X-Git-Url: http://www.aleph1.co.uk/gitweb/?p=yaffs2.git;a=blobdiff_plain;f=yaffs_list.h;fp=yaffs_list.h;h=09d80b856224851961e1af66496f426f31151685;hp=0000000000000000000000000000000000000000;hb=4a700fe570d217c2c5df87070db7c2652bc0eaaf;hpb=25f6e492e7010f585367a4f6abf4d2e17c5c0e1a

diff --git a/yaffs_list.h b/yaffs_list.h
new file mode 100644
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--- /dev/null
+++ b/yaffs_list.h
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+/*
+ * 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 ylist_head {
+	struct ylist_head *next; /* next in chain */
+	struct ylist_head *prev; /* previous in chain */
+};
+
+
+/* Initialise a static list */
+#define YLIST_HEAD(name) \
+struct ylist_head name = { &(name), &(name)}
+
+
+
+/* Initialise a list head to an empty list */
+#define YINIT_LIST_HEAD(p) \
+do { \
+	(p)->next = (p);\
+	(p)->prev = (p); \
+} while (0)
+
+
+/* Add an element to a list */
+static Y_INLINE void ylist_add(struct ylist_head *newEntry,
+				struct ylist_head *list)
+{
+	struct ylist_head *listNext = list->next;
+
+	list->next = newEntry;
+	newEntry->prev = list;
+	newEntry->next = listNext;
+	listNext->prev = newEntry;
+
+}
+
+static Y_INLINE void ylist_add_tail(struct ylist_head *newEntry,
+				 struct ylist_head *list)
+{
+	struct ylist_head *listPrev = list->prev;
+
+	list->prev = newEntry;
+	newEntry->next = list;
+	newEntry->prev = listPrev;
+	listPrev->next = newEntry;
+
+}
+
+
+/* Take an element out of its current list, with or without
+ * reinitialising the links.of the entry*/
+static Y_INLINE void ylist_del(struct ylist_head *entry)
+{
+	struct ylist_head *listNext = entry->next;
+	struct ylist_head *listPrev = entry->prev;
+
+	listNext->prev = listPrev;
+	listPrev->next = listNext;
+
+}
+
+static Y_INLINE void ylist_del_init(struct ylist_head *entry)
+{
+	ylist_del(entry);
+	entry->next = entry->prev = entry;
+}
+
+
+/* Test if the list is empty */
+static Y_INLINE int ylist_empty(struct ylist_head *entry)
+{
+	return (entry->next == entry);
+}
+
+
+/* ylist_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 ylist_entry(entry, type, member) \
+	((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member)))
+
+
+/* ylist_for_each and list_for_each_safe  iterate over lists.
+ * ylist_for_each_safe uses temporary storage to make the list delete safe
+ */
+
+#define ylist_for_each(itervar, list) \
+	for (itervar = (list)->next; itervar != (list); itervar = itervar->next)
+
+#define ylist_for_each_safe(itervar, saveVar, list) \
+	for (itervar = (list)->next, saveVar = (list)->next->next; \
+		itervar != (list); itervar = saveVar, saveVar = saveVar->next)
+
+
+#endif