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