src/mesa/main/simple_list.h

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