lily/keyword.cc

   1 /*
   2   keyword.cc -- keywords and identifiers
   3  */
   4
   5 #include <stdlib.h>
   6
   7
   8 #include "keyword.hh"
   9
  10
  11 /* for qsort */
  12 int
  13       tabcmp (void const * p1, void const * p2)
  14 {
  15   return strcmp (((Keyword_ent const *) p1)->name,
  16                 ((Keyword_ent const *) p2)->name);
  17 }
  18
  19 Keyword_table::Keyword_table (Keyword_ent *tab)
  20 {
  21   table = tab;
  22
  23   /* count keywords */
  24   for (maxkey = 0; table[maxkey].name; maxkey++);
  25
  26   /* sort them */
  27   qsort (table, maxkey, sizeof (Keyword_ent), tabcmp);
  28 }
  29
  30 /*
  31   lookup with binsearch, return tokencode.
  32 */
  33 int
  34 Keyword_table::lookup (char const *s) const
  35 {
  36   int lo;
  37   int hi;
  38   int cmp;
  39   int result;
  40   lo = 0;
  41   hi = maxkey;
  42
  43   /* binary search */
  44   do
  45   {
  46       cmp = (lo + hi) / 2;
  47
  48       result = strcmp (s, table[cmp].name);
  49
  50       if (result < 0)
  51           hi = cmp;
  52       else
  53           lo = cmp;
  54     }
  55   while (hi - lo > 1);
  56   if (!strcmp (s, table[lo].name))
  57   {
  58       return table[lo].tokcode;
  59     }
  60   else
  61       return -1;              /* not found */
  62 }
  63