SharedLock.h

// $Id: SharedLock.h 21 2010-09-05 04:18:17Z cschwarz1 $

#ifndef BASE_SHAREDLOCK_H
#define BASE_SHAREDLOCK_H

#include "Condition.h"

namespace base {

    class PPBASE_EXPORT SharedLock: public Mutex {
    public:
        enum {
            UNLOCKED = 0,   
            READ,           
            WRITE,          
            DYNAMIC         
        };


        SharedLock(size_t priority = DYNAMIC);

        ~SharedLock();


        void lock(size_t mode = READ);

        void unlock();

    protected:
        size_t     _priority;         
        Condition *_rcond;            
        size_t     _reader;           
        size_t     _reader_waiting;   
        size_t     _state;            
        Condition *_wcond;            
        size_t     _writer_waiting;   
    };
}

#endif