| 1 | /* |
| 2 | * YAFFS: Yet another Flash File System . A NAND-flash specific file system. |
| 3 | * |
| 4 | * Copyright (C) 2002-2010 Aleph One Ltd. |
| 5 | * for Toby Churchill Ltd and Brightstar Engineering |
| 6 | * |
| 7 | * Created by Charles Manning <charles@aleph1.co.uk> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU Lesser General Public License version 2.1 as |
| 11 | * published by the Free Software Foundation. |
| 12 | * |
| 13 | * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL. |
| 14 | */ |
| 15 | |
| 16 | /* |
| 17 | * This file is just holds extra declarations of macros that would normally |
| 18 | * be providesd in the Linux kernel. These macros have been written from |
| 19 | * scratch but are functionally equivalent to the Linux ones. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #ifndef __YAFFS_LIST_H__ |
| 24 | #define __YAFFS_LIST_H__ |
| 25 | |
| 26 | |
| 27 | #include "yportenv.h" |
| 28 | |
| 29 | /* |
| 30 | * This is a simple doubly linked list implementation that matches the |
| 31 | * way the Linux kernel doubly linked list implementation works. |
| 32 | */ |
| 33 | |
| 34 | struct ylist_head { |
| 35 | struct ylist_head *next; /* next in chain */ |
| 36 | struct ylist_head *prev; /* previous in chain */ |
| 37 | }; |
| 38 | |
| 39 | |
| 40 | /* Initialise a static list */ |
| 41 | #define YLIST_HEAD(name) \ |
| 42 | struct ylist_head name = { &(name), &(name)} |
| 43 | |
| 44 | |
| 45 | |
| 46 | /* Initialise a list head to an empty list */ |
| 47 | #define YINIT_LIST_HEAD(p) \ |
| 48 | do { \ |
| 49 | (p)->next = (p);\ |
| 50 | (p)->prev = (p); \ |
| 51 | } while (0) |
| 52 | |
| 53 | |
| 54 | /* Add an element to a list */ |
| 55 | static Y_INLINE void ylist_add(struct ylist_head *newEntry, |
| 56 | struct ylist_head *list) |
| 57 | { |
| 58 | struct ylist_head *listNext = list->next; |
| 59 | |
| 60 | list->next = newEntry; |
| 61 | newEntry->prev = list; |
| 62 | newEntry->next = listNext; |
| 63 | listNext->prev = newEntry; |
| 64 | |
| 65 | } |
| 66 | |
| 67 | static Y_INLINE void ylist_add_tail(struct ylist_head *newEntry, |
| 68 | struct ylist_head *list) |
| 69 | { |
| 70 | struct ylist_head *listPrev = list->prev; |
| 71 | |
| 72 | list->prev = newEntry; |
| 73 | newEntry->next = list; |
| 74 | newEntry->prev = listPrev; |
| 75 | listPrev->next = newEntry; |
| 76 | |
| 77 | } |
| 78 | |
| 79 | |
| 80 | /* Take an element out of its current list, with or without |
| 81 | * reinitialising the links.of the entry*/ |
| 82 | static Y_INLINE void ylist_del(struct ylist_head *entry) |
| 83 | { |
| 84 | struct ylist_head *listNext = entry->next; |
| 85 | struct ylist_head *listPrev = entry->prev; |
| 86 | |
| 87 | listNext->prev = listPrev; |
| 88 | listPrev->next = listNext; |
| 89 | |
| 90 | } |
| 91 | |
| 92 | static Y_INLINE void ylist_del_init(struct ylist_head *entry) |
| 93 | { |
| 94 | ylist_del(entry); |
| 95 | entry->next = entry->prev = entry; |
| 96 | } |
| 97 | |
| 98 | |
| 99 | /* Test if the list is empty */ |
| 100 | static Y_INLINE int ylist_empty(struct ylist_head *entry) |
| 101 | { |
| 102 | return (entry->next == entry); |
| 103 | } |
| 104 | |
| 105 | |
| 106 | /* ylist_entry takes a pointer to a list entry and offsets it to that |
| 107 | * we can find a pointer to the object it is embedded in. |
| 108 | */ |
| 109 | |
| 110 | |
| 111 | #define ylist_entry(entry, type, member) \ |
| 112 | ((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member))) |
| 113 | |
| 114 | |
| 115 | /* ylist_for_each and list_for_each_safe iterate over lists. |
| 116 | * ylist_for_each_safe uses temporary storage to make the list delete safe |
| 117 | */ |
| 118 | |
| 119 | #define ylist_for_each(itervar, list) \ |
| 120 | for (itervar = (list)->next; itervar != (list); itervar = itervar->next) |
| 121 | |
| 122 | #define ylist_for_each_safe(itervar, saveVar, list) \ |
| 123 | for (itervar = (list)->next, saveVar = (list)->next->next; \ |
| 124 | itervar != (list); itervar = saveVar, saveVar = saveVar->next) |
| 125 | |
| 126 | |
| 127 | #endif |
| 128 | |
