b8f5df02ae17d932cb17b6f34f0ffc1bc7d93475
3 * $Id: assoc.c,v 1.3 2001/01/25 21:12:38 mdw Exp $
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2001/01/25 21:12:38 mdw
34 * Use @ATOM_HASH@ rather than digging in the @atom@ structure.
36 * Revision 1.2 2001/01/21 19:04:59 mdw
39 * Revision 1.1 2001/01/20 11:50:58 mdw
40 * Hash tables indexed by atoms, to avoid expense of hashing keys on each
41 * lookup, and to reduce storage used by key texts.
45 /*----- Header files ------------------------------------------------------*/
52 /*----- Main code ---------------------------------------------------------*/
54 /* --- @assoc_create@ --- *
56 * Arguments: @assoc_table *t@ = pointer to an association table
60 * Use: Creates a new association table.
63 void assoc_create(assoc_table
*t
)
65 hash_create(&t
->t
, SYM_INITSZ
);
66 t
->load
= SYM_LIMIT(SYM_INITSZ
);
69 /* --- @assoc_destroy@ --- *
71 * Arguments: @assoc_table *t@ = pointer to an association table
75 * Use: Destroys an association table.
78 void assoc_destroy(assoc_table
*t
)
82 HASH_MKITER(&i
, &t
->t
);
93 /* --- @assoc_find@ --- *
95 * Arguments: @assoc_table *t@ = pointer to an association table
96 * @atom *a@ = an atom to label the item
97 * @size_t sz@ = size of block to allocate
98 * @unsigned *f@ = pointer to `found' flag
100 * Returns: A pointer to the item located or null.
102 * Use: Looks up an atom in an association table. If the atom is
103 * found, the association is returned. If not, and @sz@ is
104 * zero, a null pointer is returned. Otherwise, a block of size
105 * @sz@ is allocated, its @assoc_base@ header is filled in, and
106 * the pointer returned. The flag @*f@ is cleared if the item
107 * couldn't be found, or set if it was.
109 * All the atoms used in a particular table should
112 void *assoc_find(assoc_table
*t
, atom
*a
, size_t sz
, unsigned *f
)
114 hash_base
**bin
= HASH_BIN(&t
->t
, ATOM_HASH(a
)), **p
;
117 /* --- Try to find the association --- */
119 for (p
= bin
; *p
; p
= &(*p
)->next
) {
120 q
= (assoc_base
*)*p
;
130 /* --- Failed to find a match --- */
135 /* --- Make a new assoication --- */
137 q
= x_alloc(t
->t
.a
, sz
);
140 q
->b
.hash
= ATOM_HASH(a
);
143 /* --- Maybe extend the table --- */
147 if (!t
->load
&& hash_extend(&t
->t
))
148 t
->load
= SYM_LIMIT(t
->t
.mask
+ 1);
152 /* --- @assoc_remove@ --- *
154 * Arguments: @assoc_table *t@ = pointer to an association table
155 * @void *p@ = pointer to a block to remove
159 * Use: Removes an association from a table.
162 void assoc_remove(assoc_table
*t
, void *p
)
165 hash_remove(&t
->t
, &q
->b
);
170 /* --- @assoc_mkiter@, @assoc_next@ --- *
172 * Arguments: @assoc_iter *i@ = pointer to an iterator
173 * @assoc_table *t@ = pointer to an association table
175 * Returns: Next association, or null, for @assoc_next@; nothing for
178 * Use: Iterates over the associations in a table.
181 void assoc_mkiter(assoc_iter
*i
, assoc_table
*t
) { ASSOC_MKITER(i
, t
); }
182 void *assoc_next(assoc_iter
*i
) { void *p
; ASSOC_NEXT(i
, p
); return (p
); }
184 /*----- That's all, folks -------------------------------------------------*/