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/* chain.h
*
* This include file contains all the constants and structures associated
* with the Doubly Linked Chain Handler.
*
* COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
* On-Line Applications Research Corporation (OAR).
* All rights assigned to U.S. Government, 1994.
*
* This material may be reproduced by or for the U.S. Government pursuant
* to the copyright license under the clause at DFARS 252.227-7013. This
* notice must appear in all copies of this file and its derivatives.
*
* $Id$
*/
#ifndef __RTEMS_CHAIN_h
#define __RTEMS_CHAIN_h
#ifdef __cplusplus
extern "C" {
#endif
#include <rtems/score/address.h>
/*
* This is used to manage each element (node) which is placed
* on a chain.
*
* NOTE: Typically, a more complicated structure will use the
* chain package. The more complicated structure will
* include a chain node as the first element in its
* control structure. It will then call the chain package
* with a pointer to that node element. The node pointer
* and the higher level structure start at the same address
* so the user can cast the pointers back and forth.
*
*/
typedef struct Chain_Node_struct Chain_Node;
struct Chain_Node_struct {
Chain_Node *next;
Chain_Node *previous;
};
/*
* This is used to manage a chain. A chain consists of a doubly
* linked list of zero or more nodes.
*
* NOTE: This implementation does not require special checks for
* manipulating the first and last elements on the chain.
* To accomplish this the chain control structure is
* treated as two overlapping chain nodes. The permanent
* head of the chain overlays a node structure on the
* first and permanent_null fields. The permanent tail
* of the chain overlays a node structure on the
* permanent_null and last elements of the structure.
*
*/
typedef struct {
Chain_Node *first;
Chain_Node *permanent_null;
Chain_Node *last;
} Chain_Control;
/*
* _Chain_Initialize
*
* DESCRIPTION:
*
* This routine initializes the_chain structure to manage the
* contiguous array of number_nodes nodes which starts at
* starting_address. Each node is of node_size bytes.
*
*/
void _Chain_Initialize(
Chain_Control *the_chain,
void *starting_address,
unsigned32 number_nodes,
unsigned32 node_size
);
/*
* _Chain_Get_first_unprotected
*/
#ifndef USE_INLINES
Chain_Node *_Chain_Get_first_unprotected(
Chain_Control *the_chain
);
#endif
/*
* _Chain_Extract
*
* DESCRIPTION:
*
* This routine extracts the_node from the chain on which it resides.
* It disables interrupts to insure the atomicity of the
* extract operation.
*
*/
void _Chain_Extract(
Chain_Node *the_node
);
/*
* _Chain_Get
*
* 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 disables interrupts to insure the atomicity of the
* get operation.
*
*/
Chain_Node *_Chain_Get(
Chain_Control *the_chain
);
/*
* _Chain_Insert
*
* DESCRIPTION:
*
* This routine inserts the_node on a chain immediately following
* after_node. It disables interrupts to insure the atomicity
* of the extract operation.
*
*/
void _Chain_Insert(
Chain_Node *after_node,
Chain_Node *the_node
);
/*
* _Chain_Append
*
* DESCRIPTION:
*
* This routine appends the_node onto the end of the_chain.
* It disables interrupts to insure the atomicity of the
* append operation.
*
*/
void _Chain_Append(
Chain_Control *the_chain,
Chain_Node *the_node
);
#ifndef __RTEMS_APPLICATION__
#include <rtems/score/chain.inl>
#endif
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
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