libs/shttpd/llist.h

   1 /*
   2  * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
   3  * All rights reserved
   4  *
   5  * "THE BEER-WARE LICENSE" (Revision 42):
   6  * Sergey Lyubka wrote this file.  As long as you retain this notice you
   7  * can do whatever you want with this stuff. If we meet some day, and you think
   8  * this stuff is worth it, you can buy me a beer in return.
   9  */
  10
  11 #ifndef LLIST_HEADER_INCLUDED
  12 #define LLIST_HEADER_INCLUDED
  13
  14 /*
  15  * Linked list macros.
  16  */
  17 struct llhead {
  18         struct llhead   *prev;
  19         struct llhead   *next;
  20 };
  21
  22 #define LL_INIT(N)      ((N)->next = (N)->prev = (N))
  23
  24 #define LL_HEAD(H)      struct llhead H = { &H, &H }
  25
  26 #define LL_ENTRY(P,T,N) ((T *)((char *)(P) - offsetof(T, N)))
  27
  28 #define LL_ADD(H, N)                                                    \
  29         do {                                                            \
  30                 ((H)->next)->prev = (N);                                \
  31                 (N)->next = ((H)->next);                                \
  32                 (N)->prev = (H);                                        \
  33                 (H)->next = (N);                                        \
  34         } while (0)
  35
  36 #define LL_TAIL(H, N)                                                   \
  37         do {                                                            \
  38                 ((H)->prev)->next = (N);                                \
  39                 (N)->prev = ((H)->prev);                                \
  40                 (N)->next = (H);                                        \
  41                 (H)->prev = (N);                                        \
  42         } while (0)
  43
  44 #define LL_DEL(N)                                                       \
  45         do {                                                            \
  46                 ((N)->next)->prev = ((N)->prev);                        \
  47                 ((N)->prev)->next = ((N)->next);                        \
  48                 LL_INIT(N);                                             \
  49         } while (0)
  50
  51 #define LL_EMPTY(N)     ((N)->next == (N))
  52
  53 #define LL_FOREACH(H,N) for (N = (H)->next; N != (H); N = (N)->next)
  54
  55 #define LL_FOREACH_SAFE(H,N,T)                                          \
  56         for (N = (H)->next, T = (N)->next; N != (H);                    \
  57                         N = (T), T = (N)->next)
  58
  59 #endif /* LLIST_HEADER_INCLUDED */