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diff --git a/camel/camel-list-utils.h b/camel/camel-list-utils.h
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+/*
+ * Authors: Michael Zucchi <notzed@ximian.com>
+ *
+ * Copyright 2004 Novell, Inc. (www.novell.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program 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 this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+#ifndef _CAMEL_LIST_UTILS_H
+#define _CAMEL_LIST_UTILS_H
+
+/* This is a copy of Amiga's Exec lists, the head and tail nodes are
+ * overlapped and merged into a single list header.  All operations
+ * are O(1), including node removal and addition from/to either end of
+ * the list.  It can be used to implement O(1) queues, fifo's and
+ * normal lists.  You don't need the list header to remove the node. */
+
+typedef struct _CamelDList CamelDList;
+typedef struct _CamelDListNode CamelDListNode;
+
+/**
+ * struct _CamelDListNode - A double-linked list node.
+ * 
+ * @next: The next node link.
+ * @prev: The previous node link.
+ * 
+ * A double-linked list node header.  Put this at the start of the
+ * list node structure.  Data is stored in the list by subclassing the
+ * node header rather than using a pointer.  Or more normally by just
+ * duplicating the next and previous pointers for better type safety.
+ **/
+struct _CamelDListNode {
+	struct _CamelDListNode *next;
+	struct _CamelDListNode *prev;
+};
+
+/**
+ * struct _CamelDList - A double-linked list header.
+ * 
+ * @head: The head node's next pointer.
+ * @tail: The tail node's next pointer.
+ * @tailpred: The previous node to the tail node.
+ * 
+ * This is the merging of two separate head and tail nodes into a
+ * single structure.  i.e. if you ahve a NULL terminated head and tail
+ * node such as head = { first, NULL } and tail = { NULL, last } then
+ * overlap them at the common NULL, you get this structure.
+ *
+ * The list header must be initialised with camel_dlist_init, or by
+ * using the static CAMEL_DLIST_INITIALISER macro.
+ **/
+struct _CamelDList {
+	struct _CamelDListNode *head;
+	struct _CamelDListNode *tail;
+	struct _CamelDListNode *tailpred;
+};
+
+#define CAMEL_DLIST_INITIALISER(l) { (CamelDListNode *)&l.tail, 0, (CamelDListNode *)&l.head }
+
+void camel_dlist_init(CamelDList *v);
+CamelDListNode *camel_dlist_addhead(CamelDList *l, CamelDListNode *n);
+CamelDListNode *camel_dlist_addtail(CamelDList *l, CamelDListNode *n);
+CamelDListNode *camel_dlist_remove(CamelDListNode *n);
+CamelDListNode *camel_dlist_remhead(CamelDList *l);
+CamelDListNode *camel_dlist_remtail(CamelDList *l);
+int camel_dlist_empty(CamelDList *l);
+int camel_dlist_length(CamelDList *l);
+
+/* This is provided mostly for orthogonality with the dlist structure.
+ * By making the nodes contain all of the data themselves it
+ * simplifies memory management.  Removing and adding from/to the head
+ * of the list is O(1), the rest of the operations are O(n). */
+
+typedef struct _CamelSListNode CamelSListNode;
+typedef struct _CamelSList CamelSList;
+
+/**
+ * struct _CamelSListNode - A single-linked list node.
+ * 
+ * @next: The next node in the list.
+ *
+ * A single-linked list node header.  Put this at hte start of the
+ * actual list node structure, or more commonly, just a next pointer.
+ * Data is stored in the list node by subclassing the node-header
+ * rather than using a pointer.
+ **/
+struct _CamelSListNode {
+	struct _CamelSListNode *next;
+};
+
+/**
+ * struct _CamelSList - A single-linked list header.
+ * 
+ * @head: The head of the list.
+ * 
+ * This is the header of a single-linked list.
+ **/
+struct _CamelSList {
+	struct _CamelSListNode *head;
+};
+
+#define CAMEL_SLIST_INITIALISER(l) { 0 }
+
+void camel_slist_init(CamelSList *l);
+CamelSListNode *camel_slist_addhead(CamelSList *l, CamelSListNode *n);
+CamelSListNode *camel_slist_addtail(CamelSList *l, CamelSListNode *n);
+CamelSListNode *camel_slist_remove(CamelSList *l, CamelSListNode *n);
+CamelSListNode *camel_slist_remhead(CamelSList *l);
+CamelSListNode *camel_slist_remtail(CamelSList *l);
+int camel_slist_empty(CamelSList *l);
+int camel_slist_length(CamelSList *l);
+
+#endif