Add functions for operations on message sets.

* configure.ac: Build libmailutils/msgset/Makefile
* include/mailutils/msgset.h: New file.
* include/mailutils/Makefile.am (pkginclude_HEADERS): Add msgset.h
* include/mailutils/mailutils.h: Include mailutils/msgset.h
* include/mailutils/sys/msgset.h: New file.
* include/mailutils/sys/Makefile.am (sysinclude_HEADERS): Add msgset.h
* include/mailutils/types.hin (mu_msgset_t): New type.
* libmailutils/Makefile.am (SUBDIRS): Add msgset.
(libmailutils_la_LIBADD): Add libmsgset.la
* libmailutils/msgset/Makefile.am: New file.
* libmailutils/msgset/add.c: New file.
* libmailutils/msgset/aggr.c: New file.
* libmailutils/msgset/clear.c: New file.
* libmailutils/msgset/create.c: New file.
* libmailutils/msgset/free.c: New file.
* libmailutils/msgset/getitr.c: New file.
* libmailutils/msgset/getlist.c: New file.
* libmailutils/msgset/locate.c: New file.
* libmailutils/msgset/parse.c: New file.
* libmailutils/msgset/print.c: New file.
* libmailutils/msgset/sub.c: New file.
* libmailutils/tests/msgset.at: New file.
* libmailutils/tests/msgset.c: New file.
* libmailutils/tests/Makefile.am (noinst_PROGRAMS): Add msgset.
(TESTSUITE_AT): Add msgset.at.
* libmailutils/tests/testsuite.at: Include msgset.at.
* testsuite/msgset.c: New file.
* testsuite/Makefile.am (noinst_PROGRAMS): Add msgset.

17 files changed, 1267 insertions, 1 deletions

diff --git a/libmailutils/Makefile.am b/libmailutils/Makefile.am
index c01b32176..bbc844768 100644
--- a/libmailutils/Makefile.am
+++ b/libmailutils/Makefile.am
@@ -15,13 +15,13 @@
 # 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/>.
 
 SUBDIRS = \
  auth base address list sockaddr cidr cfg diag\
- filter mailbox mailer mime server string stream stdstream\
+ filter mailbox mailer mime msgset server string stream stdstream\
  property url imapio datetime . tests 
 
 lib_LTLIBRARIES = libmailutils.la
 
 libmailutils_la_SOURCES =  
 
@@ -38,12 +38,13 @@ libmailutils_la_LIBADD = \
  filter/libfilter.la\
  imapio/libimapio.la\
  list/liblist.la\
  mailbox/libmailbox.la\
  mailer/libmailer.la\
  mime/libmime.la\
+ msgset/libmsgset.la\
  property/libproperty.la\
  server/libserver.la\
  string/libstring.la\
  stream/libstream.la\
  stdstream/libstdstream.la\
  url/liburl.la
diff --git a/libmailutils/msgset/Makefile.am b/libmailutils/msgset/Makefile.am
new file mode 100644
index 000000000..398806d49
--- /dev/null
+++ b/libmailutils/msgset/Makefile.am
@@ -0,0 +1,34 @@
+# GNU Mailutils -- a suite of utilities for electronic mail
+# Copyright (C) 2011 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/>.
+
+noinst_LTLIBRARIES = libmsgset.la
+
+libmsgset_la_SOURCES = \
+ add.c\
+ aggr.c\
+ clear.c\
+ create.c\
+ getitr.c\
+ getlist.c\
+ free.c\
+ locate.c\
+ parse.c\
+ print.c\
+ sub.c
+
+INCLUDES = @MU_LIB_COMMON_INCLUDES@ -I/libmailutils
+
diff --git a/libmailutils/msgset/add.c b/libmailutils/msgset/add.c
new file mode 100644
index 000000000..9d9770735
--- /dev/null
+++ b/libmailutils/msgset/add.c
@@ -0,0 +1,43 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+int
+mu_msgset_add_range (mu_msgset_t mset, size_t beg, size_t end)
+{
+  int rc;
+  struct mu_msgrange *range;
+  
+  if (!mset || beg == 0)
+    return EINVAL;
+  range = calloc (1, sizeof (*range));
+  if (!range)
+    return ENOMEM;
+  range->msg_beg = beg;
+  range->msg_end = end;
+  rc = mu_list_append (mset->list, range);
+  if (rc)
+    free (range);
+  mset->flags &= ~_MU_MSGSET_AGGREGATED;
+  return rc;
+}
diff --git a/libmailutils/msgset/aggr.c b/libmailutils/msgset/aggr.c
new file mode 100644
index 000000000..a6fe7aa19
--- /dev/null
+++ b/libmailutils/msgset/aggr.c
@@ -0,0 +1,169 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/iterator.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+/* Comparator function for sorting the message set list. */
+static int
+compare_msgrange (const void *a, const void *b)
+{
+  struct mu_msgrange const *sa = a;
+  struct mu_msgrange const *sb = b;
+  
+  if (sa->msg_end != sb->msg_end)
+    {
+      if (sa->msg_end == MU_MSGNO_LAST)
+	return 1;
+      if (sb->msg_end == MU_MSGNO_LAST)
+	return -1;
+    }
+  
+  if (sa->msg_beg < sb->msg_beg)
+    return -1;
+  if (sa->msg_beg > sb->msg_beg)
+    return 1;
+
+  if (sa->msg_end == sb->msg_end)
+    return 0;
+
+  if (sa->msg_end < sb->msg_end)
+    return -1;
+  return 1;
+}
+
+int
+mu_msgset_aggregate (mu_msgset_t mset)
+{
+  int rc;
+  mu_iterator_t itr;
+  size_t count;
+  struct mu_msgrange *prev = NULL, *mr;
+  int dir;
+  
+  if (!mset)
+    return EINVAL;
+
+  if (mset->flags & _MU_MSGSET_AGGREGATED)
+    return 0; /* nothing to do */
+  
+  rc = mu_list_count (mset->list, &count);
+  if (rc)
+    return rc;
+  if (count < 2)
+    return 0;
+  
+  mu_list_sort (mset->list, compare_msgrange);
+  
+  rc = mu_list_get_iterator (mset->list, &itr);
+  if (rc)
+    return rc;
+  /* Set backward direction */
+  dir = 1;
+  rc = mu_iterator_ctl (itr, mu_itrctl_set_direction, &dir);
+  if (rc)
+    {
+      mu_iterator_destroy (&itr);
+      return rc;
+    }
+
+  mu_iterator_first (itr);
+  mu_iterator_current (itr, (void **)&mr);
+  
+  if (mr->msg_end == MU_MSGNO_LAST)
+    {
+      struct mu_msgrange *last = mr;
+      
+      for (mu_iterator_next (itr);
+	   rc == 0 && !mu_iterator_is_done (itr); mu_iterator_next (itr))
+	{
+	  mu_iterator_current (itr, (void **)&mr);
+	  if (mr->msg_end == MU_MSGNO_LAST)
+	    {
+	      last->msg_beg = mr->msg_beg;
+	      rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+	    }
+	  else if (mr->msg_beg >= last->msg_beg)
+	    rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+	  else if (mr->msg_end + 1 >= last->msg_beg)
+	    {
+	      last->msg_beg = mr->msg_beg;
+	      rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+	    }
+	  else
+	    break;
+	}
+    }
+
+  if (rc == 0)
+    {
+      dir = 0;
+      rc = mu_iterator_ctl (itr, mu_itrctl_set_direction, &dir);
+      if (rc)
+	{
+	  mu_iterator_destroy (&itr);
+	  return rc;
+	}
+
+      for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
+	   mu_iterator_next (itr))
+	{
+	  mu_iterator_current (itr, (void **)&mr);
+	  if (mr->msg_end == MU_MSGNO_LAST)
+	    break;
+	  if (prev)
+	    {
+	      if (prev->msg_beg <= mr->msg_beg && mr->msg_beg <= prev->msg_end)
+		{
+		  /* Possible cases:
+		     1. mr lies fully within prev:
+		     mr->msg_end <= prev->msg_end
+		     Action: mr deleted
+		     2. mr overlaps with prev:
+		     mr->msg_end > prev->msg_end
+		     Action: prev->msg_end is set to mr->msg_end; mr deleted
+		  */
+		  if (mr->msg_end > prev->msg_end)
+		    prev->msg_end = mr->msg_end;
+		  rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+		  if (rc)
+		    break;
+		  continue;
+		}
+	      else if (prev->msg_end + 1 == mr->msg_beg)
+		{
+		  prev->msg_end = mr->msg_end;
+		  rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+		  if (rc)
+		    break;
+		  continue;
+		}
+	    }
+	  prev = mr;
+	}
+    }
+  mu_iterator_destroy (&itr);
+
+  if (rc == 0)
+    mset->flags |= _MU_MSGSET_AGGREGATED;
+  return rc;
+}
diff --git a/libmailutils/msgset/clear.c b/libmailutils/msgset/clear.c
new file mode 100644
index 000000000..f3f7ef874
--- /dev/null
+++ b/libmailutils/msgset/clear.c
@@ -0,0 +1,32 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+int
+mu_msgset_clear (mu_msgset_t mset)
+{
+  if (!mset)
+    return EINVAL;
+  mu_list_clear (mset->list);
+  return 0;
+}
+
diff --git a/libmailutils/msgset/create.c b/libmailutils/msgset/create.c
new file mode 100644
index 000000000..0f70ab265
--- /dev/null
+++ b/libmailutils/msgset/create.c
@@ -0,0 +1,60 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+/* Comparator function used to locate a message in the list.  Second argument
+   (b) is a pointer to the message number. */
+static int
+compare_msgnum (const void *a, const void *b)
+{
+  struct mu_msgrange const *range = a;
+  size_t msgno = *(size_t*)b;
+
+  if (range->msg_beg <= msgno && msgno <= range->msg_end)
+    return 0;
+  return 1;
+}
+
+int
+mu_msgset_create (mu_msgset_t *pres, mu_mailbox_t mbox, int flags)
+{
+  mu_msgset_t msgset;
+  int rc;
+
+  msgset = calloc (1, sizeof (*msgset));
+  if (!msgset)
+    return ENOMEM;
+  
+  rc = mu_list_create (&msgset->list);
+  if (rc)
+    {
+      free (msgset);
+      return rc;
+    }
+  mu_list_set_destroy_item (msgset->list, mu_list_free_item);
+  mu_list_set_comparator (msgset->list, compare_msgnum);
+  msgset->mbox = mbox;
+  msgset->flags = flags & _MU_MSGSET_USERFLAG_MASK;
+  *pres = msgset;
+  return 0;
+}
diff --git a/libmailutils/msgset/free.c b/libmailutils/msgset/free.c
new file mode 100644
index 000000000..77a348e14
--- /dev/null
+++ b/libmailutils/msgset/free.c
@@ -0,0 +1,42 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+void
+mu_msgset_free (mu_msgset_t mset)
+{
+  if (mset)
+    {
+      mu_list_destroy (&mset->list);
+      free (mset);
+    }
+}
+
+void
+mu_msgset_destroy (mu_msgset_t *pset)
+{
+  if (pset)
+    {
+      mu_msgset_free (*pset);
+      *pset = NULL;
+    }
+}
+  
diff --git a/libmailutils/msgset/getitr.c b/libmailutils/msgset/getitr.c
new file mode 100644
index 000000000..75cfb3df0
--- /dev/null
+++ b/libmailutils/msgset/getitr.c
@@ -0,0 +1,30 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+int
+mu_msgset_get_iterator (mu_msgset_t msgset, mu_iterator_t *pitr)
+{
+  if (!msgset)
+    return EINVAL;
+  return mu_list_get_iterator (msgset->list, pitr);
+}
diff --git a/libmailutils/msgset/getlist.c b/libmailutils/msgset/getlist.c
new file mode 100644
index 000000000..5f7370dc1
--- /dev/null
+++ b/libmailutils/msgset/getlist.c
@@ -0,0 +1,33 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+int
+mu_msgset_get_list (mu_msgset_t msgset, mu_list_t *plist)
+{
+  if (!msgset)
+    return EINVAL;
+  if (!plist)
+    return MU_ERR_OUT_PTR_NULL;
+  *plist = msgset->list;
+  return 0;
+}
diff --git a/libmailutils/msgset/locate.c b/libmailutils/msgset/locate.c
new file mode 100644
index 000000000..7b94ece89
--- /dev/null
+++ b/libmailutils/msgset/locate.c
@@ -0,0 +1,32 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+int
+mu_msgset_locate (mu_msgset_t msgset, size_t n,
+		  struct mu_msgrange const **prange)
+{
+  if (!msgset || n == 0)
+    return EINVAL;
+  return mu_list_locate (msgset->list, &n, (void**)prange);
+}
diff --git a/libmailutils/msgset/parse.c b/libmailutils/msgset/parse.c
new file mode 100644
index 000000000..6e139fc53
--- /dev/null
+++ b/libmailutils/msgset/parse.c
@@ -0,0 +1,179 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/iterator.h>
+#include <mailutils/mailbox.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+/* This structure keeps parser state while parsing message set. */
+struct parse_msgnum_env
+{
+  char *s;               /* Current position in string */
+  size_t minval;         /* Min. sequence number or UID */
+  size_t maxval;         /* Max. sequence number or UID */
+  mu_msgset_t msgset;    /* Message set being built. */
+};
+
+/* Get a single message number/UID from env->s and store it into *PN.
+   Return 0 on success and error code on error.
+
+   Advance env->s to the point past the parsed message number.
+ */
+static int
+get_msgnum (struct parse_msgnum_env *env, size_t *pn)
+{
+  size_t msgnum;
+  char *p;
+  
+  errno = 0;
+  msgnum = strtoul (env->s, &p, 10);
+  if (msgnum == ULONG_MAX && errno == ERANGE)
+    return MU_ERR_PARSE;
+  env->s = p;
+  if (env->msgset->mbox && env->maxval && msgnum > env->maxval)
+    msgnum = env->maxval;
+  *pn = msgnum;
+  return 0;
+}
+
+/* Parse a single message range (A:B). Treat '*' as the largest number/UID
+   in use. */
+static int
+parse_msgrange (struct parse_msgnum_env *env)
+{
+  int rc;
+  struct mu_msgrange msgrange;
+  
+  if (*env->s == '*')
+    {
+      msgrange.msg_beg = env->maxval;
+      env->s++;
+    }
+  else if ((rc = get_msgnum (env, &msgrange.msg_beg)))
+    return rc;
+
+  if (*env->s == ':')
+    {
+      if (*++env->s == '*')
+	{
+	  msgrange.msg_end = env->maxval;
+	  ++env->s;
+	}
+      else if (*env->s == 0)
+	return MU_ERR_PARSE;
+      else if ((rc = get_msgnum (env, &msgrange.msg_end)))
+	return rc;
+    }
+  else
+    msgrange.msg_end = msgrange.msg_beg;
+
+  if (msgrange.msg_end && msgrange.msg_end < msgrange.msg_beg)
+    {
+      size_t tmp = msgrange.msg_end;
+      msgrange.msg_end = msgrange.msg_beg;
+      msgrange.msg_beg = tmp;
+    }
+
+  if ((env->msgset->flags & MU_MSGSET_UID) && env->msgset->mbox)
+    {
+      int rc;
+
+      rc = mu_mailbox_translate (env->msgset->mbox,
+				 MU_MAILBOX_UID_TO_MSGNO,
+				 msgrange.msg_beg, &msgrange.msg_beg);
+      if (rc == MU_ERR_NOENT)
+	msgrange.msg_beg = env->minval;
+      else if (rc)
+	return rc;
+      
+      rc = mu_mailbox_translate (env->msgset->mbox,
+				 MU_MAILBOX_UID_TO_MSGNO,
+				 msgrange.msg_end, &msgrange.msg_end);
+      if (rc == MU_ERR_NOENT)
+	msgrange.msg_end = env->maxval;
+      else if (rc)
+	return rc;
+    }      
+
+  return mu_msgset_add_range (env->msgset, msgrange.msg_beg, msgrange.msg_end);
+}
+
+/* Parse IMAP-style message set specification S.
+
+   On success, return 0 and populate MSET with the resulting message ranges.
+   On error, return error code and point END to the position in the input
+   string where parsing has failed. */
+int
+mu_msgset_parse_imap (mu_msgset_t mset, char *s, char **end)
+{
+  int rc;
+  struct parse_msgnum_env env;
+  
+  if (!s || !mset)
+    return EINVAL;
+  if (!*s)
+    return MU_ERR_PARSE;
+
+  memset (&env, 0, sizeof (env));
+  env.s = s;
+  env.msgset = mset;
+  env.minval = 1;
+  
+  if (end)
+    *end = s;
+  if (mset->mbox)
+    {
+      size_t lastmsgno;      /* Max. sequence number. */
+
+      rc = mu_mailbox_messages_count (mset->mbox, &lastmsgno);
+      if (rc == 0)
+	{
+	  if (mset->flags & MU_MSGSET_UID)
+	    {
+	      rc = mu_mailbox_translate (mset->mbox, MU_MAILBOX_MSGNO_TO_UID,
+					 lastmsgno, &env.maxval);
+	      if (rc == 0)
+		rc = mu_mailbox_translate (mset->mbox, MU_MAILBOX_MSGNO_TO_UID,
+					   1, &env.minval);
+	    }
+	  else
+	    env.maxval = lastmsgno;
+	}
+      if (rc)
+	return rc;
+    }
+  
+  while ((rc = parse_msgrange (&env)) == 0 && *env.s)
+    {
+      if (*env.s != ',' || *++env.s == 0)
+	{
+	  rc = MU_ERR_PARSE;
+	  break;
+	}
+    }
+
+  if (end)
+    *end = env.s;
+  return rc;
+}
diff --git a/libmailutils/msgset/print.c b/libmailutils/msgset/print.c
new file mode 100644
index 000000000..e7f990e5b
--- /dev/null
+++ b/libmailutils/msgset/print.c
@@ -0,0 +1,74 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/stream.h>
+#include <mailutils/io.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+struct print_env
+{
+  mu_stream_t stream;
+  int cont;
+};
+
+static int
+_msgrange_printer (void *item, void *data)
+{
+  int rc;
+  struct mu_msgrange *range = item;
+  struct print_env *env = data;
+
+  if (env->cont)
+    {
+      rc = mu_stream_write (env->stream, ",", 1, NULL);
+      if (rc)
+	return rc;
+    }
+  else
+    env->cont = 1;
+  if (range->msg_beg == range->msg_end)
+    rc = mu_stream_printf (env->stream, "%lu", (unsigned long) range->msg_beg);
+  else if (range->msg_end == 0)
+    rc = mu_stream_printf (env->stream, "%lu:*",
+			   (unsigned long) range->msg_beg);
+  else
+    rc = mu_stream_printf (env->stream, "%lu:%lu",
+			   (unsigned long) range->msg_beg,
+			   (unsigned long) range->msg_end);
+  return rc;
+}
+
+int
+mu_msgset_print (mu_stream_t str, mu_msgset_t mset)
+{
+  struct print_env env;
+  int rc;
+  
+  if (mu_list_is_empty (mset->list))
+    return MU_ERR_NOENT;
+  rc = mu_msgset_aggregate (mset);
+  if (rc)
+    return rc;
+  env.stream = str;
+  env.cont = 0;
+  return mu_list_foreach (mset->list, _msgrange_printer, &env);
+}
diff --git a/libmailutils/msgset/sub.c b/libmailutils/msgset/sub.c
new file mode 100644
index 000000000..2840781dc
--- /dev/null
+++ b/libmailutils/msgset/sub.c
@@ -0,0 +1,233 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdlib.h>
+#include <mailutils/types.h>
+#include <mailutils/errno.h>
+#include <mailutils/list.h>
+#include <mailutils/iterator.h>
+#include <mailutils/msgset.h>
+#include <mailutils/sys/msgset.h>
+
+/* Remove range R from the set S.
+
+   There are following basic cases:
+
+   1. S does not contain R.
+
+      Return imeediately, there is nothing to do here.
+
+   2. S contains a range X that matches exactly R.
+
+      Action: Remove X entirely and return.
+
+   3. There is a range X in S such that R falls entirely within it.
+
+      Action: Split X into two ranges:
+
+         X.msg_beg   : R.msg_beg-1
+	 R.msg_end+1 : X.msg_end
+
+      and return.
+      In border cases one of the new ranges may be empty.
+
+   4. There is a range X which contains an initial subrange of R.
+
+      Action: Remove the subrange from X. If the resulting range is
+      empty, remove it. Continue iteration with X.msg_end:R.msg_end
+      in place of R.
+
+   5. There is a range X such that its initial subrange is contained
+      in R.
+
+      Action: Remove X.msg_beg:R.msg_end and return.
+
+   6. There is a range X that is contained within R.
+
+      Action: Remove X and continue.
+
+There are two special cases.  First is when R.msg_end is 0, meaning the last
+available message number in the mailbox.  In this case the problem is reduced
+to either 2 or a combination of 4 and zero or more 6.  It is handled by the
+sub_msgno_last function below.
+
+Yet another special case is when the last element of S has msg_end == 0.  If
+so, the problem is reduced to either 2 or 4.
+*/
+
+static int
+sub_msgno_last (mu_msgset_t mset, size_t beg)
+{
+  int rc;
+  struct mu_msgrange *range;
+
+  if (beg == 1)
+    mu_list_clear (mset->list);
+  else
+    {
+      mu_iterator_t itr;
+      
+      rc = mu_list_get_iterator (mset->list, &itr);
+      if (rc)
+	return rc;
+      rc = 1;
+      rc = mu_iterator_ctl (itr, mu_itrctl_set_direction, &rc);
+      if (rc)
+	{
+	  mu_iterator_destroy (&itr);
+	  return rc;
+	}
+	  
+      for (mu_iterator_first (itr); rc == 0 && !mu_iterator_is_done (itr);
+	   mu_iterator_next (itr))
+	{
+	  mu_iterator_current (itr, (void **)&range);
+	  if (range->msg_beg > beg)
+	    rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+	  else if (range->msg_beg == beg)
+	    {
+	      rc = mu_iterator_ctl (itr, mu_itrctl_delete, NULL);
+	      break;
+	    }
+	  else
+	    break;
+	}