external/bsd/byacc/dist/symtab.c

   1 /*      $NetBSD$        */
   2 /* $Id: symtab.c,v 1.2 2009/10/29 00:56:20 christos Exp $ */
   3
   4 #include "defs.h"
   5
   6 #include <sys/cdefs.h>
   7 __RCSID("$NetBSD: closure.c,v 1.8 2006/05/24 18:01:43 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 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);
  39     bp = (bucket *)MALLOC(sizeof(bucket));
  40     if (bp == 0)
  41         no_space();
  42     bp->link = 0;
  43     bp->next = 0;
  44     bp->name = MALLOC(strlen(name) + 1);
  45     if (bp->name == 0)
  46         no_space();
  47     bp->tag = 0;
  48     bp->value = UNDEFINED;
  49     bp->index = 0;
  50     bp->prec = 0;
  51     bp->class = UNKNOWN;
  52     bp->assoc = TOKEN;
  53
  54     if (bp->name == 0)
  55         no_space();
  56     strcpy(bp->name, name);
  57
  58     return (bp);
  59 }
  60
  61 bucket *
  62 lookup(const char *name)
  63 {
  64     bucket *bp, **bpp;
  65
  66     bpp = symbol_table + hash(name);
  67     bp = *bpp;
  68
  69     while (bp)
  70     {
  71         if (strcmp(name, bp->name) == 0)
  72             return (bp);
  73         bpp = &bp->link;
  74         bp = *bpp;
  75     }
  76
  77     *bpp = bp = make_bucket(name);
  78     last_symbol->next = bp;
  79     last_symbol = bp;
  80
  81     return (bp);
  82 }
  83
  84 void
  85 create_symbol_table(void)
  86 {
  87     int i;
  88     bucket *bp;
  89
  90     symbol_table = (bucket **)MALLOC(TABLE_SIZE * sizeof(bucket *));
  91     if (symbol_table == 0)
  92         no_space();
  93     for (i = 0; i < TABLE_SIZE; i++)
  94         symbol_table[i] = 0;
  95
  96     bp = make_bucket("error");
  97     bp->index = 1;
  98     bp->class = TERM;
  99
 100     first_symbol = bp;
 101     last_symbol = bp;
 102     symbol_table[hash("error")] = bp;
 103 }
 104
 105 void
 106 free_symbol_table(void)
 107 {
 108     FREE(symbol_table);
 109     symbol_table = 0;
 110 }
 111
 112 void
 113 free_symbols(void)
 114 {
 115     bucket *p, *q;
 116
 117     for (p = first_symbol; p; p = q)
 118     {
 119         q = p->next;
 120         FREE(p);
 121     }
 122 }