usr.bin/yacc/symtab.c

   1 /*
   2  * Copyright (c) 1989 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Robert Paul Corbett.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/usr.bin/yacc/symtab.c,v 1.6 1999/08/28 01:08:03 peter Exp $
  37  * $DragonFly: src/usr.bin/yacc/symtab.c,v 1.5 2005/01/05 15:26:05 joerg Exp $
  38  *
  39  * @(#)symtab.c 5.3 (Berkeley) 6/1/90
  40  */
  41
  42 #include <stdlib.h>
  43 #include <string.h>
  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 static int hash(const char *);
  52
  53 bucket **symbol_table;
  54 bucket *first_symbol;
  55 bucket *last_symbol;
  56
  57
  58 static int
  59 hash(const char *name)
  60 {
  61     const char *s;
  62     int c, k;
  63
  64     assert(name && *name);
  65     s = name;
  66     k = *s;
  67     while ((c = *++s))
  68         k = (31*k + c) & (TABLE_SIZE - 1);
  69
  70     return (k);
  71 }
  72
  73
  74 bucket *
  75 make_bucket(const char *name)
  76 {
  77     bucket *bp;
  78
  79     assert(name);
  80     bp = (bucket *) MALLOC(sizeof(bucket));
  81     if (bp == 0) no_space();
  82     bp->link = 0;
  83     bp->next = 0;
  84     bp->name = MALLOC(strlen(name) + 1);
  85     if (bp->name == 0) no_space();
  86     bp->tag = 0;
  87     bp->value = UNDEFINED;
  88     bp->index = 0;
  89     bp->prec = 0;
  90     bp-> class = UNKNOWN;
  91     bp->assoc = TOKEN;
  92
  93     if (bp->name == 0) no_space();
  94     strcpy(bp->name, name);
  95
  96     return (bp);
  97 }
  98
  99
 100 bucket *
 101 lookup(char *name)
 102 {
 103     bucket *bp, **bpp;
 104
 105     bpp = symbol_table + hash(name);
 106     bp = *bpp;
 107
 108     while (bp)
 109     {
 110         if (strcmp(name, bp->name) == 0) return (bp);
 111         bpp = &bp->link;
 112         bp = *bpp;
 113     }
 114
 115     *bpp = bp = make_bucket(name);
 116     last_symbol->next = bp;
 117     last_symbol = bp;
 118
 119     return (bp);
 120 }
 121
 122
 123 void
 124 create_symbol_table(void)
 125 {
 126     int i;
 127     bucket *bp;
 128
 129     symbol_table = (bucket **) MALLOC(TABLE_SIZE*sizeof(bucket *));
 130     if (symbol_table == 0) no_space();
 131     for (i = 0; i < TABLE_SIZE; i++)
 132         symbol_table[i] = 0;
 133
 134     bp = make_bucket("error");
 135     bp->index = 1;
 136     bp->class = TERM;
 137
 138     first_symbol = bp;
 139     last_symbol = bp;
 140     symbol_table[hash("error")] = bp;
 141 }
 142
 143
 144 void
 145 free_symbol_table(void)
 146 {
 147     FREE(symbol_table);
 148     symbol_table = 0;
 149 }
 150
 151
 152 void
 153 free_symbols(void)
 154 {
 155     bucket *p, *q;
 156
 157     for (p = first_symbol; p; p = q)
 158     {
 159         q = p->next;
 160         FREE(p);
 161     }
 162 }