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db: avoid use of errno field name
[nvi.git] / db.1.85 / hash / hash.c
blob72007950b96c48d87fd7ef3a557a4bcbb1cbe04e
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
41 #include <sys/param.h>
42 #include <sys/stat.h>
43
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 #ifdef DEBUG
51 #include <assert.h>
52 #endif
53
54 #include <db.h>
55 #include "hash.h"
56 #include "page.h"
57 #include "extern.h"
58
59 static int alloc_segs __P((HTAB *, int));
60 static int flush_meta __P((HTAB *));
61 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *));
62 static int hash_close __P((DB *));
63 static int hash_delete __P((const DB *, const DBT *, u_int32_t));
64 static int hash_fd __P((const DB *));
65 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t));
66 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t));
67 static void *hash_realloc __P((SEGMENT **, int, int));
68 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t));
69 static int hash_sync __P((const DB *, u_int32_t));
70 static int hdestroy __P((HTAB *));
71 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *));
72 static int init_htab __P((HTAB *, int));
73 #if BYTE_ORDER == LITTLE_ENDIAN
74 static void swap_header __P((HTAB *));
75 static void swap_header_copy __P((HASHHDR *, HASHHDR *));
76 #endif
77
78 /* Fast arithmetic, relying on powers of 2, */
79 #define MOD(x, y) ((x) & ((y) - 1))
80
81 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
82
83 /* Return values */
84 #define SUCCESS (0)
85 #define ERROR (-1)
86 #define ABNORMAL (1)
87
88 #ifdef HASH_STATISTICS
89 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
90 #endif
91
92 /************************** INTERFACE ROUTINES ***************************/
93 /* OPEN/CLOSE */
94
95 extern DB *
96 __hash_open(file, flags, mode, info, dflags)
97 const char *file;
98 int flags, mode, dflags;
99 const HASHINFO *info; /* Special directives for create */
100 {
101 HTAB *hashp;
102 struct stat statbuf;
103 DB *dbp;
104 int bpages, hdrsize, new_table, nsegs, save_errno;
105
106 if ((flags & O_ACCMODE) == O_WRONLY) {
107 errno = EINVAL;
108 return (NULL);
109 }
110
111 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB))))
112 return (NULL);
113 hashp->fp = -1;
114
115 /*
116 * Even if user wants write only, we need to be able to read
117 * the actual file, so we need to open it read/write. But, the
118 * field in the hashp structure needs to be accurate so that
119 * we can check accesses.
120 */
121 hashp->flags = flags;
122
123 new_table = 0;
124 if (!file || (flags & O_TRUNC) ||
125 (stat(file, &statbuf) && (errno == ENOENT))) {
126 if (errno == ENOENT)
127 errno = 0; /* Just in case someone looks at errno */
128 new_table = 1;
129 }
130 if (file) {
131 if ((hashp->fp = open(file, flags, mode)) == -1)
132 RETURN_ERROR(errno, error0);
133 (void)fcntl(hashp->fp, F_SETFD, 1);
134 }
135 if (new_table) {
136 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info)))
137 RETURN_ERROR(errno, error1);
138 } else {
139 /* Table already exists */
140 if (info && info->hash)
141 hashp->hash = info->hash;
142 else
143 hashp->hash = __default_hash;
144
145 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
146 #if BYTE_ORDER == LITTLE_ENDIAN
147 swap_header(hashp);
148 #endif
149 if (hdrsize == -1)
150 RETURN_ERROR(errno, error1);
151 if (hdrsize != sizeof(HASHHDR))
152 RETURN_ERROR(EFTYPE, error1);
153 /* Verify file type, versions and hash function */
154 if (hashp->MAGIC != HASHMAGIC)
155 RETURN_ERROR(EFTYPE, error1);
156 #define OLDHASHVERSION 1
157 if (hashp->VERSION != HASHVERSION &&
158 hashp->VERSION != OLDHASHVERSION)
159 RETURN_ERROR(EFTYPE, error1);
160 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
161 RETURN_ERROR(EFTYPE, error1);
162 /*
163 * Figure out how many segments we need. Max_Bucket is the
164 * maximum bucket number, so the number of buckets is
165 * max_bucket + 1.
166 */
167 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
168 hashp->SGSIZE;
169 hashp->nsegs = 0;
170 if (alloc_segs(hashp, nsegs))
171 /*
172 * If alloc_segs fails, table will have been destroyed
173 * and errno will have been set.
174 */
175 return (NULL);
176 /* Read in bitmaps */
177 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
178 (hashp->BSIZE << BYTE_SHIFT) - 1) >>
179 (hashp->BSHIFT + BYTE_SHIFT);
180
181 hashp->nmaps = bpages;
182 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
183 }
184
185 /* Initialize Buffer Manager */
186 if (info && info->cachesize)
187 __buf_init(hashp, info->cachesize);
188 else
189 __buf_init(hashp, DEF_BUFSIZE);
190
191 hashp->new_file = new_table;
192 hashp->save_file = file && (hashp->flags & O_RDWR);
193 hashp->cbucket = -1;
194 if (!(dbp = (DB *)malloc(sizeof(DB)))) {
195 save_errno = errno;
196 hdestroy(hashp);
197 errno = save_errno;
198 return (NULL);
199 }
200 dbp->internal = hashp;
201 dbp->close = hash_close;
202 dbp->del = hash_delete;
203 dbp->fd = hash_fd;
204 dbp->get = hash_get;
205 dbp->put = hash_put;
206 dbp->seq = hash_seq;
207 dbp->sync = hash_sync;
208 dbp->type = DB_HASH;
209
210 #ifdef DEBUG
211 (void)fprintf(stderr,
212 "%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",
213 "init_htab:",
214 "TABLE POINTER ", hashp,
215 "BUCKET SIZE ", hashp->BSIZE,
216 "BUCKET SHIFT ", hashp->BSHIFT,
217 "DIRECTORY SIZE ", hashp->DSIZE,
218 "SEGMENT SIZE ", hashp->SGSIZE,
219 "SEGMENT SHIFT ", hashp->SSHIFT,
220 "FILL FACTOR ", hashp->FFACTOR,
221 "MAX BUCKET ", hashp->MAX_BUCKET,
222 "OVFL POINT ", hashp->OVFL_POINT,
223 "LAST FREED ", hashp->LAST_FREED,
224 "HIGH MASK ", hashp->HIGH_MASK,
225 "LOW MASK ", hashp->LOW_MASK,
226 "NSEGS ", hashp->nsegs,
227 "NKEYS ", hashp->NKEYS);
228 #endif
229 #ifdef HASH_STATISTICS
230 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
231 #endif
232 return (dbp);
233
234 error1:
235 if (hashp != NULL)
236 (void)close(hashp->fp);
237
238 error0:
239 free(hashp);
240 errno = save_errno;
241 return (NULL);
242 }
243
244 static int
245 hash_close(dbp)
246 DB *dbp;
247 {
248 HTAB *hashp;
249 int retval;
250
251 if (!dbp)
252 return (ERROR);
253
254 hashp = (HTAB *)dbp->internal;
255 retval = hdestroy(hashp);
256 free(dbp);
257 return (retval);
258 }
259
260 static int
261 hash_fd(dbp)
262 const DB *dbp;
263 {
264 HTAB *hashp;
265
266 if (!dbp)
267 return (ERROR);
268
269 hashp = (HTAB *)dbp->internal;
270 if (hashp->fp == -1) {
271 errno = ENOENT;
272 return (-1);
273 }
274 return (hashp->fp);
275 }
276
277 /************************** LOCAL CREATION ROUTINES **********************/
278 static HTAB *
279 init_hash(hashp, file, info)
280 HTAB *hashp;
281 const char *file;
282 HASHINFO *info;
283 {
284 struct stat statbuf;
285 int nelem;
286
287 nelem = 1;
288 hashp->NKEYS = 0;
289 hashp->LORDER = BYTE_ORDER;
290 hashp->BSIZE = DEF_BUCKET_SIZE;
291 hashp->BSHIFT = DEF_BUCKET_SHIFT;
292 hashp->SGSIZE = DEF_SEGSIZE;
293 hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
294 hashp->DSIZE = DEF_DIRSIZE;
295 hashp->FFACTOR = DEF_FFACTOR;
296 hashp->hash = __default_hash;
297 memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
298 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
299
300 /* Fix bucket size to be optimal for file system */
301 if (file != NULL) {
302 if (stat(file, &statbuf))
303 return (NULL);
304 hashp->BSIZE = statbuf.st_blksize;
305 hashp->BSHIFT = __log2(hashp->BSIZE);
306 }
307
308 if (info) {
309 if (info->bsize) {
310 /* Round pagesize up to power of 2 */
311 hashp->BSHIFT = __log2(info->bsize);
312 hashp->BSIZE = 1 << hashp->BSHIFT;
313 if (hashp->BSIZE > MAX_BSIZE) {
314 errno = EINVAL;
315 return (NULL);
316 }
317 }
318 if (info->ffactor)
319 hashp->FFACTOR = info->ffactor;
320 if (info->hash)
321 hashp->hash = info->hash;
322 if (info->nelem)
323 nelem = info->nelem;
324 if (info->lorder) {
325 if (info->lorder != BIG_ENDIAN &&
326 info->lorder != LITTLE_ENDIAN) {
327 errno = EINVAL;
328 return (NULL);
329 }
330 hashp->LORDER = info->lorder;
331 }
332 }
333 /* init_htab should destroy the table and set errno if it fails */
334 if (init_htab(hashp, nelem))
335 return (NULL);
336 else
337 return (hashp);
338 }
339 /*
340 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy
341 * the table and set errno, so we just pass the error information along.
342 *
343 * Returns 0 on No Error
344 */
345 static int
346 init_htab(hashp, nelem)
347 HTAB *hashp;
348 int nelem;
349 {
350 register int nbuckets, nsegs;
351 int l2;
352
353 /*
354 * Divide number of elements by the fill factor and determine a
355 * desired number of buckets. Allocate space for the next greater
356 * power of two number of buckets.
357 */
358 nelem = (nelem - 1) / hashp->FFACTOR + 1;
359
360 l2 = __log2(MAX(nelem, 2));
361 nbuckets = 1 << l2;
362
363 hashp->SPARES[l2] = l2 + 1;
364 hashp->SPARES[l2 + 1] = l2 + 1;
365 hashp->OVFL_POINT = l2;
366 hashp->LAST_FREED = 2;
367
368 /* First bitmap page is at: splitpoint l2 page offset 1 */
369 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0))
370 return (-1);
371
372 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
373 hashp->HIGH_MASK = (nbuckets << 1) - 1;
374 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
375 hashp->BSHIFT) + 1;
376
377 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
378 nsegs = 1 << __log2(nsegs);
379
380 if (nsegs > hashp->DSIZE)
381 hashp->DSIZE = nsegs;
382 return (alloc_segs(hashp, nsegs));
383 }
384
385 /********************** DESTROY/CLOSE ROUTINES ************************/
386
387 /*
388 * Flushes any changes to the file if necessary and destroys the hashp
389 * structure, freeing all allocated space.
390 */
391 static int
392 hdestroy(hashp)
393 HTAB *hashp;
394 {
395 int i, save_errno;
396
397 save_errno = 0;
398
399 #ifdef HASH_STATISTICS
400 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
401 hash_accesses, hash_collisions);
402 (void)fprintf(stderr, "hdestroy: expansions %ld\n",
403 hash_expansions);
404 (void)fprintf(stderr, "hdestroy: overflows %ld\n",
405 hash_overflows);
406 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
407 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
408
409 for (i = 0; i < NCACHED; i++)
410 (void)fprintf(stderr,
411 "spares[%d] = %d\n", i, hashp->SPARES[i]);
412 #endif
413 /*
414 * Call on buffer manager to free buffers, and if required,
415 * write them to disk.
416 */
417 if (__buf_free(hashp, 1, hashp->save_file))
418 save_errno = errno;
419 if (hashp->dir) {
420 free(*hashp->dir); /* Free initial segments */
421 /* Free extra segments */
422 while (hashp->exsegs--)
423 free(hashp->dir[--hashp->nsegs]);
424 free(hashp->dir);
425 }
426 if (flush_meta(hashp) && !save_errno)
427 save_errno = errno;
428 /* Free Bigmaps */
429 for (i = 0; i < hashp->nmaps; i++)
430 if (hashp->mapp[i])
431 free(hashp->mapp[i]);
432
433 if (hashp->fp != -1)
434 (void)close(hashp->fp);
435
436 free(hashp);
437
438 if (save_errno) {
439 errno = save_errno;
440 return (ERROR);
441 }
442 return (SUCCESS);
443 }
444 /*
445 * Write modified pages to disk
446 *
447 * Returns:
448 * 0 == OK
449 * -1 ERROR
450 */
451 static int
452 hash_sync(dbp, flags)
453 const DB *dbp;
454 u_int32_t flags;
455 {
456 HTAB *hashp;
457
458 if (flags != 0) {
459 errno = EINVAL;
460 return (ERROR);
461 }
462
463 if (!dbp)
464 return (ERROR);
465
466 hashp = (HTAB *)dbp->internal;
467 if (!hashp->save_file)
468 return (0);
469 if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
470 return (ERROR);
471 hashp->new_file = 0;
472 return (0);
473 }
474
475 /*
476 * Returns:
477 * 0 == OK
478 * -1 indicates that errno should be set
479 */
480 static int
481 flush_meta(hashp)
482 HTAB *hashp;
483 {
484 HASHHDR *whdrp;
485 #if BYTE_ORDER == LITTLE_ENDIAN
486 HASHHDR whdr;
487 #endif
488 int fp, i, wsize;
489
490 if (!hashp->save_file)
491 return (0);
492 hashp->MAGIC = HASHMAGIC;
493 hashp->VERSION = HASHVERSION;
494 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
495
496 fp = hashp->fp;
497 whdrp = &hashp->hdr;
498 #if BYTE_ORDER == LITTLE_ENDIAN
499 whdrp = &whdr;
500 swap_header_copy(&hashp->hdr, whdrp);
501 #endif
502 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) ||
503 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1))
504 return (-1);
505 else
506 if (wsize != sizeof(HASHHDR)) {
507 errno = EFTYPE;
508 hashp->_errno = errno;
509 return (-1);
510 }
511 for (i = 0; i < NCACHED; i++)
512 if (hashp->mapp[i])
513 if (__put_page(hashp, (char *)hashp->mapp[i],
514 hashp->BITMAPS[i], 0, 1))
515 return (-1);
516 return (0);
517 }
518
519 /*******************************SEARCH ROUTINES *****************************/
520 /*
521 * All the access routines return
522 *
523 * Returns:
524 * 0 on SUCCESS
525 * 1 to indicate an external ERROR (i.e. key not found, etc)
526 * -1 to indicate an internal ERROR (i.e. out of memory, etc)
527 */
528 static int
529 hash_get(dbp, key, data, flag)
530 const DB *dbp;
531 const DBT *key;
532 DBT *data;
533 u_int32_t flag;
534 {
535 HTAB *hashp;
536
537 hashp = (HTAB *)dbp->internal;
538 if (flag) {
539 hashp->_errno = errno = EINVAL;
540 return (ERROR);
541 }
542 return (hash_access(hashp, HASH_GET, (DBT *)key, data));
543 }
544
545 static int
546 hash_put(dbp, key, data, flag)
547 const DB *dbp;
548 DBT *key;
549 const DBT *data;
550 u_int32_t flag;
551 {
552 HTAB *hashp;
553
554 hashp = (HTAB *)dbp->internal;
555 if (flag && flag != R_NOOVERWRITE) {
556 hashp->_errno = errno = EINVAL;
557 return (ERROR);
558 }
559 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
560 hashp->_errno = errno = EPERM;
561 return (ERROR);
562 }
563 return (hash_access(hashp, flag == R_NOOVERWRITE ?
564 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
565 }
566
567 static int
568 hash_delete(dbp, key, flag)
569 const DB *dbp;
570 const DBT *key;
571 u_int32_t flag; /* Ignored */
572 {
573 HTAB *hashp;
574
575 hashp = (HTAB *)dbp->internal;
576 if (flag && flag != R_CURSOR) {
577 hashp->_errno = errno = EINVAL;
578 return (ERROR);
579 }
580 if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
581 hashp->_errno = errno = EPERM;
582 return (ERROR);
583 }
584 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
585 }
586
587 /*
588 * Assume that hashp has been set in wrapper routine.
589 */
590 static int
591 hash_access(hashp, action, key, val)
592 HTAB *hashp;
593 ACTION action;
594 DBT *key, *val;
595 {
596 register BUFHEAD *rbufp;
597 BUFHEAD *bufp, *save_bufp;
598 register u_int16_t *bp;
599 register int n, ndx, off, size;
600 register char *kp;
601 u_int16_t pageno;
602
603 #ifdef HASH_STATISTICS
604 hash_accesses++;
605 #endif
606
607 off = hashp->BSIZE;
608 size = key->size;
609 kp = (char *)key->data;
610 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
611 if (!rbufp)
612 return (ERROR);
613 save_bufp = rbufp;
614
615 /* Pin the bucket chain */
616 rbufp->flags |= BUF_PIN;
617 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
618 if (bp[1] >= REAL_KEY) {
619 /* Real key/data pair */
620 if (size == off - *bp &&
621 memcmp(kp, rbufp->page + *bp, size) == 0)
622 goto found;
623 off = bp[1];
624 #ifdef HASH_STATISTICS
625 hash_collisions++;
626 #endif
627 bp += 2;
628 ndx += 2;
629 } else if (bp[1] == OVFLPAGE) {
630 rbufp = __get_buf(hashp, *bp, rbufp, 0);
631 if (!rbufp) {
632 save_bufp->flags &= ~BUF_PIN;
633 return (ERROR);
634 }
635 /* FOR LOOP INIT */
636 bp = (u_int16_t *)rbufp->page;
637 n = *bp++;
638 ndx = 1;
639 off = hashp->BSIZE;
640 } else if (bp[1] < REAL_KEY) {
641 if ((ndx =
642 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
643 goto found;
644 if (ndx == -2) {
645 bufp = rbufp;
646 if (!(pageno =
647 __find_last_page(hashp, &bufp))) {
648 ndx = 0;
649 rbufp = bufp;
650 break; /* FOR */
651 }
652 rbufp = __get_buf(hashp, pageno, bufp, 0);
653 if (!rbufp) {
654 save_bufp->flags &= ~BUF_PIN;
655 return (ERROR);
656 }
657 /* FOR LOOP INIT */
658 bp = (u_int16_t *)rbufp->page;
659 n = *bp++;
660 ndx = 1;
661 off = hashp->BSIZE;
662 } else {
663 save_bufp->flags &= ~BUF_PIN;
664 return (ERROR);
665 }
666 }
667
668 /* Not found */
669 switch (action) {
670 case HASH_PUT:
671 case HASH_PUTNEW:
672 if (__addel(hashp, rbufp, key, val)) {
673 save_bufp->flags &= ~BUF_PIN;
674 return (ERROR);
675 } else {
676 save_bufp->flags &= ~BUF_PIN;
677 return (SUCCESS);
678 }
679 case HASH_GET:
680 case HASH_DELETE:
681 default:
682 save_bufp->flags &= ~BUF_PIN;
683 return (ABNORMAL);
684 }
685
686 found:
687 switch (action) {
688 case HASH_PUTNEW:
689 save_bufp->flags &= ~BUF_PIN;
690 return (ABNORMAL);
691 case HASH_GET:
692 bp = (u_int16_t *)rbufp->page;
693 if (bp[ndx + 1] < REAL_KEY) {
694 if (__big_return(hashp, rbufp, ndx, val, 0))
695 return (ERROR);
696 } else {
697 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
698 val->size = bp[ndx] - bp[ndx + 1];
699 }
700 break;
701 case HASH_PUT:
702 if ((__delpair(hashp, rbufp, ndx)) ||
703 (__addel(hashp, rbufp, key, val))) {
704 save_bufp->flags &= ~BUF_PIN;
705 return (ERROR);
706 }
707 break;
708 case HASH_DELETE:
709 if (__delpair(hashp, rbufp, ndx))
710 return (ERROR);
711 break;
712 default:
713 abort();
714 }
715 save_bufp->flags &= ~BUF_PIN;
716 return (SUCCESS);
717 }
718
719 static int
720 hash_seq(dbp, key, data, flag)
721 const DB *dbp;
722 DBT *key, *data;
723 u_int32_t flag;
724 {
725 register u_int32_t bucket;
726 register BUFHEAD *bufp;
727 HTAB *hashp;
728 u_int16_t *bp, ndx;
729
730 hashp = (HTAB *)dbp->internal;
731 if (flag && flag != R_FIRST && flag != R_NEXT) {
732 hashp->_errno = errno = EINVAL;
733 return (ERROR);
734 }
735 #ifdef HASH_STATISTICS
736 hash_accesses++;
737 #endif
738 if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
739 hashp->cbucket = 0;
740 hashp->cndx = 1;
741 hashp->cpage = NULL;
742 }
743
744 for (bp = NULL; !bp || !bp[0]; ) {
745 if (!(bufp = hashp->cpage)) {
746 for (bucket = hashp->cbucket;
747 bucket <= hashp->MAX_BUCKET;
748 bucket++, hashp->cndx = 1) {
749 bufp = __get_buf(hashp, bucket, NULL, 0);
750 if (!bufp)
751 return (ERROR);
752 hashp->cpage = bufp;
753 bp = (u_int16_t *)bufp->page;
754 if (bp[0])
755 break;
756 }
757 hashp->cbucket = bucket;
758 if (hashp->cbucket > hashp->MAX_BUCKET) {
759 hashp->cbucket = -1;
760 return (ABNORMAL);
761 }
762 } else
763 bp = (u_int16_t *)hashp->cpage->page;
764
765 #ifdef DEBUG
766 assert(bp);
767 assert(bufp);
768 #endif
769 while (bp[hashp->cndx + 1] == OVFLPAGE) {
770 bufp = hashp->cpage =
771 __get_buf(hashp, bp[hashp->cndx], bufp, 0);
772 if (!bufp)
773 return (ERROR);
774 bp = (u_int16_t *)(bufp->page);
775 hashp->cndx = 1;
776 }
777 if (!bp[0]) {
778 hashp->cpage = NULL;
779 ++hashp->cbucket;
780 }
781 }
782 ndx = hashp->cndx;
783 if (bp[ndx + 1] < REAL_KEY) {
784 if (__big_keydata(hashp, bufp, key, data, 1))
785 return (ERROR);
786 } else {
787 key->data = (u_char *)hashp->cpage->page + bp[ndx];
788 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
789 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
790 data->size = bp[ndx] - bp[ndx + 1];
791 ndx += 2;
792 if (ndx > bp[0]) {
793 hashp->cpage = NULL;
794 hashp->cbucket++;
795 hashp->cndx = 1;
796 } else
797 hashp->cndx = ndx;
798 }
799 return (SUCCESS);
800 }
801
802 /********************************* UTILITIES ************************/
803
804 /*
805 * Returns:
806 * 0 ==> OK
807 * -1 ==> Error
808 */
809 extern int
810 __expand_table(hashp)
811 HTAB *hashp;
812 {
813 u_int32_t old_bucket, new_bucket;
814 int dirsize, new_segnum, spare_ndx;
815
816 #ifdef HASH_STATISTICS
817 hash_expansions++;
818 #endif
819 new_bucket = ++hashp->MAX_BUCKET;
820 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
821
822 new_segnum = new_bucket >> hashp->SSHIFT;
823
824 /* Check if we need a new segment */
825 if (new_segnum >= hashp->nsegs) {
826 /* Check if we need to expand directory */
827 if (new_segnum >= hashp->DSIZE) {
828 /* Reallocate directory */
829 dirsize = hashp->DSIZE * sizeof(SEGMENT *);
830 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
831 return (-1);
832 hashp->DSIZE = dirsize << 1;
833 }
834 if ((hashp->dir[new_segnum] =
835 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
836 return (-1);
837 hashp->exsegs++;
838 hashp->nsegs++;
839 }
840 /*
841 * If the split point is increasing (MAX_BUCKET's log base 2
842 * * increases), we need to copy the current contents of the spare
843 * split bucket to the next bucket.
844 */
845 spare_ndx = __log2(hashp->MAX_BUCKET + 1);
846 if (spare_ndx > hashp->OVFL_POINT) {
847 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
848 hashp->OVFL_POINT = spare_ndx;
849 }
850
851 if (new_bucket > hashp->HIGH_MASK) {
852 /* Starting a new doubling */
853 hashp->LOW_MASK = hashp->HIGH_MASK;
854 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
855 }
856 /* Relocate records to the new bucket */
857 return (__split_page(hashp, old_bucket, new_bucket));
858 }
859
860 /*
861 * If realloc guarantees that the pointer is not destroyed if the realloc
862 * fails, then this routine can go away.
863 */
864 static void *
865 hash_realloc(p_ptr, oldsize, newsize)
866 SEGMENT **p_ptr;
867 int oldsize, newsize;
868 {
869 register void *p;
870
871 if (p = malloc(newsize)) {
872 memmove(p, *p_ptr, oldsize);
873 memset((char *)p + oldsize, 0, newsize - oldsize);
874 free(*p_ptr);
875 *p_ptr = p;
876 }
877 return (p);
878 }
879
880 extern u_int32_t
881 __call_hash(hashp, k, len)
882 HTAB *hashp;
883 char *k;
884 int len;
885 {
886 int n, bucket;
887
888 n = hashp->hash(k, len);
889 bucket = n & hashp->HIGH_MASK;
890 if (bucket > hashp->MAX_BUCKET)
891 bucket = bucket & hashp->LOW_MASK;
892 return (bucket);
893 }
894
895 /*
896 * Allocate segment table. On error, destroy the table and set errno.
897 *
898 * Returns 0 on success
899 */
900 static int
901 alloc_segs(hashp, nsegs)
902 HTAB *hashp;
903 int nsegs;
904 {
905 register int i;
906 register SEGMENT store;
907
908 int save_errno;
909
910 if ((hashp->dir =
911 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
912 save_errno = errno;
913 (void)hdestroy(hashp);
914 errno = save_errno;
915 return (-1);
916 }
917 /* Allocate segments */
918 if ((store =
919 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) {
920 save_errno = errno;
921 (void)hdestroy(hashp);
922 errno = save_errno;
923 return (-1);
924 }
925 for (i = 0; i < nsegs; i++, hashp->nsegs++)
926 hashp->dir[i] = &store[i << hashp->SSHIFT];
927 return (0);
928 }
929
930 #if BYTE_ORDER == LITTLE_ENDIAN
931 /*
932 * Hashp->hdr needs to be byteswapped.
933 */
934 static void
935 swap_header_copy(srcp, destp)
936 HASHHDR *srcp, *destp;
937 {
938 int i;
939
940 P_32_COPY(srcp->magic, destp->magic);
941 P_32_COPY(srcp->version, destp->version);
942 P_32_COPY(srcp->lorder, destp->lorder);
943 P_32_COPY(srcp->bsize, destp->bsize);
944 P_32_COPY(srcp->bshift, destp->bshift);
945 P_32_COPY(srcp->dsize, destp->dsize);
946 P_32_COPY(srcp->ssize, destp->ssize);
947 P_32_COPY(srcp->sshift, destp->sshift);
948 P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
949 P_32_COPY(srcp->last_freed, destp->last_freed);
950 P_32_COPY(srcp->max_bucket, destp->max_bucket);
951 P_32_COPY(srcp->high_mask, destp->high_mask);
952 P_32_COPY(srcp->low_mask, destp->low_mask);
953 P_32_COPY(srcp->ffactor, destp->ffactor);
954 P_32_COPY(srcp->nkeys, destp->nkeys);
955 P_32_COPY(srcp->hdrpages, destp->hdrpages);
956 P_32_COPY(srcp->h_charkey, destp->h_charkey);
957 for (i = 0; i < NCACHED; i++) {
958 P_32_COPY(srcp->spares[i], destp->spares[i]);
959 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
960 }
961 }
962
963 static void
964 swap_header(hashp)
965 HTAB *hashp;
966 {
967 HASHHDR *hdrp;
968 int i;
969
970 hdrp = &hashp->hdr;
971
972 M_32_SWAP(hdrp->magic);
973 M_32_SWAP(hdrp->version);
974 M_32_SWAP(hdrp->lorder);
975 M_32_SWAP(hdrp->bsize);
976 M_32_SWAP(hdrp->bshift);
977 M_32_SWAP(hdrp->dsize);
978 M_32_SWAP(hdrp->ssize);
979 M_32_SWAP(hdrp->sshift);
980 M_32_SWAP(hdrp->ovfl_point);
981 M_32_SWAP(hdrp->last_freed);
982 M_32_SWAP(hdrp->max_bucket);
983 M_32_SWAP(hdrp->high_mask);
984 M_32_SWAP(hdrp->low_mask);
985 M_32_SWAP(hdrp->ffactor);
986 M_32_SWAP(hdrp->nkeys);
987 M_32_SWAP(hdrp->hdrpages);
988 M_32_SWAP(hdrp->h_charkey);
989 for (i = 0; i < NCACHED; i++) {
990 M_32_SWAP(hdrp->spares[i]);
991 M_16_SWAP(hdrp->bitmaps[i]);
992 }
993 }
994 #endif
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