reactos/dll/3rdparty/mesa32/src/main/simple_list.h

   1 /**
   2  * \file simple_list.h
   3  * Simple macros for type-safe, intrusive lists.
   4  *
   5  *  Intended to work with a list sentinal which is created as an empty
   6  *  list.  Insert & delete are O(1).
   7  *
   8  * \author
   9  *  (C) 1997, Keith Whitwell
  10  */
  11
  12 /*
  13  * Mesa 3-D graphics library
  14  * Version:  3.5
  15  *
  16  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
  17  *
  18  * Permission is hereby granted, free of charge, to any person obtaining a
  19  * copy of this software and associated documentation files (the "Software"),
  20  * to deal in the Software without restriction, including without limitation
  21  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  22  * and/or sell copies of the Software, and to permit persons to whom the
  23  * Software is furnished to do so, subject to the following conditions:
  24  *
  25  * The above copyright notice and this permission notice shall be included
  26  * in all copies or substantial portions of the Software.
  27  *
  28  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  29  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  31  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  32  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  33  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  34  */
  35
  36
  37 #ifndef _SIMPLE_LIST_H
  38 #define _SIMPLE_LIST_H
  39
  40 /**
  41  * Remove an element from list.
  42  *
  43  * \param elem element to remove.
  44  */
  45 #define remove_from_list(elem)                  \
  46 do {                                            \
  47    (elem)->next->prev = (elem)->prev;           \
  48    (elem)->prev->next = (elem)->next;           \
  49 } while (0)
  50
  51 /**
  52  * Insert an element to the list head.
  53  *
  54  * \param list list.
  55  * \param elem element to insert.
  56  */
  57 #define insert_at_head(list, elem)              \
  58 do {                                            \
  59    (elem)->prev = list;                         \
  60    (elem)->next = (list)->next;                 \
  61    (list)->next->prev = elem;                   \
  62    (list)->next = elem;                         \
  63 } while(0)
  64
  65 /**
  66  * Insert an element to the list tail.
  67  *
  68  * \param list list.
  69  * \param elem element to insert.
  70  */
  71 #define insert_at_tail(list, elem)              \
  72 do {                                            \
  73    (elem)->next = list;                         \
  74    (elem)->prev = (list)->prev;                 \
  75    (list)->prev->next = elem;                   \
  76    (list)->prev = elem;                         \
  77 } while(0)
  78
  79 /**
  80  * Move an element to the list head.
  81  *
  82  * \param list list.
  83  * \param elem element to move.
  84  */
  85 #define move_to_head(list, elem)                \
  86 do {                                            \
  87    remove_from_list(elem);                      \
  88    insert_at_head(list, elem);                  \
  89 } while (0)
  90
  91 /**
  92  * Move an element to the list tail.
  93  *
  94  * \param list list.
  95  * \param elem element to move.
  96  */
  97 #define move_to_tail(list, elem)                \
  98 do {                                            \
  99    remove_from_list(elem);                      \
 100    insert_at_tail(list, elem);                  \
 101 } while (0)
 102
 103 /**
 104  * Make a empty list empty.
 105  *
 106  * \param sentinal list (sentinal element).
 107  */
 108 #define make_empty_list(sentinal)               \
 109 do {                                            \
 110    (sentinal)->next = sentinal;                 \
 111    (sentinal)->prev = sentinal;                 \
 112 } while (0)
 113
 114 /**
 115  * Get list first element.
 116  *
 117  * \param list list.
 118  *
 119  * \return pointer to first element.
 120  */
 121 #define first_elem(list)       ((list)->next)
 122
 123 /**
 124  * Get list last element.
 125  *
 126  * \param list list.
 127  *
 128  * \return pointer to last element.
 129  */
 130 #define last_elem(list)        ((list)->prev)
 131
 132 /**
 133  * Get next element.
 134  *
 135  * \param elem element.
 136  *
 137  * \return pointer to next element.
 138  */
 139 #define next_elem(elem)        ((elem)->next)
 140
 141 /**
 142  * Get previous element.
 143  *
 144  * \param elem element.
 145  *
 146  * \return pointer to previous element.
 147  */
 148 #define prev_elem(elem)        ((elem)->prev)
 149
 150 /**
 151  * Test whether element is at end of the list.
 152  *
 153  * \param list list.
 154  * \param elem element.
 155  *
 156  * \return non-zero if element is at end of list, or zero otherwise.
 157  */
 158 #define at_end(list, elem)     ((elem) == (list))
 159
 160 /**
 161  * Test if a list is empty.
 162  *
 163  * \param list list.
 164  *
 165  * \return non-zero if list empty, or zero otherwise.
 166  */
 167 #define is_empty_list(list)    ((list)->next == (list))
 168
 169 /**
 170  * Walk through the elements of a list.
 171  *
 172  * \param ptr pointer to the current element.
 173  * \param list list.
 174  *
 175  * \note It should be followed by a { } block or a single statement, as in a \c
 176  * for loop.
 177  */
 178 #define foreach(ptr, list)     \
 179         for( ptr=(list)->next ;  ptr!=list ;  ptr=(ptr)->next )
 180
 181 /**
 182  * Walk through the elements of a list.
 183  *
 184  * Same as #foreach but lets you unlink the current value during a list
 185  * traversal.  Useful for freeing a list, element by element.
 186  *
 187  * \param ptr pointer to the current element.
 188  * \param t temporary pointer.
 189  * \param list list.
 190  *
 191  * \note It should be followed by a { } block or a single statement, as in a \c
 192  * for loop.
 193  */
 194 #define foreach_s(ptr, t, list)   \
 195         for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)
 196
 197 #endif