;
+  hbuf.line_max = line_width;
+  rc = mime_header_format (value, params, &hbuf);
+  if (rc == 0)
+    {
+      mu_off_t pos;
+      char *fmtval;
+      
+      mu_stream_seek (hbuf.str, 0, MU_SEEK_CUR, &pos);
+      fmtval = malloc (pos + 1);
+      mu_stream_seek (hbuf.str, 0, MU_SEEK_SET, NULL);
+      mu_stream_read (hbuf.str, fmtval, pos, NULL);
+      fmtval[pos] = 0;
+      rc = mu_header_set_value (hdr, name, fmtval, 1);
+      free (fmtval);
+    }
+  mu_stream_destroy (&hbuf.str);
+  return rc;