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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: sym.h,v 1.3 1999/05/05 18:50:31 mdw Exp $ |
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4 | * |
5 | * Symbol table management |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
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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 | * |
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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 |
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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 Software |
26 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: sym.h,v $ |
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32 | * Revision 1.3 1999/05/05 18:50:31 mdw |
33 | * Change licensing conditions to LGPL. |
34 | * |
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35 | * Revision 1.2 1998/11/26 19:27:34 mdw |
36 | * Move SYM_NAME into the header file. Fix bugs. |
37 | * |
38 | * Revision 1.1.1.1 1998/06/17 23:44:42 mdw |
39 | * Initial version of mLib |
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40 | * |
41 | */ |
42 | |
43 | #ifndef SYM_H |
44 | #define SYM_H |
45 | |
46 | #ifdef __cplusplus |
47 | extern "C" { |
48 | #endif |
49 | |
50 | /*----- Required headers --------------------------------------------------*/ |
51 | |
52 | #include <stddef.h> |
53 | |
54 | /*----- Type definitions --------------------------------------------------*/ |
55 | |
56 | /* --- Symbol table --- * |
57 | * |
58 | * A @sym_table@ contains the information needed to manage a symbol table. |
59 | * Users shouldn't fiddle with this information directly, but it needs to be |
60 | * here so that objects of the correct type can be created. |
61 | */ |
62 | |
63 | typedef struct sym_table { |
64 | unsigned long mask; /* Bit mask for hashing purposes */ |
65 | size_t c; /* Down counter for growing table */ |
66 | struct sym_base **a; /* Array of hash bins */ |
67 | } sym_table; |
68 | |
69 | /* --- A symbol table entry --- * |
70 | * |
71 | * I don't care what actually gets stored in symbol entries because I don't |
72 | * create them: that's the responsibility of my client. All I care about |
73 | * here is that whatever gets passed to me is a structure whose first member |
74 | * is a @sym_base@. The ANSI guarantees about structure layout are |
75 | * sufficient to allow me to manipulate such objects. |
76 | */ |
77 | |
78 | #define SYM_BUFSZ 16 /* Size of local string buffer */ |
79 | |
80 | typedef struct sym_base { |
81 | struct sym_base *next; /* Next symbol in hash bin */ |
82 | unsigned long hash; /* Hash value for symbol's name */ |
83 | union { |
84 | char *p; /* Pointer to name string */ |
85 | char b[SYM_BUFSZ]; /* Buffer containing a short name */ |
86 | } name; /* Name of this symbol */ |
87 | size_t len; /* Length of the symbol's name */ |
88 | } sym_base; |
89 | |
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90 | /* --- A macro to pick a symbol's name out from the mess --- */ |
91 | |
92 | #define SYM_NAME(sy) \ |
93 | (((sym_base *)(sy))->len > SYM_BUFSZ ? \ |
94 | ((sym_base *)(sy))->name.p : \ |
95 | ((sym_base *)(sy))->name.b) |
96 | |
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97 | /* --- An iterator block --- */ |
98 | |
99 | typedef struct sym_iter { |
100 | sym_table *t; /* Symbol table being iterated */ |
101 | sym_base *n; /* Address of next item to return */ |
102 | size_t i; /* Index of next hash bin to use */ |
103 | } sym_iter; |
104 | |
105 | /*----- External functions ------------------------------------------------*/ |
106 | |
107 | /* --- @sym_createTable@ --- * |
108 | * |
109 | * Arguments: @sym_table *t@ = symbol table to initialise |
110 | * |
111 | * Returns: --- |
112 | * |
113 | * Use: Initialises the given symbol table. Raises @EXC_NOMEM@ if |
114 | * there isn't enough memory. |
115 | */ |
116 | |
117 | extern void sym_createTable(sym_table */*t*/); |
118 | |
119 | /* --- @sym_destroyTable@ --- * |
120 | * |
121 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
122 | * |
123 | * Returns: --- |
124 | * |
125 | * Use: Destroys a symbol table, freeing all the memory it used to |
126 | * occupy. |
127 | */ |
128 | |
129 | extern void sym_destroyTable(sym_table */*t*/); |
130 | |
131 | /* --- @sym_find@ --- * |
132 | * |
133 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
134 | * @const char *n@ = pointer to symbol table to look up |
135 | * @long l@ = length of the name string or negative to measure |
136 | * @size_t sz@ = size of desired symbol object, or zero |
137 | * @unsigned *f@ = pointer to a flag, or null. |
138 | * |
139 | * Returns: The address of a @sym_base@ structure, or null if not found |
140 | * and @sz@ is zero. |
141 | * |
142 | * Use: Looks up a symbol in a given symbol table. The name is |
143 | * passed by the address of its first character. The length |
144 | * may be given, in which case the name may contain arbitrary |
145 | * binary data, or it may be given as a negative number, in |
146 | * which case the length of the name is calculated as |
147 | * @strlen(n)@. |
148 | * |
149 | * The return value is the address of a pointer to a @sym_base@ |
150 | * block (which may have other things on the end, as above). If |
151 | * the symbol could be found, the return value points to the |
152 | * symbol block. If the symbol wasn't there, then if @sz@ is |
153 | * nonzero, a new symbol is created and its address is returned; |
154 | * otherwise a null pointer is returned. The exception |
155 | * @EXC_NOMEM@ is raised if the block can't be allocated. |
156 | * |
157 | * The value of @*f@ indicates whether a new symbol entry was |
158 | * created: a nonzero value indicates that an old value was |
159 | * found. |
160 | */ |
161 | |
162 | extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/, |
163 | size_t /*sz*/, unsigned */*f*/); |
164 | |
165 | /* --- @sym_remove@ --- * |
166 | * |
167 | * Arguments: @sym_table *i@ = pointer to a symbol table object |
168 | * @void *b@ = pointer to symbol table entry |
169 | * |
170 | * Returns: --- |
171 | * |
172 | * Use: Removes the object from the symbol table. The space occupied |
173 | * by the object and its name is freed; anything else attached |
174 | * to the entry should already be gone by this point. |
175 | */ |
176 | |
177 | extern void sym_remove(sym_table */*t*/, void */*b*/); |
178 | |
179 | /* --- @sym_createIter@ --- * |
180 | * |
181 | * Arguments: @sym_iter *i@ = pointer to an iterator object |
182 | * @sym_table *t@ = pointer to a symbol table object |
183 | * |
184 | * Returns: --- |
185 | * |
186 | * Use: Creates a new symbol table iterator which may be used to |
187 | * iterate through a symbol table. |
188 | */ |
189 | |
190 | extern void sym_createIter(sym_iter */*i*/, sym_table */*t*/); |
191 | |
192 | /* --- @sym_next@ --- * |
193 | * |
194 | * Arguments: @sym_iter *i@ = pointer to iterator object |
195 | * |
196 | * Returns: Pointer to the next symbol found, or null when finished. |
197 | * |
198 | * Use: Returns the next symbol from the table. Symbols are not |
199 | * returned in any particular order. |
200 | */ |
201 | |
202 | extern void *sym_next(sym_iter */*i*/); |
203 | |
204 | /*----- That's all, folks -------------------------------------------------*/ |
205 | |
206 | #ifdef __cplusplus |
207 | } |
208 | #endif |
209 | |
210 | #endif |