chiark / gitweb /
Improve type safety for sym_iter objects.
[mLib] / sym.h
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0875b58f 1/* -*-c-*-
2 *
dc2feaa9 3 * $Id: sym.h,v 1.9 1999/08/02 16:53:48 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
30/*----- Revision history --------------------------------------------------*
31 *
32 * $Log: sym.h,v $
dc2feaa9 33 * Revision 1.9 1999/08/02 16:53:48 mdw
34 * Improve type safety for sym_iter objects.
35 *
03d53b73 36 * Revision 1.8 1999/08/02 14:45:48 mdw
37 * Break low-level hashtable code out from sym.
38 *
d4d7a053 39 * Revision 1.7 1999/06/01 09:49:33 mdw
40 * Allow things to be looked up by just their caller-supplied hashes. This
41 * actually needs to be thought through better.
42 *
34b97201 43 * Revision 1.6 1999/05/26 21:08:31 mdw
44 * Rename symbols in line with newer conventions.
45 *
8c6d948b 46 * Revision 1.5 1999/05/13 22:48:37 mdw
47 * Change `-ise' to `-ize' throughout.
48 *
0bd98442 49 * Revision 1.4 1999/05/06 19:51:35 mdw
50 * Reformatted the LGPL notice a little bit.
51 *
c846879c 52 * Revision 1.3 1999/05/05 18:50:31 mdw
53 * Change licensing conditions to LGPL.
54 *
a5d14ede 55 * Revision 1.2 1998/11/26 19:27:34 mdw
56 * Move SYM_NAME into the header file. Fix bugs.
57 *
58 * Revision 1.1.1.1 1998/06/17 23:44:42 mdw
59 * Initial version of mLib
0875b58f 60 *
61 */
62
63#ifndef SYM_H
64#define SYM_H
65
66#ifdef __cplusplus
67 extern "C" {
68#endif
69
70/*----- Required headers --------------------------------------------------*/
71
72#include <stddef.h>
73
d4d7a053 74#ifndef BITS_H
75# include "bits.h"
76#endif
77
03d53b73 78#ifndef HASH_H
79# include "hash.h"
80#endif
81
0875b58f 82/*----- Type definitions --------------------------------------------------*/
83
84/* --- Symbol table --- *
85 *
86 * A @sym_table@ contains the information needed to manage a symbol table.
87 * Users shouldn't fiddle with this information directly, but it needs to be
88 * here so that objects of the correct type can be created.
89 */
90
91typedef struct sym_table {
03d53b73 92 hash_table t;
93 size_t load;
0875b58f 94} sym_table;
95
96/* --- A symbol table entry --- *
97 *
98 * I don't care what actually gets stored in symbol entries because I don't
99 * create them: that's the responsibility of my client. All I care about
100 * here is that whatever gets passed to me is a structure whose first member
101 * is a @sym_base@. The ANSI guarantees about structure layout are
102 * sufficient to allow me to manipulate such objects.
103 */
104
105#define SYM_BUFSZ 16 /* Size of local string buffer */
106
107typedef struct sym_base {
03d53b73 108 hash_base b;
0875b58f 109 union {
110 char *p; /* Pointer to name string */
111 char b[SYM_BUFSZ]; /* Buffer containing a short name */
112 } name; /* Name of this symbol */
113 size_t len; /* Length of the symbol's name */
114} sym_base;
115
a5d14ede 116/* --- A macro to pick a symbol's name out from the mess --- */
117
118#define SYM_NAME(sy) \
119 (((sym_base *)(sy))->len > SYM_BUFSZ ? \
120 ((sym_base *)(sy))->name.p : \
121 ((sym_base *)(sy))->name.b)
122
0875b58f 123/* --- An iterator block --- */
124
dc2feaa9 125typedef struct { hash_iter i; } sym_iter;
0875b58f 126
127/*----- External functions ------------------------------------------------*/
128
34b97201 129/* --- @sym_create@ --- *
0875b58f 130 *
8c6d948b 131 * Arguments: @sym_table *t@ = symbol table to initialize
0875b58f 132 *
133 * Returns: ---
134 *
8c6d948b 135 * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if
0875b58f 136 * there isn't enough memory.
137 */
138
34b97201 139extern void sym_create(sym_table */*t*/);
0875b58f 140
34b97201 141/* --- @sym_destroy@ --- *
0875b58f 142 *
143 * Arguments: @sym_table *t@ = pointer to symbol table in question
144 *
145 * Returns: ---
146 *
147 * Use: Destroys a symbol table, freeing all the memory it used to
148 * occupy.
149 */
150
34b97201 151extern void sym_destroy(sym_table */*t*/);
0875b58f 152
153/* --- @sym_find@ --- *
154 *
155 * Arguments: @sym_table *t@ = pointer to symbol table in question
156 * @const char *n@ = pointer to symbol table to look up
157 * @long l@ = length of the name string or negative to measure
158 * @size_t sz@ = size of desired symbol object, or zero
159 * @unsigned *f@ = pointer to a flag, or null.
160 *
161 * Returns: The address of a @sym_base@ structure, or null if not found
162 * and @sz@ is zero.
163 *
164 * Use: Looks up a symbol in a given symbol table. The name is
165 * passed by the address of its first character. The length
166 * may be given, in which case the name may contain arbitrary
167 * binary data, or it may be given as a negative number, in
168 * which case the length of the name is calculated as
03d53b73 169 * @strlen(n) + 1@.
0875b58f 170 *
171 * The return value is the address of a pointer to a @sym_base@
172 * block (which may have other things on the end, as above). If
173 * the symbol could be found, the return value points to the
174 * symbol block. If the symbol wasn't there, then if @sz@ is
175 * nonzero, a new symbol is created and its address is returned;
176 * otherwise a null pointer is returned. The exception
177 * @EXC_NOMEM@ is raised if the block can't be allocated.
178 *
179 * The value of @*f@ indicates whether a new symbol entry was
180 * created: a nonzero value indicates that an old value was
181 * found.
182 */
183
184extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/,
185 size_t /*sz*/, unsigned */*f*/);
186
187/* --- @sym_remove@ --- *
188 *
189 * Arguments: @sym_table *i@ = pointer to a symbol table object
190 * @void *b@ = pointer to symbol table entry
191 *
192 * Returns: ---
193 *
194 * Use: Removes the object from the symbol table. The space occupied
195 * by the object and its name is freed; anything else attached
196 * to the entry should already be gone by this point.
197 */
198
199extern void sym_remove(sym_table */*t*/, void */*b*/);
200
34b97201 201/* --- @sym_mkiter@ --- *
0875b58f 202 *
203 * Arguments: @sym_iter *i@ = pointer to an iterator object
204 * @sym_table *t@ = pointer to a symbol table object
205 *
206 * Returns: ---
207 *
208 * Use: Creates a new symbol table iterator which may be used to
209 * iterate through a symbol table.
210 */
211
dc2feaa9 212#define SYM_MKITER(i_, t_) HASH_MKITER(&(i_)->i, &(t_)->t)
03d53b73 213
34b97201 214extern void sym_mkiter(sym_iter */*i*/, sym_table */*t*/);
0875b58f 215
216/* --- @sym_next@ --- *
217 *
218 * Arguments: @sym_iter *i@ = pointer to iterator object
219 *
220 * Returns: Pointer to the next symbol found, or null when finished.
221 *
222 * Use: Returns the next symbol from the table. Symbols are not
223 * returned in any particular order.
224 */
225
dc2feaa9 226#define SYM_NEXT(i_, p) do { \
03d53b73 227 hash_base *_q; \
dc2feaa9 228 HASH_NEXT(&(i_)->i, _q); \
03d53b73 229 (p) = (void *)_q; \
230} while (0)
231
0875b58f 232extern void *sym_next(sym_iter */*i*/);
233
234/*----- That's all, folks -------------------------------------------------*/
235
236#ifdef __cplusplus
237 }
238#endif
239
240#endif