1/* Hash tables.
2 Copyright (C) 2000-2025 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 /* We know the 'len'gth of the 'str'ing; use it in the GTY markup. */
33 const unsigned char * GTY((string_length ("1 + %h.len"))) str;
34 unsigned int len;
35 unsigned int hash_value;
36};
37
38#define HT_LEN(NODE) ((NODE)->len)
39#define HT_STR(NODE) ((NODE)->str)
40
41typedef struct ht cpp_hash_table;
42typedef struct ht_identifier *hashnode;
43
44enum ht_lookup_option {HT_NO_INSERT = 0, HT_ALLOC};
45
46/* An identifier hash table for cpplib and the front ends. */
47struct ht
48{
49 /* Identifiers are allocated from here. */
50 struct obstack stack;
51
52 hashnode *entries;
53 /* Call back, allocate a node. */
54 hashnode (*alloc_node) (cpp_hash_table *);
55 /* Call back, allocate something that hangs off a node like a cpp_macro.
56 NULL means use the usual allocator. */
57 void * (*alloc_subobject) (size_t);
58
59 unsigned int nslots; /* Total slots in the entries array. */
60 unsigned int nelements; /* Number of live elements. */
61
62 /* Link to reader, if any. For the benefit of cpplib. */
63 struct cpp_reader *pfile;
64
65 /* Table usage statistics. */
66 unsigned int searches;
67 unsigned int collisions;
68
69 /* Should 'entries' be freed when it is no longer needed? */
70 bool entries_owned;
71};
72
73/* Initialize the hashtable with 2 ^ order entries. */
74extern cpp_hash_table *ht_create (unsigned int order);
75
76/* Frees all memory associated with a hash table. */
77extern void ht_destroy (cpp_hash_table *);
78
79extern hashnode ht_lookup (cpp_hash_table *, const unsigned char *,
80 size_t, enum ht_lookup_option);
81extern hashnode ht_lookup_with_hash (cpp_hash_table *, const unsigned char *,
82 size_t, unsigned int,
83 enum ht_lookup_option);
84inline hashnode ht_lookup (cpp_hash_table *ht, const ht_identifier &id,
85 ht_lookup_option opt)
86{
87 return ht_lookup_with_hash (ht, id.str, id.len, id.hash_value, opt);
88}
89
90#define HT_HASHSTEP(r, c) ((r) * 67 + ((c) - 113));
91#define HT_HASHFINISH(r, len) ((r) + (len))
92
93/* For all nodes in TABLE, make a callback. The callback takes
94 TABLE->PFILE, the node, and a PTR, and the callback sequence stops
95 if the callback returns zero. */
96typedef int (*ht_cb) (struct cpp_reader *, hashnode, const void *);
97extern void ht_forall (cpp_hash_table *, ht_cb, const void *);
98
99/* For all nodes in TABLE, call the callback. If the callback returns
100 a nonzero value, the node is removed from the table. */
101extern void ht_purge (cpp_hash_table *, ht_cb, const void *);
102
103/* Restore the hash table. */
104extern void ht_load (cpp_hash_table *ht, hashnode *entries,
105 unsigned int nslots, unsigned int nelements, bool own);
106
107/* Dump allocation statistics to stderr. */
108extern void ht_dump_statistics (cpp_hash_table *);
109
110#endif /* LIBCPP_SYMTAB_H */
111

source code of libcpp/include/symtab.h