Implement list mapping.

* include/mailutils/list.h (MU_LIST_MAP_OK)
(MU_LIST_MAP_SKIP,MU_LIST_MAP_STOP): New constants.
(mu_list_mapper_t): New typedef.
(mu_list_map): New proto.
* libmailutils/list/gmap.c: New file.
* libmailutils/list/map.c: New file.
* libmailutils/list/Makefile.am: Add gmap.c and map.c
* libmailutils/tests/listop.c: New command "map".
* libmailutils/tests/list.at: Test the list mapping.

@@ -72,7 +72,51 @@ extern int mu_list_insert_list (mu_list_t list, void *item, mu_list_t new_list,
 				int insert_before);
 extern void mu_list_append_list (mu_list_t list, mu_list_t new_list);
 extern void mu_list_prepend_list (mu_list_t list, mu_list_t new_list);
+
+/* List mapper functions */
+typedef int (*mu_list_mapper_t) (void **itmv, size_t itmc, void *call_data);
+
+/* A generalized list mapping function.
+
+   Mu_list_gmap iterates over the LIST, gathering its elements in an
+   array of type void **.  When NELEM elements has been collected, it
+   calls the MAP function, passing it as arguments the constructed array,
+   number of elements in it (can be less than NELEM on the last call),
+   and call-specific DATA.  Iteration continues while MAP returns 0 and
+   until all elements from the array have been visited.
+
+   Mu_list_gmap returns 0 on success and a non-zero error code on failure.
+   If MAP returns !0, its return value is propagated to the caller.
+*/
+   
+int mu_list_gmap (mu_list_t list, mu_list_mapper_t map, size_t nelem,
+		  void *data);
   
+  
+#define MU_LIST_MAP_OK     0x00
+#define MU_LIST_MAP_SKIP   0x01
+#define MU_LIST_MAP_STOP   0x02
+
+/* List-to-list mapping.
+   
+   Apply the list mapping function MAP to each NELEM elements from the source
+   LIST and use its return values to form a new list, which will be returned
+   in RES.
+
+   MAP gets pointers to the collected elements in its first argument (ITMV).
+   Its second argument (ITMC) gives the number of elements filled in ARR.
+   It can be less than NELEM on the last call to MAP.  The DATA pointer is
+   passed as the 3rd argument.
+
+   Return value from MAP governs the mapping process.  Unless it has the
+   MU_LIST_MAP_SKIP bit set, the itmv[0] element is appended to the new
+   list.  If it has MU_LIST_MAP_STOP bit set, iteration is stopped
+   immediately and any remaining elements in LIST are ignored.
+*/
+
+int mu_list_map (mu_list_t list, mu_list_mapper_t map,
+		 void *data, size_t nelem,
+		 mu_list_t *res);
 #ifdef __cplusplus
 }
 #endif

@@ -28,11 +28,13 @@ liblist_la_SOURCES = \
  empty.c\
  get.c\
  getcomp.c\
+ gmap.c\
  insert.c\
  intersect.c\
  iterator.c\
  listlist.c\
  locate.c\
+ map.c\
  prepend.c\
  remove.c\
  replace.c\

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 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/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/errno.h>
+#include <mailutils/sys/list.h>
+
+int
+mu_list_gmap (mu_list_t list, mu_list_mapper_t map, size_t nelem, void *data)
+{
+  int rc;
+  int status;
+  mu_iterator_t itr;
+  void **buf;
+  size_t i;
+  
+  if (!list || !map || nelem == 0)
+    return EINVAL;
+  rc = mu_list_get_iterator (list, &itr);
+  if (rc)
+    return status;
+  buf = calloc (nelem, sizeof (buf[0]));
+  if (!buf)
+    {
+      mu_iterator_destroy (&itr);
+      return ENOMEM;
+    }
+  for (i = 0, mu_iterator_first (itr); !mu_iterator_is_done (itr);
+       mu_iterator_next (itr))
+    {
+      void *item;
+      mu_iterator_current (itr, &item);
+      buf[i++] = item;
+      if (i == nelem)
+	{
+	  i = 0;
+	  rc = map (buf, nelem, data);
+	  if (rc)
+	    break;
+	}
+    }
+  if (rc == 0 && i > 0 && i < nelem)
+    rc = map (buf, i, data);
+  mu_iterator_destroy (&itr);
+  free (buf);
+  return rc;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 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/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/errno.h>
+#include <mailutils/sys/list.h>
+
+struct map_closure
+{
+  mu_list_mapper_t map;
+  void *data;
+  mu_list_t list;
+  int status;
+};
+
+static int
+_list_mapper (void **itmv, size_t itmc, void *data)
+{
+  struct map_closure *clos = data;
+  int rc, status;
+      
+  if (!clos->list)
+    {
+      status = mu_list_create (&clos->list);
+      if (status)
+	{
+	  clos->status = status;
+	  return MU_ERR_FAILURE;
+	}
+    }
+  
+  rc = clos->map (itmv, itmc, clos->data);
+  if (!(rc & MU_LIST_MAP_SKIP))
+    {
+      status = mu_list_append (clos->list, itmv[0]);
+      if (status)
+	{
+	  clos->status = status;
+	  return MU_ERR_FAILURE;
+	}
+    }
+  if (rc & MU_LIST_MAP_STOP)
+    return MU_ERR_CANCELED;
+  return 0;
+}
+		
+int
+mu_list_map (mu_list_t list, mu_list_mapper_t map, void *data, size_t nelem,
+	     mu_list_t *res)
+{
+  int rc;
+  struct map_closure cl;
+
+  if (!res)
+    return MU_ERR_OUT_PTR_NULL;
+
+  cl.map = map;
+  cl.data = data;
+  cl.list = NULL;
+  cl.status = 0;
+
+  rc = mu_list_gmap (list, _list_mapper, nelem, &cl);
+
+  if (cl.list)
+    *res = cl.list;
+  if (rc == MU_ERR_FAILURE)
+    return cl.status;
+  return 0;
+}

@@ -109,7 +109,7 @@ TESTLIST([get],[],
 # ------------------------------------------------------------
 
 m4_define([MU_TEST_GROUP],[Iterator])
-m4_define([MU_TEST_KEYWORDS],MU_TEST_KEYWORDS[ iterator itr])
+m4_pushdef([MU_TEST_KEYWORDS],MU_TEST_KEYWORDS[ iterator itr])
 
 TESTLIST([forward],[],
 [add en to tre fire fem
@@ -246,6 +246,84 @@ cur
 0:2:fire
 ])
 
+m4_popdef([MU_TEST_KEYWORDS])
+
+
+# ------------------------------------------------------------
+# Maps
+# ------------------------------------------------------------
+
+m4_define([MU_TEST_GROUP],[Map])
+m4_pushdef([MU_TEST_KEYWORDS],MU_TEST_KEYWORDS[ map])
+
+TESTLIST([even],[],
+[add null en to tre fire fem
+map even
+],
+[# items: 3
+null
+to
+fire
+])
+
+TESTLIST([odd],[],
+[add null en to tre fire fem
+map odd
+],
+[# items: 3
+en
+tre
+fem
+])
+
+TESTLIST([odd0],[],
+[add null
+map odd
+],
+[# items: 0
+])
+
+TESTLIST([concat],[],
+[add en to tre fire fem
+map concat 2 -
+],
+[# items: 3
+en-to
+tre-fire
+fem
+])
+
+TESTLIST([concat3],[],
+[add en to tre fire fem
+map concat 3 -
+],
+[# items: 2
+en-to-tre
+fire-fem
+])
+
+TESTLIST([skip],[],
+[add null en to tre fire fem
+map skip 3
+],
+[# items: 3
+tre
+fire
+fem
+])
+
+TESTLIST([trim],[],
+[add null en to tre fire fem
+map trim 3
+],
+[# items: 3
+null
+en
+to
+])
+
+m4_popdef([MU_TEST_KEYWORDS])
+
 dnl ------------------------------------------------------------
 dnl Cleanup
 m4_popdef([TESTLIST])

@@ -428,6 +428,197 @@ cur (int num, mu_iterator_t itr)
   printf ("%s\n", text);
 }
 
+static int
+map_even (void **itmv, size_t itmc, void *call_data)
+{
+  int *num = call_data, n = *num;
+  *num = !*num;
+  if ((n % 2) == 0)
+    {
+      itmv[0] = strdup (itmv[0]);
+      return MU_LIST_MAP_OK;
+    }
+  return MU_LIST_MAP_SKIP;
+}
+
+static int
+map_odd (void **itmv, size_t itmc, void *call_data)
+{
+  int *num = call_data, n = *num;
+  *num = !*num;
+  if (n % 2)
+    {
+      itmv[0] = strdup (itmv[0]);
+      return MU_LIST_MAP_OK;
+    }
+  return MU_LIST_MAP_SKIP;
+}
+
+static int
+map_concat (void **itmv, size_t itmc, void *call_data)
+{
+  char *delim = call_data;
+  size_t dlen = strlen (delim);
+  size_t i;
+  size_t len = 0;
+  char *res, *p;
+  
+  for (i = 0; i < itmc; i++)
+    len += strlen (itmv[i]);
+  len += (itmc - 1) * dlen + 1;
+
+  res = malloc (len);
+  if (!res)
+    abort ();
+  p = res;
+  for (i = 0; ; )
+    {
+      p = mu_stpcpy (p, itmv[i++]);
+      if (i == itmc)
+	break;
+      p = mu_stpcpy (p, delim);
+    }
+  itmv[0] = res;
+  return MU_LIST_MAP_OK;
+}
+
+struct trim_data
+{
+  size_t n;
+  size_t lim;
+};
+
+static int
+map_skip (void **itmv, size_t itmc, void *call_data)
+{
+  struct trim_data *td = call_data;
+
+  if (td->n++ < td->lim)
+    return MU_LIST_MAP_SKIP;
+  itmv[0] = strdup (itmv[0]);
+  return MU_LIST_MAP_OK;
+}
+
+static int
+map_trim (void **itmv, size_t itmc, void *call_data)
+{
+  struct trim_data *td = call_data;
+
+  if (td->n++ < td->lim)
+    {
+      itmv[0] = strdup (itmv[0]);
+      return MU_LIST_MAP_OK;
+    }
+  return MU_LIST_MAP_STOP|MU_LIST_MAP_SKIP;
+}
+
+int
+map (mu_list_t *plist, int argc, char **argv)
+{
+  mu_list_t list = *plist;
+  mu_list_t result;
+  int rc;
+  int replace = 0;
+
+  if (argc > 1 && strcmp (argv[1], "-replace") == 0)
+    {
+      replace = 1;
+      argc--;
+      argv++;
+    }
+  
+  if (argc < 2)
+    {
+      fprintf (stderr, "map [-replace] even|odd|concat|keep|trim\n");
+      return 0;
+    }
+
+  if (strcmp (argv[1], "even") == 0)
+    {
+      int n = 0;
+      rc = mu_list_map (list, map_even, &n, 1, &result);
+    }
+  else if (strcmp (argv[1], "odd") == 0)
+    {
+      int n = 0;
+      rc = mu_list_map (list, map_odd, &n, 1, &result);
+    }
+  else if (strcmp (argv[1], "concat") == 0)
+    {
+      size_t num;
+      char *delim = "";
+      
+      if (argc < 3 || argc > 4)
+	{
+	  fprintf (stderr, "map concat NUM [DELIM]?\n");
+	  return 0;
+	}
+      num = atoi (argv[2]);
+      if (argc == 4)
+	delim = argv[3];
+      
+      rc = mu_list_map (list, map_concat, delim, num, &result);
+    }
+  else if (strcmp (argv[1], "skip") == 0)
+    {
+      struct trim_data td;
+
+      if (argc < 3 || argc > 4)
+	{
+	  fprintf (stderr, "map skip NUM?\n");
+	  return 0;
+	}
+      td.n = 0;
+      td.lim = atoi (argv[2]);
+      rc = mu_list_map (list, map_skip, &td, 1, &result);
+    }
+  else if (strcmp (argv[1], "trim") == 0)
+    {
+      struct trim_data td;
+
+      if (argc < 3 || argc > 4)
+	{
+	  fprintf (stderr, "map trim NUM?\n");
+	  return 0;
+	}
+      td.n = 0;
+      td.lim = atoi (argv[2]);
+      rc = mu_list_map (list, map_trim, &td, 1, &result);
+    }
+  else
+    {
+      mu_error ("unknown map name\n");
+      return 0;
+    }
+  
+  if (rc)
+    {
+      mu_error ("map failed: %s", mu_strerror (rc));
+      return 0;
+    }
+
+  mu_list_set_destroy_item (result, mu_list_free_item);
+
+  if (replace)
+    {
+      size_t count[2];
+      mu_list_count (list, &count[0]);
+      mu_list_count (result, &count[1]);
+      
+      printf ("%lu in, %lu out\n", (unsigned long) count[0],
+	      (unsigned long) count[1]);
+      mu_list_destroy (&list);
+      *plist = result;
+      return 1;
+    }
+  else
+    {
+      print (result);
+      mu_list_destroy (&result);
+    }
+  return 0;
+}
+
 void
 help ()
 {
@@ -446,6 +637,7 @@ help ()
   printf ("ictl repl item\n");
   printf ("ictl ins item [item*]\n");
   printf ("ictl dir [backwards|forwards]\n");
+  printf ("map NAME [ARGS]\n");
   printf ("print\n");
   printf ("quit\n");
   printf ("iter num\n");
@@ -517,6 +709,14 @@ shell (mu_list_t list)
 	    print (list);
 	  else if (strcmp (ws.ws_wordv[0], "cur") == 0)
 	    cur (num, itr[num]);
+	  else if (strcmp (ws.ws_wordv[0], "map") == 0)
+	    {
+	      int i;
+	      
+	      if (map (&list, ws.ws_wordc, ws.ws_wordv))
+		for (i = 0; i < NITR; i++)
+		  mu_iterator_destroy (&itr[i]);
+	    }
 	  else if (strcmp (ws.ws_wordv[0], "quit") == 0)
 	    return;
 	  else if (strcmp (ws.ws_wordv[0], "iter") == 0)
@@ -591,7 +791,7 @@ main (int argc, char **argv)
   
   while (argc--)
     {
-      rc = mu_list_append (list, *argv++);
+      rc = mu_list_append (list, strdup (*argv++));
       if (rc)
 	lperror ("mu_list_append", rc);
     }