| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Symbol table management |
| 4 | * |
| 5 | * (c) 1998 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the mLib utilities library. |
| 11 | * |
| 12 | * mLib is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * mLib is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with mLib; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | /* --- ANSI headers --- */ |
| 31 | |
| 32 | #include <stdio.h> |
| 33 | #include <stdlib.h> |
| 34 | #include <string.h> |
| 35 | |
| 36 | /* --- Local headers --- */ |
| 37 | |
| 38 | #include "alloc.h" |
| 39 | #include "arena.h" |
| 40 | #include "bits.h" |
| 41 | #include "exc.h" |
| 42 | #include "hash.h" |
| 43 | #include "macros.h" |
| 44 | #include "sub.h" |
| 45 | #include "sym.h" |
| 46 | #include "unihash.h" |
| 47 | |
| 48 | /*----- Main code ---------------------------------------------------------*/ |
| 49 | |
| 50 | /* --- @sym_create@ --- * |
| 51 | * |
| 52 | * Arguments: @sym_table *t@ = symbol table to initialize |
| 53 | * |
| 54 | * Returns: --- |
| 55 | * |
| 56 | * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if |
| 57 | * there isn't enough memory. |
| 58 | */ |
| 59 | |
| 60 | void sym_create(sym_table *t) |
| 61 | { |
| 62 | hash_create(&t->t, SYM_INITSZ); |
| 63 | t->s = &sub_global; |
| 64 | t->load = SYM_LIMIT(SYM_INITSZ); |
| 65 | } |
| 66 | |
| 67 | /* --- @sym_destroy@ --- * |
| 68 | * |
| 69 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 70 | * |
| 71 | * Returns: --- |
| 72 | * |
| 73 | * Use: Destroys a symbol table, freeing all the memory it used to |
| 74 | * occupy. |
| 75 | */ |
| 76 | |
| 77 | void sym_destroy(sym_table *t) |
| 78 | { |
| 79 | sym_iter i; |
| 80 | |
| 81 | SYM_MKITER(&i, t); |
| 82 | for (;;) { |
| 83 | sym_base *p; |
| 84 | SYM_NEXT(&i, p); |
| 85 | if (!p) |
| 86 | break; |
| 87 | x_free(t->t.a, p); |
| 88 | } |
| 89 | hash_destroy(&t->t); |
| 90 | } |
| 91 | |
| 92 | /* --- @sym_find@ --- * |
| 93 | * |
| 94 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 95 | * @const char *n@ = pointer to symbol name to look up |
| 96 | * @long l@ = length of the name string or negative to measure |
| 97 | * @size_t sz@ = size of desired symbol object, or zero |
| 98 | * @unsigned *f@ = pointer to a flag, or null. |
| 99 | * |
| 100 | * Returns: The address of a @sym_base@ structure, or null if not found |
| 101 | * and @sz@ is zero. |
| 102 | * |
| 103 | * Use: Looks up a symbol in a given symbol table. The name is |
| 104 | * passed by the address of its first character. The length |
| 105 | * may be given, in which case the name may contain arbitrary |
| 106 | * binary data, or it may be given as a negative number, in |
| 107 | * which case the length of the name is calculated as |
| 108 | * @strlen(n) + 1@. |
| 109 | * |
| 110 | * The return value is the address of a pointer to a @sym_base@ |
| 111 | * block (which may have other things on the end, as above). If |
| 112 | * the symbol could be found, the return value points to the |
| 113 | * symbol block. If the symbol wasn't there, then if @sz@ is |
| 114 | * nonzero, a new symbol is created and its address is returned; |
| 115 | * otherwise a null pointer is returned. The exception |
| 116 | * @EXC_NOMEM@ is raised if the block can't be allocated. |
| 117 | * |
| 118 | * The value of @*f@ indicates whether a new symbol entry was |
| 119 | * created: a nonzero value indicates that an old value was |
| 120 | * found. |
| 121 | */ |
| 122 | |
| 123 | void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f) |
| 124 | { |
| 125 | uint32 hash; |
| 126 | size_t len = 0; |
| 127 | hash_base **bin, **p; |
| 128 | sym_base *q; |
| 129 | |
| 130 | /* --- Find the correct bin --- */ |
| 131 | |
| 132 | len = l < 0 ? strlen(n) : l; |
| 133 | hash = UNIHASH(&unihash_global, n, len); |
| 134 | bin = HASH_BIN(&t->t, hash); |
| 135 | |
| 136 | /* --- Search the bin list --- */ |
| 137 | |
| 138 | for (p = bin; *p; p = &(*p)->next) { |
| 139 | q = (sym_base *)*p; |
| 140 | if (hash == q->b.hash && len == q->len && |
| 141 | MEMCMP(n, ==, SYM_NAME(q), len)) { |
| 142 | |
| 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 | |
| 149 | (*p) = q->b.next; |
| 150 | q->b.next = *bin; |
| 151 | *bin = &q->b; |
| 152 | |
| 153 | /* --- Return the block --- */ |
| 154 | |
| 155 | if (f) *f = 1; |
| 156 | return (q); |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | /* --- Couldn't find the item there --- */ |
| 161 | |
| 162 | if (f) *f = 0; |
| 163 | if (!sz) return (0); |
| 164 | |
| 165 | /* --- Create a new symbol block and initialize it --- * |
| 166 | * |
| 167 | * The name is attached to the end of the symbol block. |
| 168 | */ |
| 169 | |
| 170 | q = x_alloc(t->t.a, sz + len + 1); |
| 171 | q->b.next = *bin; |
| 172 | q->b.hash = hash; |
| 173 | q->name = (char *)q + sz; |
| 174 | memcpy(q->name, n, len); |
| 175 | q->name[len] = 0; |
| 176 | q->len = len; |
| 177 | *bin = &q->b; |
| 178 | |
| 179 | /* --- Consider growing the array --- */ |
| 180 | |
| 181 | if (t->load) |
| 182 | t->load--; |
| 183 | if (!t->load && hash_extend(&t->t)) |
| 184 | t->load = SYM_LIMIT(t->t.mask + 1); |
| 185 | |
| 186 | /* --- Finished that, so return the new symbol block --- */ |
| 187 | |
| 188 | return (q); |
| 189 | } |
| 190 | |
| 191 | /* --- @sym_remove@ --- * |
| 192 | * |
| 193 | * Arguments: @sym_table *t@ = pointer to a symbol table object |
| 194 | * @void *p@ = pointer to symbol table entry |
| 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 | |
| 203 | void sym_remove(sym_table *t, void *p) |
| 204 | { |
| 205 | sym_base *q = p; |
| 206 | hash_remove(&t->t, &q->b); |
| 207 | xfree(q); |
| 208 | t->load++; |
| 209 | } |
| 210 | |
| 211 | /* --- @sym_mkiter@ --- * |
| 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 | |
| 222 | void sym_mkiter(sym_iter *i, sym_table *t) { SYM_MKITER(i, t); } |
| 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 | { |
| 236 | void *p; |
| 237 | SYM_NEXT(i, p); |
| 238 | return (p); |
| 239 | } |
| 240 | |
| 241 | /*----- That's all, folks -------------------------------------------------*/ |