source: rtems/cpukit/include/rtems/score/chain.h @ 7ebce359

Last change on this file since 7ebce359 was 7ebce359, checked in by Joel Sherrill <joel@…>, on 02/16/22 at 21:15:58

cpukit/include/rtems/score/[a-r]*.h: Change license to BSD-2

Updates #3053.

  • Property mode set to 100644
File size: 3.9 KB
Line 
1/* SPDX-License-Identifier: BSD-2-Clause */
2
3/**
4 * @file
5 *
6 * @ingroup RTEMSScoreChain
7 *
8 * @brief This header file provides interfaces of the
9 *   @ref RTEMSScoreChain which are used by the implementation and the API.
10 */
11
12/*
13 *  Copyright (c) 2010 embedded brains GmbH.
14 *
15 *  COPYRIGHT (c) 1989-2006.
16 *  On-Line Applications Research Corporation (OAR).
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 *    notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 *    notice, this list of conditions and the following disclaimer in the
25 *    documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
28 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
31 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40#ifndef _RTEMS_SCORE_CHAIN_H
41#define _RTEMS_SCORE_CHAIN_H
42
43#ifdef __cplusplus
44extern "C" {
45#endif
46
47/**
48 * @defgroup RTEMSScoreChain Chain Handler
49 *
50 * @ingroup RTEMSScore
51 *
52 * @brief This group contains the Chain Handler implementation.
53 *
54 * The Chain Handler is used to manage sets of entities.  This handler
55 * provides two data structures.  The Chain Node data structure is included
56 * as the first part of every data structure that will be placed on
57 * a chain.  The second data structure is Chain Control which is used
58 * to manage a set of Chain Nodes.
59 *
60 * @{
61 */
62
63/**
64 *  @typedef Chain_Node
65 *
66 *  This type definition promotes the name for the Chain Node used by
67 *  all RTEMS code.  It is a separate type definition because a forward
68 *  reference is required to define it.  See @ref Chain_Node_struct for
69 *  detailed information.
70 */
71typedef struct Chain_Node_struct Chain_Node;
72
73/**
74 *  @struct Chain_Node_struct
75 *
76 *  This is used to manage each element (node) which is placed
77 *  on a chain.
78 *
79 *  @note Typically, a more complicated structure will use the
80 *        chain package.  The more complicated structure will
81 *        include a chain node as the first element in its
82 *        control structure.  It will then call the chain package
83 *        with a pointer to that node element.  The node pointer
84 *        and the higher level structure start at the same address
85 *        so the user can cast the pointers back and forth.
86 *
87 */
88struct Chain_Node_struct {
89  /** This points to the node after this one on this chain. */
90  Chain_Node *next;
91  /** This points to the node immediate prior to this one on this chain. */
92  Chain_Node *previous;
93};
94
95/**
96 *  @struct Chain_Control
97 *
98 * This is used to manage a chain.  A chain consists of a doubly
99 * linked list of zero or more nodes.
100 *
101 * @note This implementation does not require special checks for
102 *   manipulating the first and last elements on the chain.
103 *   To accomplish this the @a Chain_Control structure is
104 *   treated as two overlapping @ref Chain_Node structures.
105 */
106typedef union {
107  struct {
108    Chain_Node Node;
109    Chain_Node *fill;
110  } Head;
111
112  struct {
113    Chain_Node *fill;
114    Chain_Node Node;
115  } Tail;
116} Chain_Control;
117
118/** @} */
119
120#ifdef __cplusplus
121}
122#endif
123
124#endif
125/* end of include file */
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