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

Copyright (c) 2006, 2021, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

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

/*******************************************************************//**
@file ut/ut0list.cc
A double-linked list

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

#include "ut0list.h"
#ifdef UNIV_NONINL
#include "ut0list.ic"
#endif

/****************************************************************//**
Create a new list.
@return list */
ib_list_t*
ib_list_create(void)
/*=================*/
{
	ib_list_t*	list;

	list = static_cast<ib_list_t*>(ut_malloc_nokey(sizeof(*list)));

	list->first = NULL;
	list->last = NULL;
	list->is_heap_list = FALSE;

	return(list);
}

/****************************************************************//**
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 */
{
	ib_list_t*	list;

	list = static_cast<ib_list_t*>(mem_heap_alloc(heap, sizeof(*list)));

	list->first = NULL;
	list->last = NULL;
	list->is_heap_list = TRUE;

	return(list);
}

/****************************************************************//**
Free a list. */
void
ib_list_free(
/*=========*/
	ib_list_t*	list)	/*!< in: list */
{
	ut_a(!list->is_heap_list);

	/* We don't check that the list is empty because it's entirely valid
	to e.g. have all the nodes allocated from a single heap that is then
	freed after the list itself is freed. */

	ut_free(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 */
{
	return(ib_list_add_after(list, ib_list_get_first(list), data, heap));
}

/****************************************************************//**
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 */
{
	return(ib_list_add_after(list, ib_list_get_last(list), data, heap));
}

/****************************************************************//**
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 */
{
	ib_list_node_t*	node;

	node = static_cast<ib_list_node_t*>(
		mem_heap_alloc(heap, sizeof(*node)));

	node->data = data;

	if (!list->first) {
		/* Empty list. */

		ut_a(!prev_node);

		node->prev = NULL;
		node->next = NULL;

		list->first = node;
		list->last = node;
	} else if (!prev_node) {
		/* Start of list. */

		node->prev = NULL;
		node->next = list->first;

		list->first->prev = node;

		list->first = node;
	} else {
		/* Middle or end of list. */

		node->prev = prev_node;
		node->next = prev_node->next;

		prev_node->next = node;

		if (node->next) {
			node->next->prev = node;
		} else {
			list->last = node;
		}
	}

	return(node);
}

/****************************************************************//**
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 */
{
	if (node->prev) {
		node->prev->next = node->next;
	} else {
		/* First item in list. */

		ut_ad(list->first == node);

		list->first = node->next;
	}

	if (node->next) {
		node->next->prev = node->prev;
	} else {
		/* Last item in list. */

		ut_ad(list->last == node);

		list->last = node->prev;
	}

	node->prev = node->next = NULL;
}
