condition.h File Reference

‎//*****************************************************************************
// Copyright 1986, 2016 NVIDIA Corporation. All rights reserved.
//*****************************************************************************
//*****************************************************************************

#ifndef MI_BASE_CONDITION_H
#define MI_BASE_CONDITION_H

#include <mi/base/config.h>
#include <mi/base/types.h>

#ifndef MI_PLATFORM_WINDOWS
#include <cerrno>
#include <pthread.h>
#include <sys/time.h>
#else
#include <mi/base/miwindows.h>
#endif

namespace mi {

namespace base {


class Condition
{
public:
    Condition()
    {
#ifndef MI_PLATFORM_WINDOWS
        m_signaled = false;
        pthread_mutex_init( &m_mutex, NULL);
        pthread_cond_init( &m_condvar, NULL);
#else
        m_handle = CreateEvent( NULL, false, false, NULL);
#endif
    }

    ~Condition()
    {
#ifndef MI_PLATFORM_WINDOWS
        pthread_mutex_destroy( &m_mutex);
        pthread_cond_destroy( &m_condvar);
#else
        CloseHandle( m_handle);
#endif
    }

    void wait()
    {
#ifndef MI_PLATFORM_WINDOWS
        pthread_mutex_lock( &m_mutex);
        while( !m_signaled)
            pthread_cond_wait( &m_condvar, &m_mutex);
        m_signaled = false;
        pthread_mutex_unlock( &m_mutex);
#else
        WaitForSingleObject( m_handle, INFINITE);
#endif
    }

    bool timed_wait( Float64 timeout) {
#ifndef MI_PLATFORM_WINDOWS
        struct timeval now;
        gettimeofday( &now, NULL);
        struct timespec timeout_abs;
        timeout_abs.tv_sec = now.tv_sec + static_cast<long>( floor( timeout));
        timeout_abs.tv_nsec
            = 1000 * now.tv_usec + static_cast<long>( 1E9 * ( timeout - floor( timeout)));
        if( timeout_abs.tv_nsec > 1000000000) {
            timeout_abs.tv_sec  += 1;
            timeout_abs.tv_nsec -= 1000000000;
        }

        bool timed_out = false;
        pthread_mutex_lock( &m_mutex);
        while( !m_signaled)
        {
            int result = pthread_cond_timedwait( &m_condvar, &m_mutex, &timeout_abs);
            timed_out = result == ETIMEDOUT;
            if( result != EINTR)
                break;
        }
        m_signaled = false;
        pthread_mutex_unlock( &m_mutex);
        return timed_out;
#else
        DWORD timeout_ms = static_cast<DWORD>( 1000 * timeout);
        DWORD result = WaitForSingleObject( m_handle, timeout_ms);
        return result == WAIT_TIMEOUT;   
#endif    
    }

    void signal()
    {
#ifndef MI_PLATFORM_WINDOWS
        pthread_mutex_lock( &m_mutex);
        m_signaled = true;
        pthread_cond_signal( &m_condvar);
        pthread_mutex_unlock( &m_mutex);
#else
        SetEvent( m_handle);
#endif
    }

    void reset()
    {
#ifndef MI_PLATFORM_WINDOWS
        pthread_mutex_lock( &m_mutex);
        m_signaled = false;
        pthread_mutex_unlock( &m_mutex);
#else
        ResetEvent( m_handle);
#endif
    }

private:
#ifndef MI_PLATFORM_WINDOWS
    pthread_mutex_t m_mutex;
    pthread_cond_t m_condvar;
    bool m_signaled;
#else
    HANDLE m_handle;
#endif
};
 // end group mi_base_threads

} // namespace base

} // namespace mi

#endif // MI_BASE_CONDITION_H