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[mLib] / sym.c
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0875b58f 1/* -*-c-*-
2 *
8656dc50 3 * $Id: sym.c,v 1.15 2004/04/08 01:36:13 mdw Exp $
0875b58f 4 *
5 * Symbol table management
6 *
7 * (c) 1998 Straylight/Edgeware
8 */
9
c846879c 10/*----- Licensing notice --------------------------------------------------*
0875b58f 11 *
12 * This file is part of the mLib utilities library.
13 *
14 * mLib is free software; you can redistribute it and/or modify
c846879c 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 *
0875b58f 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
c846879c 22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
0bd98442 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.
0875b58f 28 */
29
0875b58f 30/*----- Header files ------------------------------------------------------*/
31
32/* --- ANSI headers --- */
33
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37
38/* --- Local headers --- */
39
40#include "alloc.h"
20eb516f 41#include "arena.h"
d4d7a053 42#include "bits.h"
0875b58f 43#include "exc.h"
03d53b73 44#include "hash.h"
0875b58f 45#include "sub.h"
46#include "sym.h"
6f444bda 47#include "unihash.h"
0875b58f 48
0875b58f 49/*----- Main code ---------------------------------------------------------*/
50
34b97201 51/* --- @sym_create@ --- *
0875b58f 52 *
a7a37c4a 53 * Arguments: @sym_table *t@ = symbol table to initialize
0875b58f 54 *
55 * Returns: ---
56 *
a7a37c4a 57 * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if
0875b58f 58 * there isn't enough memory.
59 */
60
34b97201 61void sym_create(sym_table *t)
0875b58f 62{
03d53b73 63 hash_create(&t->t, SYM_INITSZ);
20eb516f 64 t->s = &sub_global;
03d53b73 65 t->load = SYM_LIMIT(SYM_INITSZ);
0875b58f 66}
67
34b97201 68/* --- @sym_destroy@ --- *
0875b58f 69 *
70 * Arguments: @sym_table *t@ = pointer to symbol table in question
71 *
72 * Returns: ---
73 *
74 * Use: Destroys a symbol table, freeing all the memory it used to
75 * occupy.
76 */
77
34b97201 78void sym_destroy(sym_table *t)
0875b58f 79{
03d53b73 80 sym_iter i;
0875b58f 81
03d53b73 82 SYM_MKITER(&i, t);
83 for (;;) {
84 sym_base *p;
85 SYM_NEXT(&i, p);
86 if (!p)
87 break;
20eb516f 88 x_free(t->t.a, p);
0875b58f 89 }
03d53b73 90 hash_destroy(&t->t);
0875b58f 91}
92
93/* --- @sym_find@ --- *
94 *
95 * Arguments: @sym_table *t@ = pointer to symbol table in question
6f444bda 96 * @const char *n@ = pointer to symbol name to look up
0875b58f 97 * @long l@ = length of the name string or negative to measure
98 * @size_t sz@ = size of desired symbol object, or zero
99 * @unsigned *f@ = pointer to a flag, or null.
100 *
101 * Returns: The address of a @sym_base@ structure, or null if not found
102 * and @sz@ is zero.
103 *
104 * Use: Looks up a symbol in a given symbol table. The name is
105 * passed by the address of its first character. The length
106 * may be given, in which case the name may contain arbitrary
107 * binary data, or it may be given as a negative number, in
108 * which case the length of the name is calculated as
03d53b73 109 * @strlen(n) + 1@.
0875b58f 110 *
111 * The return value is the address of a pointer to a @sym_base@
112 * block (which may have other things on the end, as above). If
113 * the symbol could be found, the return value points to the
114 * symbol block. If the symbol wasn't there, then if @sz@ is
115 * nonzero, a new symbol is created and its address is returned;
116 * otherwise a null pointer is returned. The exception
117 * @EXC_NOMEM@ is raised if the block can't be allocated.
118 *
119 * The value of @*f@ indicates whether a new symbol entry was
120 * created: a nonzero value indicates that an old value was
121 * found.
122 */
123
124void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
125{
d4d7a053 126 uint32 hash;
127 size_t len = 0;
03d53b73 128 hash_base **bin, **p;
129 sym_base *q;
0875b58f 130
131 /* --- Find the correct bin --- */
132
ec6770dd 133 len = l < 0 ? strlen(n) : l;
6f444bda 134 hash = UNIHASH(&unihash_global, n, len);
03d53b73 135 bin = HASH_BIN(&t->t, hash);
0875b58f 136
137 /* --- Search the bin list --- */
138
03d53b73 139 for (p = bin; *p; p = &(*p)->next) {
140 q = (sym_base *)*p;
141 if (hash == q->b.hash && len == q->len && !memcmp(n, SYM_NAME(q), len)) {
142
0875b58f 143 /* --- Found a match --- *
144 *
145 * As a minor, and probably pointless, tweak, move the item to the
146 * front of its bin list.
147 */
148
03d53b73 149 (*p) = q->b.next;
150 q->b.next = *bin;
151 *bin = &q->b;
0875b58f 152
153 /* --- Return the block --- */
154
d4d7a053 155 if (f) *f = 1;
156 return (q);
0875b58f 157 }
0875b58f 158 }
159
160 /* --- Couldn't find the item there --- */
161
d4d7a053 162 if (f) *f = 0;
163 if (!sz) return (0);
0875b58f 164
2ae5376b 165 /* --- Create a new symbol block and initialize it --- *
166 *
167 * The name is attached to the end of the symbol block.
168 */
0875b58f 169
ec6770dd 170 q = x_alloc(t->t.a, sz + len + 1);
20eb516f 171 q->b.next = *bin;
172 q->b.hash = hash;
2ae5376b 173 q->name = (char *)q + sz;
174 memcpy(q->name, n, len);
ec6770dd 175 q->name[len] = 0;
20eb516f 176 q->len = len;
03d53b73 177 *bin = &q->b;
0875b58f 178
179 /* --- Consider growing the array --- */
180
03d53b73 181 if (t->load)
182 t->load--;
183 if (!t->load && hash_extend(&t->t))
2ae5376b 184 t->load = SYM_LIMIT(t->t.mask + 1);
0875b58f 185
186 /* --- Finished that, so return the new symbol block --- */
187
03d53b73 188 return (q);
0875b58f 189}
190
191/* --- @sym_remove@ --- *
192 *
c6e0eaf0 193 * Arguments: @sym_table *t@ = pointer to a symbol table object
03d53b73 194 * @void *p@ = pointer to symbol table entry
0875b58f 195 *
196 * Returns: ---
197 *
198 * Use: Removes the object from the symbol table. The space occupied
199 * by the object and its name is freed; anything else attached
200 * to the entry should already be gone by this point.
201 */
202
03d53b73 203void sym_remove(sym_table *t, void *p)
0875b58f 204{
03d53b73 205 sym_base *q = p;
206 hash_remove(&t->t, &q->b);
20eb516f 207 xfree(q);
03d53b73 208 t->load++;
0875b58f 209}
210
34b97201 211/* --- @sym_mkiter@ --- *
0875b58f 212 *
213 * Arguments: @sym_iter *i@ = pointer to an iterator object
214 * @sym_table *t@ = pointer to a symbol table object
215 *
216 * Returns: ---
217 *
218 * Use: Creates a new symbol table iterator which may be used to
219 * iterate through a symbol table.
220 */
221
03d53b73 222void sym_mkiter(sym_iter *i, sym_table *t) { SYM_MKITER(i, t); }
0875b58f 223
224/* --- @sym_next@ --- *
225 *
226 * Arguments: @sym_iter *i@ = pointer to iterator object
227 *
228 * Returns: Pointer to the next symbol found, or null when finished.
229 *
230 * Use: Returns the next symbol from the table. Symbols are not
231 * returned in any particular order.
232 */
233
234void *sym_next(sym_iter *i)
235{
03d53b73 236 void *p;
237 SYM_NEXT(i, p);
0875b58f 238 return (p);
239}
240
0875b58f 241/*----- That's all, folks -------------------------------------------------*/