| 1 | /*
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| 2 | * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
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| 3 | * Copyright (c) 1988, 1989 by Adam de Boor
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| 4 | * Copyright (c) 1989 by Berkeley Softworks
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| 5 | * All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to Berkeley by
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| 8 | * Adam de Boor.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | * 3. All advertising materials mentioning features or use of this software
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| 19 | * must display the following acknowledgement:
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| 20 | * This product includes software developed by the University of
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| 21 | * California, Berkeley and its contributors.
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| 22 | * 4. Neither the name of the University nor the names of its contributors
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| 23 | * may be used to endorse or promote products derived from this software
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| 24 | * without specific prior written permission.
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| 25 | *
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| 26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 36 | * SUCH DAMAGE.
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| 37 | *
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| 38 | * from: @(#)list.h 8.1 (Berkeley) 6/6/93
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| 39 | * $FreeBSD: src/usr.bin/make/list.h,v 1.8 1999/08/28 01:03:32 peter Exp $
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| 40 | */
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| 41 |
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| 42 | /*
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| 43 | * list.h --
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| 44 | *
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| 45 | * Structures, macros, and routines exported by the List module.
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| 46 | */
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| 47 |
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| 48 | #ifndef _LIST
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| 49 | #define _LIST
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| 50 |
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| 51 | #ifndef _SPRITE
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| 52 | #include "sprite.h"
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| 53 | #endif _SPRITE
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| 54 |
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| 55 | /*
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| 56 | * This module defines the list abstraction, which enables one to link
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| 57 | * together arbitrary data structures. Lists are doubly-linked and
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| 58 | * circular. A list contains a header followed by its real members, if
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| 59 | * any. (An empty list therefore consists of a single element, the
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| 60 | * header, whose nextPtr and prevPtr fields point to itself). To refer
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| 61 | * to a list as a whole, the user keeps a pointer to the header; that
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| 62 | * header is initialized by a call to List_Init(), which creates an empty
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| 63 | * list given a pointer to a List_Links structure (described below).
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| 64 | *
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| 65 | * The links are contained in a two-element structure called List_Links.
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| 66 | * A list joins List_Links records (that is, each List_Links structure
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| 67 | * points to other List_Links structures), but if the List_Links is the
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| 68 | * first field within a larger structure, then the larger structures are
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| 69 | * effectively linked together as follows:
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| 70 | *
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| 71 | * header
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| 72 | * (List_Links) first elt. second elt.
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| 73 | * ----------------- ----------------- -----------------
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| 74 | * ..-> | nextPtr | ----> | List_Links | ----> | List_Links |----..
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| 75 | * | - - - - - - - | | | | |
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| 76 | * ..-- | prevPtr | <---- | | <---- | |<---..
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| 77 | * ----------------- - --- --- --- - - --- --- --- -
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| 78 | * | rest of | | rest of |
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| 79 | * | structure | | structure |
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| 80 | * | | | |
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| 81 | * | ... | | ... |
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| 82 | * ----------------- -----------------
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| 83 | *
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| 84 | * It is possible to link structures through List_Links fields that are
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| 85 | * not at the beginning of the larger structure, but it is then necessary
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| 86 | * to perform pointer arithmetic to find the beginning of the larger
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| 87 | * structure, given a pointer to some point within it.
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| 88 | *
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| 89 | * A typical structure might be something like:
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| 90 | *
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| 91 | * typedef struct {
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| 92 | * List_Links links;
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| 93 | * char ch;
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| 94 | * integer flags;
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| 95 | * } EditChar;
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| 96 | *
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| 97 | * Before an element is inserted in a list for the first time, it must
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| 98 | * be initialized by calling the macro List_InitElement().
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| 99 | */
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| 100 | |
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| 101 |
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| 102 |
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| 103 | /*
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| 104 | * data structure for lists
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| 105 | */
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| 106 |
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| 107 | typedef struct List_Links {
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| 108 | struct List_Links *prevPtr;
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| 109 | struct List_Links *nextPtr;
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| 110 | } List_Links;
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| 111 |
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| 112 | /*
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| 113 | * procedures
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| 114 | */
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| 115 |
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| 116 | void List_Init(); /* initialize a header to a list */
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| 117 | void List_Insert(); /* insert an element into a list */
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| 118 | void List_Remove(); /* remove an element from a list */
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| 119 | void List_Move(); /* move an element elsewhere in a list */
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| 120 | |
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| 121 |
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| 122 | /*
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| 123 | * ----------------------------------------------------------------------------
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| 124 | *
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| 125 | * List_InitElement --
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| 126 | *
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| 127 | * Initialize a list element. Must be called before an element is first
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| 128 | * inserted into a list.
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| 129 | *
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| 130 | * ----------------------------------------------------------------------------
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| 131 | */
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| 132 | #define List_InitElement(elementPtr) \
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| 133 | (elementPtr)->prevPtr = (List_Links *) NIL; \
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| 134 | (elementPtr)->nextPtr = (List_Links *) NIL;
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| 135 |
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| 136 | /*
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| 137 | * Macros for stepping through or selecting parts of lists
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| 138 | */
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| 139 |
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| 140 | /*
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| 141 | * ----------------------------------------------------------------------------
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| 142 | *
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| 143 | * LIST_FORALL --
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| 144 | *
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| 145 | * Macro to loop through a list and perform an operation on each member.
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| 146 | *
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| 147 | * Usage: LIST_FORALL(headerPtr, itemPtr) {
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| 148 | * / *
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| 149 | * * operation on itemPtr, which points to successive members
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| 150 | * * of the list
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| 151 | * *
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| 152 | * * It may be appropriate to first assign
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| 153 | * * foobarPtr = (Foobar *) itemPtr;
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| 154 | * * to refer to the entire Foobar structure.
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| 155 | * * /
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| 156 | * }
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| 157 | *
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| 158 | * Note: itemPtr must be a List_Links pointer variable, and headerPtr
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| 159 | * must evaluate to a pointer to a List_Links structure.
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| 160 | *
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| 161 | * ----------------------------------------------------------------------------
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| 162 | */
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| 163 |
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| 164 | #define LIST_FORALL(headerPtr, itemPtr) \
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| 165 | for (itemPtr = List_First(headerPtr); \
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| 166 | !List_IsAtEnd((headerPtr),itemPtr); \
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| 167 | itemPtr = List_Next(itemPtr))
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| 168 |
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| 169 | /*
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| 170 | * ----------------------------------------------------------------------------
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| 171 | *
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| 172 | * List_IsEmpty --
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| 173 | *
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| 174 | * Macro: Boolean value, TRUE if the given list does not contain any
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| 175 | * members.
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| 176 | *
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| 177 | * Usage: if (List_IsEmpty(headerPtr)) ...
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| 178 | *
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| 179 | * ----------------------------------------------------------------------------
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| 180 | */
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| 181 |
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| 182 | #define List_IsEmpty(headerPtr) \
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| 183 | ((headerPtr) == (headerPtr)->nextPtr)
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| 184 |
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| 185 | /*
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| 186 | * ----------------------------------------------------------------------------
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| 187 | *
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| 188 | * List_IsAtEnd --
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| 189 | *
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| 190 | * Macro: Boolean value, TRUE if itemPtr is after the end of headerPtr
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| 191 | * (i.e., itemPtr is the header of the list).
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| 192 | *
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| 193 | * Usage: if (List_IsAtEnd(headerPtr, itemPtr)) ...
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| 194 | *
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| 195 | * ----------------------------------------------------------------------------
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| 196 | */
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| 197 |
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| 198 |
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| 199 | #define List_IsAtEnd(headerPtr, itemPtr) \
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| 200 | ((itemPtr) == (headerPtr))
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| 201 |
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| 202 | |
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| 203 |
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| 204 | /*
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| 205 | * ----------------------------------------------------------------------------
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| 206 | *
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| 207 | * List_First --
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| 208 | *
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| 209 | * Macro to return the first member in a list, which is the header if
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| 210 | * the list is empty.
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| 211 | *
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| 212 | * Usage: firstPtr = List_First(headerPtr);
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| 213 | *
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| 214 | * ----------------------------------------------------------------------------
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| 215 | */
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| 216 |
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| 217 | #define List_First(headerPtr) ((headerPtr)->nextPtr)
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| 218 |
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| 219 | /*
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| 220 | * ----------------------------------------------------------------------------
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| 221 | *
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| 222 | * List_Last --
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| 223 | *
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| 224 | * Macro to return the last member in a list, which is the header if
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| 225 | * the list is empty.
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| 226 | *
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| 227 | * Usage: lastPtr = List_Last(headerPtr);
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| 228 | *
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| 229 | * ----------------------------------------------------------------------------
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| 230 | */
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| 231 |
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| 232 | #define List_Last(headerPtr) ((headerPtr)->prevPtr)
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| 233 |
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| 234 | /*
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| 235 | * ----------------------------------------------------------------------------
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| 236 | *
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| 237 | * List_Prev --
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| 238 | *
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| 239 | * Macro to return the member preceding the given member in its list.
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| 240 | * If the given list member is the first element in the list, List_Prev
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| 241 | * returns the list header.
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| 242 | *
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| 243 | * Usage: prevPtr = List_Prev(itemPtr);
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| 244 | *
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| 245 | * ----------------------------------------------------------------------------
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| 246 | */
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| 247 |
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| 248 | #define List_Prev(itemPtr) ((itemPtr)->prevPtr)
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| 249 |
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| 250 | /*
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| 251 | * ----------------------------------------------------------------------------
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| 252 | *
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| 253 | * List_Next --
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| 254 | *
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| 255 | * Macro to return the member following the given member in its list.
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| 256 | * If the given list member is the last element in the list, List_Next
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| 257 | * returns the list header.
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| 258 | *
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| 259 | * Usage: nextPtr = List_Next(itemPtr);
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| 260 | *
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| 261 | * ----------------------------------------------------------------------------
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| 262 | */
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| 263 |
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| 264 | #define List_Next(itemPtr) ((itemPtr)->nextPtr)
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| 265 |
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| 266 | |
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| 267 |
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| 268 | /*
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| 269 | * ----------------------------------------------------------------------------
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| 270 | * The List_Insert procedure takes two arguments. The first argument
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| 271 | * is a pointer to the structure to be inserted into a list, and
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| 272 | * the second argument is a pointer to the list member after which
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| 273 | * the new element is to be inserted. Macros are used to determine
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| 274 | * which existing member will precede the new one.
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| 275 | *
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| 276 | * The List_Move procedure takes a destination argument with the same
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| 277 | * semantics as List_Insert.
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| 278 | *
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| 279 | * The following macros define where to insert the new element
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| 280 | * in the list:
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| 281 | *
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| 282 | * LIST_AFTER(itemPtr) -- insert after itemPtr
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| 283 | * LIST_BEFORE(itemPtr) -- insert before itemPtr
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| 284 | * LIST_ATFRONT(headerPtr) -- insert at front of list
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| 285 | * LIST_ATREAR(headerPtr) -- insert at end of list
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| 286 | *
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| 287 | * For example,
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| 288 | *
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| 289 | * List_Insert(itemPtr, LIST_AFTER(otherPtr));
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| 290 | *
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| 291 | * will insert itemPtr following otherPtr in the list containing otherPtr.
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| 292 | * ----------------------------------------------------------------------------
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| 293 | */
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| 294 |
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| 295 | #define LIST_AFTER(itemPtr) ((List_Links *) itemPtr)
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| 296 |
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| 297 | #define LIST_BEFORE(itemPtr) (((List_Links *) itemPtr)->prevPtr)
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| 298 |
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| 299 | #define LIST_ATFRONT(headerPtr) ((List_Links *) headerPtr)
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| 300 |
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| 301 | #define LIST_ATREAR(headerPtr) (((List_Links *) headerPtr)->prevPtr)
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| 302 |
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| 303 | #endif /* _LIST */
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