reader_writer_lock.h

/*
    Copyright 2005-2011 Intel Corporation.  All Rights Reserved.

    The source code contained or described herein and all documents related
    to the source code ("Material") are owned by Intel Corporation or its
    suppliers or licensors.  Title to the Material remains with Intel
    Corporation or its suppliers and licensors.  The Material is protected
    by worldwide copyright laws and treaty provisions.  No part of the
    Material may be used, copied, reproduced, modified, published, uploaded,
    posted, transmitted, distributed, or disclosed in any way without
    Intel's prior express written permission.

    No license under any patent, copyright, trade secret or other
    intellectual property right is granted to or conferred upon you by
    disclosure or delivery of the Materials, either expressly, by
    implication, inducement, estoppel or otherwise.  Any license under such
    intellectual property rights must be express and approved by Intel in
    writing.
*/

#ifndef __TBB_reader_writer_lock_H
#define __TBB_reader_writer_lock_H

#include "tbb_thread.h"
#include "tbb_allocator.h"
#include "atomic.h"

namespace tbb {
namespace interface5 {

    class reader_writer_lock : tbb::internal::no_copy {
 public:
    friend class scoped_lock;
    friend class scoped_lock_read;

    enum status_t { waiting_nonblocking, waiting, active, invalid };

    reader_writer_lock() {
        internal_construct();
    }

    ~reader_writer_lock() {
        internal_destroy();
    }


    class scoped_lock : tbb::internal::no_copy {
    public:
        friend class reader_writer_lock;
 
        scoped_lock(reader_writer_lock& lock) {
            internal_construct(lock);
        }
        
        ~scoped_lock() {
            internal_destroy();
        }

        void* operator new(size_t s) {
            return tbb::internal::allocate_via_handler_v3(s);
        }
        void operator delete(void* p) {
            tbb::internal::deallocate_via_handler_v3(p);
        }

    private:
        reader_writer_lock *mutex;
        scoped_lock* next;
        atomic<status_t> status;

        scoped_lock();

        void __TBB_EXPORTED_METHOD internal_construct(reader_writer_lock&);
        void __TBB_EXPORTED_METHOD internal_destroy();
   };

    class scoped_lock_read : tbb::internal::no_copy {
    public:
        friend class reader_writer_lock;

        scoped_lock_read(reader_writer_lock& lock) {
            internal_construct(lock);
        }

        ~scoped_lock_read() { 
            internal_destroy();
        }
        
        void* operator new(size_t s) {
            return tbb::internal::allocate_via_handler_v3(s);
        }
        void operator delete(void* p) {
            tbb::internal::deallocate_via_handler_v3(p);
        }

    private:
        reader_writer_lock *mutex;
        scoped_lock_read *next;
        atomic<status_t> status;

        scoped_lock_read();

        void __TBB_EXPORTED_METHOD internal_construct(reader_writer_lock&);
        void __TBB_EXPORTED_METHOD internal_destroy();
    };
    

    void __TBB_EXPORTED_METHOD lock();


    bool __TBB_EXPORTED_METHOD try_lock();


    void __TBB_EXPORTED_METHOD lock_read(); 


    bool __TBB_EXPORTED_METHOD try_lock_read();

    void __TBB_EXPORTED_METHOD unlock();

 private:
    void __TBB_EXPORTED_METHOD internal_construct();
    void __TBB_EXPORTED_METHOD internal_destroy();


    bool start_write(scoped_lock *);
    void set_next_writer(scoped_lock *w);
    void end_write(scoped_lock *);
    bool is_current_writer();


    void start_read(scoped_lock_read *);
    void unblock_readers();
    void end_read();

    atomic<scoped_lock_read*> reader_head;
    atomic<scoped_lock*> writer_head;
    atomic<scoped_lock*> writer_tail;
    tbb_thread::id my_current_writer;
    atomic<unsigned> rdr_count_and_flags;
};

} // namespace interface5

using interface5::reader_writer_lock;

} // namespace tbb

#endif /* __TBB_reader_writer_lock_H */

---

Copyright © 2005-2011 Intel Corporation. All Rights Reserved.

Intel, Pentium, Intel Xeon, Itanium, Intel XScale and VTune are registered trademarks or trademarks of Intel Corporation or its subsidiaries in the United States and other countries.

* Other names and brands may be claimed as the property of others.