3 * $Id: sym.c,v 1.1 2000/05/21 11:28:30 mdw Exp $
5 * Symbol table management
8 * (c) 2000 Mark Wooding
11 /*----- Licensing notice --------------------------------------------------*
13 * Copyright (c) 2000 Mark Wooding
14 * All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions are
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
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.
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
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 REGENTS 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.
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.
50 /*----- Revision history --------------------------------------------------*
53 * Revision 1.1 2000/05/21 11:28:30 mdw
56 * --- Past lives (Become) --- *
58 * Revision 1.4 1998/01/12 16:46:28 mdw
61 * Revision 1.3 1997/08/20 16:22:59 mdw
64 * Revision 1.2 1997/08/04 10:24:25 mdw
65 * Sources placed under CVS control.
67 * Revision 1.1 1997/07/21 13:47:44 mdw
72 /*----- Header files ------------------------------------------------------*/
81 /*----- Tuning parameters -------------------------------------------------*/
83 /* --- Initial hash table size --- *
85 * This is the initial @mask@ value. It must be of the form %$2^n - 1$%,
86 * so that it can be used to mask of the bottom bits of a hash value.
89 #define SYM_INITSZ 256 /* Size of a new hash table */
91 /* --- Maximum load factor --- *
93 * This parameter controls how much the table has to be loaded before the
94 * table is extended. The number of elements %$n$%, the number of bins %$b$%
95 * and the limit %$l$% satisfy the relation %$n < bl$%; if a new item is
96 * added to the table and this relation is found to be false, the table is
100 #define SYM_LIMIT(n) ((n) * 2) /* Load factor for growing table */
102 /*----- CRC table ---------------------------------------------------------*/
104 /*****************************************************************/
106 /* CRC LOOKUP TABLE */
107 /* ================ */
109 /* The following CRC lookup table was generated automagically */
110 /* by `crcgen', which is based on the Rocksoft^tm Model CRC */
111 /* Algorithm Table Generation Program. The model parameters */
112 /* supplied to `crcgen' were: */
114 /* Width : 32 bits */
115 /* Poly : 0x04C11DB7 */
116 /* Init : 0xFFFFFFFF */
117 /* XorOut : 0xFFFFFFFF */
119 /* Check : 0xCBF43926 */
121 /* For more information on the Rocksoft^tm Model CRC Algorithm, */
122 /* see the document titled `A Painless Guide to CRC Error */
123 /* Detection Algorithms' by Ross Williams */
124 /* (ross@@guest.adelaide.edu.au.). This document is likely to be */
125 /* in the FTP archive `ftp.adelaide.edu.au/pub/rocksoft'. */
127 /*****************************************************************/
129 static uint32 crctab[256] = {
130 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
131 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
132 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
133 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
134 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
135 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
136 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
137 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
138 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
139 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
140 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
141 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
142 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
143 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
144 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
145 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
146 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
147 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
148 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
149 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
150 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
151 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
152 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
153 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
154 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
155 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
156 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
157 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
158 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
159 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
160 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
161 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
162 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
163 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
164 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
165 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
166 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
167 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
168 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
169 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
170 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
171 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
172 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
173 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
174 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
175 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
176 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
177 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
178 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
179 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
180 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
181 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
182 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
183 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
184 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
185 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
186 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
187 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
188 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
189 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
190 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
191 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
192 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
193 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
196 /*****************************************************************/
197 /* End of CRC Lookup Table */
198 /*****************************************************************/
200 /* --- Work out the CRC of a bytestring --- */
202 #define CRC(_s, _l, _hv) do { \
203 uint32 _h = 0xffffffff; \
204 const char *_p = _s; \
205 const char *_e = (_s) + (_l); \
208 _h = (_h >> 8) ^ (crctab[(*_p++ ^ _h) & 0xFF]); \
209 _hv = ~_h & 0xffffffff; \
212 /*----- Memory allocation -------------------------------------------------*/
214 static void die(const char *p)
216 fprintf(stderr, "%s\n", p);
220 static void *xmalloc(size_t sz)
222 void *p = malloc(sz);
224 die("not enough memory");
228 static void *xrealloc(void *p, size_t sz)
232 die("not enough memory");
237 /*----- Main code ---------------------------------------------------------*/
239 /* --- @sym_create@ --- *
241 * Arguments: @sym_table *t@ = symbol table to initialize
245 * Use: Initialises the given symbol table.
248 void sym_create(sym_table *t)
252 t->mask = SYM_INITSZ - 1;
253 t->c = SYM_LIMIT(SYM_INITSZ);
254 t->a = xmalloc((t->mask + 1) * sizeof(sym_base *));
256 for (i = 0; i < SYM_INITSZ + 1; i++)
260 /* --- @sym_destroy@ --- *
262 * Arguments: @sym_table *t@ = pointer to symbol table in question
266 * Use: Destroys a symbol table, freeing all the memory it used to
270 void sym_destroy(sym_table *t)
275 for (i = 0; i <= t->mask; i++) {
287 /* --- @sym_find@ --- *
289 * Arguments: @sym_table *t@ = pointer to symbol table in question
290 * @const char *n@ = pointer to symbol table to look up
291 * @long l@ = length of the name string or negative to measure
292 * @size_t sz@ = size of desired symbol object, or zero
293 * @unsigned *f@ = pointer to a flag, or null.
295 * Returns: The address of a @sym_base@ structure, or null if not found
298 * Use: Looks up a symbol in a given symbol table. The name is
299 * passed by the address of its first character. The length
300 * may be given, in which case the name may contain arbitrary
301 * binary data, or it may be given as a negative number, in
302 * which case the length of the name is calculated as
305 * The return value is the address of a pointer to a @sym_base@
306 * block (which may have other things on the end, as above). If
307 * the symbol could be found, the return value points to the
308 * symbol block. If the symbol wasn't there, then if @sz@ is
309 * nonzero, a new symbol is created and its address is returned;
310 * otherwise a null pointer is returned.
312 * The value of @*f@ indicates whether a new symbol entry was
313 * created: a nonzero value indicates that an old value was
317 void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
320 size_t len = l < 0 ? strlen(n) + 1 : l;
324 /* --- Find the correct bin --- */
327 bin = p = (sym_base *)(t->a + (hash & t->mask));
329 /* --- Search the bin list --- */
332 if (hash == p->next->hash && len == p->next->len &&
333 !memcmp(n, p->next->name, len)) {
335 /* --- Found a match --- *
337 * As a minor, and probably pointless, tweak, move the item to the
338 * front of its bin list.
346 /* --- Return the block --- */
355 /* --- Couldn't find the item there --- */
360 /* --- Create a new symbol block and initialize it --- */
365 p->name = xmalloc(len);
367 memcpy(p->name, n, len);
371 /* --- Consider growing the array --- */
374 uint32 m = t->mask + 1;
378 /* --- Update values in the anchor block --- */
380 t->c = SYM_LIMIT(t->mask + 1);
381 t->mask = (t->mask + 1) * 2 - 1;
382 t->a = xrealloc(t->a, (t->mask + 1) * sizeof(sym_base *));
384 /* --- Now wander through the table rehashing things --- *
386 * This loop is very careful to avoid problems with aliasing. The items
387 * are dealt with from the end backwards to avoid overwriting bins before
388 * they've been processed.
391 lim = (t->mask + 1) >> 1;
392 for (i = 0; i < lim; i++) {
394 /* --- Some initialization --- */
397 p = (sym_base *)(t->a + i);
398 q = (sym_base *)(t->a + i + lim);
400 /* --- Now go through the @r@ list --- */
409 p->next = q->next = 0;
413 /* --- Finished that, so return the new symbol block --- */
418 /* --- @sym_remove@ --- *
420 * Arguments: @sym_table *i@ = pointer to a symbol table object
421 * @void *b@ = pointer to symbol table entry
425 * Use: Removes the object from the symbol table. The space occupied
426 * by the object and its name is freed; anything else attached
427 * to the entry should already be gone by this point.
430 void sym_remove(sym_table *t, void *b)
432 /* --- A quick comment --- *
434 * Since the @sym_base@ block contains the hash, finding the element in the
435 * bin list is really quick -- it's not worth bothering with things like
436 * doubly linked lists.
440 sym_base *bin = (sym_base *)(t->a + (p->hash & t->mask));
442 /* --- Find the item in the bin list --- */
452 /* --- Now just remove the item from the list and free it --- *
454 * Oh, and bump the load counter.
463 /* --- @sym_mkiter@ --- *
465 * Arguments: @sym_iter *i@ = pointer to an iterator object
466 * @sym_table *t@ = pointer to a symbol table object
470 * Use: Creates a new symbol table iterator which may be used to
471 * iterate through a symbol table.
474 void sym_mkiter(sym_iter *i, sym_table *t)
481 /* --- @sym_next@ --- *
483 * Arguments: @sym_iter *i@ = pointer to iterator object
485 * Returns: Pointer to the next symbol found, or null when finished.
487 * Use: Returns the next symbol from the table. Symbols are not
488 * returned in any particular order.
491 void *sym_next(sym_iter *i)
495 /* --- Find the next item --- */
498 if (i->i > i->t->mask)
500 i->n = i->t->a[i->i++];
503 /* --- Update the iterator block --- */
513 /*----- That's all, folks -------------------------------------------------*/