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#ifndef CYGONCE_KERNEL_LLISTT_HXX

#define CYGONCE_KERNEL_LLISTT_HXX

//==========================================================================

//

//      llistt.hxx

//

//      Llistt linked list template class declarations

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later

// version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License

// along with eCos; if not, write to the Free Software Foundation, Inc.,

// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

//

// As a special exception, if other files instantiate templates or use

// macros or inline functions from this file, or you compile this file

// and link it with other works to produce a work based on this file,

// this file does not by itself cause the resulting work to be covered by

// the GNU General Public License. However the source code for this file

// must still be made available in accordance with section (3) of the GNU

// General Public License v2.

//

// This exception does not invalidate any other reasons why a work based

// on this file might be covered by the GNU General Public License.

// -------------------------------------------

// ####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   hmt

// Contributors:        hmt

// Date:        1998-02-10

// Purpose:     Define Llistt template class

// Description: The classes defined here provide the APIs for llistts.

// Usage:       #include 

//

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include 

#include             // assertion macros

#include 

// -------------------------------------------------------------------------

// A simple linked list template; each item also contains a pointer of type

// T, and you can search for a particular T* in a list.

//

// It is intended that this list be amenable to the trick of using the

// address of the pointer that is the list head, cast to an item pointer,

// as the "zeroth" element of the list; prev of the first item is the

// address of the head pointer, and inserting before the first item works

// correctly.  For this reason, a "getprev" is not provided; iteration may

// only be forwards, until a NULL is found.

//

// It is expected that derived classes will be used to hold other

// information than just the T* but that is beyond our discussion here;

// only the T* can be searched for using code provided here.

//

// This module is NOT thread-safe; it is expected that all clients will be

// seeing that that themselves.

template 

class Cyg_Llistt

{

private:

    Cyg_Llistt *next, *prev;

    T *tptr;

private:

    // make initialisation _without_ a T* impossible.

    Cyg_Llistt &operator=(Cyg_Llistt &);

    Cyg_Llistt(Cyg_Llistt &);

    Cyg_Llistt();

public:

    CYGDBG_DEFINE_CHECK_THIS

    Cyg_Llistt( T *tvalue ) // Constructor

    {

        tptr = tvalue;

        next = prev = NULL;

    }

    ~Cyg_Llistt()                       // Destructor

    {

        CYG_ASSERT( NULL == next, "bad item next - still in list" );

        CYG_ASSERT( NULL == prev, "bad item prev - still in list" );

    }

    // iterator, basically.

    Cyg_Llistt * getnext() { return next; }

    // get the value

    T * getitem() { return tptr; }

    // look up a particular T value in the llist

    static Cyg_Llistt *

    find( Cyg_Llistt *list, T *tvalue )

    {

        for ( ; list ; list = list->next ) {

            if ( list->tptr == tvalue )

                break;

        }

        return list;

    }

    // unlink an item from the list

    void

    unlink()

    {

        CYG_ASSERT( prev, "not in a list" );

        prev->next = next;

        if ( next ) {

            next->prev = prev;

        }

        next = prev = NULL;

    }

    // insert a new item in the list after "this"

    void

    insertafter( Cyg_Llistt *item )

    {

        CYG_ASSERT( item, "null item" );

        CYG_ASSERT( NULL == item->next, "bad item next - already linked" );

        CYG_ASSERT( NULL == item->prev, "bad item prev - already linked" );

        item->next = next;

        item->prev = this;

        if ( next )

            next->prev = item;

        next = item;

    }

    // insert a new item in the list before "this"

    void

    insertbefore( Cyg_Llistt *item )

    {

        CYG_ASSERT( prev, "this not in a list" );

        CYG_ASSERT( item, "null item" );

        CYG_ASSERT( NULL == item->next, "bad item next - already linked" );

        CYG_ASSERT( NULL == item->prev, "bad item prev - already linked" );

        item->prev = prev;

        item->next = this;

        prev->next = item;

              prev = item;

    }

};

// -------------------------------------------------------------------------

#endif // ifndef CYGONCE_KERNEL_LLISTT_HXX

// EOF llistt.hxx