| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: atom.c,v 1.3 2001/01/25 21:13:15 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 1.3 2001/01/25 21:13:15 mdw |
| 34 | * New function allowing an atom's length to be specified at intern time. |
| 35 | * |
| 36 | * Revision 1.2 2001/01/21 19:04:51 mdw |
| 37 | * Include `crc32.h' for @CRC32@ macro. |
| 38 | * |
| 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" |
| 51 | #include "crc32.h" |
| 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 | |
| 111 | /* --- @atom_intern@, @atom_nintern@ --- * |
| 112 | * |
| 113 | * Arguments: @atom_table *t@ = pointer to an atom table |
| 114 | * @const char *p@ = pointer to the string to intern |
| 115 | * @size_t n@ = size of the string (for @atom_nintern) |
| 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 | |
| 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 | |
| 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 -------------------------------------------------*/ |