source: trunk/src/emx/bsd/db/hash/hash.c@ 272

Last change on this file since 272 was 272, checked in by bird, 23 years ago

Initial revision
  • Property cvs2svn:cvs-rev set to 1.1
  • Property svn:eol-style set to native
  • Property svn:executable set to *
File size: 23.8 KB
Line 
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)
38static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/param.h>
42#ifdef __EMX__
43#include <sys/types.h>
44#endif /* not __EMX__ */
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
57#include <db.h>
58#include "hash.h"
59#include "page.h"
60#include "extern.h"
61
62static int alloc_segs __P((HTAB *, int));
63static int flush_meta __P((HTAB *));
64static int hash_access __P((HTAB *, ACTION, DBT *, DBT *));
65static int hash_close __P((DB *));
66static int hash_delete __P((const DB *, const DBT *, u_int32_t));
67static int hash_fd __P((const DB *));
68static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t));
69static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t));
70static void *hash_realloc __P((SEGMENT **, int, int));
71static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t));
72static int hash_sync __P((const DB *, u_int32_t));
73static int hdestroy __P((HTAB *));
74static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *));
75static int init_htab __P((HTAB *, int));
76#if BYTE_ORDER == LITTLE_ENDIAN
77static void swap_header __P((HTAB *));
78static void swap_header_copy __P((HASHHDR *, HASHHDR *));
79#endif
80
81/* Fast arithmetic, relying on powers of 2, */
82#define MOD(x, y) ((x) & ((y) - 1))
83
84#define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
85
86/* Return values */
87#define SUCCESS (0)
88#define ERROR (-1)
89#define ABNORMAL (1)
90
91#ifdef HASH_STATISTICS
92int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
93#endif
94
95/************************** INTERFACE ROUTINES ***************************/
96/* OPEN/CLOSE */
97
98extern DB *
99__hash_open(file, flags, mode, info, dflags)
100 const char *file;
101 int flags, mode, dflags;
102 const HASHINFO *info; /* Special directives for create */
103{
104 HTAB *hashp;
105 struct stat statbuf;
106 DB *dbp;
107 int bpages, hdrsize, new_table, nsegs, save_errno;
108
109 if ((flags & O_ACCMODE) == O_WRONLY) {
110 errno = EINVAL;
111 return (NULL);
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 (void)fcntl(hashp->fp, F_SETFD, 1);
137 }
138 if (new_table) {
139 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info)))
140 RETURN_ERROR(errno, error1);
141 } else {
142 /* Table already exists */
143 if (info && info->hash)
144 hashp->hash = info->hash;
145 else
146 hashp->hash = __default_hash;
147
148 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
149#if BYTE_ORDER == LITTLE_ENDIAN
150 swap_header(hashp);
151#endif
152 if (hdrsize == -1)
153 RETURN_ERROR(errno, error1);
154 if (hdrsize != sizeof(HASHHDR))
155 RETURN_ERROR(EFTYPE, error1);
156 /* Verify file type, versions and hash function */
157 if (hashp->MAGIC != HASHMAGIC)
158 RETURN_ERROR(EFTYPE, error1);
159#define OLDHASHVERSION 1
160 if (hashp->VERSION != HASHVERSION &&
161 hashp->VERSION != OLDHASHVERSION)
162 RETURN_ERROR(EFTYPE, error1);
163 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
164 RETURN_ERROR(EFTYPE, error1);
165 /*
166 * Figure out how many segments we need. Max_Bucket is the
167 * maximum bucket number, so the number of buckets is
168 * max_bucket + 1.
169 */
170 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
171 hashp->SGSIZE;
172 hashp->nsegs = 0;
173 if (alloc_segs(hashp, nsegs))
174 /*
175 * If alloc_segs fails, table will have been destroyed
176 * and errno will have been set.
177 */
178 return (NULL);
179 /* Read in bitmaps */
180 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
181 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
182 (hashp->BSHIFT + BYTE_SHIFT);
183
184 hashp->nmaps = bpages;
185 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
186 }
187
188 /* Initialize Buffer Manager */
189 if (info && info->cachesize)
190 __buf_init(hashp, info->cachesize);
191 else
192 __buf_init(hashp, DEF_BUFSIZE);
193
194 hashp->new_file = new_table;
195 hashp->save_file = file && (hashp->flags & O_RDWR);
196 hashp->cbucket = -1;
197 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
198 save_errno = errno;
199 hdestroy(hashp);
200 errno = save_errno;
201 return (NULL);
202 }
203 dbp->internal = hashp;
204 dbp->close = hash_close;
205 dbp->del = hash_delete;
206 dbp->fd = hash_fd;
207 dbp->get = hash_get;
208 dbp->put = hash_put;
209 dbp->seq = hash_seq;
210 dbp->sync = hash_sync;
211 dbp->type = DB_HASH;
212
213#ifdef DEBUG
214 (void)fprintf(stderr,
215"%s\n%s%x\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",
216 "init_htab:",
217 "TABLE POINTER ", hashp,
218 "BUCKET SIZE ", hashp->BSIZE,
219 "BUCKET SHIFT ", hashp->BSHIFT,
220 "DIRECTORY SIZE ", hashp->DSIZE,
221 "SEGMENT SIZE ", hashp->SGSIZE,
222 "SEGMENT SHIFT ", hashp->SSHIFT,
223 "FILL FACTOR ", hashp->FFACTOR,
224 "MAX BUCKET ", hashp->MAX_BUCKET,
225 "OVFL POINT ", hashp->OVFL_POINT,
226 "LAST FREED ", hashp->LAST_FREED,
227 "HIGH MASK ", hashp->HIGH_MASK,
228 "LOW MASK ", hashp->LOW_MASK,
229 "NSEGS ", hashp->nsegs,
230 "NKEYS ", hashp->NKEYS);
231#endif
232#ifdef HASH_STATISTICS
233 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
234#endif
235 return (dbp);
236
237error1:
238 if (hashp != NULL)
239 (void)close(hashp->fp);
240
241error0:
242 free(hashp);
243 errno = save_errno;
244 return (NULL);
245}
246
247static int
248hash_close(dbp)
249 DB *dbp;
250{
251 HTAB *hashp;
252 int retval;
253
254 if (!dbp)
255 return (ERROR);
256
257 hashp = (HTAB *)dbp->internal;
258 retval = hdestroy(hashp);
259 free(dbp);
260 return (retval);
261}
262
263static int
264hash_fd(dbp)
265 const DB *dbp;
266{
267 HTAB *hashp;
268
269 if (!dbp)
270 return (ERROR);
271
272 hashp = (HTAB *)dbp->internal;
273 if (hashp->fp == -1) {
274 errno = ENOENT;
275 return (-1);
276 }
277 return (hashp->fp);
278}
279
280/************************** LOCAL CREATION ROUTINES **********************/
281static HTAB *
282init_hash(hashp, file, info)
283 HTAB *hashp;
284 const char *file;
285 HASHINFO *info;
286{
287 struct stat statbuf;
288 int nelem;
289
290 nelem = 1;
291 hashp->NKEYS = 0;
292 hashp->LORDER = BYTE_ORDER;
293 hashp->BSIZE = DEF_BUCKET_SIZE;
294 hashp->BSHIFT = DEF_BUCKET_SHIFT;
295 hashp->SGSIZE = DEF_SEGSIZE;
296 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
297 hashp->DSIZE = DEF_DIRSIZE;
298 hashp->FFACTOR = DEF_FFACTOR;
299 hashp->hash = __default_hash;
300 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
301 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
302
303 /* Fix bucket size to be optimal for file system */
304 if (file != NULL) {
305 if (stat(file, &statbuf))
306 return (NULL);
307#ifdef __EMX__
308 hashp->BSIZE = 512;
309#else /* not __EMX__ */
310 hashp->BSIZE = statbuf.st_blksize;
311#endif /* not __EMX__ */
312 hashp->BSHIFT = __log2(hashp->BSIZE);
313 }
314
315 if (info) {
316 if (info->bsize) {
317 /* Round pagesize up to power of 2 */
318 hashp->BSHIFT = __log2(info->bsize);
319 hashp->BSIZE = 1 << hashp->BSHIFT;
320 if (hashp->BSIZE > MAX_BSIZE) {
321 errno = EINVAL;
322 return (NULL);
323 }
324 }
325 if (info->ffactor)
326 hashp->FFACTOR = info->ffactor;
327 if (info->hash)
328 hashp->hash = info->hash;
329 if (info->nelem)
330 nelem = info->nelem;
331 if (info->lorder) {
332 if (info->lorder != BIG_ENDIAN &&
333 info->lorder != LITTLE_ENDIAN) {
334 errno = EINVAL;
335 return (NULL);
336 }
337 hashp->LORDER = info->lorder;
338 }
339 }
340 /* init_htab should destroy the table and set errno if it fails */
341 if (init_htab(hashp, nelem))
342 return (NULL);
343 else
344 return (hashp);
345}
346/*
347 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
348 * the table and set errno, so we just pass the error information along.
349 *
350 * Returns 0 on No Error
351 */
352static int
353init_htab(hashp, nelem)
354 HTAB *hashp;
355 int nelem;
356{
357 register int nbuckets, nsegs;
358 int l2;
359
360 /*
361 * Divide number of elements by the fill factor and determine a
362 * desired number of buckets. Allocate space for the next greater
363 * power of two number of buckets.
364 */
365 nelem = (nelem - 1) / hashp->FFACTOR + 1;
366
367 l2 = __log2(MAX(nelem, 2));
368 nbuckets = 1 << l2;
369
370 hashp->SPARES[l2] = l2 + 1;
371 hashp->SPARES[l2 + 1] = l2 + 1;
372 hashp->OVFL_POINT = l2;
373 hashp->LAST_FREED = 2;
374
375 /* First bitmap page is at: splitpoint l2 page offset 1 */
376 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
377 return (-1);
378
379 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
380 hashp->HIGH_MASK = (nbuckets << 1) - 1;
381 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
382 hashp->BSHIFT) + 1;
383
384 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
385 nsegs = 1 << __log2(nsegs);
386
387 if (nsegs > hashp->DSIZE)
388 hashp->DSIZE = nsegs;
389 return (alloc_segs(hashp, nsegs));
390}
391
392/********************** DESTROY/CLOSE ROUTINES ************************/
393
394/*
395 * Flushes any changes to the file if necessary and destroys the hashp
396 * structure, freeing all allocated space.
397 */
398static int
399hdestroy(hashp)
400 HTAB *hashp;
401{
402 int i, save_errno;
403
404 save_errno = 0;
405
406#ifdef HASH_STATISTICS
407 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
408 hash_accesses, hash_collisions);
409 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
410 hash_expansions);
411 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
412 hash_overflows);
413 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
414 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
415
416 for (i = 0; i < NCACHED; i++)
417 (void)fprintf(stderr,
418 "spares[%d] = %d\n", i, hashp->SPARES[i]);
419#endif
420 /*
421 * Call on buffer manager to free buffers, and if required,
422 * write them to disk.
423 */
424 if (__buf_free(hashp, 1, hashp->save_file))
425 save_errno = errno;
426 if (hashp->dir) {
427 free(*hashp->dir); /* Free initial segments */
428 /* Free extra segments */
429 while (hashp->exsegs--)
430 free(hashp->dir[--hashp->nsegs]);
431 free(hashp->dir);
432 }
433 if (flush_meta(hashp) && !save_errno)
434 save_errno = errno;
435 /* Free Bigmaps */
436 for (i = 0; i < hashp->nmaps; i++)
437 if (hashp->mapp[i])
438 free(hashp->mapp[i]);
439
440 if (hashp->fp != -1)
441 (void)close(hashp->fp);
442#ifdef __EMX__
443 if (hashp->tempname != NULL) {
444 (void)unlink (hashp->tempname);
445 free (hashp->tempname);
446 }
447#endif /* __EMX__ */
448
449 free(hashp);
450
451 if (save_errno) {
452 errno = save_errno;
453 return (ERROR);
454 }
455 return (SUCCESS);
456}
457/*
458 * Write modified pages to disk
459 *
460 * Returns:
461 * 0 == OK
462 * -1 ERROR
463 */
464static int
465hash_sync(dbp, flags)
466 const DB *dbp;
467 u_int32_t flags;
468{
469 HTAB *hashp;
470
471 if (flags != 0) {
472 errno = EINVAL;
473 return (ERROR);
474 }
475
476 if (!dbp)
477 return (ERROR);
478
479 hashp = (HTAB *)dbp->internal;
480 if (!hashp->save_file)
481 return (0);
482 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
483 return (ERROR);
484 hashp->new_file = 0;
485 return (0);
486}
487
488/*
489 * Returns:
490 * 0 == OK
491 * -1 indicates that errno should be set
492 */
493static int
494flush_meta(hashp)
495 HTAB *hashp;
496{
497 HASHHDR *whdrp;
498#if BYTE_ORDER == LITTLE_ENDIAN
499 HASHHDR whdr;
500#endif
501 int fp, i, wsize;
502
503 if (!hashp->save_file)
504 return (0);
505 hashp->MAGIC = HASHMAGIC;
506 hashp->VERSION = HASHVERSION;
507 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
508
509 fp = hashp->fp;
510 whdrp = &hashp->hdr;
511#if BYTE_ORDER == LITTLE_ENDIAN
512 whdrp = &whdr;
513 swap_header_copy(&hashp->hdr, whdrp);
514#endif
515 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) ||
516 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1))
517 return (-1);
518 else
519 if (wsize != sizeof(HASHHDR)) {
520 errno = EFTYPE;
521 hashp->errno = errno;
522 return (-1);
523 }
524 for (i = 0; i < NCACHED; i++)
525 if (hashp->mapp[i])
526 if (__put_page(hashp, (char *)hashp->mapp[i],
527 hashp->BITMAPS[i], 0, 1))
528 return (-1);
529 return (0);
530}
531
532/*******************************SEARCH ROUTINES *****************************/
533/*
534 * All the access routines return
535 *
536 * Returns:
537 * 0 on SUCCESS
538 * 1 to indicate an external ERROR (i.e. key not found, etc)
539 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
540 */
541static int
542hash_get(dbp, key, data, flag)
543 const DB *dbp;
544 const DBT *key;
545 DBT *data;
546 u_int32_t flag;
547{
548 HTAB *hashp;
549
550 hashp = (HTAB *)dbp->internal;
551 if (flag) {
552 hashp->errno = errno = EINVAL;
553 return (ERROR);
554 }
555 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
556}
557
558static int
559hash_put(dbp, key, data, flag)
560 const DB *dbp;
561 DBT *key;
562 const DBT *data;
563 u_int32_t flag;
564{
565 HTAB *hashp;
566
567 hashp = (HTAB *)dbp->internal;
568 if (flag && flag != R_NOOVERWRITE) {
569 hashp->errno = errno = EINVAL;
570 return (ERROR);
571 }
572 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
573 hashp->errno = errno = EPERM;
574 return (ERROR);
575 }
576 return (hash_access(hashp, flag == R_NOOVERWRITE ?
577 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
578}
579
580static int
581hash_delete(dbp, key, flag)
582 const DB *dbp;
583 const DBT *key;
584 u_int32_t flag; /* Ignored */
585{
586 HTAB *hashp;
587
588 hashp = (HTAB *)dbp->internal;
589 if (flag && flag != R_CURSOR) {
590 hashp->errno = errno = EINVAL;
591 return (ERROR);
592 }
593 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
594 hashp->errno = errno = EPERM;
595 return (ERROR);
596 }
597 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
598}
599
600/*
601 * Assume that hashp has been set in wrapper routine.
602 */
603static int
604hash_access(hashp, action, key, val)
605 HTAB *hashp;
606 ACTION action;
607 DBT *key, *val;
608{
609 register BUFHEAD *rbufp;
610 BUFHEAD *bufp, *save_bufp;
611 register u_int16_t *bp;
612 register int n, ndx, off, size;
613 register char *kp;
614 u_int16_t pageno;
615
616#ifdef HASH_STATISTICS
617 hash_accesses++;
618#endif
619
620 off = hashp->BSIZE;
621 size = key->size;
622 kp = (char *)key->data;
623 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
624 if (!rbufp)
625 return (ERROR);
626 save_bufp = rbufp;
627
628 /* Pin the bucket chain */
629 rbufp->flags |= BUF_PIN;
630 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
631 if (bp[1] >= REAL_KEY) {
632 /* Real key/data pair */
633 if (size == off - *bp &&
634 memcmp(kp, rbufp->page + *bp, size) == 0)
635 goto found;
636 off = bp[1];
637#ifdef HASH_STATISTICS
638 hash_collisions++;
639#endif
640 bp += 2;
641 ndx += 2;
642 } else if (bp[1] == OVFLPAGE) {
643 rbufp = __get_buf(hashp, *bp, rbufp, 0);
644 if (!rbufp) {
645 save_bufp->flags &= ~BUF_PIN;
646 return (ERROR);
647 }
648 /* FOR LOOP INIT */
649 bp = (u_int16_t *)rbufp->page;
650 n = *bp++;
651 ndx = 1;
652 off = hashp->BSIZE;
653 } else if (bp[1] < REAL_KEY) {
654 if ((ndx =
655 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
656 goto found;
657 if (ndx == -2) {
658 bufp = rbufp;
659 if (!(pageno =
660 __find_last_page(hashp, &bufp))) {
661 ndx = 0;
662 rbufp = bufp;
663 break; /* FOR */
664 }
665 rbufp = __get_buf(hashp, pageno, bufp, 0);
666 if (!rbufp) {
667 save_bufp->flags &= ~BUF_PIN;
668 return (ERROR);
669 }
670 /* FOR LOOP INIT */
671 bp = (u_int16_t *)rbufp->page;
672 n = *bp++;
673 ndx = 1;
674 off = hashp->BSIZE;
675 } else {
676 save_bufp->flags &= ~BUF_PIN;
677 return (ERROR);
678 }
679 }
680
681 /* Not found */
682 switch (action) {
683 case HASH_PUT:
684 case HASH_PUTNEW:
685 if (__addel(hashp, rbufp, key, val)) {
686 save_bufp->flags &= ~BUF_PIN;
687 return (ERROR);
688 } else {
689 save_bufp->flags &= ~BUF_PIN;
690 return (SUCCESS);
691 }
692 case HASH_GET:
693 case HASH_DELETE:
694 default:
695 save_bufp->flags &= ~BUF_PIN;
696 return (ABNORMAL);
697 }
698
699found:
700 switch (action) {
701 case HASH_PUTNEW:
702 save_bufp->flags &= ~BUF_PIN;
703 return (ABNORMAL);
704 case HASH_GET:
705 bp = (u_int16_t *)rbufp->page;
706 if (bp[ndx + 1] < REAL_KEY) {
707 if (__big_return(hashp, rbufp, ndx, val, 0))
708 return (ERROR);
709 } else {
710 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
711 val->size = bp[ndx] - bp[ndx + 1];
712 }
713 break;
714 case HASH_PUT:
715 if ((__delpair(hashp, rbufp, ndx)) ||
716 (__addel(hashp, rbufp, key, val))) {
717 save_bufp->flags &= ~BUF_PIN;
718 return (ERROR);
719 }
720 break;
721 case HASH_DELETE:
722 if (__delpair(hashp, rbufp, ndx))
723 return (ERROR);
724 break;
725 default:
726 abort();
727 }
728 save_bufp->flags &= ~BUF_PIN;
729 return (SUCCESS);
730}
731
732static int
733hash_seq(dbp, key, data, flag)
734 const DB *dbp;
735 DBT *key, *data;
736 u_int32_t flag;
737{
738 register u_int32_t bucket;
739 register BUFHEAD *bufp;
740 HTAB *hashp;
741 u_int16_t *bp, ndx;
742
743 hashp = (HTAB *)dbp->internal;
744 if (flag && flag != R_FIRST && flag != R_NEXT) {
745 hashp->errno = errno = EINVAL;
746 return (ERROR);
747 }
748#ifdef HASH_STATISTICS
749 hash_accesses++;
750#endif
751 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
752 hashp->cbucket = 0;
753 hashp->cndx = 1;
754 hashp->cpage = NULL;
755 }
756
757 for (bp = NULL; !bp || !bp[0]; ) {
758 if (!(bufp = hashp->cpage)) {
759 for (bucket = hashp->cbucket;
760 bucket <= hashp->MAX_BUCKET;
761 bucket++, hashp->cndx = 1) {
762 bufp = __get_buf(hashp, bucket, NULL, 0);
763 if (!bufp)
764 return (ERROR);
765 hashp->cpage = bufp;
766 bp = (u_int16_t *)bufp->page;
767 if (bp[0])
768 break;
769 }
770 hashp->cbucket = bucket;
771 if (hashp->cbucket > hashp->MAX_BUCKET) {
772 hashp->cbucket = -1;
773 return (ABNORMAL);
774 }
775 } else
776 bp = (u_int16_t *)hashp->cpage->page;
777
778#ifdef DEBUG
779 assert(bp);
780 assert(bufp);
781#endif
782 while (bp[hashp->cndx + 1] == OVFLPAGE) {
783 bufp = hashp->cpage =
784 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
785 if (!bufp)
786 return (ERROR);
787 bp = (u_int16_t *)(bufp->page);
788 hashp->cndx = 1;
789 }
790 if (!bp[0]) {
791 hashp->cpage = NULL;
792 ++hashp->cbucket;
793 }
794 }
795 ndx = hashp->cndx;
796 if (bp[ndx + 1] < REAL_KEY) {
797 if (__big_keydata(hashp, bufp, key, data, 1))
798 return (ERROR);
799 } else {
800 key->data = (u_char *)hashp->cpage->page + bp[ndx];
801 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
802 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
803 data->size = bp[ndx] - bp[ndx + 1];
804 ndx += 2;
805 if (ndx > bp[0]) {
806 hashp->cpage = NULL;
807 hashp->cbucket++;
808 hashp->cndx = 1;
809 } else
810 hashp->cndx = ndx;
811 }
812 return (SUCCESS);
813}
814
815/********************************* UTILITIES ************************/
816
817/*
818 * Returns:
819 * 0 ==> OK
820 * -1 ==> Error
821 */
822extern int
823__expand_table(hashp)
824 HTAB *hashp;
825{
826 u_int32_t old_bucket, new_bucket;
827 int dirsize, new_segnum, spare_ndx;
828
829#ifdef HASH_STATISTICS
830 hash_expansions++;
831#endif
832 new_bucket = ++hashp->MAX_BUCKET;
833 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
834
835 new_segnum = new_bucket >> hashp->SSHIFT;
836
837 /* Check if we need a new segment */
838 if (new_segnum >= hashp->nsegs) {
839 /* Check if we need to expand directory */
840 if (new_segnum >= hashp->DSIZE) {
841 /* Reallocate directory */
842 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
843 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
844 return (-1);
845 hashp->DSIZE = dirsize << 1;
846 }
847 if ((hashp->dir[new_segnum] =
848 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
849 return (-1);
850 hashp->exsegs++;
851 hashp->nsegs++;
852 }
853 /*
854 * If the split point is increasing (MAX_BUCKET's log base 2
855 * * increases), we need to copy the current contents of the spare
856 * split bucket to the next bucket.
857 */
858 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
859 if (spare_ndx > hashp->OVFL_POINT) {
860 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
861 hashp->OVFL_POINT = spare_ndx;
862 }
863
864 if (new_bucket > hashp->HIGH_MASK) {
865 /* Starting a new doubling */
866 hashp->LOW_MASK = hashp->HIGH_MASK;
867 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
868 }
869 /* Relocate records to the new bucket */
870 return (__split_page(hashp, old_bucket, new_bucket));
871}
872
873/*
874 * If realloc guarantees that the pointer is not destroyed if the realloc
875 * fails, then this routine can go away.
876 */
877static void *
878hash_realloc(p_ptr, oldsize, newsize)
879 SEGMENT **p_ptr;
880 int oldsize, newsize;
881{
882 register void *p;
883
884 if (p = malloc(newsize)) {
885 memmove(p, *p_ptr, oldsize);
886 memset((char *)p + oldsize, 0, newsize - oldsize);
887 free(*p_ptr);
888 *p_ptr = p;
889 }
890 return (p);
891}
892
893extern u_int32_t
894__call_hash(hashp, k, len)
895 HTAB *hashp;
896 char *k;
897 int len;
898{
899 int n, bucket;
900
901 n = hashp->hash(k, len);
902 bucket = n & hashp->HIGH_MASK;
903 if (bucket > hashp->MAX_BUCKET)
904 bucket = bucket & hashp->LOW_MASK;
905 return (bucket);
906}
907
908/*
909 * Allocate segment table. On error, destroy the table and set errno.
910 *
911 * Returns 0 on success
912 */
913static int
914alloc_segs(hashp, nsegs)
915 HTAB *hashp;
916 int nsegs;
917{
918 register int i;
919 register SEGMENT store;
920
921 int save_errno;
922
923 if ((hashp->dir =
924 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
925 save_errno = errno;
926 (void)hdestroy(hashp);
927 errno = save_errno;
928 return (-1);
929 }
930 /* Allocate segments */
931 if ((store =
932 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) {
933 save_errno = errno;
934 (void)hdestroy(hashp);
935 errno = save_errno;
936 return (-1);
937 }
938 for (i = 0; i < nsegs; i++, hashp->nsegs++)
939 hashp->dir[i] = &store[i << hashp->SSHIFT];
940 return (0);
941}
942
943#if BYTE_ORDER == LITTLE_ENDIAN
944/*
945 * Hashp->hdr needs to be byteswapped.
946 */
947static void
948swap_header_copy(srcp, destp)
949 HASHHDR *srcp, *destp;
950{
951 int i;
952
953 P_32_COPY(srcp->magic, destp->magic);
954 P_32_COPY(srcp->version, destp->version);
955 P_32_COPY(srcp->lorder, destp->lorder);
956 P_32_COPY(srcp->bsize, destp->bsize);
957 P_32_COPY(srcp->bshift, destp->bshift);
958 P_32_COPY(srcp->dsize, destp->dsize);
959 P_32_COPY(srcp->ssize, destp->ssize);
960 P_32_COPY(srcp->sshift, destp->sshift);
961 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
962 P_32_COPY(srcp->last_freed, destp->last_freed);
963 P_32_COPY(srcp->max_bucket, destp->max_bucket);
964 P_32_COPY(srcp->high_mask, destp->high_mask);
965 P_32_COPY(srcp->low_mask, destp->low_mask);
966 P_32_COPY(srcp->ffactor, destp->ffactor);
967 P_32_COPY(srcp->nkeys, destp->nkeys);
968 P_32_COPY(srcp->hdrpages, destp->hdrpages);
969 P_32_COPY(srcp->h_charkey, destp->h_charkey);
970 for (i = 0; i < NCACHED; i++) {
971 P_32_COPY(srcp->spares[i], destp->spares[i]);
972 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
973 }
974}
975
976static void
977swap_header(hashp)
978 HTAB *hashp;
979{
980 HASHHDR *hdrp;
981 int i;
982
983 hdrp = &hashp->hdr;
984
985 M_32_SWAP(hdrp->magic);
986 M_32_SWAP(hdrp->version);
987 M_32_SWAP(hdrp->lorder);
988 M_32_SWAP(hdrp->bsize);
989 M_32_SWAP(hdrp->bshift);
990 M_32_SWAP(hdrp->dsize);
991 M_32_SWAP(hdrp->ssize);
992 M_32_SWAP(hdrp->sshift);
993 M_32_SWAP(hdrp->ovfl_point);
994 M_32_SWAP(hdrp->last_freed);
995 M_32_SWAP(hdrp->max_bucket);
996 M_32_SWAP(hdrp->high_mask);
997 M_32_SWAP(hdrp->low_mask);
998 M_32_SWAP(hdrp->ffactor);
999 M_32_SWAP(hdrp->nkeys);
1000 M_32_SWAP(hdrp->hdrpages);
1001 M_32_SWAP(hdrp->h_charkey);
1002 for (i = 0; i < NCACHED; i++) {
1003 M_32_SWAP(hdrp->spares[i]);
1004 M_16_SWAP(hdrp->bitmaps[i]);
1005 }
1006}
1007#endif
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