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*****************************************************************************/

/*******************************************************************//**
@file include/ut0list.h
A double-linked list

Created 4/26/2006 Osku Salerma
************************************************************************/

/*******************************************************************//**
A double-linked list. This differs from the one in ut0lst.h in that in this
one, each list node contains a pointer to the data, whereas the one in
ut0lst.h uses a strategy where the list pointers are embedded in the data
items themselves.

Use this one when you need to store arbitrary data in the list where you
can't embed the list pointers in the data, if a data item needs to be
stored in multiple lists, etc.

Note about the memory management: ib_list_t is a fixed-size struct whose
allocation/deallocation is done through ib_list_create/ib_list_free, but the
memory for the list nodes is allocated through a user-given memory heap,
which can either be the same for all nodes or vary per node. Most users will
probably want to create a memory heap to store the item-specific data, and
pass in this same heap to the list node creation functions, thus
automatically freeing the list node when the item's heap is freed.

************************************************************************/

#ifndef IB_LIST_H
#define IB_LIST_H

#include "mem0mem.h"

struct ib_list_t;
struct ib_list_node_t;

/****************************************************************//**
Create a new list using mem_alloc. Lists created with this function must be
freed with ib_list_free.
@return list */
ib_list_t*
ib_list_create(void);
/*=================*/


/****************************************************************//**
Create a new list using the given heap. ib_list_free MUST NOT BE CALLED for
lists created with this function.
@return list */
ib_list_t*
ib_list_create_heap(
/*================*/
	mem_heap_t*	heap);	/*!< in: memory heap to use */

/****************************************************************//**
Free a list. */
void
ib_list_free(
/*=========*/
	ib_list_t*	list);	/*!< in: list */

/****************************************************************//**
Add the data to the start of the list.
@return new list node */
ib_list_node_t*
ib_list_add_first(
/*==============*/
	ib_list_t*	list,	/*!< in: list */
	void*		data,	/*!< in: data */
	mem_heap_t*	heap);	/*!< in: memory heap to use */

/****************************************************************//**
Add the data to the end of the list.
@return new list node */
ib_list_node_t*
ib_list_add_last(
/*=============*/
	ib_list_t*	list,	/*!< in: list */
	void*		data,	/*!< in: data */
	mem_heap_t*	heap);	/*!< in: memory heap to use */

/****************************************************************//**
Add the data after the indicated node.
@return new list node */
ib_list_node_t*
ib_list_add_after(
/*==============*/
	ib_list_t*	list,		/*!< in: list */
	ib_list_node_t*	prev_node,	/*!< in: node preceding new node (can
					be NULL) */
	void*		data,		/*!< in: data */
	mem_heap_t*	heap);		/*!< in: memory heap to use */

/****************************************************************//**
Remove the node from the list. */
void
ib_list_remove(
/*===========*/
	ib_list_t*	list,	/*!< in: list */
	ib_list_node_t*	node);	/*!< in: node to remove */

/****************************************************************//**
Get the first node in the list.
@return first node, or NULL */
UNIV_INLINE
ib_list_node_t*
ib_list_get_first(
/*==============*/
	ib_list_t*	list);	/*!< in: list */

/****************************************************************//**
Get the last node in the list.
@return last node, or NULL */
UNIV_INLINE
ib_list_node_t*
ib_list_get_last(
/*=============*/
	ib_list_t*	list);	/*!< in: list */

/********************************************************************
Check if list is empty. */
UNIV_INLINE
ibool
ib_list_is_empty(
/*=============*/
					/* out: TRUE if empty else  */
	const ib_list_t*	list);	/* in: list */

/* List. */
struct ib_list_t {
	ib_list_node_t*		first;		/*!< first node */
	ib_list_node_t*		last;		/*!< last node */
	ibool			is_heap_list;	/*!< TRUE if this list was
						allocated through a heap */
};

/* A list node. */
struct ib_list_node_t {
	ib_list_node_t*		prev;		/*!< previous node */
	ib_list_node_t*		next;		/*!< next node */
	void*			data;		/*!< user data */
};

/* Quite often, the only additional piece of data you need is the per-item
memory heap, so we have this generic struct available to use in those
cases. */
struct ib_list_helper_t {
	mem_heap_t*	heap;		/*!< memory heap */
	void*		data;		/*!< user data */
};

#ifndef UNIV_NONINL
#include "ut0list.ic"
#endif

#endif
