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/*  macros/chain.h

 *

 *  This include file contains the bodies of the routines which are

 *  associated with doubly linked chains and inlined.

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  chain.inl,v 1.9 1999/11/17 17:50:38 joel Exp

 */

#ifndef __MACROS_CHAIN_h

#define __MACROS_CHAIN_h

/*PAGE

 *

 *  _Chain_Are_nodes_equal

 */

#define _Chain_Are_nodes_equal( _left, _right ) \

  ( (_left) == (_right) )

/*PAGE

 *

 *  _Chain_Is_null

 */

#define _Chain_Is_null( _the_chain ) \

  ( (_the_chain) == NULL )

/*PAGE

 *

 *  _Chain_Is_null_node

 */

#define _Chain_Is_null_node( _the_node ) \

  ( (_the_node) == NULL )

/*PAGE

 *

 *  _Chain_Head

 */

#define _Chain_Head( _the_chain ) \

   ((Chain_Node *) (_the_chain))

/*PAGE

 *

 *  _Chain_Tail

 */

#define _Chain_Tail( _the_chain ) \

   ((Chain_Node *) &(_the_chain)->permanent_null)

/*PAGE

 *

 *  _Chain_Is_empty

 */

#define _Chain_Is_empty( _the_chain ) \

  ( (_the_chain)->first == _Chain_Tail( (_the_chain) ) )

/*PAGE

 *

 *  _Chain_Is_first

 */

#define _Chain_Is_first( _the_node ) \

  ( (the_node)->previous == NULL )

/*PAGE

 *

 *  _Chain_Is_last

 */

#define _Chain_Is_last( _the_node ) \

  ( (_the_node)->next == NULL )

/*PAGE

 *

 *  _Chain_Has_only_one_node

 */

#define _Chain_Has_only_one_node( _the_chain ) \

  ( (_the_chain)->first == (_the_chain)->last )

/*PAGE

 *

 *  _Chain_Is_head

 */

#define _Chain_Is_head( _the_chain, _the_node ) \

   ( (_the_node) == _Chain_Head( (_the_chain) ) )

/*PAGE

 *

 *  _Chain_Is_tail

 */

#define _Chain_Is_tail( _the_chain, _the_node ) \

   ( (_the_node) == _Chain_Tail( (_the_chain) ) )

/*PAGE

 *

 *  Chain_Initialize_empty

 */

#define _Chain_Initialize_empty( _the_chain ) \

{ \

  (_the_chain)->first          = _Chain_Tail( (_the_chain) ); \

  (_the_chain)->permanent_null = NULL; \

  (_the_chain)->last           = _Chain_Head( (_the_chain) ); \

}

/*PAGE

 *

 *  _Chain_Extract_unprotected

 */

#define _Chain_Extract_unprotected( _the_node ) \

{ \

  Chain_Node *_next; \

  Chain_Node *_previous; \

   \

  _next           = (_the_node)->next; \

  _previous       = (_the_node)->previous; \

  _next->previous = _previous; \

  _previous->next = _next; \

}

/*PAGE

 *

 *  _Chain_Get_unprotected

 */

/*PAGE

 *

 *  Chain_Get_unprotected

 */

#define _Chain_Get_unprotected( _the_chain ) \

  (( !_Chain_Is_empty( (_the_chain) ) ) \

    ? _Chain_Get_first_unprotected( (_the_chain) ) \

    : NULL)

/*PAGE

 *

 *  _Chain_Insert_unprotected

 */

#define _Chain_Insert_unprotected( _after_node, _the_node ) \

do {  \

  Chain_Node *_before_node; \

   \

  (_the_node)->previous  = (_after_node); \

  _before_node           = (_after_node)->next; \

  (_after_node)->next    = (_the_node);  \

  (_the_node)->next      = _before_node;  \

  _before_node->previous = (_the_node);  \

} while (0)

/*PAGE

 *

 *  _Chain_Append_unprotected

 */

#define _Chain_Append_unprotected( _the_chain, _the_node ) \

{ \

  Chain_Node *_old_last_node; \

    \

  (_the_node)->next     = _Chain_Tail( (_the_chain) ); \

  _old_last_node        = (_the_chain)->last; \

  (_the_chain)->last    = (_the_node); \

  _old_last_node->next  = (_the_node); \

  (_the_node)->previous = _old_last_node; \

}

/*PAGE

 *

 *  _Chain_Prepend_unprotected

 */

#define _Chain_Prepend_unprotected( _the_chain, _the_node ) \

  _Chain_Insert_unprotected( _Chain_Head( (_the_chain) ), (_the_node) )

/*PAGE

 *

 *  _Chain_Prepend

 */

#define _Chain_Prepend( _the_chain, _the_node ) \

  _Chain_Insert( _Chain_Head( (_the_chain) ), (_the_node) )

#endif

/* end of include file */