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
  23 /* This is what each hash table entry points to.  It may be embedded
  24    deeply within another object.  */
  25 typedef struct ht_identifier ht_identifier;
  26 struct ht_identifier GTY(())
  27 {
  28   const unsigned char *str;
  29   unsigned int len;
  30   unsigned int hash_value;
  31 };
  32
  33 #define HT_LEN(NODE) ((NODE)->len)
  34 #define HT_STR(NODE) ((NODE)->str)
  35
  36 typedef struct ht hash_table;
  37 typedef struct ht_identifier *hashnode;
  38
  39 enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC, HT_ALLOCED};
  40
  41 /* An identifier hash table for cpplib and the front ends.  */
  42 struct ht
  43 {
  44   /* Identifiers are allocated from here.  */
  45   struct obstack stack;
  46
  47   hashnode *entries;
  48   /* Call back.  */
  49   hashnode (*alloc_node) (hash_table *);
  50
  51   unsigned int nslots;          /* Total slots in the entries array.  */
  52   unsigned int nelements;       /* Number of live elements.  */
  53
  54   /* Link to reader, if any.  For the benefit of cpplib.  */
  55   struct cpp_reader *pfile;
  56
  57   /* Table usage statistics.  */
  58   unsigned int searches;
  59   unsigned int collisions;
  60 };
  61
  62 /* Initialize the hashtable with 2 ^ order entries.  */
  63 extern hash_table *ht_create (unsigned int order);
  64
  65 /* Frees all memory associated with a hash table.  */
  66 extern void ht_destroy (hash_table *);
  67
  68 extern hashnode ht_lookup (hash_table *, const unsigned char *,
  69                            unsigned int, enum ht_lookup_option);
  70
  71 /* For all nodes in TABLE, make a callback.  The callback takes
  72    TABLE->PFILE, the node, and a PTR, and the callback sequence stops
  73    if the callback returns zero.  */
  74 typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
  75 extern void ht_forall (hash_table *, ht_cb, const void *);
  76
  77 /* Dump allocation statistics to stderr.  */
  78 extern void ht_dump_statistics (hash_table *);
  79
  80 /* Approximate positive square root of a host double.  This is for
  81    statistical reports, not code generation.  */
  82 extern double approx_sqrt (double);
  83
  84 #endif /* GCC_HASHTABLE_H */