Commit | Line | Data |
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dcda5944 | 1 | /* -*-c-*- |
2 | * | |
dcda5944 | 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 | * | |
f61b7e2c MW |
92 | * All the atoms used in a particular table should come from the |
93 | * same atom table. | |
dcda5944 | 94 | */ |
95 | ||
96 | void *assoc_find(assoc_table *t, atom *a, size_t sz, unsigned *f) | |
97 | { | |
efa99d05 | 98 | hash_base **bin = HASH_BIN(&t->t, ATOM_HASH(a)), **p; |
dcda5944 | 99 | assoc_base *q; |
100 | ||
101 | /* --- Try to find the association --- */ | |
102 | ||
103 | for (p = bin; *p; p = &(*p)->next) { | |
104 | q = (assoc_base *)*p; | |
105 | if (q->a == a) { | |
106 | *p = q->b.next; | |
107 | q->b.next = *bin; | |
108 | *bin = &q->b; | |
109 | if (f) *f = 1; | |
110 | return (q); | |
111 | } | |
112 | } | |
113 | ||
114 | /* --- Failed to find a match --- */ | |
115 | ||
116 | if (f) *f = 0; | |
117 | if (!sz) return (0); | |
118 | ||
f61b7e2c | 119 | /* --- Make a new association --- */ |
dcda5944 | 120 | |
121 | q = x_alloc(t->t.a, sz); | |
6f5e97ac | 122 | q->a = a; |
dcda5944 | 123 | q->b.next = *bin; |
124 | q->b.hash = ATOM_HASH(a); | |
125 | *bin = &q->b; | |
126 | ||
127 | /* --- Maybe extend the table --- */ | |
128 | ||
129 | if (t->load) | |
130 | t->load--; | |
131 | if (!t->load && hash_extend(&t->t)) | |
132 | t->load = SYM_LIMIT(t->t.mask + 1); | |
133 | return (q); | |
134 | } | |
135 | ||
136 | /* --- @assoc_remove@ --- * | |
137 | * | |
138 | * Arguments: @assoc_table *t@ = pointer to an association table | |
139 | * @void *p@ = pointer to a block to remove | |
140 | * | |
141 | * Returns: --- | |
142 | * | |
143 | * Use: Removes an association from a table. | |
144 | */ | |
145 | ||
146 | void assoc_remove(assoc_table *t, void *p) | |
147 | { | |
148 | assoc_base *q = p; | |
149 | hash_remove(&t->t, &q->b); | |
150 | x_free(t->t.a, q); | |
151 | t->load++; | |
152 | } | |
153 | ||
154 | /* --- @assoc_mkiter@, @assoc_next@ --- * | |
155 | * | |
156 | * Arguments: @assoc_iter *i@ = pointer to an iterator | |
157 | * @assoc_table *t@ = pointer to an association table | |
158 | * | |
159 | * Returns: Next association, or null, for @assoc_next@; nothing for | |
160 | * @assoc_mkiter@. | |
161 | * | |
162 | * Use: Iterates over the associations in a table. | |
163 | */ | |
164 | ||
165 | void assoc_mkiter(assoc_iter *i, assoc_table *t) { ASSOC_MKITER(i, t); } | |
166 | void *assoc_next(assoc_iter *i) { void *p; ASSOC_NEXT(i, p); return (p); } | |
167 | ||
168 | /*----- That's all, folks -------------------------------------------------*/ |