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
  33
  34 int
  35 hash(key)
  36 char *key;
  37 {
  38   register char *cp;
  39   register int k;
  40
  41   cp = key;
  42   k = 0;
  43   while (*cp)
  44     k = ((k << 1) ^ (*cp++)) & 0x3fff;
  45
  46   return (k % TABSIZE);
  47 }
  48
  49
  50
  51 char *
  52 copys(s)
  53 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()
  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(key)
  83 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()
 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 }