usr.bin/yacc/symtab.c

   1 /*      $NetBSD: symtab.c,v 1.11 2006/05/24 18:06:58 christos Exp $     */
   2
   3 /*
   4  * Copyright (c) 1989 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Robert Paul Corbett.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(__RCSID) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)symtab.c    5.3 (Berkeley) 6/1/90";
  39 #else
  40 __RCSID("$NetBSD: symtab.c,v 1.11 2006/05/24 18:06:58 christos Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include "defs.h"
  45
  46 /* TABLE_SIZE is the number of entries in the symbol table. */
  47 /* TABLE_SIZE must be a power of two.                       */
  48
  49 #define TABLE_SIZE 1024
  50
  51
  52 bucket *first_symbol;
  53 bucket *last_symbol;
  54
  55 static bucket **symbol_table;
  56
  57 static int hash(const char *);
  58
  59
  60 static int
  61 hash(const char *name)
  62 {
  63     const char *s;
  64     int c, k;
  65
  66     assert(name && *name);
  67     s = name;
  68     k = *s;
  69     while ((c = *++s) != '\0')
  70         k = (31*k + c) & (TABLE_SIZE - 1);
  71
  72     return (k);
  73 }
  74
  75
  76 bucket *
  77 make_bucket(const char *name)
  78 {
  79     bucket *bp;
  80
  81     assert(name);
  82     bp = (bucket *) MALLOC(sizeof(bucket));
  83     if (bp == 0) no_space();
  84     bp->link = 0;
  85     bp->next = 0;
  86     bp->name = strdup(name);
  87     if (bp->name == 0) no_space();
  88     bp->tag = 0;
  89     bp->value = UNDEFINED;
  90     bp->index = 0;
  91     bp->prec = 0;
  92     bp-> class = UNKNOWN;
  93     bp->assoc = TOKEN;
  94
  95     return (bp);
  96 }
  97
  98
  99 bucket *
 100 lookup(char *name)
 101 {
 102     bucket *bp, **bpp;
 103
 104     bpp = symbol_table + hash(name);
 105     bp = *bpp;
 106
 107     while (bp)
 108     {
 109         if (strcmp(name, bp->name) == 0) return (bp);
 110         bpp = &bp->link;
 111         bp = *bpp;
 112     }
 113
 114     *bpp = bp = make_bucket(name);
 115     last_symbol->next = bp;
 116     last_symbol = bp;
 117
 118     return (bp);
 119 }
 120
 121
 122 void
 123 create_symbol_table(void)
 124 {
 125     int i;
 126     bucket *bp;
 127
 128     symbol_table = (bucket **) MALLOC(TABLE_SIZE*sizeof(bucket *));
 129     if (symbol_table == 0) no_space();
 130     for (i = 0; i < TABLE_SIZE; i++)
 131         symbol_table[i] = 0;
 132
 133     bp = make_bucket("error");
 134     bp->index = 1;
 135     bp->class = TERM;
 136
 137     first_symbol = bp;
 138     last_symbol = bp;
 139     symbol_table[hash("error")] = bp;
 140 }
 141
 142
 143 void
 144 free_symbol_table(void)
 145 {
 146     FREE(symbol_table);
 147     symbol_table = 0;
 148 }
 149
 150
 151 void
 152 free_symbols(void)
 153 {
 154     bucket *p, *q;
 155
 156     for (p = first_symbol; p; p = q)
 157     {
 158         q = p->next;
 159         FREE(p);
 160     }
 161 }