gcc/cpphash.c

   1 /* Hash tables for the CPP library.
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1998,
   3    1999, 2000 Free Software Foundation, Inc.
   4    Written by Per Bothner, 1994.
   5    Based on CCCP program by Paul Rubin, June 1986
   6    Adapted to ANSI C, Richard Stallman, Jan 1987
   7
   8 This program is free software; you can redistribute it and/or modify it
   9 under the terms of the GNU General Public License as published by the
  10 Free Software Foundation; either version 2, or (at your option) any
  11 later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21
  22  In other words, you are welcome to use, share and improve this program.
  23  You are forbidden to forbid anyone else to use, share and improve
  24  what you give them.   Help stamp out software-hoarding!  */
  25
  26 #include "config.h"
  27 #include "system.h"
  28 #include "cpplib.h"
  29 #include "cpphash.h"
  30
  31 static cpp_hashnode *alloc_node PARAMS ((hash_table *));
  32
  33 /* Return an identifier node for hashtable.c.  Used by cpplib except
  34    when integrated with the C front ends.  */
  35
  36 static cpp_hashnode *
  37 alloc_node (table)
  38      hash_table *table;
  39 {
  40   cpp_hashnode *node;
  41
  42   node = (cpp_hashnode *) obstack_alloc (&table->pfile->hash_ob,
  43                                          sizeof (cpp_hashnode));
  44   memset ((PTR) node, 0, sizeof (cpp_hashnode));
  45   return node;
  46 }
  47
  48 /* Set up the identifier hash table.  Use TABLE if non-null, otherwise
  49    create our own.  */
  50
  51 void
  52 _cpp_init_hashtable (pfile, table)
  53      cpp_reader *pfile;
  54      hash_table *table;
  55 {
  56   if (table == NULL)
  57     {
  58       pfile->our_hashtable = 1;
  59       table = ht_create (13);   /* 8K (=2^13) entries.  */
  60       table->alloc_node = (hashnode (*) PARAMS ((hash_table *))) alloc_node;
  61       gcc_obstack_init (&pfile->hash_ob);
  62     }
  63
  64   table->pfile = pfile;
  65   pfile->hash_table = table;
  66 }
  67
  68 /* Tear down the identifier hash table.  */
  69
  70 void
  71 _cpp_destroy_hashtable (pfile)
  72      cpp_reader *pfile;
  73 {
  74   if (pfile->our_hashtable)
  75     {
  76       ht_destroy (pfile->hash_table);
  77       obstack_free (&pfile->hash_ob, 0);
  78     }
  79 }
  80
  81 /* Returns the hash entry for the STR of length LEN, creating one
  82    if necessary.  */
  83
  84 cpp_hashnode *
  85 cpp_lookup (pfile, str, len)
  86      cpp_reader *pfile;
  87      const unsigned char *str;
  88      unsigned int len;
  89 {
  90   /* ht_lookup cannot return NULL.  */
  91   return CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_ALLOC));
  92 }
  93
  94 /* Determine whether the str STR, of length LEN, is a defined macro.  */
  95
  96 int
  97 cpp_defined (pfile, str, len)
  98      cpp_reader *pfile;
  99      const unsigned char *str;
 100      int len;
 101 {
 102   cpp_hashnode *node;
 103
 104   node = CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_NO_INSERT));
 105
 106   /* If it's of type NT_MACRO, it cannot be poisoned.  */
 107   return node && node->type == NT_MACRO;
 108 }
 109
 110 /* For all nodes in the hashtable, callback CB with parameters PFILE,
 111    the node, and V.  */
 112
 113 void
 114 cpp_forall_identifiers (pfile, cb, v)
 115      cpp_reader *pfile;
 116      cpp_cb cb;
 117      PTR v;
 118 {
 119   /* We don't need a proxy since the hash table's identifier comes
 120      first in cpp_hashnode.  */
 121   ht_forall (pfile->hash_table, (ht_cb) cb, v);
 122 }