yaffs: More clean up

[yaffs2.git] / direct / yaffs_list.h

diff --git a/direct/yaffs_list.h b/direct/yaffs_list.h
new file mode 100644 (file)
index 0000000..624cd5f
--- /dev/null
+++ b/direct/yaffs_list.h
@@ -0,0 +1,127 @@
+/*
+ * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2010 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
+ */
+
+/*
+ * This file is just holds extra declarations of macros that would normally
+ * be providesd in the Linux kernel. These macros have been written from
+ * scratch but are functionally equivalent to the Linux ones.
+ *
+ */
+
+#ifndef __YAFFS_LIST_H__
+#define __YAFFS_LIST_H__
+
+
+#include "yportenv.h"
+
+/*
+ * This is a simple doubly linked list implementation that matches the
+ * way the Linux kernel doubly linked list implementation works.
+ */
+
+struct list_head {
+       struct list_head *next; /* next in chain */
+       struct list_head *prev; /* previous in chain */
+};
+
+
+/* Initialise a static list */
+#define LIST_HEAD(name) \
+struct list_head name = { &(name), &(name)}
+
+
+
+/* Initialise a list head to an empty list */
+#define INIT_LIST_HEAD(p) \
+do { \
+       (p)->next = (p);\
+       (p)->prev = (p); \
+} while (0)
+
+
+/* Add an element to a list */
+static Y_INLINE void list_add(struct list_head *new_entry,
+                               struct list_head *list)
+{
+       struct list_head *list_next = list->next;
+
+       list->next = new_entry;
+       new_entry->prev = list;
+       new_entry->next = list_next;
+       list_next->prev = new_entry;
+
+}
+
+static Y_INLINE void list_add_tail(struct list_head *new_entry,
+                                struct list_head *list)
+{
+       struct list_head *list_prev = list->prev;
+
+       list->prev = new_entry;
+       new_entry->next = list;
+       new_entry->prev = list_prev;
+       list_prev->next = new_entry;
+
+}
+
+
+/* Take an element out of its current list, with or without
+ * reinitialising the links.of the entry*/
+static Y_INLINE void list_del(struct list_head *entry)
+{
+       struct list_head *list_next = entry->next;
+       struct list_head *list_prev = entry->prev;
+
+       list_next->prev = list_prev;
+       list_prev->next = list_next;
+
+}
+
+static Y_INLINE void list_del_init(struct list_head *entry)
+{
+       list_del(entry);
+       entry->next = entry->prev = entry;
+}
+
+
+/* Test if the list is empty */
+static Y_INLINE int list_empty(struct list_head *entry)
+{
+       return (entry->next == entry);
+}
+
+
+/* list_entry takes a pointer to a list entry and offsets it to that
+ * we can find a pointer to the object it is embedded in.
+ */
+
+
+#define list_entry(entry, type, member) \
+       ((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member)))
+
+
+/* list_for_each and list_for_each_safe  iterate over lists.
+ * list_for_each_safe uses temporary storage to make the list delete safe
+ */
+
+#define list_for_each(itervar, list) \
+       for (itervar = (list)->next; itervar != (list); itervar = itervar->next)
+
+#define list_for_each_safe(itervar, save_var, list) \
+       for (itervar = (list)->next, save_var = (list)->next->next; \
+               itervar != (list); itervar = save_var, save_var = save_var->next)
+
+
+#endif