MutexClass.cpp

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//
// MutexClass.cpp: implementation file
//
// Copyright (C) Walter E. Capers.  All rights reserved
//
// This source is free to use as you like.  If you make
// any changes please keep me in the loop.  Email them to
// walt.capers@comcast.net.
//
// PURPOSE:
//
//  To implement mutexes as a C++ object
//
// REVISIONS
// =======================================================
// Date: 10.25.07        
// Name: Walter E. Capers
// Description: File creation
//
// Date:
// Name:
// Description:
//
//
#include <blort/ThreadObject/Thread.h>

CMutexClass::CMutexClass(void)
:m_bCreated(TRUE)
{
#ifdef WINDOWS
   m_mutex = CreateMutex(NULL,FALSE,NULL);
   if( !m_mutex ) m_bCreated = FALSE;
#else
   pthread_mutexattr_t mattr;

   pthread_mutexattr_init( &mattr );
   pthread_mutex_init(&m_mutex,&mattr);

#endif

}

CMutexClass::~CMutexClass(void)
{
#ifdef WINDOWS
        WaitForSingleObject(m_mutex,INFINITE);
        CloseHandle(m_mutex);
#else
        pthread_mutex_lock(&m_mutex);
        pthread_mutex_unlock(&m_mutex);
        pthread_mutex_destroy(&m_mutex);
#endif
}

void
CMutexClass::Lock()
{
        ThreadId_t id = CThread::ThreadId();
        if(CThread::ThreadIdsEqual(&m_owner,&id) )
                return; // the mutex is already locked by this thread
#ifdef WINDOWS
        WaitForSingleObject(m_mutex,INFINITE);
#else
        pthread_mutex_lock(&m_mutex);
#endif
        m_owner = CThread::ThreadId();
}

void 
CMutexClass::Unlock()
{
        ThreadId_t id = CThread::ThreadId();
        if( ! CThread::ThreadIdsEqual(&id,&m_owner) )
                return; // on the thread that has locked the mutex can release 
                    // the mutex

        memset(&m_owner,0,sizeof(ThreadId_t));
#ifdef WINDOWS
        ReleaseMutex(m_mutex);
#else
        pthread_mutex_unlock(&m_mutex);
#endif
}

void
CMutexClass::Wait()
{
        Lock();
        Unlock();
}