gcc/hashtable.h

   1 /* Hash tables.
   2    Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify it
   5 under the terms of the GNU General Public License as published by the
   6 Free Software Foundation; either version 2, or (at your option) any
   7 later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #ifndef GCC_HASHTABLE_H
  19 #define GCC_HASHTABLE_H
  20
  21 #include "obstack.h"
  22 #define GTY(x) /* nothing */
  23
  24 /* This is what each hash table entry points to.  It may be embedded
  25    deeply within another object.  */
  26 typedef struct ht_identifier ht_identifier;
  27 struct ht_identifier GTY(())
  28 {
  29   const unsigned char *str;
  30   unsigned int len;
  31   unsigned int hash_value;
  32 };
  33
  34 #define HT_LEN(NODE) ((NODE)->len)
  35 #define HT_STR(NODE) ((NODE)->str)
  36
  37 typedef struct ht hash_table;
  38 typedef struct ht_identifier *hashnode;
  39
  40 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC, HT_ALLOCED};
  41
  42 /* An identifier hash table for cpplib and the front ends.  */
  43 struct ht
  44 {
  45   /* Identifiers are allocated from here.  */
  46   struct obstack stack;
  47
  48   hashnode *entries;
  49   /* Call back.  */
  50   hashnode (*alloc_node) (hash_table *);
  51
  52   unsigned int nslots;          /* Total slots in the entries array.  */
  53   unsigned int nelements;       /* Number of live elements.  */
  54
  55   /* Link to reader, if any.  For the benefit of cpplib.  */
  56   struct cpp_reader *pfile;
  57
  58   /* Table usage statistics.  */
  59   unsigned int searches;
  60   unsigned int collisions;
  61 };
  62
  63 /* Initialize the hashtable with 2 ^ order entries.  */
  64 extern hash_table *ht_create (unsigned int order);
  65
  66 /* Frees all memory associated with a hash table.  */
  67 extern void ht_destroy (hash_table *);
  68
  69 extern hashnode ht_lookup (hash_table *, const unsigned char *,
  70                            size_t, enum ht_lookup_option);
  71
  72 /* For all nodes in TABLE, make a callback.  The callback takes
  73    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  74    if the callback returns zero.  */
  75 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  76 extern void ht_forall (hash_table *, ht_cb, const void *);
  77
  78 /* Dump allocation statistics to stderr.  */
  79 extern void ht_dump_statistics (hash_table *);
  80
  81 #endif /* GCC_HASHTABLE_H */