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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: atom.c,v 1.3 2001/01/25 21:13:15 mdw Exp $ |
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4 | * |
5 | * Atom management |
6 | * |
7 | * (c) 2000 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
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. |
18 | * |
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. |
23 | * |
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, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: atom.c,v $ |
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33 | * Revision 1.3 2001/01/25 21:13:15 mdw |
34 | * New function allowing an atom's length to be specified at intern time. |
35 | * |
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36 | * Revision 1.2 2001/01/21 19:04:51 mdw |
37 | * Include `crc32.h' for @CRC32@ macro. |
38 | * |
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39 | * Revision 1.1 2001/01/20 11:50:16 mdw |
40 | * Implementation of atom tables (for example, as found in X11). |
41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include <stdio.h> |
47 | #include <string.h> |
48 | |
49 | #include "alloc.h" |
50 | #include "atom.h" |
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51 | #include "crc32.h" |
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52 | #include "hash.h" |
53 | #include "sym.h" |
54 | |
55 | /*----- Static variables --------------------------------------------------*/ |
56 | |
57 | static atom_table atoms; |
58 | |
59 | /*----- Handy macros ------------------------------------------------------*/ |
60 | |
61 | #define ATOM_RESOLVE(t) do { \ |
62 | if (t == ATOM_GLOBAL) \ |
63 | t = &atoms; \ |
64 | if (!t->t.t.v) \ |
65 | atom_createtable(t); \ |
66 | } while (0) |
67 | |
68 | /*----- Main code ---------------------------------------------------------*/ |
69 | |
70 | /* --- @atom_createtable@ --- * |
71 | * |
72 | * Arguments: @atom_table *t@ = pointer to an atom table |
73 | * |
74 | * Returns: --- |
75 | * |
76 | * Use: Initializes an atom table. |
77 | */ |
78 | |
79 | void atom_createtable(atom_table *t) |
80 | { |
81 | sym_create(&t->t); |
82 | t->g = 0; |
83 | t->gseq = 0; |
84 | } |
85 | |
86 | /* --- @atom_destroytable@ --- * |
87 | * |
88 | * Arguments: @atom_table *t@ = pointer to an atom table |
89 | * |
90 | * Returns: --- |
91 | * |
92 | * Use: Destroys all of the atoms in an atom table. All of the atoms |
93 | * (including uninterned atoms) are freed. Any references to |
94 | * atoms from the table become invalid, and any association |
95 | * tables dependent on the atom table are unusable, except that |
96 | * they may be destroyed safely. |
97 | */ |
98 | |
99 | void atom_destroytable(atom_table *t) |
100 | { |
101 | atom *a, *aa; |
102 | |
103 | ATOM_RESOLVE(t); |
104 | for (a = (atom *)t->g; a; a = aa) { |
105 | aa = (atom *)a->b.b.next; |
106 | x_free(t->t.t.a, a); |
107 | } |
108 | sym_destroy(&t->t); |
109 | } |
110 | |
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111 | /* --- @atom_intern@, @atom_nintern@ --- * |
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112 | * |
113 | * Arguments: @atom_table *t@ = pointer to an atom table |
114 | * @const char *p@ = pointer to the string to intern |
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115 | * @size_t n@ = size of the string (for @atom_nintern) |
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116 | * |
117 | * Returns: A pointer to the atom block for the given symbol string. |
118 | * |
119 | * Use: Interns an atom, returning the atom block. The string can be |
120 | * extracted from the atom by means of the @ATOM_NAME@ macro. |
121 | */ |
122 | |
123 | atom *atom_intern(atom_table *t, const char *p) |
124 | { |
125 | atom *a; |
126 | unsigned f; |
127 | |
128 | ATOM_RESOLVE(t); |
129 | a = sym_find(&t->t, p, -1, sizeof(atom), &f); |
130 | if (!f) |
131 | a->f = 0; |
132 | return (a); |
133 | } |
134 | |
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135 | atom *atom_nintern(atom_table *t, const char *p, size_t n) |
136 | { |
137 | atom *a; |
138 | unsigned f; |
139 | |
140 | ATOM_RESOLVE(t); |
141 | a = sym_find(&t->t, p, n, sizeof(atom), &f); |
142 | if (!f) |
143 | a->f = 0; |
144 | return (a); |
145 | } |
146 | |
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147 | /* --- @atom_gensym@ --- * |
148 | * |
149 | * Arguments: @atom_table *t@ = pointer to a symbol table |
150 | * |
151 | * Returns: A pointer to a new atom block, not previously interned. |
152 | * |
153 | * Use: Creates a new, uninterned atom. This atom will never be |
154 | * returned by either @atom_intern@ or any other call to |
155 | * @atom_gensym@, while the symbol table exists. |
156 | */ |
157 | |
158 | atom *atom_gensym(atom_table *t) |
159 | { |
160 | atom *a; |
161 | char buf[64]; |
162 | size_t sz; |
163 | |
164 | ATOM_RESOLVE(t); |
165 | sprintf(buf, "*gen-%lu*", t->gseq++); |
166 | sz = strlen(buf) + 1; |
167 | a = x_alloc(t->t.t.a, sizeof(atom) + sz); |
168 | a->b.name = (char *)(a + 1); |
169 | memcpy(a->b.name, buf, sz); |
170 | a->b.len = sz; |
171 | CRC32(a->b.b.hash, 0, buf, sz); |
172 | a->f = ATOMF_GENSYM; |
173 | a->b.b.next = t->g; |
174 | t->g = &a->b.b; |
175 | return (a); |
176 | } |
177 | |
178 | /* --- @atom_name@ --- * |
179 | * |
180 | * Arguments: @atom *a@ = pointer to an atom |
181 | * |
182 | * Returns: The atom's textual name. |
183 | * |
184 | * Use: Given an atom, returns the name with which it was interned |
185 | * (or a made-up name if it was created using @gensym@. |
186 | */ |
187 | |
188 | const char *atom_name(const atom *a) { return ATOM_NAME(a); } |
189 | |
190 | /* --- @atom_len@ --- * |
191 | * |
192 | * Arguments: @atom *a@ = pointer to an atom |
193 | * |
194 | * Returns: The atom string's length. |
195 | * |
196 | * Use: Given an atom, return the length of its textual |
197 | * representation. |
198 | */ |
199 | |
200 | size_t atom_len(const atom *a) { return ATOM_LEN(a); } |
201 | |
202 | /* --- @atom_hash@ --- * |
203 | * |
204 | * Arguments: @atom *a@ = pointer to an atom |
205 | * |
206 | * Returns: The atom's hash. |
207 | * |
208 | * Use: Given an atom, returns its hash. |
209 | */ |
210 | |
211 | uint32 atom_hash(const atom *a) { return ATOM_HASH(a); } |
212 | |
213 | /* --- @atom_mkiter@ , @atom_next@ --- * |
214 | * |
215 | * Arguments: @atom_table *t@ = pointer to an atom table |
216 | * @atom_iter *i@ = pointer to an iterator structure |
217 | * |
218 | * Returns: Next atom, for @atom_next@; nothing for @atom_mkiter@. |
219 | * |
220 | * Use: Iterates over atoms (both interned and uninterned). |
221 | */ |
222 | |
223 | void atom_mkiter(atom_iter *i, atom_table *t) |
224 | { |
225 | ATOM_RESOLVE(t); |
226 | i->i.i.t = &t->t.t; |
227 | i->i.i.p = t->g; |
228 | i->i.i.i = 0; |
229 | } |
230 | |
231 | atom *atom_next(atom_iter *i) |
232 | { |
233 | atom *a; |
234 | SYM_NEXT(&i->i, a); |
235 | return (a); |
236 | } |
237 | |
238 | /*----- That's all, folks -------------------------------------------------*/ |