| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id$ |
| 4 | * |
| 5 | * Symbol table management |
| 6 | * |
| 7 | * (c) 1998 Straylight |
| 8 | * (c) 2000 Mark Wooding |
| 9 | */ |
| 10 | |
| 11 | /*----- Licensing notice --------------------------------------------------* |
| 12 | * |
| 13 | * Copyright (c) 2000 Mark Wooding |
| 14 | * All rights reserved. |
| 15 | * |
| 16 | * Redistribution and use in source and binary forms, with or without |
| 17 | * modification, are permitted provided that the following conditions are |
| 18 | * met: |
| 19 | * |
| 20 | * 1. Redistributions of source code must retain the above copyright |
| 21 | * notice, this list of conditions and the following disclaimer. |
| 22 | * |
| 23 | * 2, Redistributions in binary form must reproduce the above copyright |
| 24 | * notice, this list of conditions and the following disclaimer in the |
| 25 | * documentation and/or other materials provided with the distribution. |
| 26 | * |
| 27 | * 3. The name of the authors may not be used to endorse or promote |
| 28 | * products derived from this software without specific prior written |
| 29 | * permission. |
| 30 | * |
| 31 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 32 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 33 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN |
| 34 | * NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| 35 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 36 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 37 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| 40 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 41 | * POSSIBILITY OF SUCH DAMAGE. |
| 42 | * |
| 43 | * Instead of accepting the above terms, you may redistribute and/or modify |
| 44 | * this software under the terms of either the GNU General Public License, |
| 45 | * or the GNU Library General Public License, published by the Free |
| 46 | * Software Foundation; either version 2 of the License, or (at your |
| 47 | * option) any later version. |
| 48 | */ |
| 49 | |
| 50 | /*----- Revision history --------------------------------------------------* |
| 51 | * |
| 52 | * $Log: sym.c,v $ |
| 53 | * Revision 1.2 2000/07/02 15:21:20 mdw |
| 54 | * Fix licence text. |
| 55 | * |
| 56 | * Revision 1.1 2000/05/21 11:28:30 mdw |
| 57 | * Initial check-in. |
| 58 | * |
| 59 | * --- Past lives (Become) --- * |
| 60 | * |
| 61 | * Revision 1.4 1998/01/12 16:46:28 mdw |
| 62 | * Fix copyright date. |
| 63 | * |
| 64 | * Revision 1.3 1997/08/20 16:22:59 mdw |
| 65 | * Patch memory leak. |
| 66 | * |
| 67 | * Revision 1.2 1997/08/04 10:24:25 mdw |
| 68 | * Sources placed under CVS control. |
| 69 | * |
| 70 | * Revision 1.1 1997/07/21 13:47:44 mdw |
| 71 | * Initial revision |
| 72 | * |
| 73 | */ |
| 74 | |
| 75 | /*----- Header files ------------------------------------------------------*/ |
| 76 | |
| 77 | #include <stdio.h> |
| 78 | #include <stdlib.h> |
| 79 | #include <string.h> |
| 80 | |
| 81 | #include "bits.h" |
| 82 | #include "sym.h" |
| 83 | |
| 84 | /*----- Tuning parameters -------------------------------------------------*/ |
| 85 | |
| 86 | /* --- Initial hash table size --- * |
| 87 | * |
| 88 | * This is the initial @mask@ value. It must be of the form %$2^n - 1$%, |
| 89 | * so that it can be used to mask of the bottom bits of a hash value. |
| 90 | */ |
| 91 | |
| 92 | #define SYM_INITSZ 256 /* Size of a new hash table */ |
| 93 | |
| 94 | /* --- Maximum load factor --- * |
| 95 | * |
| 96 | * This parameter controls how much the table has to be loaded before the |
| 97 | * table is extended. The number of elements %$n$%, the number of bins %$b$% |
| 98 | * and the limit %$l$% satisfy the relation %$n < bl$%; if a new item is |
| 99 | * added to the table and this relation is found to be false, the table is |
| 100 | * doubled in size. |
| 101 | */ |
| 102 | |
| 103 | #define SYM_LIMIT(n) ((n) * 2) /* Load factor for growing table */ |
| 104 | |
| 105 | /*----- CRC table ---------------------------------------------------------*/ |
| 106 | |
| 107 | /*****************************************************************/ |
| 108 | /* */ |
| 109 | /* CRC LOOKUP TABLE */ |
| 110 | /* ================ */ |
| 111 | /* */ |
| 112 | /* The following CRC lookup table was generated automagically */ |
| 113 | /* by `crcgen', which is based on the Rocksoft^tm Model CRC */ |
| 114 | /* Algorithm Table Generation Program. The model parameters */ |
| 115 | /* supplied to `crcgen' were: */ |
| 116 | /* */ |
| 117 | /* Width : 32 bits */ |
| 118 | /* Poly : 0x04C11DB7 */ |
| 119 | /* Init : 0xFFFFFFFF */ |
| 120 | /* XorOut : 0xFFFFFFFF */ |
| 121 | /* Reverse : Yes */ |
| 122 | /* Check : 0xCBF43926 */ |
| 123 | /* */ |
| 124 | /* For more information on the Rocksoft^tm Model CRC Algorithm, */ |
| 125 | /* see the document titled `A Painless Guide to CRC Error */ |
| 126 | /* Detection Algorithms' by Ross Williams */ |
| 127 | /* (ross@@guest.adelaide.edu.au.). This document is likely to be */ |
| 128 | /* in the FTP archive `ftp.adelaide.edu.au/pub/rocksoft'. */ |
| 129 | /* */ |
| 130 | /*****************************************************************/ |
| 131 | |
| 132 | static uint32 crctab[256] = { |
| 133 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, |
| 134 | 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, |
| 135 | 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, |
| 136 | 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, |
| 137 | 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, |
| 138 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, |
| 139 | 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, |
| 140 | 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, |
| 141 | 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, |
| 142 | 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, |
| 143 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, |
| 144 | 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, |
| 145 | 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, |
| 146 | 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, |
| 147 | 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, |
| 148 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, |
| 149 | 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, |
| 150 | 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, |
| 151 | 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, |
| 152 | 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, |
| 153 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, |
| 154 | 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, |
| 155 | 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, |
| 156 | 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, |
| 157 | 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, |
| 158 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, |
| 159 | 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, |
| 160 | 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, |
| 161 | 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, |
| 162 | 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, |
| 163 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, |
| 164 | 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, |
| 165 | 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, |
| 166 | 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, |
| 167 | 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, |
| 168 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, |
| 169 | 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, |
| 170 | 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, |
| 171 | 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, |
| 172 | 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, |
| 173 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, |
| 174 | 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, |
| 175 | 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, |
| 176 | 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, |
| 177 | 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, |
| 178 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, |
| 179 | 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, |
| 180 | 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, |
| 181 | 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, |
| 182 | 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, |
| 183 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, |
| 184 | 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, |
| 185 | 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, |
| 186 | 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, |
| 187 | 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, |
| 188 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, |
| 189 | 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, |
| 190 | 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, |
| 191 | 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, |
| 192 | 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, |
| 193 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, |
| 194 | 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, |
| 195 | 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, |
| 196 | 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d |
| 197 | }; |
| 198 | |
| 199 | /*****************************************************************/ |
| 200 | /* End of CRC Lookup Table */ |
| 201 | /*****************************************************************/ |
| 202 | |
| 203 | /* --- Work out the CRC of a bytestring --- */ |
| 204 | |
| 205 | #define CRC(_s, _l, _hv) do { \ |
| 206 | uint32 _h = 0xffffffff; \ |
| 207 | const char *_p = _s; \ |
| 208 | const char *_e = (_s) + (_l); \ |
| 209 | \ |
| 210 | while (_p < _e) \ |
| 211 | _h = (_h >> 8) ^ (crctab[(*_p++ ^ _h) & 0xFF]); \ |
| 212 | _hv = ~_h & 0xffffffff; \ |
| 213 | } while (0) |
| 214 | |
| 215 | /*----- Memory allocation -------------------------------------------------*/ |
| 216 | |
| 217 | static void die(const char *p) |
| 218 | { |
| 219 | fprintf(stderr, "%s\n", p); |
| 220 | exit(EXIT_FAILURE); |
| 221 | } |
| 222 | |
| 223 | static void *xmalloc(size_t sz) |
| 224 | { |
| 225 | void *p = malloc(sz); |
| 226 | if (!p) |
| 227 | die("not enough memory"); |
| 228 | return (p); |
| 229 | } |
| 230 | |
| 231 | static void *xrealloc(void *p, size_t sz) |
| 232 | { |
| 233 | p = realloc(p, sz); |
| 234 | if (!p) |
| 235 | die("not enough memory"); |
| 236 | return (p); |
| 237 | } |
| 238 | |
| 239 | |
| 240 | /*----- Main code ---------------------------------------------------------*/ |
| 241 | |
| 242 | /* --- @sym_create@ --- * |
| 243 | * |
| 244 | * Arguments: @sym_table *t@ = symbol table to initialize |
| 245 | * |
| 246 | * Returns: --- |
| 247 | * |
| 248 | * Use: Initialises the given symbol table. |
| 249 | */ |
| 250 | |
| 251 | void sym_create(sym_table *t) |
| 252 | { |
| 253 | size_t i; |
| 254 | |
| 255 | t->mask = SYM_INITSZ - 1; |
| 256 | t->c = SYM_LIMIT(SYM_INITSZ); |
| 257 | t->a = xmalloc((t->mask + 1) * sizeof(sym_base *)); |
| 258 | |
| 259 | for (i = 0; i < SYM_INITSZ + 1; i++) |
| 260 | t->a[i] = 0; |
| 261 | } |
| 262 | |
| 263 | /* --- @sym_destroy@ --- * |
| 264 | * |
| 265 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 266 | * |
| 267 | * Returns: --- |
| 268 | * |
| 269 | * Use: Destroys a symbol table, freeing all the memory it used to |
| 270 | * occupy. |
| 271 | */ |
| 272 | |
| 273 | void sym_destroy(sym_table *t) |
| 274 | { |
| 275 | size_t i; |
| 276 | sym_base *p, *q; |
| 277 | |
| 278 | for (i = 0; i <= t->mask; i++) { |
| 279 | p = t->a[i]; |
| 280 | while (p) { |
| 281 | q = p->next; |
| 282 | free(p->name); |
| 283 | free(p); |
| 284 | p = q; |
| 285 | } |
| 286 | } |
| 287 | free(t->a); |
| 288 | } |
| 289 | |
| 290 | /* --- @sym_find@ --- * |
| 291 | * |
| 292 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 293 | * @const char *n@ = pointer to symbol table to look up |
| 294 | * @long l@ = length of the name string or negative to measure |
| 295 | * @size_t sz@ = size of desired symbol object, or zero |
| 296 | * @unsigned *f@ = pointer to a flag, or null. |
| 297 | * |
| 298 | * Returns: The address of a @sym_base@ structure, or null if not found |
| 299 | * and @sz@ is zero. |
| 300 | * |
| 301 | * Use: Looks up a symbol in a given symbol table. The name is |
| 302 | * passed by the address of its first character. The length |
| 303 | * may be given, in which case the name may contain arbitrary |
| 304 | * binary data, or it may be given as a negative number, in |
| 305 | * which case the length of the name is calculated as |
| 306 | * @strlen(n) + 1@. |
| 307 | * |
| 308 | * The return value is the address of a pointer to a @sym_base@ |
| 309 | * block (which may have other things on the end, as above). If |
| 310 | * the symbol could be found, the return value points to the |
| 311 | * symbol block. If the symbol wasn't there, then if @sz@ is |
| 312 | * nonzero, a new symbol is created and its address is returned; |
| 313 | * otherwise a null pointer is returned. |
| 314 | * |
| 315 | * The value of @*f@ indicates whether a new symbol entry was |
| 316 | * created: a nonzero value indicates that an old value was |
| 317 | * found. |
| 318 | */ |
| 319 | |
| 320 | void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f) |
| 321 | { |
| 322 | uint32 hash; |
| 323 | size_t len = l < 0 ? strlen(n) + 1 : l; |
| 324 | sym_base *bin; |
| 325 | sym_base *p, *q; |
| 326 | |
| 327 | /* --- Find the correct bin --- */ |
| 328 | |
| 329 | CRC(n, len, hash); |
| 330 | bin = p = (sym_base *)(t->a + (hash & t->mask)); |
| 331 | |
| 332 | /* --- Search the bin list --- */ |
| 333 | |
| 334 | while (p->next) { |
| 335 | if (hash == p->next->hash && len == p->next->len && |
| 336 | !memcmp(n, p->next->name, len)) { |
| 337 | |
| 338 | /* --- Found a match --- * |
| 339 | * |
| 340 | * As a minor, and probably pointless, tweak, move the item to the |
| 341 | * front of its bin list. |
| 342 | */ |
| 343 | |
| 344 | q = p->next; |
| 345 | p->next = q->next; |
| 346 | q->next = bin->next; |
| 347 | bin->next = q; |
| 348 | |
| 349 | /* --- Return the block --- */ |
| 350 | |
| 351 | if (f) *f = 1; |
| 352 | return (q); |
| 353 | } |
| 354 | |
| 355 | p = p->next; |
| 356 | } |
| 357 | |
| 358 | /* --- Couldn't find the item there --- */ |
| 359 | |
| 360 | if (f) *f = 0; |
| 361 | if (!sz) return (0); |
| 362 | |
| 363 | /* --- Create a new symbol block and initialize it --- */ |
| 364 | |
| 365 | p = xmalloc(sz); |
| 366 | p->next = bin->next; |
| 367 | p->hash = hash; |
| 368 | p->name = xmalloc(len); |
| 369 | p->len = len; |
| 370 | memcpy(p->name, n, len); |
| 371 | |
| 372 | bin->next = p; |
| 373 | |
| 374 | /* --- Consider growing the array --- */ |
| 375 | |
| 376 | if (!--t->c) { |
| 377 | uint32 m = t->mask + 1; |
| 378 | sym_base *p, *q, *r; |
| 379 | size_t i, lim; |
| 380 | |
| 381 | /* --- Update values in the anchor block --- */ |
| 382 | |
| 383 | t->c = SYM_LIMIT(t->mask + 1); |
| 384 | t->mask = (t->mask + 1) * 2 - 1; |
| 385 | t->a = xrealloc(t->a, (t->mask + 1) * sizeof(sym_base *)); |
| 386 | |
| 387 | /* --- Now wander through the table rehashing things --- * |
| 388 | * |
| 389 | * This loop is very careful to avoid problems with aliasing. The items |
| 390 | * are dealt with from the end backwards to avoid overwriting bins before |
| 391 | * they've been processed. |
| 392 | */ |
| 393 | |
| 394 | lim = (t->mask + 1) >> 1; |
| 395 | for (i = 0; i < lim; i++) { |
| 396 | |
| 397 | /* --- Some initialization --- */ |
| 398 | |
| 399 | r = t->a[i]; |
| 400 | p = (sym_base *)(t->a + i); |
| 401 | q = (sym_base *)(t->a + i + lim); |
| 402 | |
| 403 | /* --- Now go through the @r@ list --- */ |
| 404 | |
| 405 | while (r) { |
| 406 | if (r->hash & m) |
| 407 | q = q->next = r; |
| 408 | else |
| 409 | p = p->next = r; |
| 410 | r = r->next; |
| 411 | } |
| 412 | p->next = q->next = 0; |
| 413 | } |
| 414 | } |
| 415 | |
| 416 | /* --- Finished that, so return the new symbol block --- */ |
| 417 | |
| 418 | return (p); |
| 419 | } |
| 420 | |
| 421 | /* --- @sym_remove@ --- * |
| 422 | * |
| 423 | * Arguments: @sym_table *i@ = pointer to a symbol table object |
| 424 | * @void *b@ = pointer to symbol table entry |
| 425 | * |
| 426 | * Returns: --- |
| 427 | * |
| 428 | * Use: Removes the object from the symbol table. The space occupied |
| 429 | * by the object and its name is freed; anything else attached |
| 430 | * to the entry should already be gone by this point. |
| 431 | */ |
| 432 | |
| 433 | void sym_remove(sym_table *t, void *b) |
| 434 | { |
| 435 | /* --- A quick comment --- * |
| 436 | * |
| 437 | * Since the @sym_base@ block contains the hash, finding the element in the |
| 438 | * bin list is really quick -- it's not worth bothering with things like |
| 439 | * doubly linked lists. |
| 440 | */ |
| 441 | |
| 442 | sym_base *p = b; |
| 443 | sym_base *bin = (sym_base *)(t->a + (p->hash & t->mask)); |
| 444 | |
| 445 | /* --- Find the item in the bin list --- */ |
| 446 | |
| 447 | while (bin->next) { |
| 448 | if (bin->next == p) |
| 449 | break; |
| 450 | bin = bin->next; |
| 451 | } |
| 452 | if (!bin->next) |
| 453 | return; |
| 454 | |
| 455 | /* --- Now just remove the item from the list and free it --- * |
| 456 | * |
| 457 | * Oh, and bump the load counter. |
| 458 | */ |
| 459 | |
| 460 | bin->next = p->next; |
| 461 | free(p->name); |
| 462 | free(p); |
| 463 | t->c++; |
| 464 | } |
| 465 | |
| 466 | /* --- @sym_mkiter@ --- * |
| 467 | * |
| 468 | * Arguments: @sym_iter *i@ = pointer to an iterator object |
| 469 | * @sym_table *t@ = pointer to a symbol table object |
| 470 | * |
| 471 | * Returns: --- |
| 472 | * |
| 473 | * Use: Creates a new symbol table iterator which may be used to |
| 474 | * iterate through a symbol table. |
| 475 | */ |
| 476 | |
| 477 | void sym_mkiter(sym_iter *i, sym_table *t) |
| 478 | { |
| 479 | i->t = t; |
| 480 | i->i = 0; |
| 481 | i->n = 0; |
| 482 | } |
| 483 | |
| 484 | /* --- @sym_next@ --- * |
| 485 | * |
| 486 | * Arguments: @sym_iter *i@ = pointer to iterator object |
| 487 | * |
| 488 | * Returns: Pointer to the next symbol found, or null when finished. |
| 489 | * |
| 490 | * Use: Returns the next symbol from the table. Symbols are not |
| 491 | * returned in any particular order. |
| 492 | */ |
| 493 | |
| 494 | void *sym_next(sym_iter *i) |
| 495 | { |
| 496 | sym_base *p; |
| 497 | |
| 498 | /* --- Find the next item --- */ |
| 499 | |
| 500 | while (!i->n) { |
| 501 | if (i->i > i->t->mask) |
| 502 | return (0); |
| 503 | i->n = i->t->a[i->i++]; |
| 504 | } |
| 505 | |
| 506 | /* --- Update the iterator block --- */ |
| 507 | |
| 508 | p = i->n; |
| 509 | i->n = p->next; |
| 510 | |
| 511 | /* --- Done --- */ |
| 512 | |
| 513 | return (p); |
| 514 | } |
| 515 | |
| 516 | /*----- That's all, folks -------------------------------------------------*/ |