/*
?*?File:????dlist.c
?*?Author:??Li?XianJing?
?*?Brief:???double?list?implementation.
?*
?*?Copyright?（c）?Li?XianJing
?*
?*?Licensed?under?the?Academic?Free?License?version?2.1
?*
?*?This?program?is?free?software;?you?can?redistribute?it?and/or?modify
?*?it?under?the?terms?of?the?GNU?General?Public?License?as?published?by
?*?the?Free?Software?Foundation;?either?version?2?of?the?License?or
?*?（at?your?option）?any?later?version.
?*
?*?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?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.?59?Temple?Place?Suite?330?Boston?MA??02111-1307??USA
?*/

/*
?*?History:
?*?================================================================
?*?2008-11-09?Li?XianJing??created
?*
?*/
#include?
#include?“dlist.h“

typedef?struct?_DListNode
{
	struct?_DListNode*?prev;
	struct?_DListNode*?next;

	void*?data;
}DListNode;

struct?_DList
{
	DListNode*?first;
};

static?DListNode*?dlist_node_create（void*?data）
{
	DListNode*?node?=?malloc（sizeof（DListNode））;

	if（node?!=?NULL）
	{
		node->prev?=?NULL;
		node->next?=?NULL;
		node->data?=?data;
	}

	return?node;
}

static?void?dlist_node_destroy（DListNode*?node）
{
	if（node?!=?NULL）
	{
		node->next?=?NULL;
		node->prev?=?NULL;
		free（node）;
	}

	return;
}

DList*?dlist_create（void）
{
	DList*?thiz?=?malloc（sizeof（DList））;

	if（thiz?!=?NULL）
	{
		thiz->first?=?NULL;
	}

	return?thiz;
}

static?DListNode*?dlist_get_node（DList*?thiz?size_t?index?int?fail_return_last）
{
	DListNode*?iter?=?thiz->first;

	while（iter?!=?NULL?&&?iter->next?!=?NULL?&&?index?>?0）
	{
		iter?=?iter->next;
		index--;
	}

	if（!fail_return_last）
	{
		iter?=?index?>?0???NULL?:?iter;
	}

	return?iter;
}

DListRet?dlist_insert（DList*?thiz?size_t?index?void*?data）
{
	DListNode*?node?=?NULL;
	DListNode*?cursor?=?NULL;

	if（（node?=?dlist_node_create（data））?==?NULL）
	{
		return?DLIST_RET_OOM;?
	}

	if（thiz->first?==?NULL）
	{
		thiz->first?=?node;

		return?DLIST_RET_OK;
	}

	cursor?=?dlist_get_node（thiz?index?1）;
	
	if（index?	{
		if（thiz->first?==?cursor）
		{
			thiz->first?=?node;
		}
		else
		{
			cursor->prev->next?=?node;
			node->prev?=?cursor->prev;
		}
		node->next?=?cursor;
		cursor->prev?=?node;
	}
	else
	{
		cursor->next?=?node;
		node->prev?=?cursor;
	}

	return?DLIST_RET_OK;
}

DListRet?dlist_prepend（DList*?thiz?void*?data）
{
	return?dlist_insert（thiz?0?data）;
}

DListRet?dlist_append（DList*?thiz?void*?data）
{
	return?dlist_insert（thiz?-1?data）;
}

DListRet?dlist_delete（DList*?thiz?size_t?index）
{
	DListNode*?cursor?=?dlist_get_node（thiz?index?0）;

	if（cursor?!=?NULL）
	{
		if（cursor?==?thiz->first）
		{
			thiz->first?=