2 Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
4 This file is part of XEmacs.
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* Synched up with: Not in FSF. */
27 #define NULL_ENTRY ((void *) 0xdeadbeef)
29 #define COMFORTABLE_SIZE(size) (21 * (size) / 16)
31 #define KEYS_DIFFER_P(old, new, testfun) \
32 (((old) != (new)) && (!(testfun) || !(testfun) ((old),(new))))
34 static void rehash (hentry *harray, struct hash_table *ht, hash_size_t size);
37 memory_hash (const void *xv, size_t size)
40 unsigned const char *x = (unsigned const char *) xv;
48 if ((g = h & 0xf0000000) != 0)
49 h = (h ^ (g >> 24)) ^ g;
56 string_hash (const char *xv)
59 unsigned const char *x = (unsigned const char *) xv;
67 if ((g = h & 0xf0000000) != 0)
68 h = (h ^ (g >> 24)) ^ g;
74 /* Return a suitable size for a hash table, with at least SIZE slots. */
76 hash_table_size (size_t requested_size)
78 /* Return some prime near, but greater than or equal to, SIZE.
79 Decades from the time of writing, someone will have a system large
80 enough that the list below will be too short... */
81 static const size_t primes [] =
83 19, 29, 41, 59, 79, 107, 149, 197, 263, 347, 457, 599, 787, 1031,
84 1361, 1777, 2333, 3037, 3967, 5167, 6719, 8737, 11369, 14783,
85 19219, 24989, 32491, 42257, 54941, 71429, 92861, 120721, 156941,
86 204047, 265271, 344857, 448321, 582821, 757693, 985003, 1280519,
87 1664681, 2164111, 2813353, 3657361, 4754591, 6180989, 8035301,
88 10445899, 13579681, 17653589, 22949669, 29834603, 38784989,
89 50420551, 65546729, 85210757, 110774011, 144006217, 187208107,
90 243370577, 316381771, 411296309, 534685237, 695090819, 903618083,
91 1174703521, 1527114613, 1985248999, 2580823717UL, 3355070839UL
93 /* We've heard of binary search. */
95 for (low = 0, high = countof (primes) - 1; high - low > 1;)
97 /* Loop Invariant: size < primes [high] */
98 int mid = (low + high) / 2;
99 if (primes [mid] < requested_size)
104 return primes [high];
108 gethash (const void *key, struct hash_table *hash_table, const void **ret_value)
112 *ret_value = hash_table->zero_entry;
113 return (void *) hash_table->zero_set;
117 hentry *harray = hash_table->harray;
118 hash_table_test_function test_function = hash_table->test_function;
119 hash_size_t size = hash_table->size;
120 unsigned int hcode_initial =
121 hash_table->hash_function ?
122 hash_table->hash_function (key) :
124 unsigned int hcode = hcode_initial % size;
125 hentry *e = &harray [hcode];
126 const void *e_key = e->key;
129 KEYS_DIFFER_P (e_key, key, test_function) :
130 e->contents == NULL_ENTRY)
132 size_t h2 = size - 2;
133 unsigned int incr = 1 + (hcode_initial % h2);
136 hcode += incr; if (hcode >= size) hcode -= size;
141 KEYS_DIFFER_P (e_key, key, test_function) :
142 e->contents == NULL_ENTRY);
145 *ret_value = e->contents;
151 clrhash (struct hash_table *hash_table)
153 memset (hash_table->harray, 0, sizeof (hentry) * hash_table->size);
154 hash_table->zero_entry = 0;
155 hash_table->zero_set = 0;
156 hash_table->fullness = 0;
160 free_hash_table (struct hash_table *hash_table)
162 xfree (hash_table->harray);
167 make_hash_table (hash_size_t size)
169 struct hash_table *hash_table = xnew_and_zero (struct hash_table);
170 hash_table->size = hash_table_size (COMFORTABLE_SIZE (size));
171 hash_table->harray = xnew_array (hentry, hash_table->size);
172 clrhash (hash_table);
177 make_general_hash_table (hash_size_t size,
178 hash_table_hash_function hash_function,
179 hash_table_test_function test_function)
181 struct hash_table* hash_table = make_hash_table (size);
182 hash_table->hash_function = hash_function;
183 hash_table->test_function = test_function;
188 grow_hash_table (struct hash_table *hash_table, hash_size_t new_size)
190 hash_size_t old_size = hash_table->size;
191 hentry *old_harray = hash_table->harray;
193 hash_table->size = hash_table_size (new_size);
194 hash_table->harray = xnew_array (hentry, hash_table->size);
196 /* do the rehash on the "grown" table */
198 long old_zero_set = hash_table->zero_set;
199 void *old_zero_entry = hash_table->zero_entry;
200 clrhash (hash_table);
201 hash_table->zero_set = old_zero_set;
202 hash_table->zero_entry = old_zero_entry;
203 rehash (old_harray, hash_table, old_size);
210 puthash (const void *key, void *contents, struct hash_table *hash_table)
214 hash_table->zero_entry = contents;
215 hash_table->zero_set = 1;
219 hash_table_test_function test_function = hash_table->test_function;
220 hash_size_t size = hash_table->size;
221 hentry *harray = hash_table->harray;
222 unsigned int hcode_initial =
223 hash_table->hash_function ?
224 hash_table->hash_function (key) :
226 unsigned int hcode = hcode_initial % size;
227 size_t h2 = size - 2;
228 unsigned int incr = 1 + (hcode_initial % h2);
229 const void *e_key = harray [hcode].key;
230 const void *oldcontents;
232 if (e_key && KEYS_DIFFER_P (e_key, key, test_function))
236 hcode += incr; if (hcode >= size) hcode -= size;
237 e_key = harray [hcode].key;
239 while (e_key && KEYS_DIFFER_P (e_key, key, test_function));
241 oldcontents = harray [hcode].contents;
242 harray [hcode].key = key;
243 harray [hcode].contents = contents;
244 /* If the entry that we used was a deleted entry,
245 check for a non deleted entry of the same key,
247 if (!e_key && oldcontents == NULL_ENTRY)
253 hcode += incr; if (hcode >= size) hcode -= size;
258 KEYS_DIFFER_P (e_key, key, test_function):
259 e->contents == NULL_ENTRY);
264 e->contents = NULL_ENTRY;
268 /* only increment the fullness when we used up a new hentry */
269 if (!e_key || KEYS_DIFFER_P (e_key, key, test_function))
271 hash_size_t comfortable_size = COMFORTABLE_SIZE (++(hash_table->fullness));
272 if (hash_table->size < comfortable_size)
273 grow_hash_table (hash_table, comfortable_size + 1);
279 rehash (hentry *harray, struct hash_table *hash_table, hash_size_t size)
281 hentry *limit = harray + size;
283 for (e = harray; e < limit; e++)
286 puthash (e->key, e->contents, hash_table);
291 remhash (const void *key, struct hash_table *hash_table)
295 hash_table->zero_entry = 0;
296 hash_table->zero_set = 0;
300 hentry *harray = hash_table->harray;
301 hash_table_test_function test_function = hash_table->test_function;
302 hash_size_t size = hash_table->size;
303 unsigned int hcode_initial =
304 (hash_table->hash_function) ?
305 (hash_table->hash_function (key)) :
306 ((unsigned long) key);
307 unsigned int hcode = hcode_initial % size;
308 hentry *e = &harray [hcode];
309 const void *e_key = e->key;
312 KEYS_DIFFER_P (e_key, key, test_function) :
313 e->contents == NULL_ENTRY)
315 size_t h2 = size - 2;
316 unsigned int incr = 1 + (hcode_initial % h2);
319 hcode += incr; if (hcode >= size) hcode -= size;
324 KEYS_DIFFER_P (e_key, key, test_function):
325 e->contents == NULL_ENTRY);
330 e->contents = NULL_ENTRY;
331 /* Note: you can't do fullness-- here, it breaks the world. */
337 maphash (maphash_function mf, struct hash_table *hash_table, void *arg)
342 if (hash_table->zero_set)
344 if (mf (0, hash_table->zero_entry, arg))
348 for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
350 if (e->key && mf (e->key, e->contents, arg))
356 map_remhash (remhash_predicate predicate, struct hash_table *hash_table, void *arg)
361 if (hash_table->zero_set && predicate (0, hash_table->zero_entry, arg))
363 hash_table->zero_set = 0;
364 hash_table->zero_entry = 0;
367 for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
368 if (predicate (e->key, e->contents, arg))
371 e->contents = NULL_ENTRY;