src/keyword.cc

   1 /*
   2   keyword.cc -- keywords and identifiers
   3  */
   4
   5 #include <stdlib.h>
   6
   7 #include "glob.hh"
   8 #include "lexer.hh"
   9 //#include "mudobs.hh"
  10 //#include "gram.hh"
  11
  12 /* for the keyword table */
  13 struct Keyword_ent
  14 {
  15     const char   *name;
  16     int     tokcode;
  17 };
  18
  19 struct Keyword_table
  20 {
  21     Keyword_ent *table;
  22     int     maxkey;
  23     Keyword_table(Keyword_ent *);
  24     int     lookup(const char *s) const;
  25 };
  26
  27
  28 /* for qsort */
  29 int
  30         tabcmp(const void * p1, const void * p2)
  31 {
  32     return strcmp(((const Keyword_ent *) p1)->name,
  33                   ((const Keyword_ent *) p2)->name);
  34 }
  35
  36 Keyword_table::Keyword_table(Keyword_ent *tab)
  37 {
  38     table = tab;
  39
  40     /* count keywords */
  41     for (maxkey = 0; table[maxkey].name; maxkey++);
  42
  43     /* sort them */
  44     qsort(table, maxkey, sizeof(Keyword_ent), tabcmp);
  45 }
  46
  47 /*
  48   lookup with binsearch, return tokencode.
  49 */
  50 int
  51 Keyword_table::lookup(const char *s)const
  52 {
  53     int     lo,
  54             hi,
  55             cmp,
  56             result;
  57     lo = 0;
  58     hi = maxkey;
  59
  60     /* binary search */
  61     do
  62     {
  63         cmp = (lo + hi) / 2;
  64
  65         result = strcmp(s, table[cmp].name);
  66
  67         if (result < 0)
  68             hi = cmp;
  69         else
  70             lo = cmp;
  71     }
  72     while (hi - lo > 1);
  73     if (!strcmp(s, table[lo].name))
  74     {
  75         return table[lo].tokcode;
  76     } else
  77         return -1;              /* not found */
  78 }
  79