select.cpp

swain-0.5.2.zip的源代码,比较好用,希望大家喜欢.

/*
This file is part of SWAIN (http://sourceforge.net/projects/swain).
Copyright (C) 2006  Daniel Lindstr鰉 and Daniel Nilsson

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., 51 Franklin Street, Fifth Floor,
Boston, MA  02110-1301, USA.
*/
#include "StdAfx.h"
#include "Select.h"

Select::Select(void){
	for(int i=0; i<FD_SETSIZE; i++){
		sockets[i] = NULL;
		this->free_socks[i] = true;
	}
	num_socks = 0;
	InitializeCriticalSection(&lock);
	timeout = NULL;
}

Select::~Select(void){
	DeleteCriticalSection(&lock);
	if(timeout != NULL)
		free(timeout);
}

void Select::addSocket(Socket *s){
	EnterCriticalSection(&lock);
	for(int i=0; i<FD_SETSIZE; i++){
		if(free_socks[i]){
			sockets[i] = s;
			num_socks++;
			free_socks[i] = false;
			break;
		}
	}
	LeaveCriticalSection(&lock);
}
void Select::removeSocket(Socket *s){
	EnterCriticalSection(&lock);	
	for(int i=0; i<FD_SETSIZE; i++){
		if(sockets[i] == s){
			sockets[i] = NULL;
			num_socks--;
			free_socks[i] = true;
		}
	}
	LeaveCriticalSection(&lock);
}

void Select::removeSockets(){
	EnterCriticalSection(&lock);	
	for(int i=0; i<FD_SETSIZE; i++){
		if(!free_socks[i]){
			sockets[i] = NULL;
			free_socks[i] = true;
		}
	}
	LeaveCriticalSection(&lock);
}


Socket *Select::doSelect(void){
	static fd_set set;
	static int num = 0;
	Socket *s = NULL;
	int i;

	if (num == 0) {	// The set is empty, need to rebuild it. 
		EnterCriticalSection(&lock);
		FD_ZERO(&set);
		for(i=0; i<FD_SETSIZE; i++){
			if (!free_socks[i]) {
				FD_SET(sockets[i]->sock, &set);
				num++;
			}
		}
		LeaveCriticalSection(&lock);
		if (num > 0) {
			num = select(num, &set, NULL, NULL, timeout);
		} else {	// No sockets, just sleep...
			Sleep(timeout->tv_sec*1000 + timeout->tv_usec/1000);
		}
	}
	if(num == 0){
		return NULL;
	}
	if(num == SOCKET_ERROR){
		int err = WSAGetLastError();
		printf("select returned SOCKET_ERROR (error %d), sleeping...\n", err);
		Sleep(timeout->tv_sec*1000 + timeout->tv_usec/1000);
		num = 0;
		return NULL;
	}
	EnterCriticalSection(&lock);
	for(i = 0; i<FD_SETSIZE; i++){
		if(!free_socks[i] && FD_ISSET(sockets[i]->sock, &set)){
			s = sockets[i];
			FD_CLR(s->sock, &set);
			num--;
			break;
		}
	}
	if (s == NULL) { // didn't find the socket, must have been removed
		num = 0;	// force a rebuild of the fd_set next time
	}
	LeaveCriticalSection(&lock);
	return(s);
}

void Select::setTimeout(int ms){
	if(timeout == NULL)
		this->timeout = (timeval *)malloc(sizeof(TIMEVAL));
	this->timeout->tv_sec = ms/1000;
	this->timeout->tv_usec =(long)(ms%1000)*1000;
}