New file. Source for the sortm utility.

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2003 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 2, 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA  */
+
+/* MH sortm command */
+
+#include <mh.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <signal.h>
+
+const char *argp_program_version = "sortm (" PACKAGE_STRING ")";
+static char doc[] = N_("GNU MH sortm\v"
+"Use -help to obtain the list of traditional MH options.");
+static char args_doc[] = N_("[msgs]");
+
+#define ARG_QUICKSORT 1024
+#define ARG_SHELL     1025
+
+/* GNU options */
+static struct argp_option options[] = {
+  {"folder",        ARG_FOLDER,        N_("FOLDER"), 0,
+   N_("Specify folder to operate upon")},
+
+  {N_("Setting sort keys:"), 0,  NULL, OPTION_DOC,  NULL, 0},
+  {"datefield",     ARG_DATEFIELD,     N_("STRING"), 0,
+   N_("Sort on the date field (default `Date:')"), 10},
+  {"nodatefield",   ARG_NODATEFIELD,   NULL,       0,
+   N_("Undo the effect of the last --datefield option"), 10},
+  {"limit",         ARG_LIMIT,         N_("DAYS"), 0,
+   N_("Consider two datefields equal if their difference lies within the given nuber of DAYS."), 11},
+  {"nolimit",       ARG_NOLIMIT,       NULL,       0,
+   N_("Undo the effect of the last --limit option"), 11},
+  {"textfield",     ARG_TEXTFIELD,     N_("STRING"), 15,
+   N_("Sort on the text field"), 1},
+  {"notextfield",   ARG_NOTEXTFIELD,   NULL,       0,
+   N_("Undo the effect of the last --textfield option"), 15},
+  {"numfield",      ARG_NUMFIELD,      N_("STRING"), 0,
+   N_("Sort on the numeric field"), 16},
+  
+  {N_("Actions:"), 0,  NULL, OPTION_DOC,  NULL, 16},
+  {"reorder", ARG_REORDER,    0, 0,
+   N_("Reorder the messages (default)"), 20 },
+  {"dry-run", ARG_DRY_RUN,    0, 0,
+   N_("Do not do anything, only show what would have been done"), 20 },
+  {"list",    ARG_LIST,   0, 0,
+   N_("List the sorted messages"), 20 },
+  {"form",    ARG_FORM, N_("FILE"),   0,
+   N_("Read format from given file"), 23},
+  {"format",  ARG_FORMAT, N_("FORMAT"), 0,
+   N_("Use this format string"), 23},
+
+  {"verbose",       ARG_VERBOSE,       N_("BOOL"), OPTION_ARG_OPTIONAL,
+   N_("Verbosely list executed actions"), 30 },
+  {"noverbose",     ARG_NOVERBOSE,     NULL, OPTION_HIDDEN, "" },
+
+  {N_("Select sort algorithm:"), 0,  NULL, OPTION_DOC,  NULL, 30},
+
+  {"shell",     ARG_SHELL,      0, 0,
+   N_("Use shell algorithm"), 40 },
+  {"quicksort", ARG_QUICKSORT,  0, 0,
+   N_("Use quicksort algorithm (default)"), 40 },
+  { NULL },
+};
+
+/* Traditional MH options */
+struct mh_option mh_option[] = {
+  {"datefield",     1, 0, "field" },
+  {"nodatefield",   3, 0, 0 },
+  {"textfield",     1, 0, "field" },
+  {"notextfield",   3, 0, 0 },
+  {"limit",         1, 0, "days" },
+  {"nolimit",       3, 0, 0 },
+  {"verbose",       1, MH_OPT_BOOL, NULL},
+  { NULL },
+};
+
+static int limit;
+static int verbose;
+static mailbox_t mbox;
+static const char *mbox_path;
+static mh_msgset_t msgset;
+
+#define ACTION_REORDER   0
+#define ACTION_DRY_RUN   1
+#define ACTION_LIST      2  
+
+static int algorithm = ARG_QUICKSORT;
+static int action = ACTION_REORDER;
+static char *format_str = mh_list_format;
+static mh_format_t format;
+
+typedef int (*compfun) __PMT((void *, void *));
+static void addop __P((char *field, compfun comp));
+static void remop __P((compfun comp));
+static int comp_text __P((void *a, void *b));
+static int comp_date __P((void *a, void *b));
+static int comp_number __P((void *a, void *b));
+
+static int
+opt_handler (int key, char *arg, void *unused, struct argp_state *state)
+{
+  switch (key)
+    {
+    case ARG_FOLDER:
+      current_folder = arg;
+      break;
+      
+    case ARG_DATEFIELD:
+      addop (arg, comp_date);
+      break;
+      
+    case ARG_NUMFIELD:
+      addop (arg, comp_number);
+      break;
+
+    case ARG_NODATEFIELD:
+      remop (comp_date);
+      break;
+      
+    case ARG_TEXTFIELD:
+      addop (arg, comp_text);
+      break;
+      
+    case ARG_NOTEXTFIELD:
+      remop (comp_text);
+      break;
+      
+    case ARG_LIMIT:
+      limit = strtoul (arg, NULL, 0);
+      break;
+      
+    case ARG_NOLIMIT:
+      limit = -1;
+      break;
+      
+    case ARG_VERBOSE:
+      if (!arg || isalpha (arg[0]))
+	verbose = is_true (arg);
+      else
+	verbose = arg[0] - '0';
+      break;
+      
+    case ARG_NOVERBOSE:
+      verbose = 0;
+      break;
+      
+    case ARG_FORM:
+      mh_read_formfile (arg, &format_str);
+      break;
+      
+    case ARG_FORMAT:
+      format_str = arg;
+      break;
+
+    case ARG_REORDER:
+      action = ACTION_REORDER;
+      break;
+      
+    case ARG_LIST:
+      action = ACTION_LIST;
+      break;
+
+    case ARG_DRY_RUN:
+      action = ACTION_DRY_RUN;
+      if (!verbose)
+	verbose = 1;
+      break;
+
+    case ARG_SHELL:
+    case ARG_QUICKSORT:
+      algorithm = key;
+      break;
+      
+    default:
+      return 1;
+    }
+  return 0;
+}
+
+
+/* *********************** Comparison functions **************************** */
+struct comp_op {
+  char *field;
+  compfun comp;
+};
+
+static list_t oplist;
+
+static void
+addop (char *field, compfun comp)
+{
+  struct comp_op *op = xmalloc (sizeof (*op));
+  
+  if (!oplist && list_create (&oplist))
+    {
+      mh_error (_("can't create operation list"));
+      exit (1);
+    }
+  op->field = field;
+  op->comp = comp;
+  list_append (oplist, op);
+}
+
+struct rem_data {
+  struct comp_op *op;
+  compfun comp;
+};
+
+static int
+rem_action (void *item, void *data)
+{
+  struct comp_op *op = item;
+  struct rem_data *d = data;
+  if (d->comp == op->comp)
+    d->op = op;
+  return 0;
+}
+
+static void
+remop (compfun comp)
+{
+  struct rem_data d;
+  d.comp = comp;
+  d.op = NULL;
+  list_do (oplist, rem_action, &d);
+  list_remove (oplist, d.op);
+  free (d.op);
+}
+
+struct comp_data {
+  int r;
+  message_t m[2];
+};
+
+static int
+compare_action (void *item, void *data)
+{
+  struct comp_op *op = item;
+  struct comp_data *dp = data;
+  char *a, *ap, *b, *bp;
+  header_t h;
+  
+  if (message_get_header (dp->m[0], &h)
+      || header_aget_value (h, op->field, &a))
+    return 0;
+
+  if (message_get_header (dp->m[1], &h)
+      || header_aget_value (h, op->field, &b))
+    {
+      free (a);
+      return 0;
+    }
+
+  ap = a;
+  bp = b;
+  if (strcasecmp (op->field, MU_HEADER_SUBJECT) == 0)
+    {
+      if (strncasecmp (ap, "re:", 3) == 0)
+	ap += 3;
+      if (strncasecmp (b, "re:", 3) == 0)
+	bp += 3;
+    }
+  
+  dp->r = op->comp (ap, bp);
+  free (a);
+  free (b);
+
+  return dp->r; /* go on until the difference is found */
+}
+
+static int
+compare_messages (message_t a, message_t b)
+{
+  struct comp_data d;
+
+  d.r = 0;
+  d.m[0] = a;
+  d.m[1] = b;
+  list_do (oplist, compare_action, &d);
+  if (verbose > 1)
+    fprintf (stderr, "%d\n", d.r);
+  return d.r;
+}
+
+static int
+comp_text (void *a, void *b)
+{
+  return strcasecmp (a, b);
+}
+
+static int
+comp_number (void *a, void *b)
+{
+  long na, nb;
+
+  na = strtol (a, NULL, 0);
+  nb = strtol (b, NULL, 0);
+  if (na > nb)
+    return 1;
+  else if (na < nb)
+    return -1;
+  return 0;
+}
+
+/*FIXME: Also used in imap4d*/
+static int
+_parse_822_date (char *date, time_t * timep)
+{
+  struct tm tm;
+  mu_timezone tz;
+  const char *p = date;
+
+  if (parse822_date_time (&p, date + strlen (date), &tm, &tz) == 0)
+    {
+      *timep = mu_tm2time (&tm, &tz);
+      return 0;
+    }
+  return 1;
+}
+
+static int
+comp_date (void *a, void *b)
+{
+  time_t ta, tb;
+  
+  if (_parse_822_date (a, &ta) || _parse_822_date (b, &tb))
+    return 0;
+
+  if (ta < tb)
+    {
+      if (limit && tb - ta <= limit)
+	return 0;
+      return -1;
+    }
+  else if (ta > tb)
+    {
+      if (limit && ta - tb <= limit)
+	return 0;
+      return 1;
+    }
+  return 0;
+}
+
+
+/* *********************** Sorting routines ***************************** */
+
+static int
+comp0 (size_t na, size_t nb)
+{
+  message_t a, b;
+
+  if (mailbox_get_message (mbox, na, &a)
+      || mailbox_get_message (mbox, nb, &b))
+    return 0;
+  if (verbose > 1)
+    fprintf (stderr,
+	     _("comparing messages %lu and %lu: "),
+	     (unsigned long) na,
+	     (unsigned long) nb);
+  return compare_messages (a, b);
+}
+
+int
+comp (const void *a, const void *b)
+{
+  return comp0 (* (size_t*) a, * (size_t*) b);
+}
+
+
+/* ****************************** Shell sort ****************************** */
+#define prevdst(h) ((h)-1)/3
+
+static int
+startdst (unsigned count, int *num)
+{
+  int i, h;
+
+  for (i = h = 1; 9*h + 4 < count; i++, h = 3*h+1)
+    ;
+  *num = i;
+  return h;
+}
+
+void
+shell_sort ()
+{
+    int h, s, i, j;
+    size_t hold;
+
+    for (h = startdst (msgset.count, &s); s > 0; s--, h = prevdst (h))
+      {
+	if (verbose > 1)
+	  fprintf (stderr, _("distance %d\n"), h);
+        for (j = h; j < msgset.count; j++)
+	  {
+            hold = msgset.list[j];
+            for (i = j - h;
+		 i >= 0 && comp0 (hold, msgset.list[i]) < 0; i -= h)
+	      msgset.list[i + h] = msgset.list[i];
+	    msgset.list[i + h] = hold;
+	  }
+      }
+}
+
+
+/* ****************************** Actions ********************************* */
+
+void
+list_message (size_t num)
+{
+  message_t msg = NULL;
+  char *buffer;
+  mailbox_get_message (mbox, num, &msg);
+  mh_format (&format, msg, num, 76, &buffer);
+  printf ("%s\n", buffer);
+  free (buffer);
+}
+
+void
+swap_message (size_t a, size_t b)
+{
+  char *path_a, *path_b;
+  char *tmp;
+  
+  asprintf (&path_a, "%s/%lu", mbox_path, (unsigned long) a);
+  asprintf (&path_b, "%s/%lu", mbox_path, (unsigned long) b);
+  tmp = mu_tempname (mbox_path);
+  rename (path_a, tmp);
+  unlink (path_a);
+  rename (path_b, path_a);
+  unlink (path_b);
+  rename (tmp, path_b);
+  free (tmp);
+}
+
+void
+transpose(size_t i, size_t n)
+{
+  size_t j;
+
+  for (j = i+1; j < msgset.count; j++)
+    if (msgset.list[j] == n)
+      {
+	size_t t = msgset.list[i];
+	msgset.list[i] = msgset.list[j];
+	msgset.list[j] = t;
+	break;
+      }
+}
+  
+static int got_signal;
+
+RETSIGTYPE
+sighandler (int sig)
+{
+  got_signal = 1;
+}
+
+void
+sort ()
+{
+  size_t *oldlist, i;
+  oldlist = xmalloc (msgset.count * sizeof (*oldlist));
+  memcpy (oldlist, msgset.list, msgset.count * sizeof (*oldlist));
+
+  switch (algorithm)
+    {
+    case ARG_QUICKSORT:
+      qsort(msgset.list, msgset.count, sizeof(msgset.list[0]),
+	    comp);
+      break;
+
+    case ARG_SHELL:
+      shell_sort();
+      break;
+    }
+
+  switch (action)
+    {
+    case ACTION_LIST:
+      for (i = 0; i < msgset.count; i++)
+	list_message (msgset.list[i]);
+      break;
+
+    default:
+      /* Install signal handlers */
+      signal (SIGINT, sighandler);
+      signal (SIGQUIT, sighandler);
+      signal (SIGTERM, sighandler);
+      
+      if (verbose)
+	fprintf (stderr, _("Transpositions:\n"));
+      for (i = 0, got_signal = 0; !got_signal && i < msgset.count; i++)
+	{
+	  if (msgset.list[i] != oldlist[i])
+	    {
+	      size_t old_num, new_num;
+	      message_t msg;
+
+	      mailbox_get_message (mbox, oldlist[i], &msg);
+	      mh_message_number (msg, &old_num);
+	      mailbox_get_message (mbox, msgset.list[i], &msg);
+	      mh_message_number (msg, &new_num);
+	      transpose (i, oldlist[i]);
+	      if (verbose)
+		fprintf (stderr, "{%lu, %lu}\n",
+			 (unsigned long) old_num,
+			 (unsigned long) new_num);
+	      if (action == ACTION_REORDER)
+		swap_message (old_num, new_num);
+	    }
+	}
+    }
+}
+
+
+/* Main */
+
+int
+main (int argc, char **argv)
+{
+  int index;
+  url_t url;
+  
+  mu_init_nls ();
+  mh_argp_parse (argc, argv, 0, options, mh_option,
+		 args_doc, doc, opt_handler, NULL, &index);
+  if (!oplist)
+    addop ("date", comp_date);
+
+  if (action == ACTION_LIST && mh_format_parse (format_str, &format))
+    {
+      mh_error (_("Bad format string"));
+      exit (1);
+    }
+  
+  mbox = mh_open_folder (current_folder, 0);
+  mailbox_get_url (mbox, &url);
+  mbox_path = url_to_string (url);
+  if (memcmp (mbox_path, "mh:", 3) == 0)
+    mbox_path += 3;
+  
+  argc -= index;
+  argv += index;
+
+  mh_msgset_parse (mbox, &msgset, argc, argv, "all");
+  sort (mbox, msgset);
+  return 0;
+}