/*
 * Copyright (C) 2001-2011 Jacek Sieka, arnetheduck on gmail point com
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#if !defined(SEMAPHORE_H)
#define SEMAPHORE_H

#ifndef _WIN32
#include "CriticalSection.h"
#include <sys/time.h>
#endif

namespace dcpp {

class Semaphore
{
#ifdef _WIN32
public:
	Semaphore() throw() {
		h = CreateSemaphore(NULL, 0, MAXLONG, NULL);
	}

	void signal() throw() {
		ReleaseSemaphore(h, 1, NULL);
	}

	bool wait() throw() { return WaitForSingleObject(h, INFINITE) == WAIT_OBJECT_0; }
	bool wait(uint32_t millis) throw() { return WaitForSingleObject(h, millis) == WAIT_OBJECT_0; }

	~Semaphore() throw() {
		CloseHandle(h);
	}

private:
	HANDLE h;
#else
public:
	Semaphore() throw() : count(0) { pthread_cond_init(&cond, NULL); }
	~Semaphore() throw() { pthread_cond_destroy(&cond); }
	void signal() throw() {
		Lock l(cs);
		count++;
		pthread_cond_signal(&cond);
	}

	bool wait() throw() {
		Lock l(cs);
		if(count == 0) {
			pthread_cond_wait(&cond, &cs.getMutex());
		}
		count--;
		return true;
	}
	bool wait(uint32_t millis) throw() {
		Lock l(cs);
		if(count == 0) {
			timeval timev;
			timespec t;
			gettimeofday(&timev, NULL);
			millis+=timev.tv_usec/1000;
			t.tv_sec = timev.tv_sec + (millis/1000);
			t.tv_nsec = (millis%1000)*1000*1000;
			int ret = pthread_cond_timedwait(&cond, &cs.getMutex(), &t);
			if(ret != 0) {
				return false;
			}
		}
		count--;
		return true;
	}

private:
	pthread_cond_t cond;
	CriticalSection cs;
	int count;
#endif
	Semaphore(const Semaphore&);
	Semaphore& operator=(const Semaphore&);

};

} // namespace dcpp

#endif // !defined(SEMAPHORE_H)
