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C:/temp/src/j2k/nto/RWLock.hpp

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#ifndef __J2K__RWLock_HPP__
#define __J2K__RWLock_HPP__

#include <j2k/Fred/Standard.hpp>
#include <j2k/nto/Mutex.hpp>

//
// Classical Implementation of Reader/Writer lock using Mutex
// Don't use pthread_rwlock, since it's not implemented on every platforms;
// however, pthread_mutex is more common than pthread_rwlock, 
// so use it to implement the other.
//
// It's also simpler to code then to play with C structs...
//
// Use your Comp346 book as a reference for the pseudo-code.
//

class RWLock {
public:
 inline RWLock();
 inline virtual ~RWLock();

 void read();
 void write();

 void releaseRead();
 void releaseWrite();

private:
 // -1  = writing
 //  0  = NotUsed (Available)
 //  1+ = reading

 long  readers;

 int   readfail;
 int   writefail;
 int   loop;

 Mutex mutex;


// Not implemented or needed.
private:
  // Copy constructor
  inline RWLock( const RWLock& src );

  // Assign operator
  inline const RWLock& operator=( const RWLock& src );
};

#include <j2k/nto/RWLock.inl>

#endif

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