1/* hash - hashing table processing.
2   Copyright (C) 1998-1999, 2001, 2003, 2009-2012 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 <http://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;
92void hash_clear (Hash_table *);
93void hash_free (Hash_table *);
94
95/* Insertion and deletion.  */
96bool hash_rehash (Hash_table *, size_t) _GL_ATTRIBUTE_WUR;
97void *hash_insert (Hash_table *, const void *) _GL_ATTRIBUTE_WUR;
98
99/* Deprecate this interface.  It has been renamed to hash_insert_if_absent.  */
100int hash_insert0 (Hash_table *table, /* FIXME: remove in 2013 */
101                  const void *entry,
102                  const void **matched_ent) _GL_ATTRIBUTE_DEPRECATED;
103int hash_insert_if_absent (Hash_table *table, const void *entry,
104                           const void **matched_ent);
105void *hash_delete (Hash_table *, const void *);
106
107#endif
108