contrib/byacc/symtab.c

   1 /* $Id: symtab.c,v 1.11 2014/03/26 00:17:09 Tom.Shields Exp $ */
   2
   3 #include "defs.h"
   4
   5 /* TABLE_SIZE is the number of entries in the symbol table. */
   6 /* TABLE_SIZE must be a power of two.                       */
   7
   8 #define TABLE_SIZE 1024
   9
  10 static bucket **symbol_table = 0;
  11 bucket *first_symbol;
  12 bucket *last_symbol;
  13
  14 static int
  15 hash(const char *name)
  16 {
  17     const char *s;
  18     int c, k;
  19
  20     assert(name && *name);
  21     s = name;
  22     k = *s;
  23     while ((c = *++s) != 0)
  24         k = (31 * k + c) & (TABLE_SIZE - 1);
  25
  26     return (k);
  27 }
  28
  29 bucket *
  30 make_bucket(const char *name)
  31 {
  32     bucket *bp;
  33
  34     assert(name != 0);
  35
  36     bp = TMALLOC(bucket, 1);
  37     NO_SPACE(bp);
  38
  39     bp->link = 0;
  40     bp->next = 0;
  41
  42     bp->name = TMALLOC(char, strlen(name) + 1);
  43     NO_SPACE(bp->name);
  44
  45     bp->tag = 0;
  46     bp->value = UNDEFINED;
  47     bp->index = 0;
  48     bp->prec = 0;
  49     bp->class = UNKNOWN;
  50     bp->assoc = TOKEN;
  51 #if defined(YYBTYACC)
  52     bp->args = -1;
  53     bp->argnames = 0;
  54     bp->argtags = 0;
  55     bp->destructor = 0;
  56 #endif
  57     strcpy(bp->name, name);
  58
  59     return (bp);
  60 }
  61
  62 bucket *
  63 lookup(const char *name)
  64 {
  65     bucket *bp, **bpp;
  66
  67     bpp = symbol_table + hash(name);
  68     bp = *bpp;
  69
  70     while (bp)
  71     {
  72         if (strcmp(name, bp->name) == 0)
  73             return (bp);
  74         bpp = &bp->link;
  75         bp = *bpp;
  76     }
  77
  78     *bpp = bp = make_bucket(name);
  79     last_symbol->next = bp;
  80     last_symbol = bp;
  81
  82     return (bp);
  83 }
  84
  85 void
  86 create_symbol_table(void)
  87 {
  88     int i;
  89     bucket *bp;
  90
  91     symbol_table = TMALLOC(bucket *, TABLE_SIZE);
  92     NO_SPACE(symbol_table);
  93
  94     for (i = 0; i < TABLE_SIZE; i++)
  95         symbol_table[i] = 0;
  96
  97     bp = make_bucket("error");
  98     bp->index = 1;
  99     bp->class = TERM;
 100
 101     first_symbol = bp;
 102     last_symbol = bp;
 103     symbol_table[hash("error")] = bp;
 104 }
 105
 106 void
 107 free_symbol_table(void)
 108 {
 109     FREE(symbol_table);
 110     symbol_table = 0;
 111 }
 112
 113 void
 114 free_symbols(void)
 115 {
 116     bucket *p, *q;
 117
 118     for (p = first_symbol; p; p = q)
 119     {
 120         q = p->next;
 121         FREE(p);
 122     }
 123 }