1/* Hash tables.
2   Copyright (C) 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
3
4This program is free software; you can redistribute it and/or modify it
5under the terms of the GNU General Public License as published by the
6Free Software Foundation; either version 2, or (at your option) any
7later version.
8
9This program is distributed in the hope that it will be useful,
10but WITHOUT ANY WARRANTY; without even the implied warranty of
11MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12GNU General Public License for more details.
13
14You should have received a copy of the GNU General Public License
15along with this program; if not, write to the Free Software
16Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
17
18#ifndef LIBCPP_SYMTAB_H
19#define LIBCPP_SYMTAB_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.  */
26typedef struct ht_identifier ht_identifier;
27struct 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
37typedef struct ht hash_table;
38typedef struct ht_identifier *hashnode;
39
40enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC, HT_ALLOCED};
41
42/* An identifier hash table for cpplib and the front ends.  */
43struct ht
44{
45  /* Identifiers are allocated from here.  */
46  struct obstack stack;
47
48  hashnode *entries;
49  /* Call back, allocate a node.  */
50  hashnode (*alloc_node) (hash_table *);
51  /* Call back, allocate something that hangs off a node like a cpp_macro.
52     NULL means use the usual allocator.  */
53  void * (*alloc_subobject) (size_t);
54
55  unsigned int nslots;		/* Total slots in the entries array.  */
56  unsigned int nelements;	/* Number of live elements.  */
57
58  /* Link to reader, if any.  For the benefit of cpplib.  */
59  struct cpp_reader *pfile;
60
61  /* Table usage statistics.  */
62  unsigned int searches;
63  unsigned int collisions;
64
65  /* Should 'entries' be freed when it is no longer needed?  */
66  bool entries_owned;
67};
68
69/* Initialize the hashtable with 2 ^ order entries.  */
70extern hash_table *ht_create (unsigned int order);
71
72/* Frees all memory associated with a hash table.  */
73extern void ht_destroy (hash_table *);
74
75extern hashnode ht_lookup (hash_table *, const unsigned char *,
76			   size_t, enum ht_lookup_option);
77extern hashnode ht_lookup_with_hash (hash_table *, const unsigned char *,
78                                     size_t, unsigned int,
79                                     enum ht_lookup_option);
80#define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
81#define HT_HASHFINISH(r, len) ((r) + (len))
82
83/* For all nodes in TABLE, make a callback.  The callback takes
84   TABLE->PFILE, the node, and a PTR, and the callback sequence stops
85   if the callback returns zero.  */
86typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
87extern void ht_forall (hash_table *, ht_cb, const void *);
88
89/* Restore the hash table.  */
90extern void ht_load (hash_table *ht, hashnode *entries,
91		     unsigned int nslots, unsigned int nelements, bool own);
92
93/* Dump allocation statistics to stderr.  */
94extern void ht_dump_statistics (hash_table *);
95
96#endif /* LIBCPP_SYMTAB_H */
97