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/*

 *  Chain Handler

 *

 *  COPYRIGHT (c) 1988-2002.

 *  On-Line Applications Research Corporation (OAR).

 *  All rights reserved.

 *

 *  chain.c,v 1.5 2002/01/17 21:47:47 joel Exp

 */

#include "system.h"

#include "address.h"

#include "chain.h"

#include "isr.h"

/*PAGE

 *

 *  _Chain_Initialize

 *

 *  This kernel routine initializes a doubly linked chain.

 *

 *  Input parameters:

 *    the_chain        - pointer to chain header

 *    starting_address - starting address of first node

 *    number_nodes     - number of nodes in chain

 *    node_size        - size of node in bytes

 *

 *  Output parameters:  NONE

 */

void _Chain_Initialize(

  Chain_Control *the_chain,

  void           *starting_address,

  unsigned32     number_nodes,

  unsigned32     node_size

)

{

  unsigned32  count;

  Chain_Node *current;

  Chain_Node *next;

  count                     = number_nodes;

  current                   = _Chain_Head( the_chain );

  the_chain->permanent_null = NULL;

  next                      = (Chain_Node *)starting_address;

  while ( count-- ) {

    current->next  = next;

    next->previous = current;

    current        = next;

    next           = (Chain_Node *)

                        _Addresses_Add_offset( (void *) next, node_size );

  }

  current->next    = _Chain_Tail( the_chain );

  the_chain->last  = current;

}

/*PAGE

 *

 *  _Chain_Get_first_unprotected

 */

#ifndef USE_INLINES

STATIC INLINE 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;

}

#endif   /* USE_INLINES */

/*PAGE

 *

 *  _Chain_Get

 *

 *  This kernel routine returns a pointer to a node taken from the

 *  given chain.

 *

 *  Input parameters:

 *    the_chain - pointer to chain header

 *

 *  Output parameters:

 *    return_node - pointer to node in chain allocated

 *    CHAIN_END   - if no nodes available

 *

 *  INTERRUPT LATENCY:

 *    only case

 */

Chain_Node *_Chain_Get(

  Chain_Control *the_chain

)

{

  ISR_Level          level;

  Chain_Node *return_node;

  return_node = NULL;

  _ISR_Disable( level );

    if ( !_Chain_Is_empty( the_chain ) )

      return_node = _Chain_Get_first_unprotected( the_chain );

  _ISR_Enable( level );

  return return_node;

}

/*PAGE

 *

 *  _Chain_Append

 *

 *  This kernel routine puts a node on the end of the specified chain.

 *

 *  Input parameters:

 *    the_chain - pointer to chain header

 *    node      - address of node to put at rear of chain

 *

 *  Output parameters:  NONE

 *

 *  INTERRUPT LATENCY:

 *    only case

 */

void _Chain_Append(

  Chain_Control *the_chain,

  Chain_Node    *node

)

{

  ISR_Level level;

  _ISR_Disable( level );

    _Chain_Append_unprotected( the_chain, node );

  _ISR_Enable( level );

}

/*PAGE

 *

 *  _Chain_Extract

 *

 *  This kernel routine deletes the given node from a chain.

 *

 *  Input parameters:

 *    node - pointer to node in chain to be deleted

 *

 *  Output parameters:  NONE

 *

 *  INTERRUPT LATENCY:

 *    only case

 */

void _Chain_Extract(

  Chain_Node *node

)

{

  ISR_Level level;

  _ISR_Disable( level );

    _Chain_Extract_unprotected( node );

  _ISR_Enable( level );

}

/*PAGE

 *

 *  _Chain_Insert

 *

 *  This kernel routine inserts a given node after a specified node

 *  a requested chain.

 *

 *  Input parameters:

 *    after_node - pointer to node in chain to be inserted after

 *    node       - pointer to node to be inserted

 *

 *  Output parameters:  NONE

 *

 *  INTERRUPT LATENCY:

 *    only case

 */

void _Chain_Insert(

  Chain_Node *after_node,

  Chain_Node *node

)

{

  ISR_Level level;

  _ISR_Disable( level );

    _Chain_Insert_unprotected( after_node, node );

  _ISR_Enable( level );

}

/*PAGE

 *

 *  _Chain_Insert_chain

 *

 *  This routine inserts a chain after the specified node in another

 *  chain. It is assumed that the insert after node is not on the

 *  second chain.

 *

 *  Input parameters:

 *    insert_after - insert the chain after this node

 *    to_insert    - the chain to insert

 */

void _Chain_Insert_chain(

  Chain_Node    *insert_after,

  Chain_Control *to_insert

)

{

  Chain_Node *first;

  Chain_Node *last;

  Chain_Node *insert_after_next;

  first = to_insert->first;

  last = to_insert->last;

  insert_after_next = insert_after->next;

  insert_after->next = first;

  first->previous    = insert_after;

  insert_after_next->previous = last;

  last->next                  = insert_after_next;

  _Chain_Initialize_empty( to_insert );

}