3 * $Id: atom.c,v 1.1 2001/01/20 11:50:16 mdw Exp $
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
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
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19 * mLib is distributed in the hope that it will be useful,
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21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.1 2001/01/20 11:50:16 mdw
34 * Implementation of atom tables (for example, as found in X11).
38 /*----- Header files ------------------------------------------------------*/
48 /*----- Static variables --------------------------------------------------*/
50 static atom_table atoms;
52 /*----- Handy macros ------------------------------------------------------*/
54 #define ATOM_RESOLVE(t) do { \
55 if (t == ATOM_GLOBAL) \
58 atom_createtable(t); \
61 /*----- Main code ---------------------------------------------------------*/
63 /* --- @atom_createtable@ --- *
65 * Arguments: @atom_table *t@ = pointer to an atom table
69 * Use: Initializes an atom table.
72 void atom_createtable(atom_table *t)
79 /* --- @atom_destroytable@ --- *
81 * Arguments: @atom_table *t@ = pointer to an atom table
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.
92 void atom_destroytable(atom_table *t)
97 for (a = (atom *)t->g; a; a = aa) {
98 aa = (atom *)a->b.b.next;
104 /* --- @atom_intern@ --- *
106 * Arguments: @atom_table *t@ = pointer to an atom table
107 * @const char *p@ = pointer to the string to intern
109 * Returns: A pointer to the atom block for the given symbol string.
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.
115 atom *atom_intern(atom_table *t, const char *p)
121 a = sym_find(&t->t, p, -1, sizeof(atom), &f);
127 /* --- @atom_gensym@ --- *
129 * Arguments: @atom_table *t@ = pointer to a symbol table
131 * Returns: A pointer to a new atom block, not previously interned.
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.
138 atom *atom_gensym(atom_table *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);
151 CRC32(a->b.b.hash, 0, buf, sz);
158 /* --- @atom_name@ --- *
160 * Arguments: @atom *a@ = pointer to an atom
162 * Returns: The atom's textual name.
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@.
168 const char *atom_name(const atom *a) { return ATOM_NAME(a); }
170 /* --- @atom_len@ --- *
172 * Arguments: @atom *a@ = pointer to an atom
174 * Returns: The atom string's length.
176 * Use: Given an atom, return the length of its textual
180 size_t atom_len(const atom *a) { return ATOM_LEN(a); }
182 /* --- @atom_hash@ --- *
184 * Arguments: @atom *a@ = pointer to an atom
186 * Returns: The atom's hash.
188 * Use: Given an atom, returns its hash.
191 uint32 atom_hash(const atom *a) { return ATOM_HASH(a); }
193 /* --- @atom_mkiter@ , @atom_next@ --- *
195 * Arguments: @atom_table *t@ = pointer to an atom table
196 * @atom_iter *i@ = pointer to an iterator structure
198 * Returns: Next atom, for @atom_next@; nothing for @atom_mkiter@.
200 * Use: Iterates over atoms (both interned and uninterned).
203 void atom_mkiter(atom_iter *i, atom_table *t)
211 atom *atom_next(atom_iter *i)
218 /*----- That's all, folks -------------------------------------------------*/