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a6ee63bb | 1 | /* An expandable hash tables datatype. |
99dee823 | 2 | Copyright (C) 1999-2021 Free Software Foundation, Inc. |
a6ee63bb VM |
3 | Contributed by Vladimir Makarov (vmakarov@cygnus.com). |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 2 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program; if not, write to the Free Software | |
d6d47ea0 | 17 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ |
a6ee63bb VM |
18 | |
19 | /* This package implements basic hash table functionality. It is possible | |
20 | to search for an entry, create an entry and destroy an entry. | |
21 | ||
22 | Elements in the table are generic pointers. | |
23 | ||
24 | The size of the table is not fixed; if the occupancy of the table | |
25 | grows too high the hash table will be expanded. | |
26 | ||
27 | The abstract data implementation is based on generalized Algorithm D | |
28 | from Knuth's book "The art of computer programming". Hash table is | |
29 | expanded by creation of new hash table and transferring elements from | |
30 | the old table to the new table. */ | |
31 | ||
32 | #ifndef __HASHTAB_H__ | |
33 | #define __HASHTAB_H__ | |
34 | ||
35 | #ifdef __cplusplus | |
36 | extern "C" { | |
37 | #endif /* __cplusplus */ | |
38 | ||
8ff82b06 | 39 | #include "ansidecl.h" |
a6ee63bb | 40 | |
b13eb66b MM |
41 | /* The type for a hash code. */ |
42 | typedef unsigned int hashval_t; | |
43 | ||
5194cf08 | 44 | /* Callback function pointer types. */ |
a6ee63bb | 45 | |
5194cf08 | 46 | /* Calculate hash of a table entry. */ |
6da879de | 47 | typedef hashval_t (*htab_hash) (const void *); |
5194cf08 ZW |
48 | |
49 | /* Compare a table entry with a possible entry. The entry already in | |
8c5d513f BS |
50 | the table always comes first, so the second element can be of a |
51 | different type (but in this case htab_find and htab_find_slot | |
52 | cannot be used; instead the variants that accept a hash value | |
53 | must be used). */ | |
6da879de | 54 | typedef int (*htab_eq) (const void *, const void *); |
5194cf08 | 55 | |
5dc9cffd ZW |
56 | /* Cleanup function called whenever a live element is removed from |
57 | the hash table. */ | |
6da879de | 58 | typedef void (*htab_del) (void *); |
5dc9cffd | 59 | |
5194cf08 | 60 | /* Function called by htab_traverse for each live element. The first |
8c5d513f BS |
61 | arg is the slot of the element (which can be passed to htab_clear_slot |
62 | if desired), the second arg is the auxiliary pointer handed to | |
63 | htab_traverse. Return 1 to continue scan, 0 to stop. */ | |
6da879de | 64 | typedef int (*htab_trav) (void **, void *); |
a6ee63bb | 65 | |
e2500fed GK |
66 | /* Memory-allocation function, with the same functionality as calloc(). |
67 | Iff it returns NULL, the hash table implementation will pass an error | |
68 | code back to the user, so if your code doesn't handle errors, | |
69 | best if you use xcalloc instead. */ | |
8766be86 | 70 | typedef void *(*htab_alloc) (size_t, size_t); |
e2500fed GK |
71 | |
72 | /* We also need a free() routine. */ | |
8766be86 | 73 | typedef void (*htab_free) (void *); |
e2500fed | 74 | |
74828682 DJ |
75 | /* Memory allocation and deallocation; variants which take an extra |
76 | argument. */ | |
8766be86 | 77 | typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t); |
6da879de | 78 | typedef void (*htab_free_with_arg) (void *, void *); |
74828682 | 79 | |
a3648cfc DB |
80 | /* This macro defines reserved value for empty table entry. */ |
81 | ||
82 | #define HTAB_EMPTY_ENTRY ((PTR) 0) | |
83 | ||
84 | /* This macro defines reserved value for table entry which contained | |
85 | a deleted element. */ | |
86 | ||
87 | #define HTAB_DELETED_ENTRY ((PTR) 1) | |
88 | ||
a6ee63bb VM |
89 | /* Hash tables are of the following type. The structure |
90 | (implementation) of this type is not needed for using the hash | |
91 | tables. All work with hash table should be executed only through | |
74828682 DJ |
92 | functions mentioned below. The size of this structure is subject to |
93 | change. */ | |
a6ee63bb | 94 | |
63f5d5b8 | 95 | struct htab { |
5194cf08 ZW |
96 | /* Pointer to hash function. */ |
97 | htab_hash hash_f; | |
98 | ||
5dc9cffd | 99 | /* Pointer to comparison function. */ |
5194cf08 ZW |
100 | htab_eq eq_f; |
101 | ||
5dc9cffd ZW |
102 | /* Pointer to cleanup function. */ |
103 | htab_del del_f; | |
104 | ||
105 | /* Table itself. */ | |
63f5d5b8 | 106 | void **entries; |
5194cf08 | 107 | |
228c46db | 108 | /* Current size (in entries) of the hash table. */ |
a6ee63bb | 109 | size_t size; |
5194cf08 | 110 | |
228c46db | 111 | /* Current number of elements including also deleted elements. */ |
5194cf08 ZW |
112 | size_t n_elements; |
113 | ||
228c46db | 114 | /* Current number of deleted elements in the table. */ |
5194cf08 ZW |
115 | size_t n_deleted; |
116 | ||
a6ee63bb | 117 | /* The following member is used for debugging. Its value is number |
5194cf08 ZW |
118 | of all calls of `htab_find_slot' for the hash table. */ |
119 | unsigned int searches; | |
120 | ||
a6ee63bb VM |
121 | /* The following member is used for debugging. Its value is number |
122 | of collisions fixed for time of work with the hash table. */ | |
5194cf08 | 123 | unsigned int collisions; |
917ccc05 DD |
124 | |
125 | /* Pointers to allocate/free functions. */ | |
126 | htab_alloc alloc_f; | |
127 | htab_free free_f; | |
74828682 DJ |
128 | |
129 | /* Alternate allocate/free functions, which take an extra argument. */ | |
63f5d5b8 | 130 | void *alloc_arg; |
74828682 DJ |
131 | htab_alloc_with_arg alloc_with_arg_f; |
132 | htab_free_with_arg free_with_arg_f; | |
228c46db RH |
133 | |
134 | /* Current size (in entries) of the hash table, as an index into the | |
135 | table of primes. */ | |
136 | unsigned int size_prime_index; | |
5194cf08 | 137 | }; |
a6ee63bb | 138 | |
5194cf08 | 139 | typedef struct htab *htab_t; |
a6ee63bb | 140 | |
e38992e8 RK |
141 | /* An enum saying whether we insert into the hash table or not. */ |
142 | enum insert_option {NO_INSERT, INSERT}; | |
143 | ||
a6ee63bb VM |
144 | /* The prototypes of the package functions. */ |
145 | ||
6da879de GDR |
146 | extern htab_t htab_create_alloc (size_t, htab_hash, |
147 | htab_eq, htab_del, | |
148 | htab_alloc, htab_free); | |
e2500fed | 149 | |
6da879de GDR |
150 | extern htab_t htab_create_alloc_ex (size_t, htab_hash, |
151 | htab_eq, htab_del, | |
8766be86 | 152 | void *, htab_alloc_with_arg, |
6da879de | 153 | htab_free_with_arg); |
74828682 | 154 | |
a9429e29 LB |
155 | extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del, |
156 | htab_alloc, htab_alloc, htab_free); | |
157 | ||
045b3a49 | 158 | /* Backward-compatibility functions. */ |
6da879de GDR |
159 | extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del); |
160 | extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del); | |
161 | ||
162 | extern void htab_set_functions_ex (htab_t, htab_hash, | |
163 | htab_eq, htab_del, | |
8766be86 | 164 | void *, htab_alloc_with_arg, |
6da879de GDR |
165 | htab_free_with_arg); |
166 | ||
167 | extern void htab_delete (htab_t); | |
168 | extern void htab_empty (htab_t); | |
169 | ||
8766be86 KG |
170 | extern void * htab_find (htab_t, const void *); |
171 | extern void ** htab_find_slot (htab_t, const void *, enum insert_option); | |
172 | extern void * htab_find_with_hash (htab_t, const void *, hashval_t); | |
173 | extern void ** htab_find_slot_with_hash (htab_t, const void *, | |
174 | hashval_t, enum insert_option); | |
6da879de | 175 | extern void htab_clear_slot (htab_t, void **); |
5f44a434 AB |
176 | extern void htab_remove_elt (htab_t, const void *); |
177 | extern void htab_remove_elt_with_hash (htab_t, const void *, hashval_t); | |
6da879de GDR |
178 | |
179 | extern void htab_traverse (htab_t, htab_trav, void *); | |
180 | extern void htab_traverse_noresize (htab_t, htab_trav, void *); | |
181 | ||
182 | extern size_t htab_size (htab_t); | |
183 | extern size_t htab_elements (htab_t); | |
184 | extern double htab_collisions (htab_t); | |
a6ee63bb | 185 | |
18a94a2f MM |
186 | /* A hash function for pointers. */ |
187 | extern htab_hash htab_hash_pointer; | |
188 | ||
189 | /* An equality function for pointers. */ | |
190 | extern htab_eq htab_eq_pointer; | |
191 | ||
457f49df | 192 | /* A hash function for null-terminated strings. */ |
8766be86 | 193 | extern hashval_t htab_hash_string (const void *); |
457f49df | 194 | |
77380c68 TT |
195 | /* An equality function for null-terminated strings. */ |
196 | extern int htab_eq_string (const void *, const void *); | |
197 | ||
5cc5a0d0 | 198 | /* An iterative hash function for arbitrary data. */ |
8766be86 | 199 | extern hashval_t iterative_hash (const void *, size_t, hashval_t); |
5cc5a0d0 | 200 | /* Shorthand for hashing something with an intrinsic size. */ |
9d70d418 | 201 | #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT) |
5cc5a0d0 | 202 | |
a6ee63bb VM |
203 | #ifdef __cplusplus |
204 | } | |
205 | #endif /* __cplusplus */ | |
206 | ||
207 | #endif /* __HASHTAB_H */ |