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, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include <stdio.h>
  23 #include "system.h"
  24 #include "alloc.h"
  25 #include "symtab.h"
  26 #include "gram.h"
  27
  28
  29 bucket *firstsymbol;
  30 static bucket *lastsymbol;
  31 static bucket **symtab;
  32
  33 extern void tabinit PARAMS((void));
  34 extern void free_symtab PARAMS((void));
  35
  36
  37 static int
  38 hash (const char *key)
  39 {
  40   register const char *cp;
  41   register int k;
  42
  43   cp = key;
  44   k = 0;
  45   while (*cp)
  46     k = ((k << 1) ^ (*cp++)) & 0x3fff;
  47
  48   return k % TABSIZE;
  49 }
  50
  51
  52
  53 static char *
  54 copys (const char *s)
  55 {
  56   register int i;
  57   register const char *cp;
  58   register char *result;
  59
  60   i = 1;
  61   for (cp = s; *cp; cp++)
  62     i++;
  63
  64   result = xmalloc((unsigned int)i);
  65   strcpy(result, s);
  66   return result;
  67 }
  68
  69
  70 void
  71 tabinit (void)
  72 {
  73 /*   register int i; JF unused */
  74
  75   symtab = NEW2(TABSIZE, bucket *);
  76
  77   firstsymbol = NULL;
  78   lastsymbol = NULL;
  79 }
  80
  81
  82 bucket *
  83 getsym (const char *key)
  84 {
  85   register int hashval;
  86   register bucket *bp;
  87   register int found;
  88
  89   hashval = hash(key);
  90   bp = symtab[hashval];
  91
  92   found = 0;
  93   while (bp != NULL && found == 0)
  94     {
  95       if (strcmp(key, bp->tag) == 0)
  96         found = 1;
  97       else
  98         bp = bp->link;
  99     }
 100
 101   if (found == 0)
 102     {
 103       nsyms++;
 104
 105       bp = NEW(bucket);
 106       bp->link = symtab[hashval];
 107       bp->next = NULL;
 108       bp->tag = copys(key);
 109       bp->class = SUNKNOWN;
 110
 111       if (firstsymbol == NULL)
 112         {
 113           firstsymbol = bp;
 114           lastsymbol = bp;
 115         }
 116       else
 117         {
 118           lastsymbol->next = bp;
 119           lastsymbol = bp;
 120         }
 121
 122       symtab[hashval] = bp;
 123     }
 124
 125   return bp;
 126 }
 127
 128
 129 void
 130 free_symtab (void)
 131 {
 132   register int i;
 133   register bucket *bp,*bptmp;/* JF don't use ptr after free */
 134
 135   for (i = 0; i < TABSIZE; i++)
 136     {
 137       bp = symtab[i];
 138       while (bp)
 139         {
 140           bptmp = bp->link;
 141 #if 0 /* This causes crashes because one string can appear more than once.  */
 142           if (bp->type_name)
 143             FREE(bp->type_name);
 144 #endif
 145           FREE(bp);
 146           bp = bptmp;
 147         }
 148     }
 149   FREE(symtab);
 150 }