c1c43500 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: atom.c,v 1.1 2001/01/20 11:50:16 mdw Exp $ |
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 $ |
33 | * Revision 1.1 2001/01/20 11:50:16 mdw |
34 | * Implementation of atom tables (for example, as found in X11). |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include <stdio.h> |
41 | #include <string.h> |
42 | |
43 | #include "alloc.h" |
44 | #include "atom.h" |
45 | #include "hash.h" |
46 | #include "sym.h" |
47 | |
48 | /*----- Static variables --------------------------------------------------*/ |
49 | |
50 | static atom_table atoms; |
51 | |
52 | /*----- Handy macros ------------------------------------------------------*/ |
53 | |
54 | #define ATOM_RESOLVE(t) do { \ |
55 | if (t == ATOM_GLOBAL) \ |
56 | t = &atoms; \ |
57 | if (!t->t.t.v) \ |
58 | atom_createtable(t); \ |
59 | } while (0) |
60 | |
61 | /*----- Main code ---------------------------------------------------------*/ |
62 | |
63 | /* --- @atom_createtable@ --- * |
64 | * |
65 | * Arguments: @atom_table *t@ = pointer to an atom table |
66 | * |
67 | * Returns: --- |
68 | * |
69 | * Use: Initializes an atom table. |
70 | */ |
71 | |
72 | void atom_createtable(atom_table *t) |
73 | { |
74 | sym_create(&t->t); |
75 | t->g = 0; |
76 | t->gseq = 0; |
77 | } |
78 | |
79 | /* --- @atom_destroytable@ --- * |
80 | * |
81 | * Arguments: @atom_table *t@ = pointer to an atom table |
82 | * |
83 | * Returns: --- |
84 | * |
85 | * Use: Destroys all of the atoms in an atom table. All of the atoms |
86 | * (including uninterned atoms) are freed. Any references to |
87 | * atoms from the table become invalid, and any association |
88 | * tables dependent on the atom table are unusable, except that |
89 | * they may be destroyed safely. |
90 | */ |
91 | |
92 | void atom_destroytable(atom_table *t) |
93 | { |
94 | atom *a, *aa; |
95 | |
96 | ATOM_RESOLVE(t); |
97 | for (a = (atom *)t->g; a; a = aa) { |
98 | aa = (atom *)a->b.b.next; |
99 | x_free(t->t.t.a, a); |
100 | } |
101 | sym_destroy(&t->t); |
102 | } |
103 | |
104 | /* --- @atom_intern@ --- * |
105 | * |
106 | * Arguments: @atom_table *t@ = pointer to an atom table |
107 | * @const char *p@ = pointer to the string to intern |
108 | * |
109 | * Returns: A pointer to the atom block for the given symbol string. |
110 | * |
111 | * Use: Interns an atom, returning the atom block. The string can be |
112 | * extracted from the atom by means of the @ATOM_NAME@ macro. |
113 | */ |
114 | |
115 | atom *atom_intern(atom_table *t, const char *p) |
116 | { |
117 | atom *a; |
118 | unsigned f; |
119 | |
120 | ATOM_RESOLVE(t); |
121 | a = sym_find(&t->t, p, -1, sizeof(atom), &f); |
122 | if (!f) |
123 | a->f = 0; |
124 | return (a); |
125 | } |
126 | |
127 | /* --- @atom_gensym@ --- * |
128 | * |
129 | * Arguments: @atom_table *t@ = pointer to a symbol table |
130 | * |
131 | * Returns: A pointer to a new atom block, not previously interned. |
132 | * |
133 | * Use: Creates a new, uninterned atom. This atom will never be |
134 | * returned by either @atom_intern@ or any other call to |
135 | * @atom_gensym@, while the symbol table exists. |
136 | */ |
137 | |
138 | atom *atom_gensym(atom_table *t) |
139 | { |
140 | atom *a; |
141 | char buf[64]; |
142 | size_t sz; |
143 | |
144 | ATOM_RESOLVE(t); |
145 | sprintf(buf, "*gen-%lu*", t->gseq++); |
146 | sz = strlen(buf) + 1; |
147 | a = x_alloc(t->t.t.a, sizeof(atom) + sz); |
148 | a->b.name = (char *)(a + 1); |
149 | memcpy(a->b.name, buf, sz); |
150 | a->b.len = sz; |
151 | CRC32(a->b.b.hash, 0, buf, sz); |
152 | a->f = ATOMF_GENSYM; |
153 | a->b.b.next = t->g; |
154 | t->g = &a->b.b; |
155 | return (a); |
156 | } |
157 | |
158 | /* --- @atom_name@ --- * |
159 | * |
160 | * Arguments: @atom *a@ = pointer to an atom |
161 | * |
162 | * Returns: The atom's textual name. |
163 | * |
164 | * Use: Given an atom, returns the name with which it was interned |
165 | * (or a made-up name if it was created using @gensym@. |
166 | */ |
167 | |
168 | const char *atom_name(const atom *a) { return ATOM_NAME(a); } |
169 | |
170 | /* --- @atom_len@ --- * |
171 | * |
172 | * Arguments: @atom *a@ = pointer to an atom |
173 | * |
174 | * Returns: The atom string's length. |
175 | * |
176 | * Use: Given an atom, return the length of its textual |
177 | * representation. |
178 | */ |
179 | |
180 | size_t atom_len(const atom *a) { return ATOM_LEN(a); } |
181 | |
182 | /* --- @atom_hash@ --- * |
183 | * |
184 | * Arguments: @atom *a@ = pointer to an atom |
185 | * |
186 | * Returns: The atom's hash. |
187 | * |
188 | * Use: Given an atom, returns its hash. |
189 | */ |
190 | |
191 | uint32 atom_hash(const atom *a) { return ATOM_HASH(a); } |
192 | |
193 | /* --- @atom_mkiter@ , @atom_next@ --- * |
194 | * |
195 | * Arguments: @atom_table *t@ = pointer to an atom table |
196 | * @atom_iter *i@ = pointer to an iterator structure |
197 | * |
198 | * Returns: Next atom, for @atom_next@; nothing for @atom_mkiter@. |
199 | * |
200 | * Use: Iterates over atoms (both interned and uninterned). |
201 | */ |
202 | |
203 | void atom_mkiter(atom_iter *i, atom_table *t) |
204 | { |
205 | ATOM_RESOLVE(t); |
206 | i->i.i.t = &t->t.t; |
207 | i->i.i.p = t->g; |
208 | i->i.i.i = 0; |
209 | } |
210 | |
211 | atom *atom_next(atom_iter *i) |
212 | { |
213 | atom *a; |
214 | SYM_NEXT(&i->i, a); |
215 | return (a); |
216 | } |
217 | |
218 | /*----- That's all, folks -------------------------------------------------*/ |