symtab.h revision 1.11 
1/* Hash tables.
2   Copyright (C) 2000-2020 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 3, 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; see the file COPYING3.  If not see
16<http://www.gnu.org/licenses/>.  */
17
18#ifndef LIBCPP_SYMTAB_H
19#define LIBCPP_SYMTAB_H
20
21#include "obstack.h"
22
23#ifndef GTY
24#define GTY(x) /* nothing */
25#endif
26
27/* This is what each hash table entry points to.  It may be embedded
28   deeply within another object.  */
29typedef struct ht_identifier ht_identifier;
30typedef struct ht_identifier *ht_identifier_ptr;
31struct GTY(()) ht_identifier {
32  const unsigned char *str;
33  unsigned int len;
34  unsigned int hash_value;
35};
36
37#define HT_LEN(NODE) ((NODE)->len)
38#define HT_STR(NODE) ((NODE)->str)
39
40typedef struct ht cpp_hash_table;
41typedef struct ht_identifier *hashnode;
42
43enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
44
45/* An identifier hash table for cpplib and the front ends.  */
46struct ht
47{
48  /* Identifiers are allocated from here.  */
49  struct obstack stack;
50
51  hashnode *entries;
52  /* Call back, allocate a node.  */
53  hashnode (*alloc_node) (cpp_hash_table *);
54  /* Call back, allocate something that hangs off a node like a cpp_macro.
55     NULL means use the usual allocator.  */
56  void * (*alloc_subobject) (size_t);
57
58  unsigned int nslots;		/* Total slots in the entries array.  */
59  unsigned int nelements;	/* Number of live elements.  */
60
61  /* Link to reader, if any.  For the benefit of cpplib.  */
62  struct cpp_reader *pfile;
63
64  /* Table usage statistics.  */
65  unsigned int searches;
66  unsigned int collisions;
67
68  /* Should 'entries' be freed when it is no longer needed?  */
69  bool entries_owned;
70};
71
72/* Initialize the hashtable with 2 ^ order entries.  */
73extern cpp_hash_table *ht_create (unsigned int order);
74
75/* Frees all memory associated with a hash table.  */
76extern void ht_destroy (cpp_hash_table *);
77
78extern hashnode ht_lookup (cpp_hash_table *, const unsigned char *,
79			   size_t, enum ht_lookup_option);
80extern hashnode ht_lookup_with_hash (cpp_hash_table *, const unsigned char *,
81                                     size_t, unsigned int,
82                                     enum ht_lookup_option);
83#define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
84#define HT_HASHFINISH(r, len) ((r) + (len))
85
86/* For all nodes in TABLE, make a callback.  The callback takes
87   TABLE->PFILE, the node, and a PTR, and the callback sequence stops
88   if the callback returns zero.  */
89typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
90extern void ht_forall (cpp_hash_table *, ht_cb, const void *);
91
92/* For all nodes in TABLE, call the callback.  If the callback returns
93   a nonzero value, the node is removed from the table.  */
94extern void ht_purge (cpp_hash_table *, ht_cb, const void *);
95
96/* Restore the hash table.  */
97extern void ht_load (cpp_hash_table *ht, hashnode *entries,
98		     unsigned int nslots, unsigned int nelements, bool own);
99
100/* Dump allocation statistics to stderr.  */
101extern void ht_dump_statistics (cpp_hash_table *);
102
103#endif /* LIBCPP_SYMTAB_H */
104