#ifndef CYGONCE_KERNEL_MBOXT2_HXX
#define CYGONCE_KERNEL_MBOXT2_HXX

//==========================================================================
//
//      mboxt2.hxx
//
//      Mboxt2 (Message Box/Mailbox) class declarations
//
//==========================================================================
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// -------------------------------------------                              
// This file is part of eCos, the Embedded Configurable Operating System.   
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
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// for more details.                                                        
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//
// As a special exception, if other files instantiate templates or use      
// macros or inline functions from this file, or you compile this file      
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// this file does not by itself cause the resulting work to be covered by   
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//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   hmt
// Contributors:        hmt
// Date:        1998-02-10
// Purpose:     Define Mboxt2 class interfaces
// Description: The classes defined here provide the APIs for mboxt2es.
// Usage:       #include <cyg/kernel/mboxt2.hxx>
//              #include <cyg/kernel/mboxt2.inl>
//              
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h>            // assertion macros
#include <cyg/kernel/thread.hxx>
#include <cyg/kernel/thread.inl>

// -------------------------------------------------------------------------
// Message/Mail Box.  This template implements a queue of T's.
// Implemented as a template for maximal flexibility; one would hope
// that only one, with T==(void *) and the same number of them,
// is ever used without very good reason.

// Cyg_Mboxt2 has a fixed size array of T's; one size fits all.

template <class T, cyg_count32 QUEUE_SIZE>
class Cyg_Mboxt2
{
private:
    cyg_count32         base;           // index of first used slot
    cyg_count32         count;          // count of used slots
    Cyg_ThreadQueue     get_threadq;    // Queue of waiting threads
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
    Cyg_ThreadQueue     put_threadq;    // Queue of waiting threads
#endif
    static const
    cyg_count32         size = QUEUE_SIZE;
    T                   itemqueue[ QUEUE_SIZE ];
                                        // queue of items
    // private utility functions
    // wake up a thread from some queue
    inline void         wakeup_winner( const T &msg );
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
    inline void         wakeup_putter( void );
#endif

public:

    CYGDBG_DEFINE_CHECK_THIS
    
    Cyg_Mboxt2();                        // Constructor
    ~Cyg_Mboxt2();                       // Destructor
        
    cyg_bool    get( T &ritem );        // get an item; wait if none
#ifdef CYGFUN_KERNEL_THREADS_TIMER
    cyg_bool    get( T &ritem, cyg_tick_count abs_timeout );
#endif
    cyg_bool    tryget( T &ritem );     // just one attempt

    cyg_bool    peek_item( T &ritem );  // get next item without
                                        // removing it

#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
    cyg_bool    put( const T item );    // put an item; wait if full
#ifdef CYGFUN_KERNEL_THREADS_TIMER
    cyg_bool    put( const T item, cyg_tick_count abs_timeout );
#endif
#endif
    cyg_bool    tryput( const T item ); // fails if Q full

    inline
    cyg_count32 peek()                  // Get current count value
    {
        return count;
    }

    inline
    cyg_bool    waiting_to_get()        // Any threads waiting?
    {
        return ! get_threadq.empty();
    }

    inline
    cyg_bool    waiting_to_put()        // Any threads waiting?
    {
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
        return ! put_threadq.empty();
#else
        return false;
#endif
    }
};

// -------------------------------------------------------------------------
#endif // ifndef CYGONCE_KERNEL_MBOXT2_HXX
// EOF mboxt2.hxx
