condition.cpp

/*	EQEMu: Everquest Server Emulator
	Copyright (C) 2001-2006 EQEMu Development Team (http://eqemulator.net)

	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; version 2 of the License.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY except by those people which sell it, which
	are required to give you total support for your newly bought product;
	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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include "condition.h"

#ifdef _WINDOWS

	Condition::Condition()
	{
		m_events[SignalEvent] = CreateEvent (nullptr, // security
										FALSE, // is auto-reset event?
										FALSE, // is signaled initially?
										nullptr); // name
		m_events[BroadcastEvent] = CreateEvent (nullptr, // security
										TRUE, // is auto-reset event?
										FALSE, // is signaled initially?
										nullptr); // name
		m_waiters = 0;
		InitializeCriticalSection(&CSMutex);
	}

	Condition::~Condition()
	{
		DeleteCriticalSection(&CSMutex);
		CloseHandle(m_events[SignalEvent]);
		CloseHandle(m_events[BroadcastEvent]);
	}

	void Condition::Signal()
	{
		EnterCriticalSection(&CSMutex);
		if(m_waiters > 0)
			SetEvent(m_events[SignalEvent]);
		LeaveCriticalSection(&CSMutex);
	}

	void Condition::SignalAll()
	{
		EnterCriticalSection(&CSMutex);
		if(m_waiters > 0)
			SetEvent(m_events[BroadcastEvent]);
		LeaveCriticalSection(&CSMutex);
	}

	void Condition::Wait()
	{
		EnterCriticalSection(&CSMutex);

		m_waiters++;


		LeaveCriticalSection(&CSMutex);
		int result = WaitForMultipleObjects (_eventCount, m_events, FALSE, INFINITE);
		EnterCriticalSection(&CSMutex);

		m_waiters--;

		//see if we are the last person waiting on the condition, and there was a broadcast
		//if so, we need to reset the broadcast event.
		if(m_waiters == 0 && result == (WAIT_OBJECT_0+BroadcastEvent))
			ResetEvent(m_events[BroadcastEvent]);

		LeaveCriticalSection(&CSMutex);
	}

#else
	#include <pthread.h>
	#include <sys/time.h>
	#include <errno.h>
	
	Condition::Condition()
	{
		pthread_cond_init(&cond,nullptr);
		pthread_mutex_init(&mutex,nullptr);
	}

	void Condition::Signal()
	{
		pthread_mutex_lock(&mutex);
		pthread_cond_signal(&cond);
		pthread_mutex_unlock(&mutex);
	}

	void Condition::SignalAll()
	{
		pthread_mutex_lock(&mutex);
		pthread_cond_broadcast(&cond);
		pthread_mutex_unlock(&mutex);
	}

	void Condition::Wait()
	{
		pthread_mutex_lock(&mutex);
		pthread_cond_wait(&cond,&mutex);
		pthread_mutex_unlock(&mutex);
	}

	/*
	I commented this specifically because I think it might be very
	difficult to write a windows counterpart to it, so I would like
	to discourage its use until we can confirm that it can be reasonably
	implemented on windows.

	bool Condition::TimedWait(unsigned long usec)
	{
	struct timeval now;
	struct timespec timeout;
	int retcode=0;
		pthread_mutex_lock(&mutex);
		gettimeofday(&now,nullptr);
		now.tv_usec+=usec;
		timeout.tv_sec = now.tv_sec + (now.tv_usec/1000000);
		timeout.tv_nsec = (now.tv_usec%1000000) *1000;
		//cout << "now=" << now.tv_sec << "."<<now.tv_usec << endl;
		//cout << "timeout=" << timeout.tv_sec << "."<<timeout.tv_nsec << endl;
		retcode=pthread_cond_timedwait(&cond,&mutex,&timeout);
		pthread_mutex_unlock(&mutex);

		return retcode!=ETIMEDOUT;
	}
	*/

	Condition::~Condition()
	{
		pthread_mutex_lock(&mutex);
		pthread_cond_destroy(&cond);
		pthread_mutex_unlock(&mutex);
		pthread_mutex_destroy(&mutex);
	}
	
#endif