Semaphore_POSIX.cpp

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/* ES40 emulator.
 * Copyright (C) 2007-2008 by the ES40 Emulator Project
 *
 * WWW    : http://sourceforge.net/projects/es40
 * E-mail : camiel@camicom.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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 * 
 * Although this is not required, the author would appreciate being notified of, 
 * and receiving any modifications you may make to the source code that might serve
 * the general public.
 */

//
// Semaphore_POSIX.cpp
//
// $Id: Semaphore_POSIX.cpp,v 1.1 2008/03/31 19:13:33 iamcamiel Exp $
//
// Library: Foundation
// Package: Threading
// Module:  Semaphore
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "VMS/Semaphore_POSIX.h"
#include <sys/time.h>


namespace Poco {


SemaphoreImpl::SemaphoreImpl(int n, int max): _n(n), _max(max)
{
        poco_assert (n >= 0 && max > 0 && n <= max);

        if (pthread_mutex_init(&_mutex, NULL))
                throw SystemException("cannot create semaphore (mutex)");
        if (pthread_cond_init(&_cond, NULL))
                throw SystemException("cannot create semaphore (condition)");
}


SemaphoreImpl::~SemaphoreImpl()
{
        pthread_cond_destroy(&_cond);
        pthread_mutex_destroy(&_mutex);
}


void SemaphoreImpl::waitImpl()
{
        if (pthread_mutex_lock(&_mutex))
                throw SystemException("wait for semaphore failed (lock)"); 
        while (_n < 1) 
        {
                if (pthread_cond_wait(&_cond, &_mutex))
                {
                        pthread_mutex_unlock(&_mutex);
                        throw SystemException("wait for semaphore failed");
                }
        }
        --_n;
        pthread_mutex_unlock(&_mutex);
}


bool SemaphoreImpl::waitImpl(long milliseconds)
{
        int rc = 0;
        struct timespec abstime;

#if defined(__VMS)
        struct timespec delta;
        delta.tv_sec  = milliseconds / 1000;
        delta.tv_nsec = (milliseconds % 1000)*1000000;
        pthread_get_expiration_np(&delta, &abstime);
#else
        struct timeval tv;
        gettimeofday(&tv, NULL);
        abstime.tv_sec  = tv.tv_sec + milliseconds / 1000;
        abstime.tv_nsec = tv.tv_usec*1000 + (milliseconds % 1000)*1000000;
        if (abstime.tv_nsec >= 1000000000)
        {
                abstime.tv_nsec -= 1000000000;
                abstime.tv_sec++;
        }
#endif

        if (pthread_mutex_lock(&_mutex) != 0)
                throw SystemException("wait for semaphore failed (lock)"); 
        while (_n < 1) 
        {
                if ((rc = pthread_cond_timedwait(&_cond, &_mutex, &abstime)))
                {
                        if (rc == ETIMEDOUT) break;
                        pthread_mutex_unlock(&_mutex);
                        throw SystemException("cannot wait for semaphore");
                }
        }
        if (rc == 0) --_n;
        pthread_mutex_unlock(&_mutex);
        return rc == 0;
}


} // namespace Poco

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