1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/* hash - hashing table processing.
Copyright (C) 1998, 1999 Free Software Foundation, Inc.
Written by Jim Meyering <meyering@ascend.com>, 1998.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* A generic hash table package. */
/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use
obstacks instead of malloc, and recompile `hash.c' with same setting. */
#ifndef PARAMS
# if PROTOTYPES || __STDC__
# define PARAMS(Args) Args
# else
# define PARAMS(Args) ()
# endif
#endif
typedef unsigned (*Hash_hasher) PARAMS ((const void *, unsigned));
typedef bool (*Hash_comparator) PARAMS ((const void *, const void *));
typedef void (*Hash_data_freer) PARAMS ((void *));
typedef bool (*Hash_processor) PARAMS ((void *, void *));
struct hash_entry
{
void *data;
struct hash_entry *next;
};
struct hash_tuning
{
/* This structure is mainly used for `hash_initialize', see the block
documentation of `hash_reset_tuning' for more complete comments. */
float shrink_threshold; /* ratio of used buckets to trigger a shrink */
float shrink_factor; /* ratio of new smaller size to original size */
float growth_threshold; /* ratio of used buckets to trigger a growth */
float growth_factor; /* ratio of new bigger size to original size */
bool is_n_buckets; /* if CANDIDATE really means table size */
};
typedef struct hash_tuning Hash_tuning;
struct hash_table
{
/* The array of buckets starts at BUCKET and extends to BUCKET_LIMIT-1,
for a possibility of N_BUCKETS. Among those, N_BUCKETS_USED buckets
are not empty, there are N_ENTRIES active entries in the table. */
struct hash_entry *bucket;
struct hash_entry *bucket_limit;
unsigned n_buckets;
unsigned n_buckets_used;
unsigned n_entries;
/* Tuning arguments, kept in a physicaly separate structure. */
const Hash_tuning *tuning;
/* Three functions are given to `hash_initialize', see the documentation
block for this function. In a word, HASHER randomizes a user entry
into a number up from 0 up to some maximum minus 1; COMPARATOR returns
true if two user entries compare equally; and DATA_FREER is the cleanup
function for a user entry. */
Hash_hasher hasher;
Hash_comparator comparator;
Hash_data_freer data_freer;
/* A linked list of freed struct hash_entry structs. */
struct hash_entry *free_entry_list;
#if USE_OBSTACK
/* Whenever obstacks are used, it is possible to allocate all overflowed
entries into a single stack, so they all can be freed in a single
operation. It is not clear if the speedup is worth the trouble. */
struct obstack entry_stack;
#endif
};
typedef struct hash_table Hash_table;
/* Information and lookup. */
unsigned hash_get_n_buckets PARAMS ((const Hash_table *));
unsigned hash_get_n_buckets_used PARAMS ((const Hash_table *));
unsigned hash_get_n_entries PARAMS ((const Hash_table *));
unsigned hash_get_max_bucket_length PARAMS ((const Hash_table *));
bool hash_table_ok PARAMS ((const Hash_table *));
void hash_print_statistics PARAMS ((const Hash_table *, FILE *));
void *hash_lookup PARAMS ((const Hash_table *, const void *));
/* Walking. */
void *hash_get_first PARAMS ((const Hash_table *));
void *hash_get_next PARAMS ((const Hash_table *, const void *));
unsigned hash_get_entries PARAMS ((const Hash_table *, void **, unsigned));
unsigned hash_do_for_each PARAMS ((const Hash_table *, Hash_processor, void *));
/* Allocation and clean-up. */
unsigned hash_string PARAMS ((const char *, unsigned));
void hash_reset_tuning PARAMS ((Hash_tuning *));
Hash_table *hash_initialize PARAMS ((unsigned, const Hash_tuning *,
Hash_hasher, Hash_comparator,
Hash_data_freer));
void hash_clear PARAMS ((Hash_table *));
void hash_free PARAMS ((Hash_table *));
/* Insertion and deletion. */
bool hash_rehash PARAMS ((Hash_table *, unsigned));
void *hash_insert PARAMS ((Hash_table *, const void *));
void *hash_delete PARAMS ((Hash_table *, const void *));
|
