BOOST UDP 网络通信(2) --如何传输结构体

①、Struct.h -- 存放传输数据的结构体 

//由于不同操作系统之间的字节对齐方式不同，故网络传输数据时，要设置字节对齐方式
//设置变量以n字节对齐方式，指定结构体、联合以及类成员
#pragma pack(push) //保持对齐状态
#pragma pack(1) //设定为1字节对齐

#ifndef _MESSAGE_HEADER
#define _MESSAGE_HEADER

typedef struct _MESSAGE_HEADER
{
unsigned short int uhMessageCode; //消息类型
unsigned short int uhMessageLength; //消息长度
unsigned long int ulTimeTag; //时间
unsigned short int uhSerialNumber; //消息序号;
unsigned char ucSpare[22] //空余位
}SOCKET_MESSAGE_HEADER;
#endif

namespace DateStruct
{
struct DS_STATE
{
char cID[32]; //ID
char cState; //状态
}
}

#pragma pack(pop) //恢复对齐状态


②、使用socket发送数据
{
//消息头;
SOCKET_MESSAGE_HEADER header;
memset( &header, 0, sizeof(header) );
header.uhMessageCode = 2;

//消息体;
DateStruct::DS_STATE sendMsg;
memset( &sendMsg, 0, sizeof(DateStruct::DS_STATE) );

std::string tempID = "LHC010";
memcpy( sendMsg.cID, tempID, sizeof(std::string) );

char tempState("1");
sendMsg.cState = tempState;

//消息体长度;
int bodyLength = sizeof( DateStruct::DS_STATE );

//创建并初始化buffer用于存储 "消息头+消息体";
char * buff = new char[sizeof(header) + bodyLength];
memset( buff, 0, sizeof(header)+ bodyLegth );

//将消息头拷贝到buffer中;
memcpy( buff, &header, sizeof(header) );

//将消息体拷贝到buffer中;
memcpy( buff+sizeof(header), &sendMsg, sizeof(sendMsg) );

//将char*类型转换成char类型，因为boost-udp发送数据时，接收char类型，而非char*类型;
char sendBuff[2000] = {0};
int bLen = sizeof(SOCKET_MESSAGE_HEADER) + sizeof(DateStruct::DS_STATE);
memcpy( sendBuff, buff, bLen );

//使用socket发送数据;
boost::shared_ptr<boost::asio::ip::udp::socket> _ScoketPtr;
boost::asio::ip::udp::endpoint _SendEndPoint;
_SocketPtr.reset( new boost::asio::ip::udp::socket(_IOS) );

_SocketPtr->send_to( boost::asio::buffer(sendBuff), _SendEndPoint, 0 );
}③ 接收数据-创建UDP

void CreatUDP()
{
_SocketPtr.reset( new boost::asio::ip::udp::socket(_IOS) );

try
{
boost::asio::ip::udp::endpoint endpoint(boost::asio::ip::udp::v4(), _SendPort);

_SocketPtr->open( endpoint.protocol() );
_SocketPtr->bind( endpoint );

_Thread.rest( new boost::thread(&ServerProcRecv, this) );

}
catch( boost::system::system_error e )
{
const char * errMsg = e.what();
}
}

④socket循环接收数据
void ServerProcRecv()
{
size_t len;
boost::system::error_code ec;

//对方(即 发送数据端) 的端口与IP
boost::asio::ip::udp::endpoint revEndpoint;

while(true)
{
char tempBuffer[2000] = {0};
len = _SocketPtr->receive_from( boost::asio::buffer(tempBuffer), revEndpoint, 0, ec );

//发送端IP与端口号;
str::string revIP = revEndpoint.address().to_string();
unsigned short revPort = revEndpoint.port();

if( !ec )
{
if( len > 0 )
{
SOCKET_MESSAGE_HEADER mesHeader;
memcpy( &mesHeader, tempBuffer, sizeof(SOCKET_MESSAGE_HEADER) );

switch( mesHeader.uhMessageCode )
{
case 2:
{
DateStruct::DS_STATE msg;
memcpy( &msg, tempBuffer+sizeof(SOCKET_MESSAGE_HEADER), sizeof(DateStruct::DS_STATE) );

//得到发送过来的消息体msg;
//--TODO:
//--TODO:

break;
}
}
}
}
}
}