这里实际有四个类组成：
1、Socket（基类）
2、SocketServer（派生类）
3、SocketClient（派生类）
4、SocketSelect（友元）
这里的SocketSelect 可以用来在多个Socket上进行Select调用，在Sockets构造函数中，他是protected权限。
当你编译这些文件的时候，请保证链接Ws2_32.lib库。
回到头文件、执行文件、测试程序和Echo服务器，这里同样也有一个Proxy服务器和一个WEB服务器。
关于这个socket类简短的描述：每个Windows Socket程序会调用WSAStartup，这个调用在这里封装在Socket::Start里面，而这里又是由于调用Soket的构造函数。我通过在这里的V2.0版，我希望该版本进行安装。
这里的Socket构造函数将调用socket()来创建套接字(请注意小写)。它传递SOCK_STREAM参数显示TCP，如果你希望是UDP，刚你必须传递SOCK_DGRAM参数。
SocketClient：SocketClient继承于Socket，它的构造函数需要一个主机名作为参数，这个主机名是服务器的客户端希望传递的。这个主机名由gethostname()解析为一个IP地址。
SocketServer：SocketServer也是继承于Socket，它的构造函数第一个参数标示侦听的端口；第二个参数标示有能力处理的最大连接数；
下面是原作者的源代码：
1、头文件声明
/*
Socket.h
Copyright (C) 2002-2004 René Nyffenegger
This source code is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this source code must not be misrepresented; you must not
claim that you wrote the original source code. If you use this source code
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original source code.
3. This notice may not be removed or altered from any source distribution.
René Nyffenegger rene.nyffenegger@adp-gmbh.ch
*/
#ifndef SOCKET_H
#define SOCKET_H
#include <WinSock2.h>
#include <string>
enum TypeSocket {BlockingSocket, NonBlockingSocket};
class Socket {
public:
virtual ~Socket();
Socket(const Socket&);
Socket& operator=(Socket&);
std::string ReceiveLine();
std::string ReceiveBytes();
void Close();
// The parameter of SendLine is not a const reference
// because SendLine modifes the std::string passed.
void SendLine (std::string);
// The parameter of SendBytes is a const reference
// because SendBytes does not modify the std::string passed
// (in contrast to SendLine).
void SendBytes(const std::string&);
protected:
friend class SocketServer;
friend class SocketSelect;
Socket(SOCKET s);
Socket();
SOCKET s_;
int* refCounter_;
private:
static void Start();
static void End();
static int nofSockets_;
};
class SocketClient : public Socket {
public:
SocketClient(const std::string& host, int port);
};
class SocketServer : public Socket {
public:
SocketServer(int port, int connections, TypeSocket type=BlockingSocket);
Socket* Accept();
};
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/wsapiref_2tiq.asp
class SocketSelect {
public:
SocketSelect(Socket const * const s1, Socket const * const s2=NULL, TypeSocket type=BlockingSocket);
bool Readable(Socket const * const s);
private:
fd_set fds_;
};
#endif
2、CPP文件
/*
Socket.cpp
Copyright (C) 2002-2004 René Nyffenegger
This source code is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this source code must not be misrepresented; you must not
claim that you wrote the original source code. If you use this source code
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original source code.
3. This notice may not be removed or altered from any source distribution.
René Nyffenegger rene.nyffenegger@adp-gmbh.ch
*/
#include "Socket.h"
#include <iostream>
using namespace std;
int Socket::nofSockets_= 0;
void Socket::Start() {
if (!nofSockets_) {
WSADATA info;
if (WSAStartup(MAKEWORD(2,0), &info)) {
throw "Could not start WSA";
}
}
++nofSockets_;
}
void Socket::End() {
WSACleanup();
}
Socket::Socket() : s_(0) {
Start();
// UDP: use SOCK_DGRAM instead of SOCK_STREAM
s_ = socket(AF_INET,SOCK_STREAM,0);
if (s_ == INVALID_SOCKET) {
throw "INVALID_SOCKET";
}
refCounter_ = new int(1);
}
Socket::Socket(SOCKET s) : s_(s) {
Start();
refCounter_ = new int(1);
};
Socket::~Socket() {
if (! --(*refCounter_)) {
Close();
delete refCounter_;
}
--nofSockets_;
if (!nofSockets_) End();
}
Socket::Socket(const Socket& o) {
refCounter_=o.refCounter_;
(*refCounter_)++;
s_ =o.s_;
nofSockets_++;
}
Socket& Socket::operator=(Socket& o) {
(*o.refCounter_)++;
refCounter_=o.refCounter_;
s_ =o.s_;
nofSockets_++;
return *this;
}
void Socket::Close() {
closesocket(s_);
}
std::string Socket::ReceiveBytes() {
std::string ret;
char buf[1024];
while (1) {
u_long arg = 0;
if (ioctlsocket(s_, FIONREAD, &arg) != 0)
break;
if (arg == 0)
break;
if (arg > 1024) arg = 1024;
int rv = recv (s_, buf, arg, 0);
if (rv <= 0) break;
std::string t;
t.assign (buf, rv);
ret += t;
}
return ret;
}
std::string Socket::ReceiveLine() {
std::string ret;
while (1) {
char r;
switch(recv(s_, &r, 1, 0)) {
case 0: // not connected anymore;
// ... but last line sent
// might not end in /n,
// so return ret anyway.
return ret;
case -1:
return "";
// if (errno == EAGAIN) {
// return ret;
// } else {
// // not connected anymore
// return "";
// }
}
ret += r;
if (r == '/n') return ret;
}
}
void Socket::SendLine(std::string s) {
s += '/n';
send(s_,s.c_str(),s.length(),0);
}
void Socket::SendBytes(const std::string& s) {
send(s_,s.c_str(),s.length(),0);
}
SocketServer::SocketServer(int port, int connections, TypeSocket type) {
sockaddr_in sa;
memset(&sa, 0, sizeof(sa));
sa.sin_family = PF_INET;
sa.sin_port = htons(port);
s_ = socket(AF_INET, SOCK_STREAM, 0);
if (s_ == INVALID_SOCKET) {
throw "INVALID_SOCKET";
}
if(type==NonBlockingSocket) {
u_long arg = 1;
ioctlsocket(s_, FIONBIO, &arg);
}
/* bind the socket to the internet address */
if (bind(s_, (sockaddr *)&sa, sizeof(sockaddr_in)) == SOCKET_ERROR) {
closesocket(s_);
throw "INVALID_SOCKET";
}
listen(s_, connections);
}
Socket* SocketServer::Accept() {
SOCKET new_sock = accept(s_, 0, 0);
if (new_sock == INVALID_SOCKET) {
int rc = WSAGetLastError();
if(rc==WSAEWOULDBLOCK) {
return 0; // non-blocking call, no request pending
}
else {
throw "Invalid Socket";
}
}
Socket* r = new Socket(new_sock);
return r;
}
SocketClient::SocketClient(const std::string& host, int port) : Socket() {
std::string error;
hostent *he;
if ((he = gethostbyname(host.c_str())) == 0) {
error = strerror(errno);
throw error;
}
sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr = *((in_addr *)he->h_addr);
memset(&(addr.sin_zero), 0, 8);
if (::connect(s_, (sockaddr *) &addr, sizeof(sockaddr))) {
error = strerror(WSAGetLastError());
throw error;
}
}
SocketSelect::SocketSelect(Socket const * const s1, Socket const * const s2, TypeSocket type) {
FD_ZERO(&fds_);
FD_SET(const_cast<Socket*>(s1)->s_,&fds_);
if(s2) {
FD_SET(const_cast<Socket*>(s2)->s_,&fds_);
}
TIMEVAL tval;
tval.tv_sec = 0;
tval.tv_usec = 1;
TIMEVAL *ptval;
if(type==NonBlockingSocket) {
ptval = &tval;
}
else {
ptval = 0;
}
if (select (0, &fds_, (fd_set*) 0, (fd_set*) 0, ptval) == SOCKET_ERROR)
throw "Error in select";
}
bool SocketSelect::Readable(Socket const* const s) {
if (FD_ISSET(s->s_,&fds_)) return true;
return false;
}
原文出自：http://www.adp-gmbh.ch/win/misc/sockets.html
