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