linkedlist.cpp

MONA是为数不多的C++语言编写的一个很小的操作系统

/*
Copyright (c) 2004 bayside
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "baygui.h"

/** 僐儞僗僩儔僋僞 */
LinkedList::LinkedList()
{
	dataListLength = 0;
	firstItem = NULL;
	endItem = NULL;
}

/** 僨僗僩儔僋僞 */
LinkedList::~LinkedList()
{
	removeAll();
}

/** 儕僗僩偺挿偝傪摼傞 */
int LinkedList::getLength()
{
	return dataListLength;
}

/** 巜掕偟偨弴斣偺崁栚傪摼傞 */
LinkedItem *LinkedList::getItem(int index)
{
	// NULL僠僃僢僋
	if (index >= dataListLength) return NULL;
	if (firstItem == NULL) return NULL;
	// 嵟弶偲嵟屻僠僃僢僋
	if (index == 0) return firstItem;
	if (index == dataListLength - 1) return endItem;
	// index夞儖乕僾
	LinkedItem *item = firstItem;
	for (int i = 0; i < index; i++) {
		item = item->next;
	}
	return item;
}

/** 捛壛 */
void LinkedList::add(LinkedItem *item)
{
	if (item == NULL) {
		return;
	} else if (firstItem == NULL) {
		firstItem = item;
		endItem = item;
	} else {
		LinkedItem *s = firstItem;
		while (s->next != NULL) {
			s = s->next;
		}
		item->prev = s;
		s->next = item;
		endItem = item;
	}
	dataListLength++;
}

/** 嶍彍 */
void LinkedList::remove(LinkedItem *item)
{
	if (item == NULL) {
		return;
	} else if (item->next == NULL) {
		if (item->prev != NULL) {
			endItem = item->prev;
			endItem->next = NULL;
		} else {
			firstItem = NULL;
			endItem = NULL;
		}
		item->prev = NULL;
		item->next = NULL;
		delete(item);
	} else {
		if (item->prev != NULL) {
			item->prev->next = item->next;
			item->next->prev = item->prev;
		} else {
			firstItem = item->next;
			firstItem->prev = NULL;
		}
		item->prev = NULL;
		item->next = NULL;
		delete(item);
	}
	dataListLength--;
}

/** 慡嶍彍 */
void LinkedList::removeAll()
{
	while (firstItem != NULL) {
		remove(firstItem);
	}
	dataListLength = 0;
}

/** 巜掕偟偨崁栚傪堦斣嵟屻偵帩偭偰偄偔 */
void LinkedList::sort(LinkedItem *item)
{
	if (item == NULL) {
		return;
	} else if (item->next == NULL) {
		return;
	} else {
		if (item->prev != NULL) {
			item->prev->next = item->next;
			item->next->prev = item->prev;
		} else {
			firstItem = item->next;
			firstItem->prev = NULL;
		}
		item->prev = endItem;
		endItem->next = item;
		item->next = NULL;
		endItem = item;
	}
}