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   struct spec_nodes *s;
  57
  58   if (table == NULL)
  59     {
  60       pfile->our_hashtable = 1;
  61       table = ht_create (13);   /* 8K (=2^13) entries.  */
  62       table->alloc_node = (hashnode (*) PARAMS ((hash_table *))) alloc_node;
  63       gcc_obstack_init (&pfile->hash_ob);
  64     }
  65
  66   table->pfile = pfile;
  67   pfile->hash_table = table;
  68
  69   /* Now we can initialize things that use the hash table.  */
  70   _cpp_init_directives (pfile);
  71   _cpp_init_internal_pragmas (pfile);
  72
  73   s = &pfile->spec_nodes;
  74   s->n_defined          = cpp_lookup (pfile, DSC("defined"));
  75   s->n_true             = cpp_lookup (pfile, DSC("true"));
  76   s->n_false            = cpp_lookup (pfile, DSC("false"));
  77   s->n__STRICT_ANSI__   = cpp_lookup (pfile, DSC("__STRICT_ANSI__"));
  78   s->n__CHAR_UNSIGNED__ = cpp_lookup (pfile, DSC("__CHAR_UNSIGNED__"));
  79   s->n__VA_ARGS__       = cpp_lookup (pfile, DSC("__VA_ARGS__"));
  80   s->n__VA_ARGS__->flags |= NODE_DIAGNOSTIC;
  81 }
  82
  83 /* Tear down the identifier hash table.  */
  84
  85 void
  86 _cpp_destroy_hashtable (pfile)
  87      cpp_reader *pfile;
  88 {
  89   if (pfile->our_hashtable)
  90     {
  91       ht_destroy (pfile->hash_table);
  92       obstack_free (&pfile->hash_ob, 0);
  93     }
  94 }
  95
  96 /* Returns the hash entry for the STR of length LEN, creating one
  97    if necessary.  */
  98
  99 cpp_hashnode *
 100 cpp_lookup (pfile, str, len)
 101      cpp_reader *pfile;
 102      const unsigned char *str;
 103      unsigned int len;
 104 {
 105   /* ht_lookup cannot return NULL.  */
 106   return CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_ALLOC));
 107 }
 108
 109 /* Determine whether the str STR, of length LEN, is a defined macro.  */
 110
 111 int
 112 cpp_defined (pfile, str, len)
 113      cpp_reader *pfile;
 114      const unsigned char *str;
 115      int len;
 116 {
 117   cpp_hashnode *node;
 118
 119   node = CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_NO_INSERT));
 120
 121   /* If it's of type NT_MACRO, it cannot be poisoned.  */
 122   return node && node->type == NT_MACRO;
 123 }
 124
 125 /* For all nodes in the hashtable, callback CB with parameters PFILE,
 126    the node, and V.  */
 127
 128 void
 129 cpp_forall_identifiers (pfile, cb, v)
 130      cpp_reader *pfile;
 131      cpp_cb cb;
 132      PTR v;
 133 {
 134   /* We don't need a proxy since the hash table's identifier comes
 135      first in cpp_hashnode.  */
 136   ht_forall (pfile->hash_table, (ht_cb) cb, v);
 137 }