src/symtab.c

   1 /* Symbol table manager for Bison,
   2    Copyright (C) 1984, 1989 Free Software Foundation, Inc.
   3
   4 This file is part of Bison, the GNU Compiler Compiler.
   5
   6 Bison is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 Bison is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with Bison; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 #include <stdio.h>
  22 #include "system.h"
  23 #include "alloc.h"
  24 #include "symtab.h"
  25 #include "gram.h"
  26
  27
  28 bucket **symtab;
  29 bucket *firstsymbol;
  30 bucket *lastsymbol;
  31
  32 void tabinit PARAMS((void));
  33 void free_symtab PARAMS((void));
  34
  35
  36 static int
  37 hash (char *key)
  38 {
  39   register char *cp;
  40   register int k;
  41
  42   cp = key;
  43   k = 0;
  44   while (*cp)
  45     k = ((k << 1) ^ (*cp++)) & 0x3fff;
  46
  47   return (k % TABSIZE);
  48 }
  49
  50
  51
  52 static char *
  53 copys (char *s)
  54 {
  55   register int i;
  56   register char *cp;
  57   register char *result;
  58
  59   i = 1;
  60   for (cp = s; *cp; cp++)
  61     i++;
  62
  63   result = xmalloc((unsigned int)i);
  64   strcpy(result, s);
  65   return (result);
  66 }
  67
  68
  69 void
  70 tabinit (void)
  71 {
  72 /*   register int i; JF unused */
  73
  74   symtab = NEW2(TABSIZE, bucket *);
  75
  76   firstsymbol = NULL;
  77   lastsymbol = NULL;
  78 }
  79
  80
  81 bucket *
  82 getsym (char *key)
  83 {
  84   register int hashval;
  85   register bucket *bp;
  86   register int found;
  87
  88   hashval = hash(key);
  89   bp = symtab[hashval];
  90
  91   found = 0;
  92   while (bp != NULL && found == 0)
  93     {
  94       if (strcmp(key, bp->tag) == 0)
  95         found = 1;
  96       else
  97         bp = bp->link;
  98     }
  99
 100   if (found == 0)
 101     {
 102       nsyms++;
 103
 104       bp = NEW(bucket);
 105       bp->link = symtab[hashval];
 106       bp->next = NULL;
 107       bp->tag = copys(key);
 108       bp->class = SUNKNOWN;
 109
 110       if (firstsymbol == NULL)
 111         {
 112           firstsymbol = bp;
 113           lastsymbol = bp;
 114         }
 115       else
 116         {
 117           lastsymbol->next = bp;
 118           lastsymbol = bp;
 119         }
 120
 121       symtab[hashval] = bp;
 122     }
 123
 124   return (bp);
 125 }
 126
 127
 128 void
 129 free_symtab (void)
 130 {
 131   register int i;
 132   register bucket *bp,*bptmp;/* JF don't use ptr after free */
 133
 134   for (i = 0; i < TABSIZE; i++)
 135     {
 136       bp = symtab[i];
 137       while (bp)
 138         {
 139           bptmp = bp->link;
 140 #if 0 /* This causes crashes because one string can appear more than once.  */
 141           if (bp->type_name)
 142             FREE(bp->type_name);
 143 #endif
 144           FREE(bp);
 145           bp = bptmp;
 146         }
 147     }
 148   FREE(symtab);
 149 }