external/bsd/byacc/dist/symtab.c

   1 /*      $NetBSD: symtab.c,v 1.6 2011/09/10 21:29:04 christos Exp $      */
   2 /* Id: symtab.c,v 1.9 2010/11/24 15:12:29 tom Exp */
   3
   4 #include "defs.h"
   5
   6 #include <sys/cdefs.h>
   7 __RCSID("$NetBSD: symtab.c,v 1.6 2011/09/10 21:29:04 christos Exp $");
   8
   9 /* TABLE_SIZE is the number of entries in the symbol table. */
  10 /* TABLE_SIZE must be a power of two.                       */
  11
  12 #define TABLE_SIZE 1024
  13
  14 static bucket **symbol_table = 0;
  15 bucket *first_symbol;
  16 bucket *last_symbol;
  17
  18 static int
  19 hash(const char *name)
  20 {
  21     const char *s;
  22     int c, k;
  23
  24     assert(name && *name);
  25     s = name;
  26     k = *s;
  27     while ((c = *++s) != 0)
  28         k = (31 * k + c) & (TABLE_SIZE - 1);
  29
  30     return (k);
  31 }
  32
  33 bucket *
  34 make_bucket(const char *name)
  35 {
  36     bucket *bp;
  37
  38     assert(name != 0);
  39
  40     bp = (bucket *)MALLOC(sizeof(bucket));
  41     NO_SPACE(bp);
  42
  43     bp->link = 0;
  44     bp->next = 0;
  45
  46     bp->name = MALLOC(strlen(name) + 1);
  47     NO_SPACE(bp->name);
  48
  49     bp->tag = 0;
  50     bp->value = UNDEFINED;
  51     bp->index = 0;
  52     bp->prec = 0;
  53     bp->class = UNKNOWN;
  54     bp->assoc = TOKEN;
  55     strcpy(bp->name, name);
  56
  57     return (bp);
  58 }
  59
  60 bucket *
  61 lookup(const char *name)
  62 {
  63     bucket *bp, **bpp;
  64
  65     bpp = symbol_table + hash(name);
  66     bp = *bpp;
  67
  68     while (bp)
  69     {
  70         if (strcmp(name, bp->name) == 0)
  71             return (bp);
  72         bpp = &bp->link;
  73         bp = *bpp;
  74     }
  75
  76     *bpp = bp = make_bucket(name);
  77     last_symbol->next = bp;
  78     last_symbol = bp;
  79
  80     return (bp);
  81 }
  82
  83 void
  84 create_symbol_table(void)
  85 {
  86     int i;
  87     bucket *bp;
  88
  89     symbol_table = (bucket **)MALLOC(TABLE_SIZE * sizeof(bucket *));
  90     NO_SPACE(symbol_table);
  91
  92     for (i = 0; i < TABLE_SIZE; i++)
  93         symbol_table[i] = 0;
  94
  95     bp = make_bucket("error");
  96     bp->index = 1;
  97     bp->class = TERM;
  98
  99     first_symbol = bp;
 100     last_symbol = bp;
 101     symbol_table[hash("error")] = bp;
 102 }
 103
 104 void
 105 free_symbol_table(void)
 106 {
 107     FREE(symbol_table);
 108     symbol_table = 0;
 109 }
 110
 111 void
 112 free_symbols(void)
 113 {
 114     bucket *p, *q;
 115
 116     for (p = first_symbol; p; p = q)
 117     {
 118         q = p->next;
 119         FREE(p);
 120     }
 121 }