Windows平臺上實現P2P服務（四）

創建一個鏈式結構便於存儲用戶信息，以便從此處理登陸和未登陸的信息。首先咱們創建一個用戶信息的結構：

/// <summary>客戶端信息結構</summary>
typedef struct _client *lp_client;
/// <summary>客戶端信息指針結構</summary>
typedef struct _client
{
	char userName[20];		//用戶名稱
	char userPassword[20];	//用戶口令
	char appCode[20];		//應用編碼
	char machineCode[32];	//機器碼
	char runtimeCode[32];	//運行碼
	struct  in_addr addr;	//網址
	u_short port;			//通信端口
	lp_client next;			//鏈表下一個
};

如圖所示，所謂鏈式結構就是左側圖示的方式，從上面的結構上看，最後那個next就是用於連接的，爲了更好的操做這個連接，咱們須要創建兩個變量來便於操做和處理，這兩個變量是根節點和末節點變量。

/// <summary>客戶信息列表根節點</summary>
lp_client rootItem = NULL;
/// <summary>客戶信息列表末節點</summary>
lp_client lastItem = NULL;

下面提供一下整個代碼，包含查詢、增長、刪除等操做。

UDPList.h

#pragma once
#include "targetver.h"

/// <summary>信息結構的指針型</summary>
typedef struct _message *lp_message;
/// <summary>信息結構</summary>
typedef struct _message
{
	union {
		struct { char buff[1030]; };
		struct { char cmd[6]; char rt_code[32]; char data[992]; };
	};
	SOCKADDR_IN addr;
};
/// <summary>客戶端信息結構</summary>
typedef struct _client *lp_client;
/// <summary>客戶端信息指針結構</summary>
typedef struct _client
{
	char userName[20];		//用戶名稱
	char userPassword[20];	//用戶口令
	char appCode[20];		//應用編碼
	char machineCode[32];	//機器碼
	char runtimeCode[32];	//運行碼
	struct  in_addr addr;	//網址
	u_short port;			//通信端口
	lp_client next;			//鏈表下一個
};

/// <summary>根據用戶名稱獲得用戶信息節點</summary>
lp_client IndexOf(char* appCode, char * userName);
/// <summary>根據用戶名稱獲得用戶信息節點</summary>
lp_client IndexOf(char* appCode, char * userName, char * machineCode);
/// <summary>根據運行編碼獲得用戶信息節點</summary>
lp_client IndexOf(char * runtimeCode);
/// <summary>添加一個客戶端信息</summary>
lp_client addClient(char* userName, char* userPassword, char* appCode, char* machineCode);
/// <summary>添加一個客戶端信息</summary>
void addClient(lp_client client);
/// <summary>一個客戶端登陸系統</summary>
lp_client regClient(char * userName, char * userPassword, char * appCode, struct  in_addr addr, u_short port);
/// <summary>一個客戶端登陸系統</summary>
lp_client regClient(char * userName, char * userPassword, char * appCode, char * machineCode, struct  in_addr addr, u_short port);
/// <summary>根據用戶名稱刪除用戶信息節點</summary>
void removeClient(char* appCode, char * userName);
/// <summary>從文件緩存中提取客戶端列表</summary>
void loadFromFile(char* filename);
/// <summary>將客戶端列表寫入緩存文件</summary>
void saveToFile(char* filename);

下面是UDPList.cpp

#include "stdafx.h"
#include "UDPList.h"

/// <summary>客戶信息列表根節點</summary>
lp_client rootItem = NULL;
/// <summary>客戶信息列表末節點</summary>
lp_client lastItem = NULL;

void setRuntimeCode(lp_client client)
{
	GUID gid;
	CoCreateGuid(&gid);
	sprintf(client->runtimeCode, "%08x%04x%04x%02x%02x%02x%02x%02x%02x%02x%02x", gid.Data1, gid.Data2, gid.Data3, gid.Data4[0], gid.Data4[1], gid.Data4[2], gid.Data4[3], gid.Data4[4], gid.Data4[5], gid.Data4[6], gid.Data4[7]);
}
/// <summary>根據用戶名稱獲得用戶信息節點</summary>
lp_client IndexOf(char* appCode, char * userName)
{
	if (rootItem == NULL)return NULL;
	lp_client tmp = rootItem;
	while (tmp)
	{
		if (strcmp(tmp->appCode, appCode) == 0 && strcmp(tmp->userName, userName) == 0)
			return tmp;
		tmp = tmp->next;
	}
	return NULL;
}
/// <summary>根據用戶名稱獲得用戶信息節點</summary>
lp_client IndexOf(char* appCode, char * userName, char * machineCode)
{
	if (rootItem == NULL)return NULL;
	lp_client tmp = rootItem;
	while (tmp)
	{
		if (strncmp(tmp->appCode, appCode, 20) == 0 && strncmp(tmp->userName, userName, 20) == 0 && strncmp(tmp->machineCode, machineCode, 32) == 0)
			return tmp;
		tmp = tmp->next;
	}
	return NULL;
}
/// <summary>根據運行編碼獲得用戶信息節點</summary>
lp_client IndexOf(char * runtimeCode)
{
	if (rootItem == NULL)return NULL;
	lp_client tmp = rootItem;
	while (tmp)
	{
		if (strcmp(tmp->runtimeCode, runtimeCode) == 0)
			return tmp;
		tmp = tmp->next;
	}
	return NULL;
}
/// <summary>一個客戶端登陸系統</summary>
lp_client regClient(char * userName, char * userPassword, char * appCode, struct  in_addr addr, u_short port)
{
	lp_client result = IndexOf(userName, userPassword);
	if (result == NULL)return NULL;
	if (strcmp(result->userPassword, userPassword) != 0)return NULL;
	result->addr = addr;
	result->port = port;
	setRuntimeCode(result);
	return result;
}
/// <summary>一個客戶端登陸系統</summary>
lp_client regClient(char * userName, char * userPassword, char * appCode, char * machineCode, struct  in_addr addr, u_short port)
{
	lp_client result = IndexOf(appCode, userName, machineCode);
	if (result == NULL)return NULL;
	if (strcmp(result->userPassword, userPassword) != 0)return NULL;
	result->addr = addr;
	result->port = port;
	setRuntimeCode(result);
	return result;
}
/// <summary>根據用戶名稱刪除用戶信息節點</summary>
void removeClient(char * appCode, char * userName)
{
	if (rootItem == NULL)return ;
	lp_client tmp = rootItem;
	lp_client parent = NULL;
	while (tmp)
	{
		if (strcmp(tmp->appCode, appCode) == 0 && strcmp(tmp->userName, userName) == 0)
		{
			if (parent == NULL)rootItem = tmp->next;
			else parent->next = tmp->next;
			if (tmp->next == NULL)lastItem = parent;
			free(tmp);
			return;
		}
		parent = tmp;
		tmp = tmp->next;
	}
}
/// <summary>從文件緩存中提取客戶端列表</summary>
void loadFromFile(char * filename)
{
	FILE *fp;
	if ((fp = fopen(filename, "rb")) == NULL)
	{
		printf("cant open the file");
		exit(0);
	}
	lp_client client = (lp_client)malloc(sizeof(_client));
	memset(client, 0, sizeof(_client));
	while(fread(client, 20 + 20 + 20 + 32, 1, fp) > 0) {
		if (rootItem == NULL)rootItem = client;
		else lastItem->next = client;
		lastItem = client;
		client = (lp_client)malloc(sizeof(_client));
		memset(client, 0, sizeof(_client));
	}
	free(client);
	fclose(fp);
}
/// <summary>將客戶端列表寫入緩存文件</summary>
void saveToFile(char * filename)
{
	FILE * outfile = fopen(filename, "wb");
	if (outfile == NULL)
	{
		printf("cant open the file");
		exit(0);
	}
	lp_client client = rootItem;
	while (client)
	{
		fwrite(client, 20 + 20 + 20 + 32, 1, outfile);
		client = client->next;
	}
	fclose(outfile);
}
/// <summary>添加一個客戶端信息</summary>
lp_client addClient(char* userName, char* userPassword, char* appCode, char* machineCode)
{
	lp_client result = IndexOf(userName, userPassword);
	if (result != NULL)return result;
	result= (lp_client)malloc(sizeof(_client));
	memset(result, 0, sizeof(_client));
	strcpy(result->userName, userName);
	strcpy(result->userPassword, userPassword);
	strcpy(result->appCode, appCode);
	strcpy(result->machineCode, machineCode);
	addClient(result);
	return result;
}
/// <summary>添加一個客戶端信息</summary>
void addClient(lp_client client)
{
	if (rootItem == NULL)rootItem = client;
	else lastItem->next = client;
	lastItem = client;
}

同時函數還實現了文件緩存功能，經過SaveToFile和LoadFromFile來實現。