include/ListMacros.h

   1 #ifndef LISTMACROS_H
   2 #define LISTMACROS_H
   3 /*
   4 **      $Id: ListMacros.h,v 1.2 1999/02/07 14:41:02 bernie Exp $
   5 **
   6 **      Copyright (C) 1997 Bernardo Innocenti <bernardo.innocenti@usa.net>
   7 **      All rights reserved.
   8 **
   9 **      Use 4 chars wide TABs to read this source
  10 **
  11 **      Some handy macros for list operations.  Using these macros is faster
  12 **      than calling their exec.library equivalents, but they will eventually
  13 **      make your code a little bigger and are also subject to common macro
  14 **      side effects.
  15 */
  16
  17
  18 #define NEWLIST(l)      ( (l)->lh_TailPred = (struct Node *)(l),                        \
  19                                         (l)->lh_Tail = 0,                                                                       \
  20                                         (l)->lh_Head = (struct Node *)(&((l)->lh_Tail)) )
  21
  22 #define ADDHEAD(l,n) ( (n)->ln_Pred = (struct Node *)(l),                               \
  23                                         (n)->ln_Succ = (l)->lh_Head,                                            \
  24                                         (l)->lh_Head->ln_Pred = (n),                                            \
  25                                         (l)->lh_Head = (n) )
  26
  27 #define ADDTAIL(l,n) ( (n)->ln_Succ = (struct Node *)(&((l)->lh_Tail)), \
  28                                         (n)->ln_Pred = (l)->lh_TailPred,                                        \
  29                                         (l)->lh_TailPred->ln_Succ = (n),                                        \
  30                                         (l)->lh_TailPred = (n) )
  31
  32 #define REMOVE(n)       ( (n)->ln_Succ->ln_Pred = (n)->ln_Pred,                         \
  33                                         (n)->ln_Pred->ln_Succ = (n)->ln_Succ )
  34
  35 #define GETHEAD(l)      ( (l)->lh_Head->ln_Succ ? (l)->lh_Head : (struct Node *)NULL )
  36
  37 #define GETTAIL(l)  ( (l)->lh_TailPred->ln_Succ ? (l)->lh_TailPred : (struct Node *)NULL )
  38
  39 #define GETSUCC(n)  ( (n)->ln_Succ->ln_Succ ? (n)->ln_Succ : (struct Node *)NULL )
  40
  41 #define GETPRED(n)  ( (n)->ln_Pred->ln_Pred ? (n)->ln_Pred : (struct Node *)NULL )
  42
  43
  44 #ifdef __GNUC__
  45
  46 #define REMHEAD(l)                                                                                                                      \
  47 ({                                                                                                                                                      \
  48         struct Node *n = (l)->lh_Head;                                                                                  \
  49         n->ln_Succ ?                                                                                                                    \
  50                 (l)->lh_Head = n->ln_Succ,                                                                                      \
  51                         (l)->lh_Head->ln_Pred = (struct Node *)(l),                                             \
  52                         n :                                                                                                                             \
  53                 NULL;                                                                                                                           \
  54 })
  55
  56 #define REMTAIL(l)                                                                                                                      \
  57 ({                                                                                                                                                      \
  58         struct Node *n = (l)->lh_TailPred;                                                                              \
  59         n->ln_Pred ?                                                                                                                    \
  60                 (l)->lh_TailPred = n->ln_Pred,                                                                          \
  61                         (l)->lh_TailPred->ln_Succ = (struct Node *)(&((l)->lh_Tail)),   \
  62                         n :                                                                                                                             \
  63                 NULL;                                                                                                                           \
  64 })
  65
  66
  67 #else
  68
  69 /* These two can't be implemented as macros without the GCC ({...}) language extension */
  70
  71 INLINE struct Node *REMHEAD(struct List *l)
  72 {
  73         struct Node *n = l->lh_Head;
  74
  75         if (n->ln_Succ)
  76         {
  77                 l->lh_Head = n->ln_Succ;
  78                 l->lh_Head->ln_Pred = (struct Node *)l;
  79                 return n;
  80         }
  81         return NULL;
  82 }
  83
  84 INLINE struct Node *REMTAIL(struct List *l)
  85 {
  86         struct Node *n = l->lh_TailPred;
  87
  88         if (n->ln_Pred)
  89         {
  90                 l->lh_TailPred = n->ln_Pred;
  91                 l->lh_TailPred->ln_Succ = (struct Node *)(&(l->lh_Tail));
  92                 return n;
  93         }
  94         return NULL;
  95 }
  96
  97 #endif
  98
  99 #endif /* !LISTMACROS_H */