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
  27   /* sort them */
  28   qsort (table, maxkey, sizeof (Keyword_ent), tabcmp);
  29 }
  30
  31 /*
  32   lookup with binsearch, return tokencode.
  33 */
  34 int
  35 Keyword_table::lookup (char const *s) const
  36 {
  37   int lo;
  38   int hi;
  39   int cmp;
  40   int result;
  41   lo = 0;
  42   hi = maxkey;
  43
  44   /* binary search */
  45   do
  46   {
  47       cmp = (lo + hi) / 2;
  48
  49       result = strcmp (s, table[cmp].name);
  50
  51       if (result < 0)
  52           hi = cmp;
  53       else
  54           lo = cmp;
  55     }
  56   while (hi - lo > 1);
  57   if (!strcmp (s, table[lo].name))
  58   {
  59       return table[lo].tokcode;
  60     }
  61   else
  62       return -1;              /* not found */
  63 }
  64