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