1/*
2 * Copyright (c) 1988, 1989, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 1988, 1989 by Adam de Boor
5 * Copyright (c) 1989 by Berkeley Softworks
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Adam de Boor.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)hash.c 8.1 (Berkeley) 6/6/93
40 */
41
42#include <sys/cdefs.h>
| 1/*
2 * Copyright (c) 1988, 1989, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 1988, 1989 by Adam de Boor
5 * Copyright (c) 1989 by Berkeley Softworks
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Adam de Boor.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)hash.c 8.1 (Berkeley) 6/6/93
40 */
41
42#include <sys/cdefs.h>
|
43__FBSDID("$FreeBSD: head/usr.bin/make/hash.c 138435 2004-12-06 08:56:30Z harti $");
| 43__FBSDID("$FreeBSD: head/usr.bin/make/hash.c 138455 2004-12-06 15:20:12Z harti $");
|
44
45/* hash.c --
46 *
47 * This module contains routines to manipulate a hash table.
48 * See hash.h for a definition of the structure of the hash
49 * table. Hash tables grow automatically as the amount of
50 * information increases.
51 */
52#include <unistd.h>
53#include "sprite.h"
54#include "make.h"
55#include "hash.h"
56
57/*
58 * Forward references to local procedures that are used before they're
59 * defined:
60 */
61static void RebuildTable(Hash_Table *);
62
63/*
64 * The following defines the ratio of # entries to # buckets
65 * at which we rebuild the table to make it larger.
66 */
67
68#define rebuildLimit 8
69
70/*
71 *---------------------------------------------------------
72 *
73 * Hash_InitTable --
74 *
75 * Set up the hash table t with a given number of buckets, or a
76 * reasonable default if the number requested is less than or
77 * equal to zero. Hash tables will grow in size as needed.
78 *
79 *
80 * Results:
81 * None.
82 *
83 * Side Effects:
84 * Memory is allocated for the initial bucket area.
85 *
86 *---------------------------------------------------------
87 */
88void
89Hash_InitTable(Hash_Table *t, int numBuckets)
90{
91 int i;
92 struct Hash_Entry **hp;
93
94 /*
95 * Round up the size to a power of two.
96 */
97 if (numBuckets <= 0)
98 i = 16;
99 else {
100 for (i = 2; i < numBuckets; i <<= 1)
101 continue;
102 }
103 t->numEntries = 0;
104 t->size = i;
105 t->mask = i - 1;
106 t->bucketPtr = hp = emalloc(sizeof(*hp) * i);
107 while (--i >= 0)
108 *hp++ = NULL;
109}
110
111/*
112 *---------------------------------------------------------
113 *
114 * Hash_DeleteTable --
115 *
116 * This routine removes everything from a hash table
117 * and frees up the memory space it occupied (except for
118 * the space in the Hash_Table structure).
119 *
120 * Results:
121 * None.
122 *
123 * Side Effects:
124 * Lots of memory is freed up.
125 *
126 *---------------------------------------------------------
127 */
128void
129Hash_DeleteTable(Hash_Table *t)
130{
131 struct Hash_Entry **hp, *h, *nexth = NULL;
132 int i;
133
134 for (hp = t->bucketPtr, i = t->size; --i >= 0;) {
135 for (h = *hp++; h != NULL; h = nexth) {
136 nexth = h->next;
137 free(h);
138 }
139 }
140 free(t->bucketPtr);
141
142 /*
143 * Set up the hash table to cause memory faults on any future access
144 * attempts until re-initialization.
145 */
146 t->bucketPtr = NULL;
147}
148
149/*
150 *---------------------------------------------------------
151 *
152 * Hash_FindEntry --
153 *
154 * Searches a hash table for an entry corresponding to key.
155 *
156 * Results:
157 * The return value is a pointer to the entry for key,
158 * if key was present in the table. If key was not
159 * present, NULL is returned.
160 *
161 * Side Effects:
162 * None.
163 *
164 *---------------------------------------------------------
165 */
166Hash_Entry *
167Hash_FindEntry(const Hash_Table *t, const char *key)
168{
169 Hash_Entry *e;
170 unsigned h;
171 const char *p;
172
173 for (h = 0, p = key; *p;)
174 h = (h << 5) - h + *p++;
175 p = key;
176 for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next)
177 if (e->namehash == h && strcmp(e->name, p) == 0)
178 return (e);
179 return (NULL);
180}
181
182/*
183 *---------------------------------------------------------
184 *
185 * Hash_CreateEntry --
186 *
187 * Searches a hash table for an entry corresponding to
188 * key. If no entry is found, then one is created.
189 *
190 * Results:
191 * The return value is a pointer to the entry. If *newPtr
192 * isn't NULL, then *newPtr is filled in with TRUE if a
193 * new entry was created, and FALSE if an entry already existed
194 * with the given key.
195 *
196 * Side Effects:
197 * Memory may be allocated, and the hash buckets may be modified.
198 *---------------------------------------------------------
199 */
200Hash_Entry *
201Hash_CreateEntry(Hash_Table *t, const char *key, Boolean *newPtr)
202{
203 Hash_Entry *e;
204 unsigned int h;
205 const char *p;
206 int keylen;
207 struct Hash_Entry **hp;
208
209 /*
210 * Hash the key. As a side effect, save the length (strlen) of the
211 * key in case we need to create the entry.
212 */
213 for (h = 0, p = key; *p;)
214 h = (h << 5) - h + *p++;
215 keylen = p - key;
216 p = key;
217 for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next) {
218 if (e->namehash == h && strcmp(e->name, p) == 0) {
219 if (newPtr != NULL)
220 *newPtr = FALSE;
221 return (e);
222 }
223 }
224
225 /*
226 * The desired entry isn't there. Before allocating a new entry,
227 * expand the table if necessary (and this changes the resulting
228 * bucket chain).
229 */
230 if (t->numEntries >= rebuildLimit * t->size)
231 RebuildTable(t);
232 e = emalloc(sizeof(*e) + keylen);
233 hp = &t->bucketPtr[h & t->mask];
234 e->next = *hp;
235 *hp = e;
236 e->clientData = NULL;
237 e->namehash = h;
238 strcpy(e->name, p);
239 t->numEntries++;
240
241 if (newPtr != NULL)
242 *newPtr = TRUE;
243 return (e);
244}
245
246/*
247 *---------------------------------------------------------
248 *
249 * Hash_DeleteEntry --
250 *
251 * Delete the given hash table entry and free memory associated with
252 * it.
253 *
254 * Results:
255 * None.
256 *
257 * Side Effects:
258 * Hash chain that entry lives in is modified and memory is freed.
259 *
260 *---------------------------------------------------------
261 */
262void
263Hash_DeleteEntry(Hash_Table *t, Hash_Entry *e)
264{
265 Hash_Entry **hp, *p;
266
267 if (e == NULL)
268 return;
269 for (hp = &t->bucketPtr[e->namehash & t->mask];
270 (p = *hp) != NULL; hp = &p->next) {
271 if (p == e) {
272 *hp = p->next;
273 free(p);
274 t->numEntries--;
275 return;
276 }
277 }
278 write(STDERR_FILENO, "bad call to Hash_DeleteEntry\n", 29);
279 abort();
280}
281
282/*
283 *---------------------------------------------------------
284 *
285 * Hash_EnumFirst --
286 * This procedure sets things up for a complete search
287 * of all entries recorded in the hash table.
288 *
289 * Results:
290 * The return value is the address of the first entry in
291 * the hash table, or NULL if the table is empty.
292 *
293 * Side Effects:
294 * The information in searchPtr is initialized so that successive
295 * calls to Hash_Next will return successive HashEntry's
296 * from the table.
297 *
298 *---------------------------------------------------------
299 */
300Hash_Entry *
| 44
45/* hash.c --
46 *
47 * This module contains routines to manipulate a hash table.
48 * See hash.h for a definition of the structure of the hash
49 * table. Hash tables grow automatically as the amount of
50 * information increases.
51 */
52#include <unistd.h>
53#include "sprite.h"
54#include "make.h"
55#include "hash.h"
56
57/*
58 * Forward references to local procedures that are used before they're
59 * defined:
60 */
61static void RebuildTable(Hash_Table *);
62
63/*
64 * The following defines the ratio of # entries to # buckets
65 * at which we rebuild the table to make it larger.
66 */
67
68#define rebuildLimit 8
69
70/*
71 *---------------------------------------------------------
72 *
73 * Hash_InitTable --
74 *
75 * Set up the hash table t with a given number of buckets, or a
76 * reasonable default if the number requested is less than or
77 * equal to zero. Hash tables will grow in size as needed.
78 *
79 *
80 * Results:
81 * None.
82 *
83 * Side Effects:
84 * Memory is allocated for the initial bucket area.
85 *
86 *---------------------------------------------------------
87 */
88void
89Hash_InitTable(Hash_Table *t, int numBuckets)
90{
91 int i;
92 struct Hash_Entry **hp;
93
94 /*
95 * Round up the size to a power of two.
96 */
97 if (numBuckets <= 0)
98 i = 16;
99 else {
100 for (i = 2; i < numBuckets; i <<= 1)
101 continue;
102 }
103 t->numEntries = 0;
104 t->size = i;
105 t->mask = i - 1;
106 t->bucketPtr = hp = emalloc(sizeof(*hp) * i);
107 while (--i >= 0)
108 *hp++ = NULL;
109}
110
111/*
112 *---------------------------------------------------------
113 *
114 * Hash_DeleteTable --
115 *
116 * This routine removes everything from a hash table
117 * and frees up the memory space it occupied (except for
118 * the space in the Hash_Table structure).
119 *
120 * Results:
121 * None.
122 *
123 * Side Effects:
124 * Lots of memory is freed up.
125 *
126 *---------------------------------------------------------
127 */
128void
129Hash_DeleteTable(Hash_Table *t)
130{
131 struct Hash_Entry **hp, *h, *nexth = NULL;
132 int i;
133
134 for (hp = t->bucketPtr, i = t->size; --i >= 0;) {
135 for (h = *hp++; h != NULL; h = nexth) {
136 nexth = h->next;
137 free(h);
138 }
139 }
140 free(t->bucketPtr);
141
142 /*
143 * Set up the hash table to cause memory faults on any future access
144 * attempts until re-initialization.
145 */
146 t->bucketPtr = NULL;
147}
148
149/*
150 *---------------------------------------------------------
151 *
152 * Hash_FindEntry --
153 *
154 * Searches a hash table for an entry corresponding to key.
155 *
156 * Results:
157 * The return value is a pointer to the entry for key,
158 * if key was present in the table. If key was not
159 * present, NULL is returned.
160 *
161 * Side Effects:
162 * None.
163 *
164 *---------------------------------------------------------
165 */
166Hash_Entry *
167Hash_FindEntry(const Hash_Table *t, const char *key)
168{
169 Hash_Entry *e;
170 unsigned h;
171 const char *p;
172
173 for (h = 0, p = key; *p;)
174 h = (h << 5) - h + *p++;
175 p = key;
176 for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next)
177 if (e->namehash == h && strcmp(e->name, p) == 0)
178 return (e);
179 return (NULL);
180}
181
182/*
183 *---------------------------------------------------------
184 *
185 * Hash_CreateEntry --
186 *
187 * Searches a hash table for an entry corresponding to
188 * key. If no entry is found, then one is created.
189 *
190 * Results:
191 * The return value is a pointer to the entry. If *newPtr
192 * isn't NULL, then *newPtr is filled in with TRUE if a
193 * new entry was created, and FALSE if an entry already existed
194 * with the given key.
195 *
196 * Side Effects:
197 * Memory may be allocated, and the hash buckets may be modified.
198 *---------------------------------------------------------
199 */
200Hash_Entry *
201Hash_CreateEntry(Hash_Table *t, const char *key, Boolean *newPtr)
202{
203 Hash_Entry *e;
204 unsigned int h;
205 const char *p;
206 int keylen;
207 struct Hash_Entry **hp;
208
209 /*
210 * Hash the key. As a side effect, save the length (strlen) of the
211 * key in case we need to create the entry.
212 */
213 for (h = 0, p = key; *p;)
214 h = (h << 5) - h + *p++;
215 keylen = p - key;
216 p = key;
217 for (e = t->bucketPtr[h & t->mask]; e != NULL; e = e->next) {
218 if (e->namehash == h && strcmp(e->name, p) == 0) {
219 if (newPtr != NULL)
220 *newPtr = FALSE;
221 return (e);
222 }
223 }
224
225 /*
226 * The desired entry isn't there. Before allocating a new entry,
227 * expand the table if necessary (and this changes the resulting
228 * bucket chain).
229 */
230 if (t->numEntries >= rebuildLimit * t->size)
231 RebuildTable(t);
232 e = emalloc(sizeof(*e) + keylen);
233 hp = &t->bucketPtr[h & t->mask];
234 e->next = *hp;
235 *hp = e;
236 e->clientData = NULL;
237 e->namehash = h;
238 strcpy(e->name, p);
239 t->numEntries++;
240
241 if (newPtr != NULL)
242 *newPtr = TRUE;
243 return (e);
244}
245
246/*
247 *---------------------------------------------------------
248 *
249 * Hash_DeleteEntry --
250 *
251 * Delete the given hash table entry and free memory associated with
252 * it.
253 *
254 * Results:
255 * None.
256 *
257 * Side Effects:
258 * Hash chain that entry lives in is modified and memory is freed.
259 *
260 *---------------------------------------------------------
261 */
262void
263Hash_DeleteEntry(Hash_Table *t, Hash_Entry *e)
264{
265 Hash_Entry **hp, *p;
266
267 if (e == NULL)
268 return;
269 for (hp = &t->bucketPtr[e->namehash & t->mask];
270 (p = *hp) != NULL; hp = &p->next) {
271 if (p == e) {
272 *hp = p->next;
273 free(p);
274 t->numEntries--;
275 return;
276 }
277 }
278 write(STDERR_FILENO, "bad call to Hash_DeleteEntry\n", 29);
279 abort();
280}
281
282/*
283 *---------------------------------------------------------
284 *
285 * Hash_EnumFirst --
286 * This procedure sets things up for a complete search
287 * of all entries recorded in the hash table.
288 *
289 * Results:
290 * The return value is the address of the first entry in
291 * the hash table, or NULL if the table is empty.
292 *
293 * Side Effects:
294 * The information in searchPtr is initialized so that successive
295 * calls to Hash_Next will return successive HashEntry's
296 * from the table.
297 *
298 *---------------------------------------------------------
299 */
300Hash_Entry *
|
301Hash_EnumFirst(Hash_Table *t, Hash_Search *searchPtr)
| 301Hash_EnumFirst(const Hash_Table *t, Hash_Search *searchPtr)
|
302{
303
304 searchPtr->tablePtr = t;
305 searchPtr->nextIndex = 0;
306 searchPtr->hashEntryPtr = NULL;
307 return (Hash_EnumNext(searchPtr));
308}
309
310/*
311 *---------------------------------------------------------
312 *
313 * Hash_EnumNext --
314 * This procedure returns successive entries in the hash table.
315 *
316 * Results:
317 * The return value is a pointer to the next HashEntry
318 * in the table, or NULL when the end of the table is
319 * reached.
320 *
321 * Side Effects:
322 * The information in searchPtr is modified to advance to the
323 * next entry.
324 *
325 *---------------------------------------------------------
326 */
327Hash_Entry *
328Hash_EnumNext(Hash_Search *searchPtr)
329{
330 Hash_Entry *e;
| 302{
303
304 searchPtr->tablePtr = t;
305 searchPtr->nextIndex = 0;
306 searchPtr->hashEntryPtr = NULL;
307 return (Hash_EnumNext(searchPtr));
308}
309
310/*
311 *---------------------------------------------------------
312 *
313 * Hash_EnumNext --
314 * This procedure returns successive entries in the hash table.
315 *
316 * Results:
317 * The return value is a pointer to the next HashEntry
318 * in the table, or NULL when the end of the table is
319 * reached.
320 *
321 * Side Effects:
322 * The information in searchPtr is modified to advance to the
323 * next entry.
324 *
325 *---------------------------------------------------------
326 */
327Hash_Entry *
328Hash_EnumNext(Hash_Search *searchPtr)
329{
330 Hash_Entry *e;
|
331 Hash_Table *t = searchPtr->tablePtr;
| 331 const Hash_Table *t = searchPtr->tablePtr;
|
332
333 /*
334 * The hashEntryPtr field points to the most recently returned
335 * entry, or is NULL if we are starting up. If not NULL, we have
336 * to start at the next one in the chain.
337 */
338 e = searchPtr->hashEntryPtr;
339 if (e != NULL)
340 e = e->next;
341 /*
342 * If the chain ran out, or if we are starting up, we need to
343 * find the next nonempty chain.
344 */
345 while (e == NULL) {
346 if (searchPtr->nextIndex >= t->size)
347 return (NULL);
348 e = t->bucketPtr[searchPtr->nextIndex++];
349 }
350 searchPtr->hashEntryPtr = e;
351 return (e);
352}
353
354/*
355 *---------------------------------------------------------
356 *
357 * RebuildTable --
358 * This local routine makes a new hash table that
359 * is larger than the old one.
360 *
361 * Results:
362 * None.
363 *
364 * Side Effects:
365 * The entire hash table is moved, so any bucket numbers
366 * from the old table are invalid.
367 *
368 *---------------------------------------------------------
369 */
370static void
371RebuildTable(Hash_Table *t)
372{
373 Hash_Entry *e, *next = NULL, **hp, **xp;
374 int i, mask;
375 Hash_Entry **oldhp;
376 int oldsize;
377
378 oldhp = t->bucketPtr;
379 oldsize = i = t->size;
380 i <<= 1;
381 t->size = i;
382 t->mask = mask = i - 1;
383 t->bucketPtr = hp = emalloc(sizeof(*hp) * i);
384 while (--i >= 0)
385 *hp++ = NULL;
386 for (hp = oldhp, i = oldsize; --i >= 0;) {
387 for (e = *hp++; e != NULL; e = next) {
388 next = e->next;
389 xp = &t->bucketPtr[e->namehash & mask];
390 e->next = *xp;
391 *xp = e;
392 }
393 }
394 free(oldhp);
395}
| 332
333 /*
334 * The hashEntryPtr field points to the most recently returned
335 * entry, or is NULL if we are starting up. If not NULL, we have
336 * to start at the next one in the chain.
337 */
338 e = searchPtr->hashEntryPtr;
339 if (e != NULL)
340 e = e->next;
341 /*
342 * If the chain ran out, or if we are starting up, we need to
343 * find the next nonempty chain.
344 */
345 while (e == NULL) {
346 if (searchPtr->nextIndex >= t->size)
347 return (NULL);
348 e = t->bucketPtr[searchPtr->nextIndex++];
349 }
350 searchPtr->hashEntryPtr = e;
351 return (e);
352}
353
354/*
355 *---------------------------------------------------------
356 *
357 * RebuildTable --
358 * This local routine makes a new hash table that
359 * is larger than the old one.
360 *
361 * Results:
362 * None.
363 *
364 * Side Effects:
365 * The entire hash table is moved, so any bucket numbers
366 * from the old table are invalid.
367 *
368 *---------------------------------------------------------
369 */
370static void
371RebuildTable(Hash_Table *t)
372{
373 Hash_Entry *e, *next = NULL, **hp, **xp;
374 int i, mask;
375 Hash_Entry **oldhp;
376 int oldsize;
377
378 oldhp = t->bucketPtr;
379 oldsize = i = t->size;
380 i <<= 1;
381 t->size = i;
382 t->mask = mask = i - 1;
383 t->bucketPtr = hp = emalloc(sizeof(*hp) * i);
384 while (--i >= 0)
385 *hp++ = NULL;
386 for (hp = oldhp, i = oldsize; --i >= 0;) {
387 for (e = *hp++; e != NULL; e = next) {
388 next = e->next;
389 xp = &t->bucketPtr[e->namehash & mask];
390 e->next = *xp;
391 *xp = e;
392 }
393 }
394 free(oldhp);
395}
|