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C:/temp/src/j2k/nto/Mutex.cpp

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#ifndef __J2K__PThread_Mutex_CPP__
#define __J2K__PThread_Mutex_CPP__


#include <j2k/nto/Mutex.hpp>

// Uses:
// pthread_mutex_t
// pthread_mutex_attr_t

  // Default Constructor
  PThread_Mutex::PThread_Mutex() 
  {
    // Fill structure with 0
    memset( &attr,  0, sizeof( pthread_mutexattr_t ) );
    memset( &mutex, 0, sizeof( pthread_mutex_t     ) ); 

    int err = pthread_mutexattr_init( &attr );
    MC_OnError( err, Error, "An unknown error happened while initializing a mutex attribute." )

    err = pthread_mutex_init( &mutex, &attr );
    MC_OnError( err,  Error, "An error happened while initializing a mutex." )

    state = 0;
  }

  // Virtual Destructor
  PThread_Mutex::~PThread_Mutex() 
  {    
    while( state > 0 ) { printf("DELETE" ); fflush( stdout ); exit( 1 ); }

    int err = pthread_mutex_destroy( &mutex );
    MC_OnError( err, Error, "An error happened while deleting a mutex." )

 
    // Make sure the mutex is Unlock... 

    // WARNING:  Make sure that Mutex destroy
    // ========  don't destroy attribute, 
    //           so that there is no double destroy on attr.

    err = pthread_mutexattr_destroy( &attr );
    MC_OnError( err,  Error, "An error happened while deleting a mutex attribute." )
  }

  // Lock the mutex
  void PThread_Mutex::lock()
  {
//    if ( state == 1 ) return;

    if ( pthread_self() != owner ) {
      sched_yield();
    }

    state = 1;
    register int err = pthread_mutex_lock( &mutex );
    MC_OnError( err, Error, "An error happened while locking a mutex." )

    owner = pthread_self();
  }

  // Unlock the mutex
  void PThread_Mutex::unlock()
  {
//    if ( state == 0 ) return;

    if ( pthread_self() != owner ) {
      sched_yield();
      return;
    }
    register int err = pthread_mutex_unlock( &mutex );
  
    if ( err == EPERM ) { 
      printf( "Unlock. Permission denied. Not owner." );
    } else {
      MC_OnError( err, Error, "An error happened while unlocking a mutex." )
    }
    state = 0;
  }

#endif

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