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/*  inline/chain.inl

 *

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

 *  associated with doubly linked chains and inlined.

 *

 *  NOTE:  The routines in this file are ordered from simple

 *         to complex.  No other Chain Handler routine is referenced

 *         unless it has already been defined.

 *

 *  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 17:50:37 joel Exp

 */

#ifndef __INLINE_CHAIN_inl

#define __INLINE_CHAIN_inl

/*PAGE

 *

 *  _Chain_Are_nodes_equal

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if LEFT and RIGHT are equal,

 *  and FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Are_nodes_equal(

  Chain_Node *left,

  Chain_Node *right

)

{

  return left == right;

}

/*PAGE

 *

 *  _Chain_Is_null

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_chain is NULL and FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_null(

  Chain_Control *the_chain

)

{

  return ( the_chain == NULL );

}

/*PAGE

 *

 *  _Chain_Is_null_node

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_node is NULL and FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_null_node(

  Chain_Node *the_node

)

{

  return ( the_node == NULL );

}

/*PAGE

 *

 *  _Chain_Head

 *

 *  DESCRIPTION:

 *

 *  This function returns a pointer to the first node on the chain.

 */

RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Head(

  Chain_Control *the_chain

)

{

   return (Chain_Node *) the_chain;

}

/*PAGE

 *

 *  _Chain_Tail

 *

 *  DESCRIPTION:

 *

 *  This function returns a pointer to the last node on the chain.

 */

RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Tail(

  Chain_Control *the_chain

)

{

   return (Chain_Node *) &the_chain->permanent_null;

}

/*PAGE

 *

 *  _Chain_Is_empty

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if there a no nodes on the_chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_empty(

  Chain_Control *the_chain

)

{

  return ( the_chain->first == _Chain_Tail( the_chain ) );

}

/*PAGE

 *

 *  _Chain_Is_first

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_node is the first node on a chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_first(

  Chain_Node *the_node

)

{

  return ( the_node->previous == NULL );

}

/*PAGE

 *

 *  _Chain_Is_last

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_node is the last node on a chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_last(

  Chain_Node *the_node

)

{

  return ( the_node->next == NULL );

}

/*PAGE

 *

 *  _Chain_Has_only_one_node

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if there is only one node on the_chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Has_only_one_node(

  Chain_Control *the_chain

)

{

  return ( the_chain->first == the_chain->last );

}

/*PAGE

 *

 *  _Chain_Is_head

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_node is the head of the_chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_head(

  Chain_Control *the_chain,

  Chain_Node    *the_node

)

{

   return ( the_node == _Chain_Head( the_chain ) );

}

/*PAGE

 *

 *  _Chain_Is_tail

 *

 *  DESCRIPTION:

 *

 *  This function returns TRUE if the_node is the tail of the_chain and

 *  FALSE otherwise.

 */

RTEMS_INLINE_ROUTINE boolean _Chain_Is_tail(

  Chain_Control *the_chain,

  Chain_Node    *the_node

)

{

   return ( the_node == _Chain_Tail( the_chain ) );

}

/*PAGE

 *

 *  Chain_Initialize_empty

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the specified chain to contain zero nodes.

 */

RTEMS_INLINE_ROUTINE void _Chain_Initialize_empty(

  Chain_Control *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

 *

 *  DESCRIPTION:

 *

 *  This routine extracts the_node from the chain on which it resides.

 *  It does NOT disable interrupts to insure the atomicity of the

 *  extract operation.

 */

RTEMS_INLINE_ROUTINE void _Chain_Extract_unprotected(

  Chain_Node *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_first_unprotected

 *

 *  DESCRIPTION:

 *

 *  This function removes the first node from the_chain and returns

 *  a pointer to that node.  It does NOT disable interrupts to insure

 *  the atomicity of the get operation.

 */

RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_first_unprotected(

  Chain_Control *the_chain

)

{

  Chain_Node  *return_node;

  Chain_Node  *new_first;

  return_node         = the_chain->first;

  new_first           = return_node->next;

  the_chain->first    = new_first;

  new_first->previous = _Chain_Head( the_chain );

  return return_node;

}

/*PAGE

 *

 *  Chain_Get_unprotected

 *

 *  DESCRIPTION:

 *

 *  This function removes the first node from the_chain and returns

 *  a pointer to that node.  If the_chain is empty, then NULL is returned.

 *  It does NOT disable interrupts to insure the atomicity of the

 *  get operation.

 */

RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_unprotected(

  Chain_Control *the_chain

)

{

  if ( !_Chain_Is_empty( the_chain ) )

    return _Chain_Get_first_unprotected( the_chain );

  else

    return NULL;

}

/*PAGE

 *

 *  _Chain_Insert_unprotected

 *

 *  DESCRIPTION:

 *

 *  This routine inserts the_node on a chain immediately following

 *  after_node.  It does NOT disable interrupts to insure the atomicity

 *  of the extract operation.

 */

RTEMS_INLINE_ROUTINE void _Chain_Insert_unprotected(

  Chain_Node *after_node,

  Chain_Node *the_node

)

{

  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;

}

/*PAGE

 *

 *  _Chain_Append_unprotected

 *

 *  DESCRIPTION:

 *

 *  This routine appends the_node onto the end of the_chain.

 *  It does NOT disable interrupts to insure the atomicity of the

 *  append operation.

 */

RTEMS_INLINE_ROUTINE void _Chain_Append_unprotected(

  Chain_Control *the_chain,

  Chain_Node    *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

 *

 *  DESCRIPTION:

 *

 *  This routine prepends the_node onto the front of the_chain.

 *  It does NOT disable interrupts to insure the atomicity of the

 *  prepend operation.

 */

RTEMS_INLINE_ROUTINE void _Chain_Prepend_unprotected(

  Chain_Control *the_chain,

  Chain_Node    *the_node

)

{

  _Chain_Insert_unprotected( _Chain_Head( the_chain ), the_node );

}

/*PAGE

 *

 *  _Chain_Prepend

 *

 *  DESCRIPTION:

 *

 *  This routine prepends the_node onto the front of the_chain.

 *  It disables interrupts to insure the atomicity of the

 *  prepend operation.

 */

RTEMS_INLINE_ROUTINE void _Chain_Prepend(

  Chain_Control *the_chain,

  Chain_Node    *the_node

)

{

  _Chain_Insert( _Chain_Head( the_chain ), the_node );

}

#endif

/* end of include file */