event.h

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
/*
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#pragma once

#ifndef _WIN32
#include <pthread.h>
#include <sys/time.h>
#else
#include <windows.h>
#endif
#include <cassert>
#include <iostream>

namespace rp::hal
{
class Event
{
   public:
    enum
    {
        EVENT_OK = 1,
        EVENT_TIMEOUT = 2,
        EVENT_FAILED = 0,
    };

    Event(bool isAutoReset = true, bool isSignal = false)
#ifdef _WIN32
        : _event(nullptr)
#else
        : _is_signalled(isSignal), _isAutoReset(isAutoReset)
#endif
    {
#ifdef _WIN32
        _event = CreateEvent(
            nullptr, isAutoReset ? FALSE : TRUE, isSignal ? TRUE : FALSE,
            nullptr);
#else
        pthread_mutex_init(&_cond_locker, nullptr);
        pthread_cond_init(&_cond_var, nullptr);
#endif
    }

    ~Event() { release(); }
    void set(bool isSignal = true)
    {
        if (isSignal)
        {
#ifdef _WIN32
            SetEvent(_event);
#else
            pthread_mutex_lock(&_cond_locker);

            if (_is_signalled == false)
            {
                _is_signalled = true;
                pthread_cond_signal(&_cond_var);
            }
            pthread_mutex_unlock(&_cond_locker);
#endif
        }
        else
        {
#ifdef _WIN32
            ResetEvent(_event);
#else
            pthread_mutex_lock(&_cond_locker);
            _is_signalled = false;
            pthread_mutex_unlock(&_cond_locker);
#endif
        }
    }

    unsigned long wait(unsigned long timeout = 0xFFFFFFFF)
    {
#ifdef _WIN32
        switch (WaitForSingleObject(
            _event, timeout == 0xFFFFFFF ? INFINITE : (DWORD)timeout))
        {
            case WAIT_FAILED:
                return EVENT_FAILED;
            case WAIT_OBJECT_0:
                return EVENT_OK;
            case WAIT_TIMEOUT:
                return EVENT_TIMEOUT;
        }
        return EVENT_OK;
#else
        unsigned long ans = EVENT_OK;
        pthread_mutex_lock(&_cond_locker);

        if (!_is_signalled)
        {
            if (timeout == 0xFFFFFFFF)
            {
                pthread_cond_wait(&_cond_var, &_cond_locker);
            }
            else
            {
                timespec wait_time;
                timeval now;
                gettimeofday(&now, nullptr);

                wait_time.tv_sec = timeout / 1000 + now.tv_sec;
                wait_time.tv_nsec =
                    (timeout % 1000) * 1000000ULL + now.tv_usec * 1000;

                if (wait_time.tv_nsec >= 1000000000)
                {
                    ++wait_time.tv_sec;
                    wait_time.tv_nsec -= 1000000000;
                }
                switch (pthread_cond_timedwait(
                    &_cond_var, &_cond_locker, &wait_time))
                {
                    case 0:
                        // signalled
                        break;
                    case ETIMEDOUT:
                        // time up
                        ans = EVENT_TIMEOUT;
                        goto _final;
                        break;
                    default:
                        ans = EVENT_FAILED;
                        goto _final;
                }
            }
        }

        assert(_is_signalled);

        if (_isAutoReset)
        {
            _is_signalled = false;
        }
    _final:
        pthread_mutex_unlock(&_cond_locker);

        return ans;
#endif
    }

   protected:
    void release()
    {
#ifdef _WIN32
        CloseHandle(_event);
#else
        pthread_mutex_destroy(&_cond_locker);
        pthread_cond_destroy(&_cond_var);
#endif
    }

#ifdef _WIN32
    HANDLE _event;
#else
    pthread_cond_t _cond_var;
    pthread_mutex_t _cond_locker;
    bool _is_signalled;
    bool _isAutoReset;
#endif
};
}  // namespace rp::hal