1 82550776 2021-03-17 op /* $OpenBSD: ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
  2 82550776 2021-03-17 op 
  3 82550776 2021-03-17 op /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
  4 82550776 2021-03-17 op  *
  5 82550776 2021-03-17 op  * Permission to use, copy, modify, and distribute this software for any
  6 82550776 2021-03-17 op  * purpose with or without fee is hereby granted, provided that the above
  7 82550776 2021-03-17 op  * copyright notice and this permission notice appear in all copies.
  8 82550776 2021-03-17 op  *
  9 82550776 2021-03-17 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 10 82550776 2021-03-17 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 11 82550776 2021-03-17 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 12 82550776 2021-03-17 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 13 82550776 2021-03-17 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 14 82550776 2021-03-17 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 15 82550776 2021-03-17 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 16 82550776 2021-03-17 op  */
 17 82550776 2021-03-17 op 
 18 0ccaf6d8 2021-03-17 op #include "compat.h"
 19 82550776 2021-03-17 op 
 20 82550776 2021-03-17 op #include <stddef.h>
 21 82550776 2021-03-17 op #include <stdint.h>
 22 82550776 2021-03-17 op #include <stdlib.h>
 23 82550776 2021-03-17 op #include <string.h>
 24 82550776 2021-03-17 op #include <limits.h>
 25 82550776 2021-03-17 op #include "ohash.h"
 26 82550776 2021-03-17 op 
 27 82550776 2021-03-17 op struct _ohash_record {
 28 82550776 2021-03-17 op 	uint32_t	hv;
 29 82550776 2021-03-17 op 	const char	*p;
 30 82550776 2021-03-17 op };
 31 82550776 2021-03-17 op 
 32 82550776 2021-03-17 op #define DELETED		((const char *)h)
 33 82550776 2021-03-17 op #define NONE		(h->size)
 34 82550776 2021-03-17 op 
 35 82550776 2021-03-17 op /* Don't bother changing the hash table if the change is small enough.  */
 36 82550776 2021-03-17 op #define MINSIZE		(1UL << 4)
 37 82550776 2021-03-17 op #define MINDELETED	4
 38 82550776 2021-03-17 op 
 39 82550776 2021-03-17 op static void ohash_resize(struct ohash *);
 40 82550776 2021-03-17 op 
 41 82550776 2021-03-17 op 
 42 82550776 2021-03-17 op /* This handles the common case of variable length keys, where the
 43 82550776 2021-03-17 op  * key is stored at the end of the record.
 44 82550776 2021-03-17 op  */
 45 82550776 2021-03-17 op void *
 46 82550776 2021-03-17 op ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
 47 82550776 2021-03-17 op {
 48 82550776 2021-03-17 op 	char *p;
 49 82550776 2021-03-17 op 
 50 82550776 2021-03-17 op 	if (!*end)
 51 82550776 2021-03-17 op 		*end = start + strlen(start);
 52 82550776 2021-03-17 op 	p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
 53 82550776 2021-03-17 op 	if (p) {
 54 82550776 2021-03-17 op 		memcpy(p+i->key_offset, start, *end-start);
 55 82550776 2021-03-17 op 		p[i->key_offset + (*end - start)] = '\0';
 56 82550776 2021-03-17 op 	}
 57 82550776 2021-03-17 op 	return (void *)p;
 58 82550776 2021-03-17 op }
 59 82550776 2021-03-17 op 
 60 82550776 2021-03-17 op /* hash_delete only frees the hash structure. Use hash_first/hash_next
 61 82550776 2021-03-17 op  * to free entries as well.  */
 62 82550776 2021-03-17 op void
 63 82550776 2021-03-17 op ohash_delete(struct ohash *h)
 64 82550776 2021-03-17 op {
 65 82550776 2021-03-17 op 	(h->info.free)(h->t, h->info.data);
 66 82550776 2021-03-17 op #ifndef NDEBUG
 67 82550776 2021-03-17 op 	h->t = NULL;
 68 82550776 2021-03-17 op #endif
 69 82550776 2021-03-17 op }
 70 82550776 2021-03-17 op 
 71 82550776 2021-03-17 op static void
 72 82550776 2021-03-17 op ohash_resize(struct ohash *h)
 73 82550776 2021-03-17 op {
 74 82550776 2021-03-17 op 	struct _ohash_record *n;
 75 82550776 2021-03-17 op 	size_t ns;
 76 82550776 2021-03-17 op 	unsigned int	j;
 77 82550776 2021-03-17 op 	unsigned int	i, incr;
 78 82550776 2021-03-17 op 
 79 82550776 2021-03-17 op 	if (4 * h->deleted < h->total) {
 80 82550776 2021-03-17 op 		if (h->size >= (UINT_MAX >> 1U))
 81 82550776 2021-03-17 op 			ns = UINT_MAX;
 82 82550776 2021-03-17 op 		else
 83 82550776 2021-03-17 op 			ns = h->size << 1U;
 84 82550776 2021-03-17 op 	} else if (3 * h->deleted > 2 * h->total)
 85 82550776 2021-03-17 op 		ns = h->size >> 1U;
 86 82550776 2021-03-17 op 	else
 87 82550776 2021-03-17 op 		ns = h->size;
 88 82550776 2021-03-17 op 	if (ns < MINSIZE)
 89 82550776 2021-03-17 op 		ns = MINSIZE;
 90 82550776 2021-03-17 op #ifdef STATS_HASH
 91 82550776 2021-03-17 op 	STAT_HASH_EXPAND++;
 92 82550776 2021-03-17 op 	STAT_HASH_SIZE += ns - h->size;
 93 82550776 2021-03-17 op #endif
 94 82550776 2021-03-17 op 
 95 82550776 2021-03-17 op 	n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
 96 82550776 2021-03-17 op 	if (!n)
 97 82550776 2021-03-17 op 		return;
 98 82550776 2021-03-17 op 
 99 82550776 2021-03-17 op 	for (j = 0; j < h->size; j++) {
100 82550776 2021-03-17 op 		if (h->t[j].p != NULL && h->t[j].p != DELETED) {
101 82550776 2021-03-17 op 			i = h->t[j].hv % ns;
102 82550776 2021-03-17 op 			incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
103 82550776 2021-03-17 op 			while (n[i].p != NULL) {
104 82550776 2021-03-17 op 				i += incr;
105 82550776 2021-03-17 op 				if (i >= ns)
106 82550776 2021-03-17 op 					i -= ns;
107 82550776 2021-03-17 op 			}
108 82550776 2021-03-17 op 			n[i].hv = h->t[j].hv;
109 82550776 2021-03-17 op 			n[i].p = h->t[j].p;
110 82550776 2021-03-17 op 		}
111 82550776 2021-03-17 op 	}
112 82550776 2021-03-17 op 	(h->info.free)(h->t, h->info.data);
113 82550776 2021-03-17 op 	h->t = n;
114 82550776 2021-03-17 op 	h->size = ns;
115 82550776 2021-03-17 op 	h->total -= h->deleted;
116 82550776 2021-03-17 op 	h->deleted = 0;
117 82550776 2021-03-17 op }
118 82550776 2021-03-17 op 
119 82550776 2021-03-17 op void *
120 82550776 2021-03-17 op ohash_remove(struct ohash *h, unsigned int i)
121 82550776 2021-03-17 op {
122 82550776 2021-03-17 op 	void		*result = (void *)h->t[i].p;
123 82550776 2021-03-17 op 
124 82550776 2021-03-17 op 	if (result == NULL || result == DELETED)
125 82550776 2021-03-17 op 		return NULL;
126 82550776 2021-03-17 op 
127 82550776 2021-03-17 op #ifdef STATS_HASH
128 82550776 2021-03-17 op 	STAT_HASH_ENTRIES--;
129 82550776 2021-03-17 op #endif
130 82550776 2021-03-17 op 	h->t[i].p = DELETED;
131 82550776 2021-03-17 op 	h->deleted++;
132 82550776 2021-03-17 op 	if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
133 82550776 2021-03-17 op 		ohash_resize(h);
134 82550776 2021-03-17 op 	return result;
135 82550776 2021-03-17 op }
136 82550776 2021-03-17 op 
137 82550776 2021-03-17 op void *
138 82550776 2021-03-17 op ohash_find(struct ohash *h, unsigned int i)
139 82550776 2021-03-17 op {
140 82550776 2021-03-17 op 	if (h->t[i].p == DELETED)
141 82550776 2021-03-17 op 		return NULL;
142 82550776 2021-03-17 op 	else
143 82550776 2021-03-17 op 		return (void *)h->t[i].p;
144 82550776 2021-03-17 op }
145 82550776 2021-03-17 op 
146 82550776 2021-03-17 op void *
147 82550776 2021-03-17 op ohash_insert(struct ohash *h, unsigned int i, void *p)
148 82550776 2021-03-17 op {
149 82550776 2021-03-17 op #ifdef STATS_HASH
150 82550776 2021-03-17 op 	STAT_HASH_ENTRIES++;
151 82550776 2021-03-17 op #endif
152 82550776 2021-03-17 op 	if (h->t[i].p == DELETED) {
153 82550776 2021-03-17 op 		h->deleted--;
154 82550776 2021-03-17 op 		h->t[i].p = p;
155 82550776 2021-03-17 op 	} else {
156 82550776 2021-03-17 op 		h->t[i].p = p;
157 82550776 2021-03-17 op 		/* Arbitrary resize boundary.  Tweak if not efficient enough.  */
158 82550776 2021-03-17 op 		if (++h->total * 4 > h->size * 3)
159 82550776 2021-03-17 op 			ohash_resize(h);
160 82550776 2021-03-17 op 	}
161 82550776 2021-03-17 op 	return p;
162 82550776 2021-03-17 op }
163 82550776 2021-03-17 op 
164 82550776 2021-03-17 op unsigned int
165 82550776 2021-03-17 op ohash_entries(struct ohash *h)
166 82550776 2021-03-17 op {
167 82550776 2021-03-17 op 	return h->total - h->deleted;
168 82550776 2021-03-17 op }
169 82550776 2021-03-17 op 
170 82550776 2021-03-17 op void *
171 82550776 2021-03-17 op ohash_first(struct ohash *h, unsigned int *pos)
172 82550776 2021-03-17 op {
173 82550776 2021-03-17 op 	*pos = 0;
174 82550776 2021-03-17 op 	return ohash_next(h, pos);
175 82550776 2021-03-17 op }
176 82550776 2021-03-17 op 
177 82550776 2021-03-17 op void *
178 82550776 2021-03-17 op ohash_next(struct ohash *h, unsigned int *pos)
179 82550776 2021-03-17 op {
180 82550776 2021-03-17 op 	for (; *pos < h->size; (*pos)++)
181 82550776 2021-03-17 op 		if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
182 82550776 2021-03-17 op 			return (void *)h->t[(*pos)++].p;
183 82550776 2021-03-17 op 	return NULL;
184 82550776 2021-03-17 op }
185 82550776 2021-03-17 op 
186 82550776 2021-03-17 op void
187 82550776 2021-03-17 op ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
188 82550776 2021-03-17 op {
189 82550776 2021-03-17 op 	h->size = 1UL << size;
190 82550776 2021-03-17 op 	if (h->size < MINSIZE)
191 82550776 2021-03-17 op 		h->size = MINSIZE;
192 82550776 2021-03-17 op #ifdef STATS_HASH
193 82550776 2021-03-17 op 	STAT_HASH_CREATION++;
194 82550776 2021-03-17 op 	STAT_HASH_SIZE += h->size;
195 82550776 2021-03-17 op #endif
196 82550776 2021-03-17 op 	/* Copy info so that caller may free it.  */
197 82550776 2021-03-17 op 	h->info.key_offset = info->key_offset;
198 82550776 2021-03-17 op 	h->info.calloc = info->calloc;
199 82550776 2021-03-17 op 	h->info.free = info->free;
200 82550776 2021-03-17 op 	h->info.alloc = info->alloc;
201 82550776 2021-03-17 op 	h->info.data = info->data;
202 82550776 2021-03-17 op 	h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
203 82550776 2021-03-17 op 		    h->info.data);
204 82550776 2021-03-17 op 	h->total = h->deleted = 0;
205 82550776 2021-03-17 op }
206 82550776 2021-03-17 op 
207 82550776 2021-03-17 op uint32_t
208 82550776 2021-03-17 op ohash_interval(const char *s, const char **e)
209 82550776 2021-03-17 op {
210 82550776 2021-03-17 op 	uint32_t k;
211 82550776 2021-03-17 op 
212 82550776 2021-03-17 op 	if (!*e)
213 82550776 2021-03-17 op 		*e = s + strlen(s);
214 82550776 2021-03-17 op 	if (s == *e)
215 82550776 2021-03-17 op 		k = 0;
216 82550776 2021-03-17 op 	else
217 82550776 2021-03-17 op 		k = *s++;
218 82550776 2021-03-17 op 	while (s != *e)
219 82550776 2021-03-17 op 		k =  ((k << 2) | (k >> 30)) ^ *s++;
220 82550776 2021-03-17 op 	return k;
221 82550776 2021-03-17 op }
222 82550776 2021-03-17 op 
223 82550776 2021-03-17 op unsigned int
224 82550776 2021-03-17 op ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
225 82550776 2021-03-17 op     uint32_t hv)
226 82550776 2021-03-17 op {
227 82550776 2021-03-17 op 	unsigned int	i, incr;
228 82550776 2021-03-17 op 	unsigned int	empty;
229 82550776 2021-03-17 op 
230 82550776 2021-03-17 op #ifdef STATS_HASH
231 82550776 2021-03-17 op 	STAT_HASH_LOOKUP++;
232 82550776 2021-03-17 op #endif
233 82550776 2021-03-17 op 	empty = NONE;
234 82550776 2021-03-17 op 	i = hv % h->size;
235 82550776 2021-03-17 op 	incr = ((hv % (h->size-2)) & ~1) + 1;
236 82550776 2021-03-17 op 	while (h->t[i].p != NULL) {
237 82550776 2021-03-17 op #ifdef STATS_HASH
238 82550776 2021-03-17 op 		STAT_HASH_LENGTH++;
239 82550776 2021-03-17 op #endif
240 82550776 2021-03-17 op 		if (h->t[i].p == DELETED) {
241 82550776 2021-03-17 op 			if (empty == NONE)
242 82550776 2021-03-17 op 				empty = i;
243 82550776 2021-03-17 op 		} else if (h->t[i].hv == hv &&
244 82550776 2021-03-17 op 		    strncmp(h->t[i].p+h->info.key_offset, start,
245 82550776 2021-03-17 op 			end - start) == 0 &&
246 82550776 2021-03-17 op 		    (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
247 82550776 2021-03-17 op 			if (empty != NONE) {
248 82550776 2021-03-17 op 				h->t[empty].hv = hv;
249 82550776 2021-03-17 op 				h->t[empty].p = h->t[i].p;
250 82550776 2021-03-17 op 				h->t[i].p = DELETED;
251 82550776 2021-03-17 op 				return empty;
252 82550776 2021-03-17 op 			} else {
253 82550776 2021-03-17 op #ifdef STATS_HASH
254 82550776 2021-03-17 op 				STAT_HASH_POSITIVE++;
255 82550776 2021-03-17 op #endif
256 82550776 2021-03-17 op 				return i;
257 82550776 2021-03-17 op 			}
258 82550776 2021-03-17 op 		}
259 82550776 2021-03-17 op 		i += incr;
260 82550776 2021-03-17 op 		if (i >= h->size)
261 82550776 2021-03-17 op 			i -= h->size;
262 82550776 2021-03-17 op 	}
263 82550776 2021-03-17 op 
264 82550776 2021-03-17 op 	/* Found an empty position.  */
265 82550776 2021-03-17 op 	if (empty != NONE)
266 82550776 2021-03-17 op 		i = empty;
267 82550776 2021-03-17 op 	h->t[i].hv = hv;
268 82550776 2021-03-17 op 	return i;
269 82550776 2021-03-17 op }
270 82550776 2021-03-17 op 
271 82550776 2021-03-17 op unsigned int
272 82550776 2021-03-17 op ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
273 82550776 2021-03-17 op {
274 82550776 2021-03-17 op 	unsigned int	i, incr;
275 82550776 2021-03-17 op 	unsigned int	empty;
276 82550776 2021-03-17 op 
277 82550776 2021-03-17 op #ifdef STATS_HASH
278 82550776 2021-03-17 op 	STAT_HASH_LOOKUP++;
279 82550776 2021-03-17 op #endif
280 82550776 2021-03-17 op 	empty = NONE;
281 82550776 2021-03-17 op 	i = hv % h->size;
282 82550776 2021-03-17 op 	incr = ((hv % (h->size-2)) & ~1) + 1;
283 82550776 2021-03-17 op 	while (h->t[i].p != NULL) {
284 82550776 2021-03-17 op #ifdef STATS_HASH
285 82550776 2021-03-17 op 		STAT_HASH_LENGTH++;
286 82550776 2021-03-17 op #endif
287 82550776 2021-03-17 op 		if (h->t[i].p == DELETED) {
288 82550776 2021-03-17 op 			if (empty == NONE)
289 82550776 2021-03-17 op 				empty = i;
290 82550776 2021-03-17 op 		} else if (h->t[i].hv == hv &&
291 82550776 2021-03-17 op 		    memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
292 82550776 2021-03-17 op 			if (empty != NONE) {
293 82550776 2021-03-17 op 				h->t[empty].hv = hv;
294 82550776 2021-03-17 op 				h->t[empty].p = h->t[i].p;
295 82550776 2021-03-17 op 				h->t[i].p = DELETED;
296 82550776 2021-03-17 op 				return empty;
297 82550776 2021-03-17 op 			} else {
298 82550776 2021-03-17 op #ifdef STATS_HASH
299 82550776 2021-03-17 op 				STAT_HASH_POSITIVE++;
300 82550776 2021-03-17 op #endif
301 82550776 2021-03-17 op 			}	return i;
302 82550776 2021-03-17 op 		}
303 82550776 2021-03-17 op 		i += incr;
304 82550776 2021-03-17 op 		if (i >= h->size)
305 82550776 2021-03-17 op 			i -= h->size;
306 82550776 2021-03-17 op 	}
307 82550776 2021-03-17 op 
308 82550776 2021-03-17 op 	/* Found an empty position.  */
309 82550776 2021-03-17 op 	if (empty != NONE)
310 82550776 2021-03-17 op 		i = empty;
311 82550776 2021-03-17 op 	h->t[i].hv = hv;
312 82550776 2021-03-17 op 	return i;
313 82550776 2021-03-17 op }
314 82550776 2021-03-17 op 
315 82550776 2021-03-17 op unsigned int
316 82550776 2021-03-17 op ohash_qlookup(struct ohash *h, const char *s)
317 82550776 2021-03-17 op {
318 82550776 2021-03-17 op 	const char *e = NULL;
319 82550776 2021-03-17 op 	return ohash_qlookupi(h, s, &e);
320 82550776 2021-03-17 op }
321 82550776 2021-03-17 op 
322 82550776 2021-03-17 op unsigned int
323 82550776 2021-03-17 op ohash_qlookupi(struct ohash *h, const char *s, const char **e)
324 82550776 2021-03-17 op {
325 82550776 2021-03-17 op 	uint32_t hv;
326 82550776 2021-03-17 op 
327 82550776 2021-03-17 op 	hv = ohash_interval(s, e);
328 82550776 2021-03-17 op 	return ohash_lookup_interval(h, s, *e, hv);
329 82550776 2021-03-17 op }