From fc3cda204e4ff554dbe975a1607eef4d85d32060 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Axel=20D=C3=B6rfler?= <axeld@pinc-software.de>
Date: Sat, 18 Jan 2003 14:02:47 +0000
Subject: [PATCH] New list primitive. A doubly-linked list with some nice
 features.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@2478 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/private/kernel/list.h | 70 +++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 headers/private/kernel/list.h

diff --git a/headers/private/kernel/list.h b/headers/private/kernel/list.h
new file mode 100644
index 0000000000..045e260021
--- /dev/null
+++ b/headers/private/kernel/list.h
@@ -0,0 +1,70 @@
+/* 
+** Copyright 2003, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+** Distributed under the terms of the OpenBeOS License.
+*/
+#ifndef KERNEL_LIST_H
+#define KERNEL_LIST_H
+
+
+#include <SupportDefs.h>
+
+
+/* This header defines a doubly-linked list. It differentiates between a link
+ * and an item.
+ * A link is what is put into and removed from a list, an item is the whole
+ * object that contains the link. The item doesn't have to be begin with a
+ * link; the offset to the link structure is given to init_list_etc(), so that
+ * list_get_next/prev_item() will work correctly.
+ * Note, the offset value is only needed for the *_item() functions. If the
+ * offset is 0, list_link and item are identical - if you use init_list(),
+ * you don't have to care about the difference between a link and an item.
+ */
+
+typedef struct list_link list_link;
+
+/* The object that is put into the list must begin with these
+ * fields, but it doesn't have to be this structure.
+ */
+
+struct list_link {
+	list_link *next;
+	list_link *prev;
+};
+
+struct list {
+	list_link	link;
+	int32		offset;
+};
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void list_init(struct list *list);
+extern void list_init_etc(struct list *list, int32 offset);
+extern void list_add_link_to_head(struct list *list, void *_link);
+extern void list_add_link_to_tail(struct list *list, void *_link);
+extern void list_remove_link(void *_link);
+extern void *list_get_next_item(struct list *list, void *item);
+extern void *list_get_prev_item(struct list *list, void *item);
+extern void *list_remove_head_item(struct list *list);
+extern void *list_remove_tail_item(struct list *list);
+
+static inline bool
+list_is_empty(struct list *list)
+{
+	return list->link.next == (list_link *)list;
+}
+
+static inline void *
+list_get_first_item(struct list *list)
+{
+	return list_get_next_item(list, NULL);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* KERNEL_LIST_H */