ModuleManager angefangen; libltdl zum Projekt hinzugefuegt

1 files changed, 375 insertions, 0 deletions

diff --git a/libltdl/slist.c b/libltdl/slist.c
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+/* slist.c -- generalised singly linked lists
+
+   Copyright (C) 2000, 2004, 2007, 2008 Free Software Foundation, Inc.
+   Written by Gary V. Vaughan, 2000
+
+   NOTE: The canonical source of this file is maintained with the
+   GNU Libtool package.  Report bugs to bug-libtool@gnu.org.
+
+GNU Libltdl 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 2 of the License, or (at your option) any later version.
+
+As a special exception to the GNU Lesser General Public License,
+if you distribute this file as part of a program or library that
+is built using GNU Libtool, you may include this file under the
+same distribution terms that you use for the rest of that program.
+
+GNU Libltdl 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 GNU Libltdl; see the file COPYING.LIB.  If not, a
+copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
+or obtained by writing to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+*/
+
+#include <assert.h>
+
+#include "slist.h"
+#include <stddef.h>
+
+static SList *	slist_sort_merge    (SList *left, SList *right,
+				     SListCompare *compare, void *userdata);
+
+
+/* Call DELETE repeatedly on each element of HEAD.
+
+   CAVEAT: If you call this when HEAD is the start of a list of boxed
+           items, you must remember that each item passed back to your
+	   DELETE function will be a boxed item that must be slist_unbox()ed
+	   before operating on its contents.
+
+   e.g. void boxed_delete (void *item) { item_free (slist_unbox (item)); }
+        ...
+	  slist = slist_delete (slist, boxed_delete);
+	...
+*/
+SList *
+slist_delete (SList *head, void (*delete_fct) (void *item))
+{
+  assert (delete_fct);
+
+  while (head)
+    {
+      SList *next = head->next;
+      (*delete_fct) (head);
+      head = next;
+    }
+
+  return 0;
+}
+
+/* Call FIND repeatedly with MATCHDATA and each item of *PHEAD, until
+   FIND returns non-NULL, or the list is exhausted.  If a match is found
+   the matching item is destructively removed from *PHEAD, and the value
+   returned by the matching call to FIND is returned.
+
+   CAVEAT: To avoid memory leaks, unless you already have the address of
+           the stale item, you should probably return that from FIND if
+	   it makes a successful match.  Don't forget to slist_unbox()
+	   every item in a boxed list before operating on its contents.   */
+void *
+slist_remove (SList **phead, SListCallback *find, void *matchdata)
+{
+  SList *stale = 0;
+  void *result = 0;
+
+  assert (find);
+
+  if (!phead || !*phead)
+    return 0;
+
+  /* Does the head of the passed list match? */
+  result = (*find) (*phead, matchdata);
+  if (result)
+    {
+      stale = *phead;
+      *phead = stale->next;
+    }
+  /* what about the rest of the elements? */
+  else
+    {
+      SList *head;
+      for (head = *phead; head->next; head = head->next)
+	{
+	  result = (*find) (head->next, matchdata);
+	  if (result)
+	    {
+	      stale		= head->next;
+	      head->next	= stale->next;
+	      break;
+	    }
+	}
+    }
+
+  return result;
+}
+
+/* Call FIND repeatedly with each element of SLIST and MATCHDATA, until
+   FIND returns non-NULL, or the list is exhausted.  If a match is found
+   the value returned by the matching call to FIND is returned. */
+void *
+slist_find (SList *slist, SListCallback *find, void *matchdata)
+{
+  void *result = 0;
+
+  assert (find);
+
+  for (; slist; slist = slist->next)
+    {
+      result = (*find) (slist, matchdata);
+      if (result)
+	break;
+    }
+
+  return result;
+}
+
+/* Return a single list, composed by destructively concatenating the
+   items in HEAD and TAIL.  The values of HEAD and TAIL are undefined
+   after calling this function.
+
+   CAVEAT: Don't mix boxed and unboxed items in a single list.
+
+   e.g.  slist1 = slist_concat (slist1, slist2);  */
+SList *
+slist_concat (SList *head, SList *tail)
+{
+  SList *last;
+
+  if (!head)
+    {
+      return tail;
+    }
+
+  last = head;
+  while (last->next)
+    last = last->next;
+
+  last->next = tail;
+
+  return head;
+}
+
+/* Return a single list, composed by destructively appending all of
+   the items in SLIST to ITEM.  The values of ITEM and SLIST are undefined
+   after calling this function.
+
+   CAVEAT:  Don't mix boxed and unboxed items in a single list.
+
+   e.g.  slist1 = slist_cons (slist_box (data), slist1);  */
+SList *
+slist_cons (SList *item, SList *slist)
+{
+  if (!item)
+    {
+      return slist;
+    }
+
+  assert (!item->next);
+
+  item->next = slist;
+  return item;
+}
+
+/* Return a list starting at the second item of SLIST.  */
+SList *
+slist_tail (SList *slist)
+{
+  return slist ? slist->next : NULL;
+}
+
+/* Return a list starting at the Nth item of SLIST.  If SLIST is less
+   than N items long, NULL is returned.  Just to be confusing, list items
+   are counted from 1, to get the 2nd element of slist:
+
+   e.g. shared_list = slist_nth (slist, 2);  */
+SList *
+slist_nth (SList *slist, size_t n)
+{
+  for (;n > 1 && slist; n--)
+    slist = slist->next;
+
+  return slist;
+}
+
+/* Return the number of items in SLIST.  We start counting from 1, so
+   the length of a list with no items is 0, and so on.  */
+size_t
+slist_length (SList *slist)
+{
+  size_t n;
+
+  for (n = 0; slist; ++n)
+    slist = slist->next;
+
+  return n;
+}
+
+/* Destructively reverse the order of items in SLIST.  The value of SLIST
+   is undefined after calling this function.
+
+  CAVEAT: You must store the result of this function, or you might not
+          be able to get all the items except the first one back again.
+
+  e.g.    slist = slist_reverse (slist);  */
+SList *
+slist_reverse (SList *slist)
+{
+  SList *result = 0;
+  SList *next;
+
+  while (slist)
+    {
+      next		= slist->next;
+      slist->next	= result;
+      result		= slist;
+      slist 		= next;
+    }
+
+  return result;
+}
+
+/* Call FOREACH once for each item in SLIST, passing both the item and
+   USERDATA on each call. */
+void *
+slist_foreach (SList *slist, SListCallback *foreach, void *userdata)
+{
+  void *result = 0;
+
+  assert (foreach);
+
+  while (slist)
+    {
+      SList *next = slist->next;
+      result = (*foreach) (slist, userdata);
+
+      if (result)
+	break;
+
+      slist = next;
+    }
+
+  return result;
+}
+
+/* Destructively merge the items of two ordered lists LEFT and RIGHT,
+   returning a single sorted list containing the items of both --  Part of
+   the quicksort algorithm.  The values of LEFT and RIGHT are undefined
+   after calling this function.
+
+   At each iteration, add another item to the merged list by taking the
+   lowest valued item from the head of either LEFT or RIGHT, determined
+   by passing those items and USERDATA to COMPARE.  COMPARE should return
+   less than 0 if the head of LEFT has the lower value, greater than 0 if
+   the head of RIGHT has the lower value, otherwise 0.  */
+static SList *
+slist_sort_merge (SList *left, SList *right, SListCompare *compare,
+		  void *userdata)
+{
+  SList merged, *insert;
+
+  insert = &merged;
+
+  while (left && right)
+    {
+      if ((*compare) (left, right, userdata) <= 0)
+	{
+	  insert = insert->next = left;
+	  left = left->next;
+	}
+      else
+	{
+	  insert = insert->next = right;
+	  right = right->next;
+	}
+    }
+
+  insert->next = left ? left : right;
+
+  return merged.next;
+}
+
+/* Perform a destructive quicksort on the items in SLIST, by repeatedly
+   calling COMPARE with a pair of items from SLIST along with USERDATA
+   at every iteration.  COMPARE is a function as defined above for
+   slist_sort_merge().  The value of SLIST is undefined after calling
+   this function.
+
+   e.g.  slist = slist_sort (slist, compare, 0);  */
+SList *
+slist_sort (SList *slist, SListCompare *compare, void *userdata)
+{
+  SList *left, *right;
+
+  if (!slist)
+    return slist;
+
+  /* Be sure that LEFT and RIGHT never contain the same item.  */
+  left = slist;
+  right = slist->next;
+
+  /* Skip two items with RIGHT and one with SLIST, until RIGHT falls off
+     the end.  SLIST must be about half way along.  */
+  while (right && (right = right->next))
+    {
+      if (!right || !(right = right->next))
+	break;
+      slist = slist->next;
+    }
+  right = slist->next;
+  slist->next = 0;
+
+  /* Sort LEFT and RIGHT, then merge the two.  */
+  return slist_sort_merge (slist_sort (left, compare, userdata),
+			   slist_sort (right, compare, userdata),
+			   compare, userdata);
+}
+
+
+/* Aside from using the functions above to manage chained structures of
+   any type that has a NEXT pointer as its first field, SLISTs can
+   be comprised of boxed items.  The boxes are chained together in
+   that case, so there is no need for a NEXT field in the item proper.
+   Some care must be taken to slist_box and slist_unbox each item in
+   a boxed list at the appropriate points to avoid leaking the memory
+   used for the boxes.  It us usually a very bad idea to mix boxed and
+   non-boxed items in a single list.  */
+
+/* Return a `boxed' freshly mallocated 1 element list containing
+   USERDATA.  */
+SList *
+slist_box (const void *userdata)
+{
+  SList *item = (SList *) malloc (sizeof *item);
+
+  if (item)
+    {
+      item->next     = 0;
+      item->userdata = userdata;
+    }
+
+  return item;
+}
+
+/* Return the contents of a `boxed' ITEM, recycling the box itself.  */
+void *
+slist_unbox (SList *item)
+{
+  void *userdata = 0;
+
+  if (item)
+    {
+      /* Strip the const, because responsibility for this memory
+	 passes to the caller on return.  */
+      userdata = (void *) item->userdata;
+      free (item);
+    }
+
+  return userdata;
+}