1 b4252034 2021-07-22 op /* $OpenBSD: ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
  2 b4252034 2021-07-22 op 
  3 b4252034 2021-07-22 op /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
  4 b4252034 2021-07-22 op  *
  5 b4252034 2021-07-22 op  * Permission to use, copy, modify, and distribute this software for any
  6 b4252034 2021-07-22 op  * purpose with or without fee is hereby granted, provided that the above
  7 b4252034 2021-07-22 op  * copyright notice and this permission notice appear in all copies.
  8 b4252034 2021-07-22 op  *
  9 b4252034 2021-07-22 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 10 b4252034 2021-07-22 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 11 b4252034 2021-07-22 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 12 b4252034 2021-07-22 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 13 b4252034 2021-07-22 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 14 b4252034 2021-07-22 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 15 b4252034 2021-07-22 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 16 b4252034 2021-07-22 op  */
 17 b4252034 2021-07-22 op 
 18 b4252034 2021-07-22 op #include "compat.h"
 19 b4252034 2021-07-22 op 
 20 b4252034 2021-07-22 op #include <stddef.h>
 21 b4252034 2021-07-22 op #include <stdint.h>
 22 b4252034 2021-07-22 op #include <stdlib.h>
 23 b4252034 2021-07-22 op #include <string.h>
 24 b4252034 2021-07-22 op #include <limits.h>
 25 b4252034 2021-07-22 op #include "ohash.h"
 26 b4252034 2021-07-22 op 
 27 b4252034 2021-07-22 op struct _ohash_record {
 28 b4252034 2021-07-22 op 	uint32_t	hv;
 29 b4252034 2021-07-22 op 	const char	*p;
 30 b4252034 2021-07-22 op };
 31 b4252034 2021-07-22 op 
 32 b4252034 2021-07-22 op #define DELETED		((const char *)h)
 33 b4252034 2021-07-22 op #define NONE		(h->size)
 34 b4252034 2021-07-22 op 
 35 b4252034 2021-07-22 op /* Don't bother changing the hash table if the change is small enough.  */
 36 b4252034 2021-07-22 op #define MINSIZE		(1UL << 4)
 37 b4252034 2021-07-22 op #define MINDELETED	4
 38 b4252034 2021-07-22 op 
 39 b4252034 2021-07-22 op static void ohash_resize(struct ohash *);
 40 b4252034 2021-07-22 op 
 41 b4252034 2021-07-22 op 
 42 b4252034 2021-07-22 op /* This handles the common case of variable length keys, where the
 43 b4252034 2021-07-22 op  * key is stored at the end of the record.
 44 b4252034 2021-07-22 op  */
 45 b4252034 2021-07-22 op void *
 46 b4252034 2021-07-22 op ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
 47 b4252034 2021-07-22 op {
 48 b4252034 2021-07-22 op 	char *p;
 49 b4252034 2021-07-22 op 
 50 b4252034 2021-07-22 op 	if (!*end)
 51 b4252034 2021-07-22 op 		*end = start + strlen(start);
 52 b4252034 2021-07-22 op 	p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
 53 b4252034 2021-07-22 op 	if (p) {
 54 b4252034 2021-07-22 op 		memcpy(p+i->key_offset, start, *end-start);
 55 b4252034 2021-07-22 op 		p[i->key_offset + (*end - start)] = '\0';
 56 b4252034 2021-07-22 op 	}
 57 b4252034 2021-07-22 op 	return (void *)p;
 58 b4252034 2021-07-22 op }
 59 b4252034 2021-07-22 op 
 60 b4252034 2021-07-22 op /* hash_delete only frees the hash structure. Use hash_first/hash_next
 61 b4252034 2021-07-22 op  * to free entries as well.  */
 62 b4252034 2021-07-22 op void
 63 b4252034 2021-07-22 op ohash_delete(struct ohash *h)
 64 b4252034 2021-07-22 op {
 65 b4252034 2021-07-22 op 	(h->info.free)(h->t, h->info.data);
 66 b4252034 2021-07-22 op #ifndef NDEBUG
 67 b4252034 2021-07-22 op 	h->t = NULL;
 68 b4252034 2021-07-22 op #endif
 69 b4252034 2021-07-22 op }
 70 b4252034 2021-07-22 op 
 71 b4252034 2021-07-22 op static void
 72 b4252034 2021-07-22 op ohash_resize(struct ohash *h)
 73 b4252034 2021-07-22 op {
 74 b4252034 2021-07-22 op 	struct _ohash_record *n;
 75 b4252034 2021-07-22 op 	size_t ns;
 76 b4252034 2021-07-22 op 	unsigned int	j;
 77 b4252034 2021-07-22 op 	unsigned int	i, incr;
 78 b4252034 2021-07-22 op 
 79 b4252034 2021-07-22 op 	if (4 * h->deleted < h->total) {
 80 b4252034 2021-07-22 op 		if (h->size >= (UINT_MAX >> 1U))
 81 b4252034 2021-07-22 op 			ns = UINT_MAX;
 82 b4252034 2021-07-22 op 		else
 83 b4252034 2021-07-22 op 			ns = h->size << 1U;
 84 b4252034 2021-07-22 op 	} else if (3 * h->deleted > 2 * h->total)
 85 b4252034 2021-07-22 op 		ns = h->size >> 1U;
 86 b4252034 2021-07-22 op 	else
 87 b4252034 2021-07-22 op 		ns = h->size;
 88 b4252034 2021-07-22 op 	if (ns < MINSIZE)
 89 b4252034 2021-07-22 op 		ns = MINSIZE;
 90 b4252034 2021-07-22 op #ifdef STATS_HASH
 91 b4252034 2021-07-22 op 	STAT_HASH_EXPAND++;
 92 b4252034 2021-07-22 op 	STAT_HASH_SIZE += ns - h->size;
 93 b4252034 2021-07-22 op #endif
 94 b4252034 2021-07-22 op 
 95 b4252034 2021-07-22 op 	n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
 96 b4252034 2021-07-22 op 	if (!n)
 97 b4252034 2021-07-22 op 		return;
 98 b4252034 2021-07-22 op 
 99 b4252034 2021-07-22 op 	for (j = 0; j < h->size; j++) {
100 b4252034 2021-07-22 op 		if (h->t[j].p != NULL && h->t[j].p != DELETED) {
101 b4252034 2021-07-22 op 			i = h->t[j].hv % ns;
102 b4252034 2021-07-22 op 			incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
103 b4252034 2021-07-22 op 			while (n[i].p != NULL) {
104 b4252034 2021-07-22 op 				i += incr;
105 b4252034 2021-07-22 op 				if (i >= ns)
106 b4252034 2021-07-22 op 					i -= ns;
107 b4252034 2021-07-22 op 			}
108 b4252034 2021-07-22 op 			n[i].hv = h->t[j].hv;
109 b4252034 2021-07-22 op 			n[i].p = h->t[j].p;
110 b4252034 2021-07-22 op 		}
111 b4252034 2021-07-22 op 	}
112 b4252034 2021-07-22 op 	(h->info.free)(h->t, h->info.data);
113 b4252034 2021-07-22 op 	h->t = n;
114 b4252034 2021-07-22 op 	h->size = ns;
115 b4252034 2021-07-22 op 	h->total -= h->deleted;
116 b4252034 2021-07-22 op 	h->deleted = 0;
117 b4252034 2021-07-22 op }
118 b4252034 2021-07-22 op 
119 b4252034 2021-07-22 op void *
120 b4252034 2021-07-22 op ohash_remove(struct ohash *h, unsigned int i)
121 b4252034 2021-07-22 op {
122 b4252034 2021-07-22 op 	void		*result = (void *)h->t[i].p;
123 b4252034 2021-07-22 op 
124 b4252034 2021-07-22 op 	if (result == NULL || result == DELETED)
125 b4252034 2021-07-22 op 		return NULL;
126 b4252034 2021-07-22 op 
127 b4252034 2021-07-22 op #ifdef STATS_HASH
128 b4252034 2021-07-22 op 	STAT_HASH_ENTRIES--;
129 b4252034 2021-07-22 op #endif
130 b4252034 2021-07-22 op 	h->t[i].p = DELETED;
131 b4252034 2021-07-22 op 	h->deleted++;
132 b4252034 2021-07-22 op 	if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
133 b4252034 2021-07-22 op 		ohash_resize(h);
134 b4252034 2021-07-22 op 	return result;
135 b4252034 2021-07-22 op }
136 b4252034 2021-07-22 op 
137 b4252034 2021-07-22 op void *
138 b4252034 2021-07-22 op ohash_find(struct ohash *h, unsigned int i)
139 b4252034 2021-07-22 op {
140 b4252034 2021-07-22 op 	if (h->t[i].p == DELETED)
141 b4252034 2021-07-22 op 		return NULL;
142 b4252034 2021-07-22 op 	else
143 b4252034 2021-07-22 op 		return (void *)h->t[i].p;
144 b4252034 2021-07-22 op }
145 b4252034 2021-07-22 op 
146 b4252034 2021-07-22 op void *
147 b4252034 2021-07-22 op ohash_insert(struct ohash *h, unsigned int i, void *p)
148 b4252034 2021-07-22 op {
149 b4252034 2021-07-22 op #ifdef STATS_HASH
150 b4252034 2021-07-22 op 	STAT_HASH_ENTRIES++;
151 b4252034 2021-07-22 op #endif
152 b4252034 2021-07-22 op 	if (h->t[i].p == DELETED) {
153 b4252034 2021-07-22 op 		h->deleted--;
154 b4252034 2021-07-22 op 		h->t[i].p = p;
155 b4252034 2021-07-22 op 	} else {
156 b4252034 2021-07-22 op 		h->t[i].p = p;
157 b4252034 2021-07-22 op 		/* Arbitrary resize boundary.  Tweak if not efficient enough.  */
158 b4252034 2021-07-22 op 		if (++h->total * 4 > h->size * 3)
159 b4252034 2021-07-22 op 			ohash_resize(h);
160 b4252034 2021-07-22 op 	}
161 b4252034 2021-07-22 op 	return p;
162 b4252034 2021-07-22 op }
163 b4252034 2021-07-22 op 
164 b4252034 2021-07-22 op unsigned int
165 b4252034 2021-07-22 op ohash_entries(struct ohash *h)
166 b4252034 2021-07-22 op {
167 b4252034 2021-07-22 op 	return h->total - h->deleted;
168 b4252034 2021-07-22 op }
169 b4252034 2021-07-22 op 
170 b4252034 2021-07-22 op void *
171 b4252034 2021-07-22 op ohash_first(struct ohash *h, unsigned int *pos)
172 b4252034 2021-07-22 op {
173 b4252034 2021-07-22 op 	*pos = 0;
174 b4252034 2021-07-22 op 	return ohash_next(h, pos);
175 b4252034 2021-07-22 op }
176 b4252034 2021-07-22 op 
177 b4252034 2021-07-22 op void *
178 b4252034 2021-07-22 op ohash_next(struct ohash *h, unsigned int *pos)
179 b4252034 2021-07-22 op {
180 b4252034 2021-07-22 op 	for (; *pos < h->size; (*pos)++)
181 b4252034 2021-07-22 op 		if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
182 b4252034 2021-07-22 op 			return (void *)h->t[(*pos)++].p;
183 b4252034 2021-07-22 op 	return NULL;
184 b4252034 2021-07-22 op }
185 b4252034 2021-07-22 op 
186 b4252034 2021-07-22 op void
187 b4252034 2021-07-22 op ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
188 b4252034 2021-07-22 op {
189 b4252034 2021-07-22 op 	h->size = 1UL << size;
190 b4252034 2021-07-22 op 	if (h->size < MINSIZE)
191 b4252034 2021-07-22 op 		h->size = MINSIZE;
192 b4252034 2021-07-22 op #ifdef STATS_HASH
193 b4252034 2021-07-22 op 	STAT_HASH_CREATION++;
194 b4252034 2021-07-22 op 	STAT_HASH_SIZE += h->size;
195 b4252034 2021-07-22 op #endif
196 b4252034 2021-07-22 op 	/* Copy info so that caller may free it.  */
197 b4252034 2021-07-22 op 	h->info.key_offset = info->key_offset;
198 b4252034 2021-07-22 op 	h->info.calloc = info->calloc;
199 b4252034 2021-07-22 op 	h->info.free = info->free;
200 b4252034 2021-07-22 op 	h->info.alloc = info->alloc;
201 b4252034 2021-07-22 op 	h->info.data = info->data;
202 b4252034 2021-07-22 op 	h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
203 b4252034 2021-07-22 op 		    h->info.data);
204 b4252034 2021-07-22 op 	h->total = h->deleted = 0;
205 b4252034 2021-07-22 op }
206 b4252034 2021-07-22 op 
207 b4252034 2021-07-22 op uint32_t
208 b4252034 2021-07-22 op ohash_interval(const char *s, const char **e)
209 b4252034 2021-07-22 op {
210 b4252034 2021-07-22 op 	uint32_t k;
211 b4252034 2021-07-22 op 
212 b4252034 2021-07-22 op 	if (!*e)
213 b4252034 2021-07-22 op 		*e = s + strlen(s);
214 b4252034 2021-07-22 op 	if (s == *e)
215 b4252034 2021-07-22 op 		k = 0;
216 b4252034 2021-07-22 op 	else
217 b4252034 2021-07-22 op 		k = *s++;
218 b4252034 2021-07-22 op 	while (s != *e)
219 b4252034 2021-07-22 op 		k =  ((k << 2) | (k >> 30)) ^ *s++;
220 b4252034 2021-07-22 op 	return k;
221 b4252034 2021-07-22 op }
222 b4252034 2021-07-22 op 
223 b4252034 2021-07-22 op unsigned int
224 b4252034 2021-07-22 op ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
225 b4252034 2021-07-22 op     uint32_t hv)
226 b4252034 2021-07-22 op {
227 b4252034 2021-07-22 op 	unsigned int	i, incr;
228 b4252034 2021-07-22 op 	unsigned int	empty;
229 b4252034 2021-07-22 op 
230 b4252034 2021-07-22 op #ifdef STATS_HASH
231 b4252034 2021-07-22 op 	STAT_HASH_LOOKUP++;
232 b4252034 2021-07-22 op #endif
233 b4252034 2021-07-22 op 	empty = NONE;
234 b4252034 2021-07-22 op 	i = hv % h->size;
235 b4252034 2021-07-22 op 	incr = ((hv % (h->size-2)) & ~1) + 1;
236 b4252034 2021-07-22 op 	while (h->t[i].p != NULL) {
237 b4252034 2021-07-22 op #ifdef STATS_HASH
238 b4252034 2021-07-22 op 		STAT_HASH_LENGTH++;
239 b4252034 2021-07-22 op #endif
240 b4252034 2021-07-22 op 		if (h->t[i].p == DELETED) {
241 b4252034 2021-07-22 op 			if (empty == NONE)
242 b4252034 2021-07-22 op 				empty = i;
243 b4252034 2021-07-22 op 		} else if (h->t[i].hv == hv &&
244 b4252034 2021-07-22 op 		    strncmp(h->t[i].p+h->info.key_offset, start,
245 b4252034 2021-07-22 op 			end - start) == 0 &&
246 b4252034 2021-07-22 op 		    (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
247 b4252034 2021-07-22 op 			if (empty != NONE) {
248 b4252034 2021-07-22 op 				h->t[empty].hv = hv;
249 b4252034 2021-07-22 op 				h->t[empty].p = h->t[i].p;
250 b4252034 2021-07-22 op 				h->t[i].p = DELETED;
251 b4252034 2021-07-22 op 				return empty;
252 b4252034 2021-07-22 op 			} else {
253 b4252034 2021-07-22 op #ifdef STATS_HASH
254 b4252034 2021-07-22 op 				STAT_HASH_POSITIVE++;
255 b4252034 2021-07-22 op #endif
256 b4252034 2021-07-22 op 				return i;
257 b4252034 2021-07-22 op 			}
258 b4252034 2021-07-22 op 		}
259 b4252034 2021-07-22 op 		i += incr;
260 b4252034 2021-07-22 op 		if (i >= h->size)
261 b4252034 2021-07-22 op 			i -= h->size;
262 b4252034 2021-07-22 op 	}
263 b4252034 2021-07-22 op 
264 b4252034 2021-07-22 op 	/* Found an empty position.  */
265 b4252034 2021-07-22 op 	if (empty != NONE)
266 b4252034 2021-07-22 op 		i = empty;
267 b4252034 2021-07-22 op 	h->t[i].hv = hv;
268 b4252034 2021-07-22 op 	return i;
269 b4252034 2021-07-22 op }
270 b4252034 2021-07-22 op 
271 b4252034 2021-07-22 op unsigned int
272 b4252034 2021-07-22 op ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
273 b4252034 2021-07-22 op {
274 b4252034 2021-07-22 op 	unsigned int	i, incr;
275 b4252034 2021-07-22 op 	unsigned int	empty;
276 b4252034 2021-07-22 op 
277 b4252034 2021-07-22 op #ifdef STATS_HASH
278 b4252034 2021-07-22 op 	STAT_HASH_LOOKUP++;
279 b4252034 2021-07-22 op #endif
280 b4252034 2021-07-22 op 	empty = NONE;
281 b4252034 2021-07-22 op 	i = hv % h->size;
282 b4252034 2021-07-22 op 	incr = ((hv % (h->size-2)) & ~1) + 1;
283 b4252034 2021-07-22 op 	while (h->t[i].p != NULL) {
284 b4252034 2021-07-22 op #ifdef STATS_HASH
285 b4252034 2021-07-22 op 		STAT_HASH_LENGTH++;
286 b4252034 2021-07-22 op #endif
287 b4252034 2021-07-22 op 		if (h->t[i].p == DELETED) {
288 b4252034 2021-07-22 op 			if (empty == NONE)
289 b4252034 2021-07-22 op 				empty = i;
290 b4252034 2021-07-22 op 		} else if (h->t[i].hv == hv &&
291 b4252034 2021-07-22 op 		    memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
292 b4252034 2021-07-22 op 			if (empty != NONE) {
293 b4252034 2021-07-22 op 				h->t[empty].hv = hv;
294 b4252034 2021-07-22 op 				h->t[empty].p = h->t[i].p;
295 b4252034 2021-07-22 op 				h->t[i].p = DELETED;
296 b4252034 2021-07-22 op 				return empty;
297 b4252034 2021-07-22 op 			} else {
298 b4252034 2021-07-22 op #ifdef STATS_HASH
299 b4252034 2021-07-22 op 				STAT_HASH_POSITIVE++;
300 b4252034 2021-07-22 op #endif
301 b4252034 2021-07-22 op 			}	return i;
302 b4252034 2021-07-22 op 		}
303 b4252034 2021-07-22 op 		i += incr;
304 b4252034 2021-07-22 op 		if (i >= h->size)
305 b4252034 2021-07-22 op 			i -= h->size;
306 b4252034 2021-07-22 op 	}
307 b4252034 2021-07-22 op 
308 b4252034 2021-07-22 op 	/* Found an empty position.  */
309 b4252034 2021-07-22 op 	if (empty != NONE)
310 b4252034 2021-07-22 op 		i = empty;
311 b4252034 2021-07-22 op 	h->t[i].hv = hv;
312 b4252034 2021-07-22 op 	return i;
313 b4252034 2021-07-22 op }
314 b4252034 2021-07-22 op 
315 b4252034 2021-07-22 op unsigned int
316 b4252034 2021-07-22 op ohash_qlookup(struct ohash *h, const char *s)
317 b4252034 2021-07-22 op {
318 b4252034 2021-07-22 op 	const char *e = NULL;
319 b4252034 2021-07-22 op 	return ohash_qlookupi(h, s, &e);
320 b4252034 2021-07-22 op }
321 b4252034 2021-07-22 op 
322 b4252034 2021-07-22 op unsigned int
323 b4252034 2021-07-22 op ohash_qlookupi(struct ohash *h, const char *s, const char **e)
324 b4252034 2021-07-22 op {
325 b4252034 2021-07-22 op 	uint32_t hv;
326 b4252034 2021-07-22 op 
327 b4252034 2021-07-22 op 	hv = ohash_interval(s, e);
328 b4252034 2021-07-22 op 	return ohash_lookup_interval(h, s, *e, hv);
329 b4252034 2021-07-22 op }