| 1 | /* An expandable hash tables datatype.
|
|---|
| 2 | Copyright (C) 1999-2021 Free Software Foundation, Inc.
|
|---|
| 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
|
|---|
| 17 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
|
|---|
| 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 |
|
|---|
| 39 | #include "ansidecl.h"
|
|---|
| 40 |
|
|---|
| 41 | /* The type for a hash code. */
|
|---|
| 42 | typedef unsigned int hashval_t;
|
|---|
| 43 |
|
|---|
| 44 | /* Callback function pointer types. */
|
|---|
| 45 |
|
|---|
| 46 | /* Calculate hash of a table entry. */
|
|---|
| 47 | typedef hashval_t (*htab_hash) (const void *);
|
|---|
| 48 |
|
|---|
| 49 | /* Compare a table entry with a possible entry. The entry already in
|
|---|
| 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). */
|
|---|
| 54 | typedef int (*htab_eq) (const void *, const void *);
|
|---|
| 55 |
|
|---|
| 56 | /* Cleanup function called whenever a live element is removed from
|
|---|
| 57 | the hash table. */
|
|---|
| 58 | typedef void (*htab_del) (void *);
|
|---|
| 59 |
|
|---|
| 60 | /* Function called by htab_traverse for each live element. The first
|
|---|
| 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. */
|
|---|
| 64 | typedef int (*htab_trav) (void **, void *);
|
|---|
| 65 |
|
|---|
| 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. */
|
|---|
| 70 | typedef void *(*htab_alloc) (size_t, size_t);
|
|---|
| 71 |
|
|---|
| 72 | /* We also need a free() routine. */
|
|---|
| 73 | typedef void (*htab_free) (void *);
|
|---|
| 74 |
|
|---|
| 75 | /* Memory allocation and deallocation; variants which take an extra
|
|---|
| 76 | argument. */
|
|---|
| 77 | typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t);
|
|---|
| 78 | typedef void (*htab_free_with_arg) (void *, void *);
|
|---|
| 79 |
|
|---|
| 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 |
|
|---|
| 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
|
|---|
| 92 | functions mentioned below. The size of this structure is subject to
|
|---|
| 93 | change. */
|
|---|
| 94 |
|
|---|
| 95 | struct htab {
|
|---|
| 96 | /* Pointer to hash function. */
|
|---|
| 97 | htab_hash hash_f;
|
|---|
| 98 |
|
|---|
| 99 | /* Pointer to comparison function. */
|
|---|
| 100 | htab_eq eq_f;
|
|---|
| 101 |
|
|---|
| 102 | /* Pointer to cleanup function. */
|
|---|
| 103 | htab_del del_f;
|
|---|
| 104 |
|
|---|
| 105 | /* Table itself. */
|
|---|
| 106 | void **entries;
|
|---|
| 107 |
|
|---|
| 108 | /* Current size (in entries) of the hash table. */
|
|---|
| 109 | size_t size;
|
|---|
| 110 |
|
|---|
| 111 | /* Current number of elements including also deleted elements. */
|
|---|
| 112 | size_t n_elements;
|
|---|
| 113 |
|
|---|
| 114 | /* Current number of deleted elements in the table. */
|
|---|
| 115 | size_t n_deleted;
|
|---|
| 116 |
|
|---|
| 117 | /* The following member is used for debugging. Its value is number
|
|---|
| 118 | of all calls of `htab_find_slot' for the hash table. */
|
|---|
| 119 | unsigned int searches;
|
|---|
| 120 |
|
|---|
| 121 | /* The following member is used for debugging. Its value is number
|
|---|
| 122 | of collisions fixed for time of work with the hash table. */
|
|---|
| 123 | unsigned int collisions;
|
|---|
| 124 |
|
|---|
| 125 | /* Pointers to allocate/free functions. */
|
|---|
| 126 | htab_alloc alloc_f;
|
|---|
| 127 | htab_free free_f;
|
|---|
| 128 |
|
|---|
| 129 | /* Alternate allocate/free functions, which take an extra argument. */
|
|---|
| 130 | void *alloc_arg;
|
|---|
| 131 | htab_alloc_with_arg alloc_with_arg_f;
|
|---|
| 132 | htab_free_with_arg free_with_arg_f;
|
|---|
| 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;
|
|---|
| 137 | };
|
|---|
| 138 |
|
|---|
| 139 | typedef struct htab *htab_t;
|
|---|
| 140 |
|
|---|
| 141 | /* An enum saying whether we insert into the hash table or not. */
|
|---|
| 142 | enum insert_option {NO_INSERT, INSERT};
|
|---|
| 143 |
|
|---|
| 144 | /* The prototypes of the package functions. */
|
|---|
| 145 |
|
|---|
| 146 | extern htab_t htab_create_alloc (size_t, htab_hash,
|
|---|
| 147 | htab_eq, htab_del,
|
|---|
| 148 | htab_alloc, htab_free);
|
|---|
| 149 |
|
|---|
| 150 | extern htab_t htab_create_alloc_ex (size_t, htab_hash,
|
|---|
| 151 | htab_eq, htab_del,
|
|---|
| 152 | void *, htab_alloc_with_arg,
|
|---|
| 153 | htab_free_with_arg);
|
|---|
| 154 |
|
|---|
| 155 | extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del,
|
|---|
| 156 | htab_alloc, htab_alloc, htab_free);
|
|---|
| 157 |
|
|---|
| 158 | /* Backward-compatibility functions. */
|
|---|
| 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,
|
|---|
| 164 | void *, htab_alloc_with_arg,
|
|---|
| 165 | htab_free_with_arg);
|
|---|
| 166 |
|
|---|
| 167 | extern void htab_delete (htab_t);
|
|---|
| 168 | extern void htab_empty (htab_t);
|
|---|
| 169 |
|
|---|
| 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);
|
|---|
| 175 | extern void htab_clear_slot (htab_t, void **);
|
|---|
| 176 | extern void htab_remove_elt (htab_t, const void *);
|
|---|
| 177 | extern void htab_remove_elt_with_hash (htab_t, const void *, hashval_t);
|
|---|
| 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);
|
|---|
| 185 |
|
|---|
| 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 |
|
|---|
| 192 | /* A hash function for null-terminated strings. */
|
|---|
| 193 | extern hashval_t htab_hash_string (const void *);
|
|---|
| 194 |
|
|---|
| 195 | /* An equality function for null-terminated strings. */
|
|---|
| 196 | extern int htab_eq_string (const void *, const void *);
|
|---|
| 197 |
|
|---|
| 198 | /* An iterative hash function for arbitrary data. */
|
|---|
| 199 | extern hashval_t iterative_hash (const void *, size_t, hashval_t);
|
|---|
| 200 | /* Shorthand for hashing something with an intrinsic size. */
|
|---|
| 201 | #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)
|
|---|
| 202 |
|
|---|
| 203 | #ifdef __cplusplus
|
|---|
| 204 | }
|
|---|
| 205 | #endif /* __cplusplus */
|
|---|
| 206 |
|
|---|
| 207 | #endif /* __HASHTAB_H */
|
|---|
