libcpp/identifiers.c

   1 /* Hash tables for the CPP library.
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1998,
   3    1999, 2000, 2001, 2002 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 "internal.h"
  30
  31 static cpp_hashnode *alloc_node (hash_table *);
  32
  33 /* Return an identifier node for hashtable.c.  Used by cpplib except
  34    when integrated with the C front ends.  */
  35 static cpp_hashnode *
  36 alloc_node (hash_table *table)
  37 {
  38   cpp_hashnode *node;
  39
  40   node = XOBNEW (&table->pfile->hash_ob, cpp_hashnode);
  41   memset (node, 0, sizeof (cpp_hashnode));
  42   return node;
  43 }
  44
  45 /* Set up the identifier hash table.  Use TABLE if non-null, otherwise
  46    create our own.  */
  47 void
  48 _cpp_init_hashtable (cpp_reader *pfile, hash_table *table)
  49 {
  50   struct spec_nodes *s;
  51
  52   if (table == NULL)
  53     {
  54       pfile->our_hashtable = 1;
  55       table = ht_create (13);   /* 8K (=2^13) entries.  */
  56       table->alloc_node = (hashnode (*) (hash_table *)) alloc_node;
  57
  58       _obstack_begin (&pfile->hash_ob, 0, 0,
  59                       (void *(*) (long)) xmalloc,
  60                       (void (*) (void *)) free);
  61     }
  62
  63   table->pfile = pfile;
  64   pfile->hash_table = table;
  65
  66   /* Now we can initialize things that use the hash table.  */
  67   _cpp_init_directives (pfile);
  68   _cpp_init_internal_pragmas (pfile);
  69
  70   s = &pfile->spec_nodes;
  71   s->n_defined          = cpp_lookup (pfile, DSC("defined"));
  72   s->n_true             = cpp_lookup (pfile, DSC("true"));
  73   s->n_false            = cpp_lookup (pfile, DSC("false"));
  74   s->n__VA_ARGS__       = cpp_lookup (pfile, DSC("__VA_ARGS__"));
  75   s->n__VA_ARGS__->flags |= NODE_DIAGNOSTIC;
  76 }
  77
  78 /* Tear down the identifier hash table.  */
  79 void
  80 _cpp_destroy_hashtable (cpp_reader *pfile)
  81 {
  82   if (pfile->our_hashtable)
  83     {
  84       ht_destroy (pfile->hash_table);
  85       obstack_free (&pfile->hash_ob, 0);
  86     }
  87 }
  88
  89 /* Returns the hash entry for the STR of length LEN, creating one
  90    if necessary.  */
  91 cpp_hashnode *
  92 cpp_lookup (cpp_reader *pfile, const unsigned char *str, unsigned int len)
  93 {
  94   /* ht_lookup cannot return NULL.  */
  95   return CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_ALLOC));
  96 }
  97
  98 /* Determine whether the str STR, of length LEN, is a defined macro.  */
  99 int
 100 cpp_defined (cpp_reader *pfile, const unsigned char *str, 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 void
 113 cpp_forall_identifiers (cpp_reader *pfile, cpp_cb cb, void *v)
 114 {
 115   /* We don't need a proxy since the hash table's identifier comes
 116      first in cpp_hashnode.  */
 117   ht_forall (pfile->hash_table, (ht_cb) cb, v);
 118 }