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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: atom.c,v 1.4 2003/12/15 20:53:47 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 1.4 2003/12/15 20:53:47 mdw |
34 | * Add global unihash table; use universal hashing instead of CRC. |
35 | * |
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36 | * Revision 1.3 2001/01/25 21:13:15 mdw |
37 | * New function allowing an atom's length to be specified at intern time. |
38 | * |
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39 | * Revision 1.2 2001/01/21 19:04:51 mdw |
40 | * Include `crc32.h' for @CRC32@ macro. |
41 | * |
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42 | * Revision 1.1 2001/01/20 11:50:16 mdw |
43 | * Implementation of atom tables (for example, as found in X11). |
44 | * |
45 | */ |
46 | |
47 | /*----- Header files ------------------------------------------------------*/ |
48 | |
49 | #include <stdio.h> |
50 | #include <string.h> |
51 | |
52 | #include "alloc.h" |
53 | #include "atom.h" |
54 | #include "hash.h" |
55 | #include "sym.h" |
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56 | #include "unihash.h" |
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57 | |
58 | /*----- Static variables --------------------------------------------------*/ |
59 | |
60 | static atom_table atoms; |
61 | |
62 | /*----- Handy macros ------------------------------------------------------*/ |
63 | |
64 | #define ATOM_RESOLVE(t) do { \ |
65 | if (t == ATOM_GLOBAL) \ |
66 | t = &atoms; \ |
67 | if (!t->t.t.v) \ |
68 | atom_createtable(t); \ |
69 | } while (0) |
70 | |
71 | /*----- Main code ---------------------------------------------------------*/ |
72 | |
73 | /* --- @atom_createtable@ --- * |
74 | * |
75 | * Arguments: @atom_table *t@ = pointer to an atom table |
76 | * |
77 | * Returns: --- |
78 | * |
79 | * Use: Initializes an atom table. |
80 | */ |
81 | |
82 | void atom_createtable(atom_table *t) |
83 | { |
84 | sym_create(&t->t); |
85 | t->g = 0; |
86 | t->gseq = 0; |
87 | } |
88 | |
89 | /* --- @atom_destroytable@ --- * |
90 | * |
91 | * Arguments: @atom_table *t@ = pointer to an atom table |
92 | * |
93 | * Returns: --- |
94 | * |
95 | * Use: Destroys all of the atoms in an atom table. All of the atoms |
96 | * (including uninterned atoms) are freed. Any references to |
97 | * atoms from the table become invalid, and any association |
98 | * tables dependent on the atom table are unusable, except that |
99 | * they may be destroyed safely. |
100 | */ |
101 | |
102 | void atom_destroytable(atom_table *t) |
103 | { |
104 | atom *a, *aa; |
105 | |
106 | ATOM_RESOLVE(t); |
107 | for (a = (atom *)t->g; a; a = aa) { |
108 | aa = (atom *)a->b.b.next; |
109 | x_free(t->t.t.a, a); |
110 | } |
111 | sym_destroy(&t->t); |
112 | } |
113 | |
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114 | /* --- @atom_intern@, @atom_nintern@ --- * |
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115 | * |
116 | * Arguments: @atom_table *t@ = pointer to an atom table |
117 | * @const char *p@ = pointer to the string to intern |
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118 | * @size_t n@ = size of the string (for @atom_nintern) |
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119 | * |
120 | * Returns: A pointer to the atom block for the given symbol string. |
121 | * |
122 | * Use: Interns an atom, returning the atom block. The string can be |
123 | * extracted from the atom by means of the @ATOM_NAME@ macro. |
124 | */ |
125 | |
126 | atom *atom_intern(atom_table *t, const char *p) |
127 | { |
128 | atom *a; |
129 | unsigned f; |
130 | |
131 | ATOM_RESOLVE(t); |
132 | a = sym_find(&t->t, p, -1, sizeof(atom), &f); |
133 | if (!f) |
134 | a->f = 0; |
135 | return (a); |
136 | } |
137 | |
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138 | atom *atom_nintern(atom_table *t, const char *p, size_t n) |
139 | { |
140 | atom *a; |
141 | unsigned f; |
142 | |
143 | ATOM_RESOLVE(t); |
144 | a = sym_find(&t->t, p, n, sizeof(atom), &f); |
145 | if (!f) |
146 | a->f = 0; |
147 | return (a); |
148 | } |
149 | |
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150 | /* --- @atom_gensym@ --- * |
151 | * |
152 | * Arguments: @atom_table *t@ = pointer to a symbol table |
153 | * |
154 | * Returns: A pointer to a new atom block, not previously interned. |
155 | * |
156 | * Use: Creates a new, uninterned atom. This atom will never be |
157 | * returned by either @atom_intern@ or any other call to |
158 | * @atom_gensym@, while the symbol table exists. |
159 | */ |
160 | |
161 | atom *atom_gensym(atom_table *t) |
162 | { |
163 | atom *a; |
164 | char buf[64]; |
165 | size_t sz; |
166 | |
167 | ATOM_RESOLVE(t); |
168 | sprintf(buf, "*gen-%lu*", t->gseq++); |
169 | sz = strlen(buf) + 1; |
170 | a = x_alloc(t->t.t.a, sizeof(atom) + sz); |
171 | a->b.name = (char *)(a + 1); |
172 | memcpy(a->b.name, buf, sz); |
173 | a->b.len = sz; |
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174 | a->b.b.hash = UNIHASH(&unihash_global, buf, sz); |
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175 | a->f = ATOMF_GENSYM; |
176 | a->b.b.next = t->g; |
177 | t->g = &a->b.b; |
178 | return (a); |
179 | } |
180 | |
181 | /* --- @atom_name@ --- * |
182 | * |
183 | * Arguments: @atom *a@ = pointer to an atom |
184 | * |
185 | * Returns: The atom's textual name. |
186 | * |
187 | * Use: Given an atom, returns the name with which it was interned |
188 | * (or a made-up name if it was created using @gensym@. |
189 | */ |
190 | |
191 | const char *atom_name(const atom *a) { return ATOM_NAME(a); } |
192 | |
193 | /* --- @atom_len@ --- * |
194 | * |
195 | * Arguments: @atom *a@ = pointer to an atom |
196 | * |
197 | * Returns: The atom string's length. |
198 | * |
199 | * Use: Given an atom, return the length of its textual |
200 | * representation. |
201 | */ |
202 | |
203 | size_t atom_len(const atom *a) { return ATOM_LEN(a); } |
204 | |
205 | /* --- @atom_hash@ --- * |
206 | * |
207 | * Arguments: @atom *a@ = pointer to an atom |
208 | * |
209 | * Returns: The atom's hash. |
210 | * |
211 | * Use: Given an atom, returns its hash. |
212 | */ |
213 | |
214 | uint32 atom_hash(const atom *a) { return ATOM_HASH(a); } |
215 | |
216 | /* --- @atom_mkiter@ , @atom_next@ --- * |
217 | * |
218 | * Arguments: @atom_table *t@ = pointer to an atom table |
219 | * @atom_iter *i@ = pointer to an iterator structure |
220 | * |
221 | * Returns: Next atom, for @atom_next@; nothing for @atom_mkiter@. |
222 | * |
223 | * Use: Iterates over atoms (both interned and uninterned). |
224 | */ |
225 | |
226 | void atom_mkiter(atom_iter *i, atom_table *t) |
227 | { |
228 | ATOM_RESOLVE(t); |
229 | i->i.i.t = &t->t.t; |
230 | i->i.i.p = t->g; |
231 | i->i.i.i = 0; |
232 | } |
233 | |
234 | atom *atom_next(atom_iter *i) |
235 | { |
236 | atom *a; |
237 | SYM_NEXT(&i->i, a); |
238 | return (a); |
239 | } |
240 | |
241 | /*----- That's all, folks -------------------------------------------------*/ |