Doubly linked list

//dlinklist.h
#ifndef _MY_DLINKLIST_H_
#define _MY_DLINKLIST_H_

typedef void DLinkList;
/*
typedef struct _tag_DLinkListNode DLinkListNode;
struct _tag_DLinkListNode
{
	DLinkListNode* next;
	DLinkListNode * for;
};
*/

typedef struct _tag_DLinkListNode
{
	struct _tag_DLinkListNode* next;
	struct _tag_DLinkListNode * pre;
} DLinkListNode;

DLinkList* DLinkList_Create();

void DLinkList_Destroy(DLinkList* list);

void DLinkList_Clear(DLinkList* list);

int DLinkList_Length(DLinkList* list);

int DLinkList_Insert(DLinkList* list, DLinkListNode* node, int pos);

DLinkListNode* DLinkList_Get(DLinkList* list, int pos);

DLinkListNode* DLinkList_Delete(DLinkList* list, int pos);

//-- add
DLinkListNode* DLinkList_DeleteNode(DLinkList* list, DLinkListNode* node);

DLinkListNode* DLinkList_Reset(DLinkList* list);

DLinkListNode* DLinkList_Current(DLinkList* list);

DLinkListNode* DLinkList_Next(DLinkList* list);

DLinkListNode* DLinkList_Pre(DLinkList* list);

#endif

//dlinklist.cpp
#include <stdio.h>
#include <malloc.h>
#include "DLinkList.h"

typedef struct _tag_DLinkList
{
	DLinkListNode header;
	DLinkListNode* slider;
	int length;
} TDLinkList;

DLinkList* DLinkList_Create()
{
	TDLinkList* ret = (TDLinkList*)malloc(sizeof(TDLinkList));

	if( ret != NULL )
	{
		ret->length = 0;
		ret->header.next = NULL;
		ret->header.pre = NULL;
		ret-> slider = NULL;
	}

	return ret;
}

void DLinkList_Destroy(DLinkList* list)
{
	if (list != NULL)
	{
		free(list);
	}
}

void DLinkList_Clear(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;

	if( sList != NULL )
	{
		sList->length = 0;
		sList->header.next = NULL;
		sList->header.pre = NULL;
		sList->slider = NULL;
	}
}

int DLinkList_Length(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;
	int ret = -1;

	if( sList != NULL )
	{
		ret = sList->length;
	}

	return ret;
}

//Everyone must pay attention: the textbook will not tell you how to use it on the project; which points are the key points of the project
int DLinkList_Insert(DLinkList* list, DLinkListNode* node, int pos)
{
	int ret = 0, i = 0;
	TDLinkList* sList = (TDLinkList*)list;
	
	if (list==NULL || node==NULL || pos<0)
	{
		return -1;
	}
	
	{
		DLinkListNode* current = (DLinkListNode*)sList;
		DLinkListNode* next = NULL; //Need to increase the next pointer

		for(i=0; (i<pos) && (current->next != NULL); i++)
		{
			current = current->next;
		}

		next = current->next;

		//steps 1-2
		current->next = node;
		node->next = next;

		//steps 3-4
		if( next != NULL ) //When the first element is inserted into the linked list, special processing is required
		{
			next->pre = node;
		}
		node->pre = current;

		if( sList->length == 0 )
		{
			sList->slider = node; //When the linked list inserts the first element to process the cursor
		}

		//If it is inserted at position 0, special processing is required before the new node next, pre points to null
		if( current == (DLinkListNode*)sList )
		{
			node->pre = NULL;
		}

		sList->length++;
	}

	return ret;
}

DLinkListNode* DLinkList_Get(DLinkList* list, int pos)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;
	int i = 0;

	if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
	{
		DLinkListNode* current = (DLinkListNode*)sList;

		for(i=0; i<pos; i++)
		{
			current = current->next;
		}

		ret = current->next;
	}

	return ret;
}

//insert the first node
//Deleted is the last node, how to deal with it
DLinkListNode* DLinkList_Delete(DLinkList* list, int pos)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;
	int i = 0;
	if (sList == NULL || pos <0 )
	{
		return NULL;
	}
	//if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
	{
		DLinkListNode* current = (DLinkListNode*)sList;
		DLinkListNode* next = NULL; //Need to increase the next pointer

		for(i=0; i<pos; i++)
		{
			current = current->next;
		}

		ret = current->next;
		next = ret->next;

		//step 1
		current->next = next;

		//step 2
		if( next != NULL )//special handling is required
		{
			next->pre = current;

			if( current == (DLinkListNode*)sList ) //If the 0th position, special processing is required
			{
				next->pre = NULL;
			}
		}

		if (sList-> slider == ret)
		{
			sList->slider = next;
		}

		sList->length--;
	}

	return ret;
}

DLinkListNode* DLinkList_DeleteNode(DLinkList* list, DLinkListNode* node)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;
	int i = 0;

	if( sList != NULL )
	{
		DLinkListNode* current = (DLinkListNode*)sList;

		for(i=0; i<sList->length; i++)
		{
			if( current->next == node )
			{
				ret = current->next;
				break;
			}

			current = current->next;
		}

		if( ret != NULL )
		{
			DLinkList_Delete(sList, i);
		}
	}

	return ret;
}

DLinkListNode* DLinkList_Reset(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;

	if( sList != NULL )
	{
		sList->slider = sList->header.next;
		ret = sList-> slider;
	}

	return ret;
}

DLinkListNode* DLinkList_Current(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;

	if( sList != NULL )
	{
		ret = sList-> slider;
	}

	return ret;
}

DLinkListNode* DLinkList_Next(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;

	if( (sList != NULL) && (sList->slider != NULL) )
	{
		ret = sList-> slider;
		sList->slider = ret->next;
	}

	return ret;
}

DLinkListNode* DLinkList_Pre(DLinkList* list)
{
	TDLinkList* sList = (TDLinkList*)list;
	DLinkListNode * ret = NULL;

	if( (sList != NULL) && (sList->slider != NULL) )
	{
		ret = sList-> slider;
		sList-> slider = ret-> pre;
	}

	return ret;
}

//test1
#include <stdio.h>
#include <stdlib.h>
#include "DLinkList.h"

struct Value
{
	DLinkListNode node;
	int v;
};

int main(int argc, char *argv[])
{
	int i = 0;
	DLinkList* list = DLinkList_Create();
	struct Value* pv = NULL;
	struct Value v1, v2, v3, v4, v5;

	v1.v = 1; v2.v = 2; v3.v = 3; v4.v = 4;
	v5.v = 5;

	DLinkList_Insert(list, (DLinkListNode*)&v1, DLinkList_Length(list));
	DLinkList_Insert(list, (DLinkListNode*)&v2, DLinkList_Length(list));
	DLinkList_Insert(list, (DLinkListNode*)&v3, DLinkList_Length(list));
	DLinkList_Insert(list, (DLinkListNode*)&v4, DLinkList_Length(list));
	DLinkList_Insert(list, (DLinkListNode*)&v5, DLinkList_Length(list));

	for(i=0; i<DLinkList_Length(list); i++)
	{
		pv = (struct Value*)DLinkList_Get(list, i);

		printf("%d\n", pv->v);
	}

	printf("\n");

	DLinkList_Delete(list, DLinkList_Length(list)-1);
	DLinkList_Delete(list, 0);
	//DLinkList_Delete(list, 3);
	

	for(i=0; i<DLinkList_Length(list); i++)
	{
		pv = (struct Value*)DLinkList_Next(list);

		printf("%d\n", pv->v);
	}

	printf("\n");

	DLinkList_Reset(list);
	DLinkList_Next(list);

	pv = (struct Value*)DLinkList_Current(list);

	printf("%d\n", pv->v);

	DLinkList_DeleteNode(list, (DLinkListNode*)pv);

	pv = (struct Value*)DLinkList_Current(list);

	printf("%d\n", pv->v);

	DLinkList_Pre(list);

	pv = (struct Value*)DLinkList_Current(list);

	printf("%d\n", pv->v);

	printf("Length: %d\n", DLinkList_Length(list));

	DLinkList_Destroy(list);
	system("pause");
	return 0;
}

// test2
#include <stdio.h>
#include <stdlib.h>
#include "DLinkList.h"

struct Value
{
	DLinkListNode header;
	int v;
};

int main22(int argc, char *argv[])
{
	DLinkList* list = DLinkList_Create();
	struct Value v1;
	struct Value v2;
	struct Value v3;
	struct Value v4;
	struct Value v5;

	v1.v = 1;
	v2.v = 2;
	v3.v = 3;
	v4.v = 4;
	v5.v = 5;

	DLinkList_Insert(list, (DLinkListNode*)&v1, 0);
	DLinkList_Insert(list, (DLinkListNode*)&v2, 0);
	DLinkList_Insert(list, (DLinkListNode*)&v3, 0);
	DLinkList_Insert(list, (DLinkListNode*)&v4, 0);
	DLinkList_Insert(list, (DLinkListNode*)&v5, 0);

	DLinkList_Reset(list);
	//DLinkList_Pre(list);

	printf("%x\n", DLinkList_Current(list));

	DLinkList_Destroy(list);
	system("pause");
	return 0;
}