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