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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: sym.c,v 1.15 2004/04/08 01:36:13 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 |
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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. |
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28 | */ |
29 | |
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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" |
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41 | #include "arena.h" |
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42 | #include "bits.h" |
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43 | #include "exc.h" |
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44 | #include "hash.h" |
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45 | #include "sub.h" |
46 | #include "sym.h" |
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47 | #include "unihash.h" |
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48 | |
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49 | /*----- Main code ---------------------------------------------------------*/ |
50 | |
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51 | /* --- @sym_create@ --- * |
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52 | * |
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53 | * Arguments: @sym_table *t@ = symbol table to initialize |
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54 | * |
55 | * Returns: --- |
56 | * |
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57 | * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if |
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58 | * there isn't enough memory. |
59 | */ |
60 | |
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61 | void sym_create(sym_table *t) |
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62 | { |
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63 | hash_create(&t->t, SYM_INITSZ); |
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64 | t->s = &sub_global; |
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65 | t->load = SYM_LIMIT(SYM_INITSZ); |
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66 | } |
67 | |
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68 | /* --- @sym_destroy@ --- * |
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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 | |
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78 | void sym_destroy(sym_table *t) |
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79 | { |
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80 | sym_iter i; |
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81 | |
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82 | SYM_MKITER(&i, t); |
83 | for (;;) { |
84 | sym_base *p; |
85 | SYM_NEXT(&i, p); |
86 | if (!p) |
87 | break; |
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88 | x_free(t->t.a, p); |
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89 | } |
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90 | hash_destroy(&t->t); |
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91 | } |
92 | |
93 | /* --- @sym_find@ --- * |
94 | * |
95 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
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96 | * @const char *n@ = pointer to symbol name to look up |
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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 |
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109 | * @strlen(n) + 1@. |
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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 | |
124 | void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f) |
125 | { |
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126 | uint32 hash; |
127 | size_t len = 0; |
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128 | hash_base **bin, **p; |
129 | sym_base *q; |
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130 | |
131 | /* --- Find the correct bin --- */ |
132 | |
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133 | len = l < 0 ? strlen(n) : l; |
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134 | hash = UNIHASH(&unihash_global, n, len); |
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135 | bin = HASH_BIN(&t->t, hash); |
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136 | |
137 | /* --- Search the bin list --- */ |
138 | |
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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 | |
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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 | |
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149 | (*p) = q->b.next; |
150 | q->b.next = *bin; |
151 | *bin = &q->b; |
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152 | |
153 | /* --- Return the block --- */ |
154 | |
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155 | if (f) *f = 1; |
156 | return (q); |
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157 | } |
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158 | } |
159 | |
160 | /* --- Couldn't find the item there --- */ |
161 | |
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162 | if (f) *f = 0; |
163 | if (!sz) return (0); |
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164 | |
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165 | /* --- Create a new symbol block and initialize it --- * |
166 | * |
167 | * The name is attached to the end of the symbol block. |
168 | */ |
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169 | |
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170 | q = x_alloc(t->t.a, sz + len + 1); |
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171 | q->b.next = *bin; |
172 | q->b.hash = hash; |
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173 | q->name = (char *)q + sz; |
174 | memcpy(q->name, n, len); |
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175 | q->name[len] = 0; |
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176 | q->len = len; |
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177 | *bin = &q->b; |
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178 | |
179 | /* --- Consider growing the array --- */ |
180 | |
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181 | if (t->load) |
182 | t->load--; |
183 | if (!t->load && hash_extend(&t->t)) |
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184 | t->load = SYM_LIMIT(t->t.mask + 1); |
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185 | |
186 | /* --- Finished that, so return the new symbol block --- */ |
187 | |
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188 | return (q); |
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189 | } |
190 | |
191 | /* --- @sym_remove@ --- * |
192 | * |
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193 | * Arguments: @sym_table *t@ = pointer to a symbol table object |
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194 | * @void *p@ = pointer to symbol table entry |
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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 | |
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203 | void sym_remove(sym_table *t, void *p) |
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204 | { |
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205 | sym_base *q = p; |
206 | hash_remove(&t->t, &q->b); |
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207 | xfree(q); |
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208 | t->load++; |
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209 | } |
210 | |
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211 | /* --- @sym_mkiter@ --- * |
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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 | |
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222 | void sym_mkiter(sym_iter *i, sym_table *t) { SYM_MKITER(i, t); } |
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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 | |
234 | void *sym_next(sym_iter *i) |
235 | { |
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236 | void *p; |
237 | SYM_NEXT(i, p); |
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238 | return (p); |
239 | } |
240 | |
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241 | /*----- That's all, folks -------------------------------------------------*/ |