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[apple/libc.git] / db / hash / FreeBSD / hash.c
1 /*-
2 * Copyright (c) 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Margo Seltzer.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: src/lib/libc/db/hash/hash.c,v 1.12 2004/09/10 05:41:41 kuriyama Exp $");
42
43 #include "namespace.h"
44 #include <sys/param.h>
45 #include <sys/stat.h>
46
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #ifdef DEBUG
54 #include <assert.h>
55 #endif
56 #include "un-namespace.h"
57
58 #include <db.h>
59 #include "hash.h"
60 #include "page.h"
61 #include "extern.h"
62
63 static int alloc_segs(HTAB *, int);
64 static int flush_meta(HTAB *);
65 static int hash_access(HTAB *, ACTION, DBT *, DBT *);
66 static int hash_close(DB *);
67 static int hash_delete(const DB *, const DBT *, u_int32_t);
68 static int hash_fd(const DB *);
69 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t);
70 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t);
71 static void *hash_realloc(SEGMENT **, int, int);
72 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t);
73 static int hash_sync(const DB *, u_int32_t);
74 static int hdestroy(HTAB *);
75 static HTAB *init_hash(HTAB *, const char *, HASHINFO *);
76 static int init_htab(HTAB *, int);
77 #if BYTE_ORDER == LITTLE_ENDIAN
78 static void swap_header(HTAB *);
79 static void swap_header_copy(HASHHDR *, HASHHDR *);
80 #endif
81
82 /* Fast arithmetic, relying on powers of 2, */
83 #define MOD(x, y) ((x) & ((y) - 1))
84
85 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
86
87 /* Return values */
88 #define SUCCESS (0)
89 #define ERROR (-1)
90 #define ABNORMAL (1)
91
92 #ifdef HASH_STATISTICS
93 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
94 #endif
95
96 /************************** INTERFACE ROUTINES ***************************/
97 /* OPEN/CLOSE */
98
99 extern DB *
100 __hash_open(file, flags, mode, info, dflags)
101 const char *file;
102 int flags, mode, dflags;
103 const HASHINFO *info; /* Special directives for create */
104 {
105 HTAB *hashp;
106 struct stat statbuf;
107 DB *dbp;
108 int bpages, hdrsize, new_table, nsegs, save_errno;
109
110 if ((flags & O_ACCMODE) == O_WRONLY) {
111 errno = EINVAL;
112 return (NULL);
113 }
114
115 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB))))
116 return (NULL);
117 hashp->fp = -1;
118
119 /*
120 * Even if user wants write only, we need to be able to read
121 * the actual file, so we need to open it read/write. But, the
122 * field in the hashp structure needs to be accurate so that
123 * we can check accesses.
124 */
125 hashp->flags = flags;
126
127 new_table = 0;
128 if (!file || (flags & O_TRUNC) ||
129 (stat(file, &statbuf) && (errno == ENOENT))) {
130 if (errno == ENOENT)
131 errno = 0; /* Just in case someone looks at errno */
132 new_table = 1;
133 }
134 if (file) {
135 if ((hashp->fp = _open(file, flags, mode)) == -1)
136 RETURN_ERROR(errno, error0);
137
138 /* if the .db file is empty, and we had permission to create
139 a new .db file, then reinitialize the database */
140 if ((flags & O_CREAT) &&
141 _fstat(hashp->fp, &statbuf) == 0 && statbuf.st_size == 0)
142 new_table = 1;
143
144 (void)_fcntl(hashp->fp, F_SETFD, 1);
145 }
146 if (new_table) {
147 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info)))
148 RETURN_ERROR(errno, error1);
149 } else {
150 /* Table already exists */
151 if (info && info->hash)
152 hashp->hash = info->hash;
153 else
154 hashp->hash = __default_hash;
155
156 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
157 #if BYTE_ORDER == LITTLE_ENDIAN
158 swap_header(hashp);
159 #endif
160 if (hdrsize == -1)
161 RETURN_ERROR(errno, error1);
162 if (hdrsize != sizeof(HASHHDR))
163 RETURN_ERROR(EFTYPE, error1);
164 /* Verify file type, versions and hash function */
165 if (hashp->MAGIC != HASHMAGIC)
166 RETURN_ERROR(EFTYPE, error1);
167 #define OLDHASHVERSION 1
168 if (hashp->VERSION != HASHVERSION &&
169 hashp->VERSION != OLDHASHVERSION)
170 RETURN_ERROR(EFTYPE, error1);
171 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
172 RETURN_ERROR(EFTYPE, error1);
173 /*
174 * Figure out how many segments we need. Max_Bucket is the
175 * maximum bucket number, so the number of buckets is
176 * max_bucket + 1.
177 */
178 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
179 hashp->SGSIZE;
180 hashp->nsegs = 0;
181 if (alloc_segs(hashp, nsegs))
182 /*
183 * If alloc_segs fails, table will have been destroyed
184 * and errno will have been set.
185 */
186 return (NULL);
187 /* Read in bitmaps */
188 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
189 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
190 (hashp->BSHIFT + BYTE_SHIFT);
191
192 hashp->nmaps = bpages;
193 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
194 }
195
196 /* Initialize Buffer Manager */
197 if (info && info->cachesize)
198 __buf_init(hashp, info->cachesize);
199 else
200 __buf_init(hashp, DEF_BUFSIZE);
201
202 hashp->new_file = new_table;
203 hashp->save_file = file && (hashp->flags & O_RDWR);
204 hashp->cbucket = -1;
205 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
206 save_errno = errno;
207 hdestroy(hashp);
208 errno = save_errno;
209 return (NULL);
210 }
211 dbp->internal = hashp;
212 dbp->close = hash_close;
213 dbp->del = hash_delete;
214 dbp->fd = hash_fd;
215 dbp->get = hash_get;
216 dbp->put = hash_put;
217 dbp->seq = hash_seq;
218 dbp->sync = hash_sync;
219 dbp->type = DB_HASH;
220
221 #ifdef DEBUG
222 (void)fprintf(stderr,
223 "%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n",
224 "init_htab:",
225 "TABLE POINTER ", hashp,
226 "BUCKET SIZE ", hashp->BSIZE,
227 "BUCKET SHIFT ", hashp->BSHIFT,
228 "DIRECTORY SIZE ", hashp->DSIZE,
229 "SEGMENT SIZE ", hashp->SGSIZE,
230 "SEGMENT SHIFT ", hashp->SSHIFT,
231 "FILL FACTOR ", hashp->FFACTOR,
232 "MAX BUCKET ", hashp->MAX_BUCKET,
233 "OVFL POINT ", hashp->OVFL_POINT,
234 "LAST FREED ", hashp->LAST_FREED,
235 "HIGH MASK ", hashp->HIGH_MASK,
236 "LOW MASK ", hashp->LOW_MASK,
237 "NSEGS ", hashp->nsegs,
238 "NKEYS ", hashp->NKEYS);
239 #endif
240 #ifdef HASH_STATISTICS
241 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
242 #endif
243 return (dbp);
244
245 error1:
246 if (hashp != NULL)
247 (void)_close(hashp->fp);
248
249 error0:
250 free(hashp);
251 errno = save_errno;
252 return (NULL);
253 }
254
255 static int
256 hash_close(dbp)
257 DB *dbp;
258 {
259 HTAB *hashp;
260 int retval;
261
262 if (!dbp)
263 return (ERROR);
264
265 hashp = (HTAB *)dbp->internal;
266 retval = hdestroy(hashp);
267 free(dbp);
268 return (retval);
269 }
270
271 static int
272 hash_fd(dbp)
273 const DB *dbp;
274 {
275 HTAB *hashp;
276
277 if (!dbp)
278 return (ERROR);
279
280 hashp = (HTAB *)dbp->internal;
281 if (hashp->fp == -1) {
282 errno = ENOENT;
283 return (-1);
284 }
285 return (hashp->fp);
286 }
287
288 /************************** LOCAL CREATION ROUTINES **********************/
289 static HTAB *
290 init_hash(hashp, file, info)
291 HTAB *hashp;
292 const char *file;
293 HASHINFO *info;
294 {
295 struct stat statbuf;
296 int nelem;
297
298 nelem = 1;
299 hashp->NKEYS = 0;
300 hashp->LORDER = BYTE_ORDER;
301 hashp->BSIZE = DEF_BUCKET_SIZE;
302 hashp->BSHIFT = DEF_BUCKET_SHIFT;
303 hashp->SGSIZE = DEF_SEGSIZE;
304 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
305 hashp->DSIZE = DEF_DIRSIZE;
306 hashp->FFACTOR = DEF_FFACTOR;
307 hashp->hash = __default_hash;
308 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
309 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
310
311 /* Fix bucket size to be optimal for file system */
312 if (file != NULL) {
313 if (stat(file, &statbuf))
314 return (NULL);
315 hashp->BSIZE = statbuf.st_blksize;
316 hashp->BSHIFT = __log2(hashp->BSIZE);
317 }
318
319 if (info) {
320 if (info->bsize) {
321 /* Round pagesize up to power of 2 */
322 hashp->BSHIFT = __log2(info->bsize);
323 hashp->BSIZE = 1 << hashp->BSHIFT;
324 if (hashp->BSIZE > MAX_BSIZE) {
325 errno = EINVAL;
326 return (NULL);
327 }
328 }
329 if (info->ffactor)
330 hashp->FFACTOR = info->ffactor;
331 if (info->hash)
332 hashp->hash = info->hash;
333 if (info->nelem)
334 nelem = info->nelem;
335 if (info->lorder) {
336 if (info->lorder != BIG_ENDIAN &&
337 info->lorder != LITTLE_ENDIAN) {
338 errno = EINVAL;
339 return (NULL);
340 }
341 hashp->LORDER = info->lorder;
342 }
343 }
344 /* init_htab should destroy the table and set errno if it fails */
345 if (init_htab(hashp, nelem))
346 return (NULL);
347 else
348 return (hashp);
349 }
350 /*
351 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
352 * the table and set errno, so we just pass the error information along.
353 *
354 * Returns 0 on No Error
355 */
356 static int
357 init_htab(hashp, nelem)
358 HTAB *hashp;
359 int nelem;
360 {
361 int nbuckets, nsegs;
362 int l2;
363
364 /*
365 * Divide number of elements by the fill factor and determine a
366 * desired number of buckets. Allocate space for the next greater
367 * power of two number of buckets.
368 */
369 nelem = (nelem - 1) / hashp->FFACTOR + 1;
370
371 l2 = __log2(MAX(nelem, 2));
372 nbuckets = 1 << l2;
373
374 hashp->SPARES[l2] = l2 + 1;
375 hashp->SPARES[l2 + 1] = l2 + 1;
376 hashp->OVFL_POINT = l2;
377 hashp->LAST_FREED = 2;
378
379 /* First bitmap page is at: splitpoint l2 page offset 1 */
380 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
381 return (-1);
382
383 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
384 hashp->HIGH_MASK = (nbuckets << 1) - 1;
385 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
386 hashp->BSHIFT) + 1;
387
388 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
389 nsegs = 1 << __log2(nsegs);
390
391 if (nsegs > hashp->DSIZE)
392 hashp->DSIZE = nsegs;
393 return (alloc_segs(hashp, nsegs));
394 }
395
396 /********************** DESTROY/CLOSE ROUTINES ************************/
397
398 /*
399 * Flushes any changes to the file if necessary and destroys the hashp
400 * structure, freeing all allocated space.
401 */
402 static int
403 hdestroy(hashp)
404 HTAB *hashp;
405 {
406 int i, save_errno;
407
408 save_errno = 0;
409
410 #ifdef HASH_STATISTICS
411 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
412 hash_accesses, hash_collisions);
413 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
414 hash_expansions);
415 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
416 hash_overflows);
417 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
418 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
419
420 for (i = 0; i < NCACHED; i++)
421 (void)fprintf(stderr,
422 "spares[%d] = %d\n", i, hashp->SPARES[i]);
423 #endif
424 /*
425 * Call on buffer manager to free buffers, and if required,
426 * write them to disk.
427 */
428 if (__buf_free(hashp, 1, hashp->save_file))
429 save_errno = errno;
430 if (hashp->dir) {
431 free(*hashp->dir); /* Free initial segments */
432 /* Free extra segments */
433 while (hashp->exsegs--)
434 free(hashp->dir[--hashp->nsegs]);
435 free(hashp->dir);
436 }
437 if (flush_meta(hashp) && !save_errno)
438 save_errno = errno;
439 /* Free Bigmaps */
440 for (i = 0; i < hashp->nmaps; i++)
441 if (hashp->mapp[i])
442 free(hashp->mapp[i]);
443
444 if (hashp->fp != -1)
445 (void)_close(hashp->fp);
446
447 free(hashp);
448
449 if (save_errno) {
450 errno = save_errno;
451 return (ERROR);
452 }
453 return (SUCCESS);
454 }
455 /*
456 * Write modified pages to disk
457 *
458 * Returns:
459 * 0 == OK
460 * -1 ERROR
461 */
462 static int
463 hash_sync(dbp, flags)
464 const DB *dbp;
465 u_int32_t flags;
466 {
467 HTAB *hashp;
468
469 if (flags != 0) {
470 errno = EINVAL;
471 return (ERROR);
472 }
473
474 if (!dbp)
475 return (ERROR);
476
477 hashp = (HTAB *)dbp->internal;
478 if (!hashp->save_file)
479 return (0);
480 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
481 return (ERROR);
482 hashp->new_file = 0;
483 return (0);
484 }
485
486 /*
487 * Returns:
488 * 0 == OK
489 * -1 indicates that errno should be set
490 */
491 static int
492 flush_meta(hashp)
493 HTAB *hashp;
494 {
495 HASHHDR *whdrp;
496 #if BYTE_ORDER == LITTLE_ENDIAN
497 HASHHDR whdr;
498 #endif
499 int fp, i, wsize;
500
501 if (!hashp->save_file)
502 return (0);
503 hashp->MAGIC = HASHMAGIC;
504 hashp->VERSION = HASHVERSION;
505 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
506
507 fp = hashp->fp;
508 whdrp = &hashp->hdr;
509 #if BYTE_ORDER == LITTLE_ENDIAN
510 whdrp = &whdr;
511 swap_header_copy(&hashp->hdr, whdrp);
512 #endif
513 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) ||
514 ((wsize = _write(fp, whdrp, sizeof(HASHHDR))) == -1))
515 return (-1);
516 else
517 if (wsize != sizeof(HASHHDR)) {
518 errno = EFTYPE;
519 hashp->error = errno;
520 return (-1);
521 }
522 for (i = 0; i < NCACHED; i++)
523 if (hashp->mapp[i])
524 if (__put_page(hashp, (char *)hashp->mapp[i],
525 hashp->BITMAPS[i], 0, 1))
526 return (-1);
527 return (0);
528 }
529
530 /*******************************SEARCH ROUTINES *****************************/
531 /*
532 * All the access routines return
533 *
534 * Returns:
535 * 0 on SUCCESS
536 * 1 to indicate an external ERROR (i.e. key not found, etc)
537 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
538 */
539 static int
540 hash_get(dbp, key, data, flag)
541 const DB *dbp;
542 const DBT *key;
543 DBT *data;
544 u_int32_t flag;
545 {
546 HTAB *hashp;
547
548 hashp = (HTAB *)dbp->internal;
549 if (flag) {
550 hashp->error = errno = EINVAL;
551 return (ERROR);
552 }
553 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
554 }
555
556 static int
557 hash_put(dbp, key, data, flag)
558 const DB *dbp;
559 DBT *key;
560 const DBT *data;
561 u_int32_t flag;
562 {
563 HTAB *hashp;
564
565 hashp = (HTAB *)dbp->internal;
566 if (flag && flag != R_NOOVERWRITE) {
567 hashp->error = EINVAL;
568 errno = EINVAL;
569 return (ERROR);
570 }
571 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
572 hashp->error = errno = EPERM;
573 return (ERROR);
574 }
575 return (hash_access(hashp, flag == R_NOOVERWRITE ?
576 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
577 }
578
579 static int
580 hash_delete(dbp, key, flag)
581 const DB *dbp;
582 const DBT *key;
583 u_int32_t flag; /* Ignored */
584 {
585 HTAB *hashp;
586
587 hashp = (HTAB *)dbp->internal;
588 if (flag && flag != R_CURSOR) {
589 hashp->error = errno = EINVAL;
590 return (ERROR);
591 }
592 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
593 hashp->error = errno = EPERM;
594 return (ERROR);
595 }
596 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
597 }
598
599 /*
600 * Assume that hashp has been set in wrapper routine.
601 */
602 static int
603 hash_access(hashp, action, key, val)
604 HTAB *hashp;
605 ACTION action;
606 DBT *key, *val;
607 {
608 BUFHEAD *rbufp;
609 BUFHEAD *bufp, *save_bufp;
610 u_int16_t *bp;
611 int n, ndx, off, size;
612 char *kp;
613 u_int16_t pageno;
614
615 #ifdef HASH_STATISTICS
616 hash_accesses++;
617 #endif
618
619 off = hashp->BSIZE;
620 size = key->size;
621 kp = (char *)key->data;
622 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
623 if (!rbufp)
624 return (ERROR);
625 save_bufp = rbufp;
626
627 /* Pin the bucket chain */
628 rbufp->flags |= BUF_PIN;
629 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
630 if (bp[1] >= REAL_KEY) {
631 /* Real key/data pair */
632 if (size == off - *bp &&
633 memcmp(kp, rbufp->page + *bp, size) == 0)
634 goto found;
635 off = bp[1];
636 #ifdef HASH_STATISTICS
637 hash_collisions++;
638 #endif
639 bp += 2;
640 ndx += 2;
641 } else if (bp[1] == OVFLPAGE) {
642 rbufp = __get_buf(hashp, *bp, rbufp, 0);
643 if (!rbufp) {
644 save_bufp->flags &= ~BUF_PIN;
645 return (ERROR);
646 }
647 /* FOR LOOP INIT */
648 bp = (u_int16_t *)rbufp->page;
649 n = *bp++;
650 ndx = 1;
651 off = hashp->BSIZE;
652 } else if (bp[1] < REAL_KEY) {
653 if ((ndx =
654 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
655 goto found;
656 if (ndx == -2) {
657 bufp = rbufp;
658 if (!(pageno =
659 __find_last_page(hashp, &bufp))) {
660 ndx = 0;
661 rbufp = bufp;
662 break; /* FOR */
663 }
664 rbufp = __get_buf(hashp, pageno, bufp, 0);
665 if (!rbufp) {
666 save_bufp->flags &= ~BUF_PIN;
667 return (ERROR);
668 }
669 /* FOR LOOP INIT */
670 bp = (u_int16_t *)rbufp->page;
671 n = *bp++;
672 ndx = 1;
673 off = hashp->BSIZE;
674 } else {
675 save_bufp->flags &= ~BUF_PIN;
676 return (ERROR);
677 }
678 }
679
680 /* Not found */
681 switch (action) {
682 case HASH_PUT:
683 case HASH_PUTNEW:
684 if (__addel(hashp, rbufp, key, val)) {
685 save_bufp->flags &= ~BUF_PIN;
686 return (ERROR);
687 } else {
688 save_bufp->flags &= ~BUF_PIN;
689 return (SUCCESS);
690 }
691 case HASH_GET:
692 case HASH_DELETE:
693 default:
694 save_bufp->flags &= ~BUF_PIN;
695 return (ABNORMAL);
696 }
697
698 found:
699 switch (action) {
700 case HASH_PUTNEW:
701 save_bufp->flags &= ~BUF_PIN;
702 return (ABNORMAL);
703 case HASH_GET:
704 bp = (u_int16_t *)rbufp->page;
705 if (bp[ndx + 1] < REAL_KEY) {
706 if (__big_return(hashp, rbufp, ndx, val, 0))
707 return (ERROR);
708 } else {
709 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
710 val->size = bp[ndx] - bp[ndx + 1];
711 }
712 break;
713 case HASH_PUT:
714 if ((__delpair(hashp, rbufp, ndx)) ||
715 (__addel(hashp, rbufp, key, val))) {
716 save_bufp->flags &= ~BUF_PIN;
717 return (ERROR);
718 }
719 break;
720 case HASH_DELETE:
721 if (__delpair(hashp, rbufp, ndx))
722 return (ERROR);
723 break;
724 default:
725 abort();
726 }
727 save_bufp->flags &= ~BUF_PIN;
728 return (SUCCESS);
729 }
730
731 static int
732 hash_seq(dbp, key, data, flag)
733 const DB *dbp;
734 DBT *key, *data;
735 u_int32_t flag;
736 {
737 u_int32_t bucket;
738 BUFHEAD *bufp;
739 HTAB *hashp;
740 u_int16_t *bp, ndx;
741
742 hashp = (HTAB *)dbp->internal;
743 if (flag && flag != R_FIRST && flag != R_NEXT) {
744 hashp->error = errno = EINVAL;
745 return (ERROR);
746 }
747 #ifdef HASH_STATISTICS
748 hash_accesses++;
749 #endif
750 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
751 hashp->cbucket = 0;
752 hashp->cndx = 1;
753 hashp->cpage = NULL;
754 }
755
756 for (bp = NULL; !bp || !bp[0]; ) {
757 if (!(bufp = hashp->cpage)) {
758 for (bucket = hashp->cbucket;
759 bucket <= hashp->MAX_BUCKET;
760 bucket++, hashp->cndx = 1) {
761 bufp = __get_buf(hashp, bucket, NULL, 0);
762 if (!bufp)
763 return (ERROR);
764 hashp->cpage = bufp;
765 bp = (u_int16_t *)bufp->page;
766 if (bp[0])
767 break;
768 }
769 hashp->cbucket = bucket;
770 if (hashp->cbucket > hashp->MAX_BUCKET) {
771 hashp->cbucket = -1;
772 return (ABNORMAL);
773 }
774 } else
775 bp = (u_int16_t *)hashp->cpage->page;
776
777 #ifdef DEBUG
778 assert(bp);
779 assert(bufp);
780 #endif
781 while (bp[hashp->cndx + 1] == OVFLPAGE) {
782 bufp = hashp->cpage =
783 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
784 if (!bufp)
785 return (ERROR);
786 bp = (u_int16_t *)(bufp->page);
787 hashp->cndx = 1;
788 }
789 if (!bp[0]) {
790 hashp->cpage = NULL;
791 ++hashp->cbucket;
792 }
793 }
794 ndx = hashp->cndx;
795 if (bp[ndx + 1] < REAL_KEY) {
796 if (__big_keydata(hashp, bufp, key, data, 1))
797 return (ERROR);
798 } else {
799 key->data = (u_char *)hashp->cpage->page + bp[ndx];
800 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
801 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
802 data->size = bp[ndx] - bp[ndx + 1];
803 ndx += 2;
804 if (ndx > bp[0]) {
805 hashp->cpage = NULL;
806 hashp->cbucket++;
807 hashp->cndx = 1;
808 } else
809 hashp->cndx = ndx;
810 }
811 return (SUCCESS);
812 }
813
814 /********************************* UTILITIES ************************/
815
816 /*
817 * Returns:
818 * 0 ==> OK
819 * -1 ==> Error
820 */
821 extern int
822 __expand_table(hashp)
823 HTAB *hashp;
824 {
825 u_int32_t old_bucket, new_bucket;
826 int dirsize, new_segnum, spare_ndx;
827
828 #ifdef HASH_STATISTICS
829 hash_expansions++;
830 #endif
831 new_bucket = ++hashp->MAX_BUCKET;
832 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
833
834 new_segnum = new_bucket >> hashp->SSHIFT;
835
836 /* Check if we need a new segment */
837 if (new_segnum >= hashp->nsegs) {
838 /* Check if we need to expand directory */
839 if (new_segnum >= hashp->DSIZE) {
840 /* Reallocate directory */
841 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
842 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
843 return (-1);
844 hashp->DSIZE = dirsize << 1;
845 }
846 if ((hashp->dir[new_segnum] =
847 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
848 return (-1);
849 hashp->exsegs++;
850 hashp->nsegs++;
851 }
852 /*
853 * If the split point is increasing (MAX_BUCKET's log base 2
854 * * increases), we need to copy the current contents of the spare
855 * split bucket to the next bucket.
856 */
857 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
858 if (spare_ndx > hashp->OVFL_POINT) {
859 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
860 hashp->OVFL_POINT = spare_ndx;
861 }
862
863 if (new_bucket > hashp->HIGH_MASK) {
864 /* Starting a new doubling */
865 hashp->LOW_MASK = hashp->HIGH_MASK;
866 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
867 }
868 /* Relocate records to the new bucket */
869 return (__split_page(hashp, old_bucket, new_bucket));
870 }
871
872 /*
873 * If realloc guarantees that the pointer is not destroyed if the realloc
874 * fails, then this routine can go away.
875 */
876 static void *
877 hash_realloc(p_ptr, oldsize, newsize)
878 SEGMENT **p_ptr;
879 int oldsize, newsize;
880 {
881 void *p;
882
883 if ( (p = malloc(newsize)) ) {
884 memmove(p, *p_ptr, oldsize);
885 memset((char *)p + oldsize, 0, newsize - oldsize);
886 free(*p_ptr);
887 *p_ptr = p;
888 }
889 return (p);
890 }
891
892 extern u_int32_t
893 __call_hash(hashp, k, len)
894 HTAB *hashp;
895 char *k;
896 int len;
897 {
898 int n, bucket;
899
900 n = hashp->hash(k, len);
901 bucket = n & hashp->HIGH_MASK;
902 if (bucket > hashp->MAX_BUCKET)
903 bucket = bucket & hashp->LOW_MASK;
904 return (bucket);
905 }
906
907 /*
908 * Allocate segment table. On error, destroy the table and set errno.
909 *
910 * Returns 0 on success
911 */
912 static int
913 alloc_segs(hashp, nsegs)
914 HTAB *hashp;
915 int nsegs;
916 {
917 int i;
918 SEGMENT store;
919
920 int save_errno;
921
922 if ((hashp->dir =
923 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
924 save_errno = errno;
925 (void)hdestroy(hashp);
926 errno = save_errno;
927 return (-1);
928 }
929 /* Allocate segments */
930 if ((store =
931 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) {
932 save_errno = errno;
933 (void)hdestroy(hashp);
934 errno = save_errno;
935 return (-1);
936 }
937 for (i = 0; i < nsegs; i++, hashp->nsegs++)
938 hashp->dir[i] = &store[i << hashp->SSHIFT];
939 return (0);
940 }
941
942 #if BYTE_ORDER == LITTLE_ENDIAN
943 /*
944 * Hashp->hdr needs to be byteswapped.
945 */
946 static void
947 swap_header_copy(srcp, destp)
948 HASHHDR *srcp, *destp;
949 {
950 int i;
951
952 P_32_COPY(srcp->magic, destp->magic);
953 P_32_COPY(srcp->version, destp->version);
954 P_32_COPY(srcp->lorder, destp->lorder);
955 P_32_COPY(srcp->bsize, destp->bsize);
956 P_32_COPY(srcp->bshift, destp->bshift);
957 P_32_COPY(srcp->dsize, destp->dsize);
958 P_32_COPY(srcp->ssize, destp->ssize);
959 P_32_COPY(srcp->sshift, destp->sshift);
960 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
961 P_32_COPY(srcp->last_freed, destp->last_freed);
962 P_32_COPY(srcp->max_bucket, destp->max_bucket);
963 P_32_COPY(srcp->high_mask, destp->high_mask);
964 P_32_COPY(srcp->low_mask, destp->low_mask);
965 P_32_COPY(srcp->ffactor, destp->ffactor);
966 P_32_COPY(srcp->nkeys, destp->nkeys);
967 P_32_COPY(srcp->hdrpages, destp->hdrpages);
968 P_32_COPY(srcp->h_charkey, destp->h_charkey);
969 for (i = 0; i < NCACHED; i++) {
970 P_32_COPY(srcp->spares[i], destp->spares[i]);
971 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
972 }
973 }
974
975 static void
976 swap_header(hashp)
977 HTAB *hashp;
978 {
979 HASHHDR *hdrp;
980 int i;
981
982 hdrp = &hashp->hdr;
983
984 M_32_SWAP(hdrp->magic);
985 M_32_SWAP(hdrp->version);
986 M_32_SWAP(hdrp->lorder);
987 M_32_SWAP(hdrp->bsize);
988 M_32_SWAP(hdrp->bshift);
989 M_32_SWAP(hdrp->dsize);
990 M_32_SWAP(hdrp->ssize);
991 M_32_SWAP(hdrp->sshift);
992 M_32_SWAP(hdrp->ovfl_point);
993 M_32_SWAP(hdrp->last_freed);
994 M_32_SWAP(hdrp->max_bucket);
995 M_32_SWAP(hdrp->high_mask);
996 M_32_SWAP(hdrp->low_mask);
997 M_32_SWAP(hdrp->ffactor);
998 M_32_SWAP(hdrp->nkeys);
999 M_32_SWAP(hdrp->hdrpages);
1000 M_32_SWAP(hdrp->h_charkey);
1001 for (i = 0; i < NCACHED; i++) {
1002 M_32_SWAP(hdrp->spares[i]);
1003 M_16_SWAP(hdrp->bitmaps[i]);
1004 }
1005 }
1006 #endif
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