src/mesa/main/simple_list.h

   1 /* $Id: simple_list.h,v 1.2 2001/03/12 00:48:38 gareth Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27 /*  Simple macros for typesafe, intrusive lists.
  28  *  (C) 1997, Keith Whitwell
  29  *
  30  *  Intended to work with a list sentinal which is created as an empty
  31  *  list.  Insert & delete are O(1).
  32  */
  33
  34
  35 #ifndef _SIMPLE_LIST_H
  36 #define _SIMPLE_LIST_H
  37
  38 #define remove_from_list(elem)                  \
  39 do {                                            \
  40    (elem)->next->prev = (elem)->prev;           \
  41    (elem)->prev->next = (elem)->next;           \
  42 } while (0)
  43
  44 #define insert_at_head(list, elem)              \
  45 do {                                            \
  46    (elem)->prev = list;                         \
  47    (elem)->next = (list)->next;                 \
  48    (list)->next->prev = elem;                   \
  49    (list)->next = elem;                         \
  50 } while(0)
  51
  52 #define insert_at_tail(list, elem)              \
  53 do {                                            \
  54    (elem)->next = list;                         \
  55    (elem)->prev = (list)->prev;                 \
  56    (list)->prev->next = elem;                   \
  57    (list)->prev = elem;                         \
  58 } while(0)
  59
  60 #define move_to_head(list, elem)                \
  61 do {                                            \
  62    remove_from_list(elem);                      \
  63    insert_at_head(list, elem);                  \
  64 } while (0)
  65
  66 #define move_to_tail(list, elem)                \
  67 do {                                            \
  68    remove_from_list(elem);                      \
  69    insert_at_tail(list, elem);                  \
  70 } while (0)
  71
  72
  73 #define make_empty_list(sentinal)               \
  74 do {                                            \
  75    (sentinal)->next = sentinal;                 \
  76    (sentinal)->prev = sentinal;                 \
  77 } while (0)
  78
  79
  80 #define first_elem(list)       ((list)->next)
  81 #define last_elem(list)        ((list)->prev)
  82 #define next_elem(elem)        ((elem)->next)
  83 #define prev_elem(elem)        ((elem)->prev)
  84 #define at_end(list, elem)     ((elem) == (list))
  85 #define is_empty_list(list)    ((list)->next == (list))
  86
  87 #define foreach(ptr, list)     \
  88         for( ptr=(list)->next ;  ptr!=list ;  ptr=(ptr)->next )
  89
  90 /* Kludgey - Lets you unlink the current value during a list
  91  *           traversal.  Useful for free()-ing a list, element
  92  *           by element.
  93  */
  94 #define foreach_s(ptr, t, list)   \
  95         for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)
  96
  97
  98 #endif