1/* hash - hashing table processing.
2 Copyright (C) 1998-1999, 2001, 2003, 2009-2019 Free Software Foundation,
3 Inc.
4 Written by Jim Meyering <meyering@ascend.com>, 1998.
5
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>. */
18
19/* A generic hash table package. */
20
21/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use
22 obstacks instead of malloc, and recompile 'hash.c' with same setting. */
23
24#ifndef HASH_H_
25# define HASH_H_
26
27# include <stdio.h>
28# include <stdbool.h>
29
30/* The __attribute__ feature is available in gcc versions 2.5 and later.
31 The warn_unused_result attribute appeared first in gcc-3.4.0. */
32# if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
33# define _GL_ATTRIBUTE_WUR __attribute__ ((__warn_unused_result__))
34# else
35# define _GL_ATTRIBUTE_WUR /* empty */
36# endif
37
38# ifndef _GL_ATTRIBUTE_DEPRECATED
39/* The __attribute__((__deprecated__)) feature
40 is available in gcc versions 3.1 and newer. */
41# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
42# define _GL_ATTRIBUTE_DEPRECATED /* empty */
43# else
44# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
45# endif
46# endif
47
48typedef size_t (*Hash_hasher) (const void *, size_t);
49typedef bool (*Hash_comparator) (const void *, const void *);
50typedef void (*Hash_data_freer) (void *);
51typedef bool (*Hash_processor) (void *, void *);
52
53struct hash_tuning
54 {
55 /* This structure is mainly used for 'hash_initialize', see the block
56 documentation of 'hash_reset_tuning' for more complete comments. */
57
58 float shrink_threshold; /* ratio of used buckets to trigger a shrink */
59 float shrink_factor; /* ratio of new smaller size to original size */
60 float growth_threshold; /* ratio of used buckets to trigger a growth */
61 float growth_factor; /* ratio of new bigger size to original size */
62 bool is_n_buckets; /* if CANDIDATE really means table size */
63 };
64
65typedef struct hash_tuning Hash_tuning;
66
67struct hash_table;
68
69typedef struct hash_table Hash_table;
70
71/* Information and lookup. */
72size_t hash_get_n_buckets (const Hash_table *) _GL_ATTRIBUTE_PURE;
73size_t hash_get_n_buckets_used (const Hash_table *) _GL_ATTRIBUTE_PURE;
74size_t hash_get_n_entries (const Hash_table *) _GL_ATTRIBUTE_PURE;
75size_t hash_get_max_bucket_length (const Hash_table *) _GL_ATTRIBUTE_PURE;
76bool hash_table_ok (const Hash_table *) _GL_ATTRIBUTE_PURE;
77void hash_print_statistics (const Hash_table *, FILE *);
78void *hash_lookup (const Hash_table *, const void *);
79
80/* Walking. */
81void *hash_get_first (const Hash_table *) _GL_ATTRIBUTE_PURE;
82void *hash_get_next (const Hash_table *, const void *);
83size_t hash_get_entries (const Hash_table *, void **, size_t);
84size_t hash_do_for_each (const Hash_table *, Hash_processor, void *);
85
86/* Allocation and clean-up. */
87size_t hash_string (const char *, size_t) _GL_ATTRIBUTE_PURE;
88void hash_reset_tuning (Hash_tuning *);
89Hash_table *hash_initialize (size_t, const Hash_tuning *,
90 Hash_hasher, Hash_comparator,
91 Hash_data_freer) _GL_ATTRIBUTE_WUR;
92Hash_table *hash_xinitialize (size_t, const Hash_tuning *,
93 Hash_hasher, Hash_comparator,
94 Hash_data_freer) _GL_ATTRIBUTE_WUR;
95void hash_clear (Hash_table *);
96void hash_free (Hash_table *);
97
98/* Insertion and deletion. */
99bool hash_rehash (Hash_table *, size_t) _GL_ATTRIBUTE_WUR;
100void *hash_insert (Hash_table *, const void *) _GL_ATTRIBUTE_WUR;
101
102int hash_insert_if_absent (Hash_table *table, const void *entry,
103 const void **matched_ent);
104void *hash_delete (Hash_table *, const void *);
105
106#endif
107