src/add-ons/kernel/generic/scsi_periph/dl_list.h

   1 /*
   2 ** Copyright 2002/03, Thomas Kurschel. All rights reserved.
   3 ** Distributed under the terms of the OpenBeOS License.
   4 */
   5
   6 /*
   7         Macros for double linked lists
   8 */
   9
  10 #ifndef _DL_LIST_H
  11 #define _DL_LIST_H
  12
  13 #define REMOVE_DL_LIST( item, head, prefix ) \
  14         do { \
  15                 if( item->prefix##prev ) \
  16                         item->prefix##prev->prefix##next = item->prefix##next; \
  17                 else \
  18                         head = item->prefix##next; \
  19 \
  20                 if( item->prefix##next ) \
  21                         item->prefix##next->prefix##prev = item->prefix##prev; \
  22         } while( 0 )
  23
  24 #define ADD_DL_LIST_HEAD( item, head, prefix ) \
  25         do { \
  26                 item->prefix##next = head; \
  27                 item->prefix##prev = NULL; \
  28 \
  29                 if( (head) ) \
  30                         (head)->prefix##prev = item; \
  31 \
  32                 (head) = item; \
  33         } while( 0 )
  34
  35 #define REMOVE_CDL_LIST( item, head, prefix ) \
  36         do { \
  37                 item->prefix##next->prefix##prev = item->prefix##prev; \
  38                 item->prefix##prev->prefix##next = item->prefix##next; \
  39  \
  40                 if( item == (head) ) { \
  41                         if( item->prefix##next != item ) \
  42                                 (head) = item->prefix##next; \
  43                         else \
  44                                 (head) = NULL; \
  45                 } \
  46         } while( 0 )
  47
  48 #define ADD_CDL_LIST_TAIL( item, type, head, prefix ) \
  49         do { \
  50                 type *old_head = head; \
  51  \
  52                 if( old_head ) { \
  53                         type *first, *last; \
  54  \
  55                         first = old_head; \
  56                         last = first->prefix##prev; \
  57  \
  58                         item->prefix##next = first; \
  59                         item->prefix##prev = last; \
  60                         first->prefix##prev = item; \
  61                         last->prefix##next = item; \
  62                 } else { \
  63                         head = item; \
  64                         item->prefix##next = item->prefix##prev = item; \
  65                 } \
  66         } while( 0 )
  67
  68 #define ADD_CDL_LIST_HEAD( item, type, head, prefix ) \
  69         do { \
  70                 type *old_head = head; \
  71  \
  72                 head = item; \
  73                 if( old_head ) { \
  74                         type *first, *last; \
  75  \
  76                         first = old_head; \
  77                         last = first->prefix##prev; \
  78  \
  79                         item->prefix##next = first; \
  80                         item->prefix##prev = last; \
  81                         first->prefix##prev = item; \
  82                         last->prefix##next = item; \
  83                 } else { \
  84                         item->prefix##next = item->prefix##prev = item; \
  85                 } \
  86         } while( 0 )
  87
  88 #endif