Semaphores.h

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/* 
 * Copyright (C) 2006-2010 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.
 */

#ifndef ADCHPP_SEMAPHORES_H
#define ADCHPP_SEMAPHORES_H

namespace adchpp {
    
#ifndef _WIN32
#include <semaphore.h>
#endif

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

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

    enum Results {
        RESULT_OK,
        RESULT_TIMEOUT,
        RESULT_MESSAGE
    };
    Results waitMsg(uint32_t millis = INFINITE) throw() { 
        switch(MsgWaitForMultipleObjects(1, &h, FALSE, millis, QS_ALLEVENTS)) {
        case WAIT_TIMEOUT: return RESULT_TIMEOUT;
        case WAIT_OBJECT_0: return RESULT_OK;
        case WAIT_OBJECT_0 + 1: return RESULT_MESSAGE;
        default: dcasserta(false);
        }
#ifndef NDEBUG
        return RESULT_TIMEOUT;
#endif
    };
    bool wait(uint32_t millis = INFINITE) throw() { return WaitForSingleObject(h, millis) == WAIT_OBJECT_0; };
    
    ~Semaphore() throw() {
        CloseHandle(h);
    };

private:
    HANDLE h;
#else
public:
    Semaphore() throw() { sem_init(&sem, 0, 0); };
    ~Semaphore() throw() { sem_destroy(&sem); };
    void signal() throw() { sem_post(&sem); };
    bool wait() throw() { sem_wait(&sem); return true; };
    bool wait(uint32_t millis) throw() {
        uint32_t w = 0;
        while(w < millis) {
            if(sem_trywait(&sem) == 0)
                return true;
            w += 100;
            Thread::sleep(100);
        }
        return false;
    }
private:
    sem_t sem;
#endif
};

}

#endif // SEMAPHORES_H