include/linklist.h

   1 /*
   2  * Copyright (C) Volition, Inc. 1999.  All rights reserved.
   3  *
   4  * All source code herein is the property of Volition, Inc. You may not sell
   5  * or otherwise commercially exploit the source or things you created based on
   6  * the source.
   7  */
   8
   9 /*
  10  * $Logfile: /Freespace2/code/GlobalIncs/LinkList.h $
  11  * $Revision$
  12  * $Date$
  13  * $Author$
  14  *
  15  * Macros to handle doubly linked lists
  16  *
  17  * $Log$
  18  * Revision 1.2  2002/06/09 04:41:13  relnev
  19  * added copyright header
  20  *
  21  * Revision 1.1.1.1  2002/05/03 03:28:12  root
  22  * Initial import.
  23  *
  24  *
  25  * 2     10/07/98 10:52a Dave
  26  * Initial checkin.
  27  *
  28  * 1     10/07/98 10:48a Dave
  29  *
  30  * 5     7/01/97 11:53a Lawrance
  31  * add list_insert_before()
  32  *
  33  * 4     4/15/97 1:27p Lawrance
  34  * added a GET_PREV() macro
  35  *
  36  * 3     2/17/97 5:18p John
  37  * Added a bunch of RCS headers to a bunch of old files that don't have
  38  * them.
  39  *
  40  * $NoKeywords: $
  41  */
  42
  43 #ifndef _LINKLIST_H
  44 #define _LINKLIST_H
  45
  46 // Initializes a list of zero elements
  47 #define list_init( head )                                       \
  48 do {                                                                                            \
  49         (head)->next = (head);                                  \
  50         (head)->prev = (head);                                  \
  51 } while (0)
  52
  53 // Inserts element onto the front of the list
  54 #define list_insert( head, elem )               \
  55 do {                                                                                            \
  56         (elem)->next = (head)->next;                    \
  57         (head)->next->prev = (elem);                    \
  58         (head)->next = (elem);                                  \
  59         (elem)->prev = (head);                                  \
  60 } while (0)
  61
  62 // Inserts new_elem before elem
  63 #define list_insert_before(elem, new_elem)              \
  64 do {                                                                                                                    \
  65         (elem)->prev->next      = (new_elem);                           \
  66         (new_elem)->prev                = (elem)->prev;                 \
  67         (elem)->prev                    = (new_elem);                           \
  68         (new_elem)->next                = (elem);                                       \
  69 } while (0)
  70
  71 // Appends an element on to the tail of the list
  72 #define list_append( head, elem )               \
  73 do      {                                                                                               \
  74         (elem)->prev = (head)->prev;                    \
  75         (elem)->next = (head);                                  \
  76         (head)->prev->next = (elem);                    \
  77         (head)->prev = (elem);                                  \
  78 } while (0)
  79
  80 // Adds list b onto the end of list a
  81 #define list_merge( a, b )                                      \
  82 do {                                                                                            \
  83         (a)->prev->next = (b)->next;                    \
  84         (b)->next->prev = (a)->prev;                    \
  85         (a)->prev = (b)->prev;                                  \
  86         (b)->prev->next = (a);                                  \
  87 } while (0)
  88
  89 // Removes an element from listit's in
  90 #define list_remove( head, elem )               \
  91 do {                                                                                            \
  92         (elem)->prev->next = (elem)->next;      \
  93         (elem)->next->prev = (elem)->prev;      \
  94         (elem)->next = NULL;                                            \
  95         (elem)->prev = NULL;                                            \
  96 } while(0)
  97
  98 #define GET_FIRST(head)         ((head)->next)
  99 #define GET_LAST(head)          ((head)->prev)
 100 #define GET_NEXT(elem)          ((elem)->next)
 101 #define GET_PREV(elem)          ((elem)->prev)
 102 #define END_OF_LIST(head)       (head)
 103 #define NOT_EMPTY(head)         ((head)->next != (head))
 104 #define EMPTY(head)                     ((head)->next == (head))
 105
 106 #endif
 107