128 lines
3.0 KiB
C
128 lines
3.0 KiB
C
/*
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* YAFFS: Yet another Flash File System . A NAND-flash specific file system.
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*
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* Copyright (C) 2002-2010 Aleph One Ltd.
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* for Toby Churchill Ltd and Brightstar Engineering
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*
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* Created by Charles Manning <charles@aleph1.co.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1 as
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* published by the Free Software Foundation.
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*
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* Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
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*/
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/*
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* This file is just holds extra declarations of macros that would normally
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* be providesd in the Linux kernel. These macros have been written from
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* scratch but are functionally equivalent to the Linux ones.
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*
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*/
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#ifndef __YAFFS_LIST_H__
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#define __YAFFS_LIST_H__
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#include "yportenv.h"
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/*
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* This is a simple doubly linked list implementation that matches the
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* way the Linux kernel doubly linked list implementation works.
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*/
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struct ylist_head {
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struct ylist_head *next; /* next in chain */
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struct ylist_head *prev; /* previous in chain */
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};
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/* Initialise a static list */
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#define YLIST_HEAD(name) \
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struct ylist_head name = { &(name), &(name)}
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/* Initialise a list head to an empty list */
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#define YINIT_LIST_HEAD(p) \
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do { \
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(p)->next = (p);\
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(p)->prev = (p); \
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} while (0)
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/* Add an element to a list */
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static Y_INLINE void ylist_add(struct ylist_head *newEntry,
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struct ylist_head *list)
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{
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struct ylist_head *listNext = list->next;
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list->next = newEntry;
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newEntry->prev = list;
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newEntry->next = listNext;
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listNext->prev = newEntry;
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}
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static Y_INLINE void ylist_add_tail(struct ylist_head *newEntry,
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struct ylist_head *list)
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{
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struct ylist_head *listPrev = list->prev;
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list->prev = newEntry;
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newEntry->next = list;
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newEntry->prev = listPrev;
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listPrev->next = newEntry;
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}
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/* Take an element out of its current list, with or without
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* reinitialising the links.of the entry*/
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static Y_INLINE void ylist_del(struct ylist_head *entry)
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{
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struct ylist_head *listNext = entry->next;
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struct ylist_head *listPrev = entry->prev;
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listNext->prev = listPrev;
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listPrev->next = listNext;
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}
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static Y_INLINE void ylist_del_init(struct ylist_head *entry)
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{
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ylist_del(entry);
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entry->next = entry->prev = entry;
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}
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/* Test if the list is empty */
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static Y_INLINE int ylist_empty(struct ylist_head *entry)
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{
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return (entry->next == entry);
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}
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/* ylist_entry takes a pointer to a list entry and offsets it to that
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* we can find a pointer to the object it is embedded in.
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*/
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#define ylist_entry(entry, type, member) \
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((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member)))
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/* ylist_for_each and list_for_each_safe iterate over lists.
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* ylist_for_each_safe uses temporary storage to make the list delete safe
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*/
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#define ylist_for_each(itervar, list) \
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for (itervar = (list)->next; itervar != (list); itervar = itervar->next)
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#define ylist_for_each_safe(itervar, saveVar, list) \
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for (itervar = (list)->next, saveVar = (list)->next->next; \
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itervar != (list); itervar = saveVar, saveVar = saveVar->next)
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#endif
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