dcda5944 |
1 | /* -*-c-*- |
dcda5944 |
2 | * |
3 | * Assocation tables |
4 | * |
5 | * (c) 2000 Straylight/Edgeware |
6 | */ |
7 | |
d4efbcd9 |
8 | /*----- Licensing notice --------------------------------------------------* |
dcda5944 |
9 | * |
10 | * This file is part of the mLib utilities library. |
11 | * |
12 | * mLib is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
d4efbcd9 |
16 | * |
dcda5944 |
17 | * mLib is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
d4efbcd9 |
21 | * |
dcda5944 |
22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with mLib; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
dcda5944 |
28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include "alloc.h" |
31 | #include "assoc.h" |
32 | #include "atom.h" |
33 | #include "hash.h" |
34 | |
35 | /*----- Main code ---------------------------------------------------------*/ |
36 | |
37 | /* --- @assoc_create@ --- * |
38 | * |
39 | * Arguments: @assoc_table *t@ = pointer to an association table |
40 | * |
41 | * Returns: --- |
42 | * |
43 | * Use: Creates a new association table. |
44 | */ |
45 | |
46 | void assoc_create(assoc_table *t) |
47 | { |
48 | hash_create(&t->t, SYM_INITSZ); |
49 | t->load = SYM_LIMIT(SYM_INITSZ); |
50 | } |
51 | |
52 | /* --- @assoc_destroy@ --- * |
53 | * |
54 | * Arguments: @assoc_table *t@ = pointer to an association table |
55 | * |
56 | * Returns: --- |
57 | * |
58 | * Use: Destroys an association table. |
59 | */ |
60 | |
61 | void assoc_destroy(assoc_table *t) |
62 | { |
63 | hash_iter i; |
64 | |
65 | HASH_MKITER(&i, &t->t); |
66 | for (;;) { |
67 | hash_base *p; |
68 | HASH_NEXT(&i, p); |
6f5e97ac |
69 | if (!p) |
70 | break; |
dcda5944 |
71 | x_free(t->t.a, p); |
72 | } |
73 | hash_destroy(&t->t); |
74 | } |
75 | |
76 | /* --- @assoc_find@ --- * |
77 | * |
78 | * Arguments: @assoc_table *t@ = pointer to an association table |
79 | * @atom *a@ = an atom to label the item |
80 | * @size_t sz@ = size of block to allocate |
81 | * @unsigned *f@ = pointer to `found' flag |
82 | * |
83 | * Returns: A pointer to the item located or null. |
84 | * |
85 | * Use: Looks up an atom in an association table. If the atom is |
86 | * found, the association is returned. If not, and @sz@ is |
87 | * zero, a null pointer is returned. Otherwise, a block of size |
88 | * @sz@ is allocated, its @assoc_base@ header is filled in, and |
89 | * the pointer returned. The flag @*f@ is cleared if the item |
90 | * couldn't be found, or set if it was. |
91 | * |
d4efbcd9 |
92 | * All the atoms used in a particular table should |
dcda5944 |
93 | */ |
94 | |
95 | void *assoc_find(assoc_table *t, atom *a, size_t sz, unsigned *f) |
96 | { |
efa99d05 |
97 | hash_base **bin = HASH_BIN(&t->t, ATOM_HASH(a)), **p; |
dcda5944 |
98 | assoc_base *q; |
99 | |
100 | /* --- Try to find the association --- */ |
101 | |
102 | for (p = bin; *p; p = &(*p)->next) { |
103 | q = (assoc_base *)*p; |
104 | if (q->a == a) { |
105 | *p = q->b.next; |
106 | q->b.next = *bin; |
107 | *bin = &q->b; |
108 | if (f) *f = 1; |
109 | return (q); |
110 | } |
111 | } |
112 | |
113 | /* --- Failed to find a match --- */ |
114 | |
115 | if (f) *f = 0; |
116 | if (!sz) return (0); |
117 | |
118 | /* --- Make a new assoication --- */ |
119 | |
120 | q = x_alloc(t->t.a, sz); |
6f5e97ac |
121 | q->a = a; |
dcda5944 |
122 | q->b.next = *bin; |
123 | q->b.hash = ATOM_HASH(a); |
124 | *bin = &q->b; |
125 | |
126 | /* --- Maybe extend the table --- */ |
127 | |
128 | if (t->load) |
129 | t->load--; |
130 | if (!t->load && hash_extend(&t->t)) |
131 | t->load = SYM_LIMIT(t->t.mask + 1); |
132 | return (q); |
133 | } |
134 | |
135 | /* --- @assoc_remove@ --- * |
136 | * |
137 | * Arguments: @assoc_table *t@ = pointer to an association table |
138 | * @void *p@ = pointer to a block to remove |
139 | * |
140 | * Returns: --- |
141 | * |
142 | * Use: Removes an association from a table. |
143 | */ |
144 | |
145 | void assoc_remove(assoc_table *t, void *p) |
146 | { |
147 | assoc_base *q = p; |
148 | hash_remove(&t->t, &q->b); |
149 | x_free(t->t.a, q); |
150 | t->load++; |
151 | } |
152 | |
153 | /* --- @assoc_mkiter@, @assoc_next@ --- * |
154 | * |
155 | * Arguments: @assoc_iter *i@ = pointer to an iterator |
156 | * @assoc_table *t@ = pointer to an association table |
157 | * |
158 | * Returns: Next association, or null, for @assoc_next@; nothing for |
159 | * @assoc_mkiter@. |
160 | * |
161 | * Use: Iterates over the associations in a table. |
162 | */ |
163 | |
164 | void assoc_mkiter(assoc_iter *i, assoc_table *t) { ASSOC_MKITER(i, t); } |
165 | void *assoc_next(assoc_iter *i) { void *p; ASSOC_NEXT(i, p); return (p); } |
166 | |
167 | /*----- That's all, folks -------------------------------------------------*/ |