/*
 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved.
 *
 * This document is the property of Apple Computer, Inc.
 * It is considered confidential and proprietary.
 *
 * This document may not be reproduced or transmitted in any form,
 * in whole or in part, without the express written permission of
 * Apple Computer, Inc.
 */
#ifndef __LIST_H
#define __LIST_H

#include <sys/types.h>
#include <debug.h>

__BEGIN_DECLS

#define containerof(ptr, type, member) \
	((type *)((addr_t)(ptr) - offsetof(type, member)))

struct list_node {
	struct list_node *prev;
	struct list_node *next;
};

#define LIST_INITIAL_VALUE(list) (struct list_node){ &(list), &(list) }

static inline void list_initialize(struct list_node *list)
{
	list->prev = list->next = list;
}

static inline void list_clear_node(struct list_node *item)
{
	item->prev = item->next = 0;
}

static inline bool list_in_list(struct list_node *item)
{
	if (item->prev == 0 && item->next == 0)
		return false;
	else
		return true;
}

static inline void list_add_head(struct list_node *list, struct list_node *item)
{
	if (list->next == NULL || list->prev == NULL || list->next->prev != list || list->prev->next != list)
		panic("linked list item %p corrupted", list);
	item->next = list->next;
	item->prev = list;
	list->next->prev = item;
	list->next = item;
}

#define list_add_after(entry, new_entry) list_add_head(entry, new_entry)

static inline void list_add_tail(struct list_node *list, struct list_node *item)
{
	if (list->next == NULL || list->prev == NULL || list->next->prev != list || list->prev->next != list)
		panic("linked list item %p corrupted", list);
	item->prev = list->prev;
	item->next = list;
	list->prev->next = item;
	list->prev = item;
}

#define list_add_before(entry, new_entry) list_add_tail(entry, new_entry)

static inline void list_delete(struct list_node *item)
{
	if (item->next == NULL || item->prev == NULL || item->next->prev != item || item->prev->next != item)
		panic("linked list item %p corrupted", item);
	item->next->prev = item->prev;
	item->prev->next = item->next;
	item->prev = item->next = 0;
}

static inline struct list_node* list_remove_head(struct list_node *list)
{
	if(list->next != list) {
		struct list_node *item = list->next;
		list_delete(item);
		return item;
	} else {
		return NULL;
	}
}

#define list_remove_head_type(list, type, element) ({\
    struct list_node *__nod = list_remove_head(list);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

static inline struct list_node* list_remove_tail(struct list_node *list)
{
	if(list->prev != list) {
		struct list_node *item = list->prev;
		list_delete(item);
		return item;
	} else {
		return NULL;
	}
}

#define list_remove_tail_type(list, type, element) ({\
    struct list_node *__nod = list_remove_tail(list);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

static inline struct list_node* list_peek_head(struct list_node *list)
{
	if(list->next != list) {
		return list->next;
	} else {
		return NULL;
	}	
}

#define list_peek_head_type(list, type, element) ({\
    struct list_node *__nod = list_peek_head(list);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

static inline struct list_node* list_peek_tail(struct list_node *list)
{
	if(list->prev != list) {
		return list->prev;
	} else {
		return NULL;
	}	
}

#define list_peek_tail_type(list, type, element) ({\
    struct list_node *__nod = list_peek_tail(list);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

static inline struct list_node* list_next(struct list_node *list, struct list_node *item)
{
	if(item->next != list)
		return item->next;
	else
		return NULL;
}

#define list_next_type(list, item, type, element) ({\
    struct list_node *__nod = list_next(list, item);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

static inline struct list_node* list_next_wrap(struct list_node *list, struct list_node *item)
{
	if(item->next != list)
		return item->next;
	else if(item->next->next != list)
		return item->next->next;
	else
		return NULL;
}

#define list_next_wrap_type(list, item, type, element) ({\
    struct list_node *__nod = list_next_wrap(list, item);\
    type *__t;\
    if(__nod)\
        __t = containerof(__nod, type, element);\
    else\
        __t = (type *)0;\
    __t;\
})

// iterates over the list, node should be struct list_node*
#define list_for_every(list, node) \
	for(node = (list)->next; node != (list); node = node->next)

// iterates over the list in a safe way for deletion of current node
// node and temp_node should be struct list_node*
#define list_for_every_safe(list, node, temp_node) \
	for(node = (list)->next, temp_node = (node)->next;\
	node != (list);\
	node = temp_node, temp_node = (node)->next)

// iterates over the list, entry should be the container structure type *
#define list_for_every_entry(list, entry, type, member) \
	for((entry) = containerof((list)->next, type, member);\
		&(entry)->member != (list);\
		(entry) = containerof((entry)->member.next, type, member))

// iterates over the list in a safe way for deletion of current node
// entry and temp_entry should be the container structure type *
#define list_for_every_entry_safe(list, entry, temp_entry, type, member) \
	for(entry = containerof((list)->next, type, member),\
		temp_entry = containerof((entry)->member.next, type, member);\
		&(entry)->member != (list);\
		entry = temp_entry, temp_entry = containerof((temp_entry)->member.next, type, member))

static inline bool list_is_empty(struct list_node *list)
{
	return (list->next == list) ? true : false;
}

__END_DECLS

#endif