hash.c revision 1.17
1 /* $NetBSD: hash.c,v 1.17 2002/12/11 21:20:15 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Margo Seltzer. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 43 #else 44 __RCSID("$NetBSD: hash.c,v 1.17 2002/12/11 21:20:15 christos Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include "namespace.h" 49 #include <sys/param.h> 50 #include <sys/stat.h> 51 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 #ifdef DEBUG 59 #include <assert.h> 60 #endif 61 62 #include <db.h> 63 #include "hash.h" 64 #include "page.h" 65 #include "extern.h" 66 67 static int alloc_segs __P((HTAB *, int)); 68 static int flush_meta __P((HTAB *)); 69 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 70 static int hash_close __P((DB *)); 71 static int hash_delete __P((const DB *, const DBT *, u_int32_t)); 72 static int hash_fd __P((const DB *)); 73 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); 74 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); 75 static void *hash_realloc __P((SEGMENT **, int, int)); 76 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); 77 static int hash_sync __P((const DB *, u_int32_t)); 78 static int hdestroy __P((HTAB *)); 79 static HTAB *init_hash __P((HTAB *, const char *, const HASHINFO *)); 80 static int init_htab __P((HTAB *, size_t)); 81 #if BYTE_ORDER == LITTLE_ENDIAN 82 static void swap_header __P((HTAB *)); 83 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 84 #endif 85 86 /* Fast arithmetic, relying on powers of 2, */ 87 #define MOD(x, y) ((x) & ((y) - 1)) 88 89 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 90 91 /* Return values */ 92 #define SUCCESS (0) 93 #define ERROR (-1) 94 #define ABNORMAL (1) 95 96 #ifdef HASH_STATISTICS 97 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 98 #endif 99 100 /************************** INTERFACE ROUTINES ***************************/ 101 /* OPEN/CLOSE */ 102 103 /* ARGSUSED */ 104 extern DB * 105 __hash_open(file, flags, mode, info, dflags) 106 const char *file; 107 int flags; 108 mode_t mode; 109 const HASHINFO *info; /* Special directives for create */ 110 int dflags; 111 { 112 HTAB *hashp; 113 struct stat statbuf; 114 DB *dbp; 115 int bpages, hdrsize, new_table, nsegs, save_errno; 116 117 if ((flags & O_ACCMODE) == O_WRONLY) { 118 errno = EINVAL; 119 return (NULL); 120 } 121 122 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 123 return (NULL); 124 hashp->fp = -1; 125 126 /* 127 * Even if user wants write only, we need to be able to read 128 * the actual file, so we need to open it read/write. But, the 129 * field in the hashp structure needs to be accurate so that 130 * we can check accesses. 131 */ 132 hashp->flags = flags; 133 134 new_table = 0; 135 if (!file || (flags & O_TRUNC) || 136 (stat(file, &statbuf) && (errno == ENOENT))) { 137 if (errno == ENOENT) 138 errno = 0; /* Just in case someone looks at errno */ 139 new_table = 1; 140 } 141 if (file) { 142 if ((hashp->fp = open(file, flags, mode)) == -1) 143 RETURN_ERROR(errno, error0); 144 (void)fcntl(hashp->fp, F_SETFD, 1); 145 } 146 if (new_table) { 147 if (!(hashp = init_hash(hashp, file, 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 (unsigned int)(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 const 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 = MIN(statbuf.st_blksize, MAX_BSIZE - 1); 316 hashp->BSHIFT = __log2((u_int32_t)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, (size_t)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 size_t nelem; 360 { 361 register int nbuckets; 362 u_int32_t nsegs; 363 int l2; 364 365 /* 366 * Divide number of elements by the fill factor and determine a 367 * desired number of buckets. Allocate space for the next greater 368 * power of two number of buckets. 369 */ 370 nelem = (nelem - 1) / hashp->FFACTOR + 1; 371 372 l2 = __log2(MAX(nelem, 2)); 373 nbuckets = 1 << l2; 374 375 hashp->SPARES[l2] = l2 + 1; 376 hashp->SPARES[l2 + 1] = l2 + 1; 377 hashp->OVFL_POINT = l2; 378 hashp->LAST_FREED = 2; 379 380 /* First bitmap page is at: splitpoint l2 page offset 1 */ 381 if (__ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0)) 382 return (-1); 383 384 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 385 hashp->HIGH_MASK = (nbuckets << 1) - 1; 386 /* LINTED constant in conditional context */ 387 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 388 hashp->BSHIFT) + 1; 389 390 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 391 nsegs = 1 << __log2(nsegs); 392 393 if (nsegs > hashp->DSIZE) 394 hashp->DSIZE = nsegs; 395 return (alloc_segs(hashp, (int)nsegs)); 396 } 397 398 /********************** DESTROY/CLOSE ROUTINES ************************/ 399 400 /* 401 * Flushes any changes to the file if necessary and destroys the hashp 402 * structure, freeing all allocated space. 403 */ 404 static int 405 hdestroy(hashp) 406 HTAB *hashp; 407 { 408 int i, save_errno; 409 410 save_errno = 0; 411 412 #ifdef HASH_STATISTICS 413 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 414 hash_accesses, hash_collisions); 415 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 416 hash_expansions); 417 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 418 hash_overflows); 419 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 420 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 421 422 for (i = 0; i < NCACHED; i++) 423 (void)fprintf(stderr, 424 "spares[%d] = %d\n", i, hashp->SPARES[i]); 425 #endif 426 /* 427 * Call on buffer manager to free buffers, and if required, 428 * write them to disk. 429 */ 430 if (__buf_free(hashp, 1, hashp->save_file)) 431 save_errno = errno; 432 if (hashp->dir) { 433 free(*hashp->dir); /* Free initial segments */ 434 /* Free extra segments */ 435 while (hashp->exsegs--) 436 free(hashp->dir[--hashp->nsegs]); 437 free(hashp->dir); 438 } 439 if (flush_meta(hashp) && !save_errno) 440 save_errno = errno; 441 /* Free Bigmaps */ 442 for (i = 0; i < hashp->nmaps; i++) 443 if (hashp->mapp[i]) 444 free(hashp->mapp[i]); 445 446 if (hashp->fp != -1) 447 (void)close(hashp->fp); 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 */ 464 static int 465 hash_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 */ 493 static int 494 flush_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 ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 516 return (-1); 517 else 518 if (wsize != sizeof(HASHHDR)) { 519 errno = EFTYPE; 520 hashp->err = errno; 521 return (-1); 522 } 523 for (i = 0; i < NCACHED; i++) 524 if (hashp->mapp[i]) 525 if (__put_page(hashp, (char *)(void *)hashp->mapp[i], 526 (u_int)hashp->BITMAPS[i], 0, 1)) 527 return (-1); 528 return (0); 529 } 530 531 /*******************************SEARCH ROUTINES *****************************/ 532 /* 533 * All the access routines return 534 * 535 * Returns: 536 * 0 on SUCCESS 537 * 1 to indicate an external ERROR (i.e. key not found, etc) 538 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 539 */ 540 static int 541 hash_get(dbp, key, data, flag) 542 const DB *dbp; 543 const DBT *key; 544 DBT *data; 545 u_int32_t flag; 546 { 547 HTAB *hashp; 548 549 hashp = (HTAB *)dbp->internal; 550 if (flag) { 551 hashp->err = errno = EINVAL; 552 return (ERROR); 553 } 554 /* LINTED const castaway */ 555 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 556 } 557 558 static int 559 hash_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->err = errno = EINVAL; 570 return (ERROR); 571 } 572 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 573 hashp->err = errno = EPERM; 574 return (ERROR); 575 } 576 /* LINTED const castaway */ 577 return (hash_access(hashp, flag == R_NOOVERWRITE ? 578 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 579 } 580 581 static int 582 hash_delete(dbp, key, flag) 583 const DB *dbp; 584 const DBT *key; 585 u_int32_t flag; /* Ignored */ 586 { 587 HTAB *hashp; 588 589 hashp = (HTAB *)dbp->internal; 590 if (flag && flag != R_CURSOR) { 591 hashp->err = errno = EINVAL; 592 return (ERROR); 593 } 594 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 595 hashp->err = errno = EPERM; 596 return (ERROR); 597 } 598 /* LINTED const castaway */ 599 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 600 } 601 602 /* 603 * Assume that hashp has been set in wrapper routine. 604 */ 605 static int 606 hash_access(hashp, action, key, val) 607 HTAB *hashp; 608 ACTION action; 609 DBT *key, *val; 610 { 611 register BUFHEAD *rbufp; 612 BUFHEAD *bufp, *save_bufp; 613 register u_int16_t *bp; 614 register int n, ndx, off; 615 size_t size; 616 register char *kp; 617 u_int16_t pageno; 618 619 #ifdef HASH_STATISTICS 620 hash_accesses++; 621 #endif 622 623 off = hashp->BSIZE; 624 size = key->size; 625 kp = (char *)key->data; 626 rbufp = __get_buf(hashp, __call_hash(hashp, kp, (int)size), NULL, 0); 627 if (!rbufp) 628 return (ERROR); 629 save_bufp = rbufp; 630 631 /* Pin the bucket chain */ 632 rbufp->flags |= BUF_PIN; 633 for (bp = (u_int16_t *)(void *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 634 if (bp[1] >= REAL_KEY) { 635 /* Real key/data pair */ 636 if (size == off - *bp && 637 memcmp(kp, rbufp->page + *bp, size) == 0) 638 goto found; 639 off = bp[1]; 640 #ifdef HASH_STATISTICS 641 hash_collisions++; 642 #endif 643 bp += 2; 644 ndx += 2; 645 } else if (bp[1] == OVFLPAGE) { 646 rbufp = __get_buf(hashp, (u_int32_t)*bp, rbufp, 0); 647 if (!rbufp) { 648 save_bufp->flags &= ~BUF_PIN; 649 return (ERROR); 650 } 651 /* FOR LOOP INIT */ 652 bp = (u_int16_t *)(void *)rbufp->page; 653 n = *bp++; 654 ndx = 1; 655 off = hashp->BSIZE; 656 } else if (bp[1] < REAL_KEY) { 657 if ((ndx = 658 __find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0) 659 goto found; 660 if (ndx == -2) { 661 bufp = rbufp; 662 if (!(pageno = 663 __find_last_page(hashp, &bufp))) { 664 ndx = 0; 665 rbufp = bufp; 666 break; /* FOR */ 667 } 668 rbufp = __get_buf(hashp, (u_int32_t)pageno, 669 bufp, 0); 670 if (!rbufp) { 671 save_bufp->flags &= ~BUF_PIN; 672 return (ERROR); 673 } 674 /* FOR LOOP INIT */ 675 bp = (u_int16_t *)(void *)rbufp->page; 676 n = *bp++; 677 ndx = 1; 678 off = hashp->BSIZE; 679 } else { 680 save_bufp->flags &= ~BUF_PIN; 681 return (ERROR); 682 } 683 } 684 685 /* Not found */ 686 switch (action) { 687 case HASH_PUT: 688 case HASH_PUTNEW: 689 if (__addel(hashp, rbufp, key, val)) { 690 save_bufp->flags &= ~BUF_PIN; 691 return (ERROR); 692 } else { 693 save_bufp->flags &= ~BUF_PIN; 694 return (SUCCESS); 695 } 696 case HASH_GET: 697 case HASH_DELETE: 698 default: 699 save_bufp->flags &= ~BUF_PIN; 700 return (ABNORMAL); 701 } 702 703 found: 704 switch (action) { 705 case HASH_PUTNEW: 706 save_bufp->flags &= ~BUF_PIN; 707 return (ABNORMAL); 708 case HASH_GET: 709 bp = (u_int16_t *)(void *)rbufp->page; 710 if (bp[ndx + 1] < REAL_KEY) { 711 if (__big_return(hashp, rbufp, ndx, val, 0)) 712 return (ERROR); 713 } else { 714 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 715 val->size = bp[ndx] - bp[ndx + 1]; 716 } 717 break; 718 case HASH_PUT: 719 if ((__delpair(hashp, rbufp, ndx)) || 720 (__addel(hashp, rbufp, key, val))) { 721 save_bufp->flags &= ~BUF_PIN; 722 return (ERROR); 723 } 724 break; 725 case HASH_DELETE: 726 if (__delpair(hashp, rbufp, ndx)) 727 return (ERROR); 728 break; 729 default: 730 abort(); 731 } 732 save_bufp->flags &= ~BUF_PIN; 733 return (SUCCESS); 734 } 735 736 static int 737 hash_seq(dbp, key, data, flag) 738 const DB *dbp; 739 DBT *key, *data; 740 u_int32_t flag; 741 { 742 register u_int32_t bucket; 743 register BUFHEAD *bufp; 744 HTAB *hashp; 745 u_int16_t *bp, ndx; 746 747 hashp = (HTAB *)dbp->internal; 748 if (flag && flag != R_FIRST && flag != R_NEXT) { 749 hashp->err = errno = EINVAL; 750 return (ERROR); 751 } 752 #ifdef HASH_STATISTICS 753 hash_accesses++; 754 #endif 755 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 756 hashp->cbucket = 0; 757 hashp->cndx = 1; 758 hashp->cpage = NULL; 759 } 760 761 for (bp = NULL; !bp || !bp[0]; ) { 762 if (!(bufp = hashp->cpage)) { 763 for (bucket = hashp->cbucket; 764 bucket <= hashp->MAX_BUCKET; 765 bucket++, hashp->cndx = 1) { 766 bufp = __get_buf(hashp, bucket, NULL, 0); 767 if (!bufp) 768 return (ERROR); 769 hashp->cpage = bufp; 770 bp = (u_int16_t *)(void *)bufp->page; 771 if (bp[0]) 772 break; 773 } 774 hashp->cbucket = bucket; 775 if (hashp->cbucket > hashp->MAX_BUCKET) { 776 hashp->cbucket = -1; 777 return (ABNORMAL); 778 } 779 } else 780 bp = (u_int16_t *)(void *)hashp->cpage->page; 781 782 #ifdef DEBUG 783 assert(bp); 784 assert(bufp); 785 #endif 786 while (bp[hashp->cndx + 1] == OVFLPAGE) { 787 bufp = hashp->cpage = 788 __get_buf(hashp, (u_int32_t)bp[hashp->cndx], bufp, 789 0); 790 if (!bufp) 791 return (ERROR); 792 bp = (u_int16_t *)(void *)(bufp->page); 793 hashp->cndx = 1; 794 } 795 if (!bp[0]) { 796 hashp->cpage = NULL; 797 ++hashp->cbucket; 798 } 799 } 800 ndx = hashp->cndx; 801 if (bp[ndx + 1] < REAL_KEY) { 802 if (__big_keydata(hashp, bufp, key, data, 1)) 803 return (ERROR); 804 } else { 805 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 806 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 807 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 808 data->size = bp[ndx] - bp[ndx + 1]; 809 ndx += 2; 810 if (ndx > bp[0]) { 811 hashp->cpage = NULL; 812 hashp->cbucket++; 813 hashp->cndx = 1; 814 } else 815 hashp->cndx = ndx; 816 } 817 return (SUCCESS); 818 } 819 820 /********************************* UTILITIES ************************/ 821 822 /* 823 * Returns: 824 * 0 ==> OK 825 * -1 ==> Error 826 */ 827 extern int 828 __expand_table(hashp) 829 HTAB *hashp; 830 { 831 u_int32_t old_bucket, new_bucket; 832 int dirsize, new_segnum, spare_ndx; 833 834 #ifdef HASH_STATISTICS 835 hash_expansions++; 836 #endif 837 new_bucket = ++hashp->MAX_BUCKET; 838 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 839 840 new_segnum = new_bucket >> hashp->SSHIFT; 841 842 /* Check if we need a new segment */ 843 if (new_segnum >= hashp->nsegs) { 844 /* Check if we need to expand directory */ 845 if (new_segnum >= hashp->DSIZE) { 846 /* Reallocate directory */ 847 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 848 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 849 return (-1); 850 hashp->DSIZE = dirsize << 1; 851 } 852 if ((hashp->dir[new_segnum] = 853 (SEGMENT)calloc((size_t)hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 854 return (-1); 855 hashp->exsegs++; 856 hashp->nsegs++; 857 } 858 /* 859 * If the split point is increasing (MAX_BUCKET's log base 2 860 * * increases), we need to copy the current contents of the spare 861 * split bucket to the next bucket. 862 */ 863 spare_ndx = __log2((u_int32_t)(hashp->MAX_BUCKET + 1)); 864 if (spare_ndx > hashp->OVFL_POINT) { 865 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 866 hashp->OVFL_POINT = spare_ndx; 867 } 868 869 if (new_bucket > hashp->HIGH_MASK) { 870 /* Starting a new doubling */ 871 hashp->LOW_MASK = hashp->HIGH_MASK; 872 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 873 } 874 /* Relocate records to the new bucket */ 875 return (__split_page(hashp, old_bucket, new_bucket)); 876 } 877 878 /* 879 * If realloc guarantees that the pointer is not destroyed if the realloc 880 * fails, then this routine can go away. 881 */ 882 static void * 883 hash_realloc(p_ptr, oldsize, newsize) 884 SEGMENT **p_ptr; 885 int oldsize, newsize; 886 { 887 register void *p; 888 889 if ((p = malloc((size_t)newsize)) != NULL) { 890 memmove(p, *p_ptr, (size_t)oldsize); 891 memset((char *)p + oldsize, 0, (size_t)(newsize - oldsize)); 892 free(*p_ptr); 893 *p_ptr = p; 894 } 895 return (p); 896 } 897 898 extern u_int32_t 899 __call_hash(hashp, k, len) 900 HTAB *hashp; 901 char *k; 902 int len; 903 { 904 int n, bucket; 905 906 n = hashp->hash(k, (size_t)len); 907 bucket = n & hashp->HIGH_MASK; 908 if (bucket > hashp->MAX_BUCKET) 909 bucket = bucket & hashp->LOW_MASK; 910 return (bucket); 911 } 912 913 /* 914 * Allocate segment table. On error, destroy the table and set errno. 915 * 916 * Returns 0 on success 917 */ 918 static int 919 alloc_segs(hashp, nsegs) 920 HTAB *hashp; 921 int nsegs; 922 { 923 register int i; 924 register SEGMENT store; 925 926 int save_errno; 927 928 if ((hashp->dir = 929 (SEGMENT *)calloc((size_t)hashp->DSIZE, 930 sizeof(SEGMENT *))) == NULL) { 931 save_errno = errno; 932 (void)hdestroy(hashp); 933 errno = save_errno; 934 return (-1); 935 } 936 /* Allocate segments */ 937 if ((store = 938 (SEGMENT)calloc((size_t)(nsegs << hashp->SSHIFT), 939 sizeof(SEGMENT))) == NULL) { 940 save_errno = errno; 941 (void)hdestroy(hashp); 942 errno = save_errno; 943 return (-1); 944 } 945 for (i = 0; i < nsegs; i++, hashp->nsegs++) 946 hashp->dir[i] = &store[i << hashp->SSHIFT]; 947 return (0); 948 } 949 950 #if BYTE_ORDER == LITTLE_ENDIAN 951 /* 952 * Hashp->hdr needs to be byteswapped. 953 */ 954 static void 955 swap_header_copy(srcp, destp) 956 HASHHDR *srcp, *destp; 957 { 958 int i; 959 960 P_32_COPY(srcp->magic, destp->magic); 961 P_32_COPY(srcp->version, destp->version); 962 P_32_COPY(srcp->lorder, destp->lorder); 963 P_32_COPY(srcp->bsize, destp->bsize); 964 P_32_COPY(srcp->bshift, destp->bshift); 965 P_32_COPY(srcp->dsize, destp->dsize); 966 P_32_COPY(srcp->ssize, destp->ssize); 967 P_32_COPY(srcp->sshift, destp->sshift); 968 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 969 P_32_COPY(srcp->last_freed, destp->last_freed); 970 P_32_COPY(srcp->max_bucket, destp->max_bucket); 971 P_32_COPY(srcp->high_mask, destp->high_mask); 972 P_32_COPY(srcp->low_mask, destp->low_mask); 973 P_32_COPY(srcp->ffactor, destp->ffactor); 974 P_32_COPY(srcp->nkeys, destp->nkeys); 975 P_32_COPY(srcp->hdrpages, destp->hdrpages); 976 P_32_COPY(srcp->h_charkey, destp->h_charkey); 977 for (i = 0; i < NCACHED; i++) { 978 P_32_COPY(srcp->spares[i], destp->spares[i]); 979 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 980 } 981 } 982 983 static void 984 swap_header(hashp) 985 HTAB *hashp; 986 { 987 HASHHDR *hdrp; 988 int i; 989 990 hdrp = &hashp->hdr; 991 992 M_32_SWAP(hdrp->magic); 993 M_32_SWAP(hdrp->version); 994 M_32_SWAP(hdrp->lorder); 995 M_32_SWAP(hdrp->bsize); 996 M_32_SWAP(hdrp->bshift); 997 M_32_SWAP(hdrp->dsize); 998 M_32_SWAP(hdrp->ssize); 999 M_32_SWAP(hdrp->sshift); 1000 M_32_SWAP(hdrp->ovfl_point); 1001 M_32_SWAP(hdrp->last_freed); 1002 M_32_SWAP(hdrp->max_bucket); 1003 M_32_SWAP(hdrp->high_mask); 1004 M_32_SWAP(hdrp->low_mask); 1005 M_32_SWAP(hdrp->ffactor); 1006 M_32_SWAP(hdrp->nkeys); 1007 M_32_SWAP(hdrp->hdrpages); 1008 M_32_SWAP(hdrp->h_charkey); 1009 for (i = 0; i < NCACHED; i++) { 1010 M_32_SWAP(hdrp->spares[i]); 1011 M_16_SWAP(hdrp->bitmaps[i]); 1012 } 1013 } 1014 #endif 1015
Indexes created Sun Sep 28 16:09:52 GMT 2025