ListMacros.h

   1 #ifndef LISTMACROS_H
   2 #define LISTMACROS_H
   3 /*
   4 **      $VER: ListMacros.h 2.1 (1.9.97)
   5 **
   6 **      Copyright (C) 1996,97 Bernardo Innocenti. All rights reserved.
   7 **
   8 **      Use 4 chars wide TABs to read this source
   9 **
  10 **      Some handy macros for list operations.  Using these macros is faster
  11 **      than calling their exec.library equivalents, but they will eventually
  12 **      make your code a little bigger and are also subject to common macro
  13 **      side effects.
  14 */
  15
  16
  17 #define NEWLIST(l)      ( (l)->lh_TailPred = (struct Node *)(l),                        \
  18                                         (l)->lh_Tail = 0,                                                                       \
  19                                         (l)->lh_Head = (struct Node *)(&((l)->lh_Tail)) )
  20
  21 #define ADDHEAD(l,n) ( (n)->ln_Pred = (struct Node *)(l),                               \
  22                                         (n)->ln_Succ = (l)->lh_Head,                                            \
  23                                         (l)->lh_Head->ln_Pred = (n),                                            \
  24                                         (l)->lh_Head = (n) )
  25
  26 #define ADDTAIL(l,n) ( (n)->ln_Succ = (struct Node *)(&((l)->lh_Tail)), \
  27                                         (n)->ln_Pred = (l)->lh_TailPred,                                        \
  28                                         (l)->lh_TailPred->ln_Succ = (n),                                        \
  29                                         (l)->lh_TailPred = (n) )
  30
  31 #define REMOVE(n)       ( (n)->ln_Succ->ln_Pred = (n)->ln_Pred,                         \
  32                                         (n)->ln_Pred->ln_Succ = (n)->ln_Succ )
  33
  34 #define GETHEAD(l)      ( (l)->lh_Head->ln_Succ ? (l)->lh_Head : (struct Node *)NULL )
  35
  36 #define GETTAIL(l)  ( (l)->lh_TailPred->ln_Succ ? (l)->lh_TailPred : (struct Node *)NULL )
  37
  38 #define GETSUCC(n)  ( (n)->ln_Succ->ln_Succ ? (n)->ln_Succ : (struct Node *)NULL )
  39
  40 #define GETPRED(n)  ( (n)->ln_Pred->ln_Pred ? (n)->ln_Pred : (struct Node *)NULL )
  41
  42
  43 #ifdef __GNUC__
  44
  45 #define REMHEAD(l)                                                                                                                      \
  46 ({                                                                                                                                                      \
  47         struct Node *n = (l)->lh_Head;                                                                                  \
  48         n->ln_Succ ?                                                                                                                    \
  49                 (l)->lh_Head = n->ln_Succ,                                                                                      \
  50                         (l)->lh_Head->ln_Pred = (struct Node *)(l),                                             \
  51                         n :                                                                                                                             \
  52                 NULL;                                                                                                                           \
  53 })
  54
  55 #define REMTAIL(l)                                                                                                                      \
  56 ({                                                                                                                                                      \
  57         struct Node *n = (l)->lh_TailPred;                                                                              \
  58         n->ln_Pred ?                                                                                                                    \
  59                 (l)->lh_TailPred = n->ln_Pred,                                                                          \
  60                         (l)->lh_TailPred->ln_Succ = (struct Node *)(&((l)->lh_Tail)),   \
  61                         n :                                                                                                                             \
  62                 NULL;                                                                                                                           \
  63 })
  64
  65
  66 #else
  67
  68 /* These two can't be implemented as macros without the GCC ({...}) language extension */
  69
  70 INLINE struct Node *REMHEAD(struct List *l)
  71 {
  72         struct Node *n = l->lh_Head;
  73
  74         if (n->ln_Succ)
  75         {
  76                 l->lh_Head = n->ln_Succ;
  77                 l->lh_Head->ln_Pred = (struct Node *)l;
  78                 return n;
  79         }
  80         return NULL;
  81 }
  82
  83 INLINE struct Node *REMTAIL(struct List *l)
  84 {
  85         struct Node *n = l->lh_TailPred;
  86
  87         if (n->ln_Pred)
  88         {
  89                 l->lh_TailPred = n->ln_Pred;
  90                 l->lh_TailPred->ln_Succ = (struct Node *)(&(l->lh_Tail));
  91                 return n;
  92         }
  93         return NULL;
  94 }
  95
  96 #endif
  97
  98 #endif /* !LISTMACROS_H */