hash.c revision 1.19
1 /* $NetBSD: hash.c,v 1.19 2005/01/19 00:23:44 mycroft 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 39 #else 40 __RCSID("$NetBSD: hash.c,v 1.19 2005/01/19 00:23:44 mycroft Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 #include <sys/param.h> 46 #include <sys/stat.h> 47 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 #ifdef DEBUG 55 #include <assert.h> 56 #endif 57 58 #include <db.h> 59 #include "hash.h" 60 #include "page.h" 61 #include "extern.h" 62 63 static int alloc_segs __P((HTAB *, int)); 64 static int flush_meta __P((HTAB *)); 65 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 66 static int hash_close __P((DB *)); 67 static int hash_delete __P((const DB *, const DBT *, u_int32_t)); 68 static int hash_fd __P((const DB *)); 69 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); 70 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); 71 static void *hash_realloc __P((SEGMENT **, int, int)); 72 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); 73 static int hash_sync __P((const DB *, u_int32_t)); 74 static int hdestroy __P((HTAB *)); 75 static HTAB *init_hash __P((HTAB *, const char *, const HASHINFO *)); 76 static int init_htab __P((HTAB *, size_t)); 77 #if BYTE_ORDER == LITTLE_ENDIAN 78 static void swap_header __P((HTAB *)); 79 static void swap_header_copy __P((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 /* ARGSUSED */ 100 extern DB * 101 __hash_open(file, flags, mode, info, dflags) 102 const char *file; 103 int flags; 104 mode_t mode; 105 const HASHINFO *info; /* Special directives for create */ 106 int dflags; 107 { 108 HTAB *hashp; 109 struct stat statbuf; 110 DB *dbp; 111 int bpages, hdrsize, new_table, nsegs, save_errno; 112 113 if ((flags & O_ACCMODE) == O_WRONLY) { 114 errno = EINVAL; 115 return (NULL); 116 } 117 118 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 119 return (NULL); 120 hashp->fp = -1; 121 122 /* 123 * Even if user wants write only, we need to be able to read 124 * the actual file, so we need to open it read/write. But, the 125 * field in the hashp structure needs to be accurate so that 126 * we can check accesses. 127 */ 128 hashp->flags = flags; 129 130 new_table = 0; 131 if (!file || (flags & O_TRUNC) || 132 (stat(file, &statbuf) && (errno == ENOENT))) { 133 if (errno == ENOENT) 134 errno = 0; /* Just in case someone looks at errno */ 135 new_table = 1; 136 } 137 if (file) { 138 if ((hashp->fp = open(file, flags, mode)) == -1) 139 RETURN_ERROR(errno, error0); 140 if (fcntl(hashp->fp, F_SETFD, FD_CLOEXEC) == -1) 141 RETURN_ERROR(errno, error1); 142 } 143 if (new_table) { 144 if (!(hashp = init_hash(hashp, file, info))) 145 RETURN_ERROR(errno, error1); 146 } else { 147 /* Table already exists */ 148 if (info && info->hash) 149 hashp->hash = info->hash; 150 else 151 hashp->hash = __default_hash; 152 153 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 154 #if BYTE_ORDER == LITTLE_ENDIAN 155 swap_header(hashp); 156 #endif 157 if (hdrsize == -1) 158 RETURN_ERROR(errno, error1); 159 if (hdrsize != sizeof(HASHHDR)) 160 RETURN_ERROR(EFTYPE, error1); 161 /* Verify file type, versions and hash function */ 162 if (hashp->MAGIC != HASHMAGIC) 163 RETURN_ERROR(EFTYPE, error1); 164 #define OLDHASHVERSION 1 165 if (hashp->VERSION != HASHVERSION && 166 hashp->VERSION != OLDHASHVERSION) 167 RETURN_ERROR(EFTYPE, error1); 168 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 169 RETURN_ERROR(EFTYPE, error1); 170 /* 171 * Figure out how many segments we need. Max_Bucket is the 172 * maximum bucket number, so the number of buckets is 173 * max_bucket + 1. 174 */ 175 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 176 hashp->SGSIZE; 177 hashp->nsegs = 0; 178 if (alloc_segs(hashp, nsegs)) 179 /* 180 * If alloc_segs fails, table will have been destroyed 181 * and errno will have been set. 182 */ 183 return (NULL); 184 /* Read in bitmaps */ 185 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 186 (unsigned int)(hashp->BSIZE << BYTE_SHIFT) - 1) >> 187 (hashp->BSHIFT + BYTE_SHIFT); 188 189 hashp->nmaps = bpages; 190 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 191 } 192 193 /* Initialize Buffer Manager */ 194 if (info && info->cachesize) 195 __buf_init(hashp, info->cachesize); 196 else 197 __buf_init(hashp, DEF_BUFSIZE); 198 199 hashp->new_file = new_table; 200 hashp->save_file = file && (hashp->flags & O_RDWR); 201 hashp->cbucket = -1; 202 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 203 save_errno = errno; 204 hdestroy(hashp); 205 errno = save_errno; 206 return (NULL); 207 } 208 dbp->internal = hashp; 209 dbp->close = hash_close; 210 dbp->del = hash_delete; 211 dbp->fd = hash_fd; 212 dbp->get = hash_get; 213 dbp->put = hash_put; 214 dbp->seq = hash_seq; 215 dbp->sync = hash_sync; 216 dbp->type = DB_HASH; 217 218 #ifdef DEBUG 219 (void)fprintf(stderr, 220 "%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", 221 "init_htab:", 222 "TABLE POINTER ", hashp, 223 "BUCKET SIZE ", hashp->BSIZE, 224 "BUCKET SHIFT ", hashp->BSHIFT, 225 "DIRECTORY SIZE ", hashp->DSIZE, 226 "SEGMENT SIZE ", hashp->SGSIZE, 227 "SEGMENT SHIFT ", hashp->SSHIFT, 228 "FILL FACTOR ", hashp->FFACTOR, 229 "MAX BUCKET ", hashp->MAX_BUCKET, 230 "OVFL POINT ", hashp->OVFL_POINT, 231 "LAST FREED ", hashp->LAST_FREED, 232 "HIGH MASK ", hashp->HIGH_MASK, 233 "LOW MASK ", hashp->LOW_MASK, 234 "NSEGS ", hashp->nsegs, 235 "NKEYS ", hashp->NKEYS); 236 #endif 237 #ifdef HASH_STATISTICS 238 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 239 #endif 240 return (dbp); 241 242 error1: 243 if (hashp != NULL) 244 (void)close(hashp->fp); 245 246 error0: 247 free(hashp); 248 errno = save_errno; 249 return (NULL); 250 } 251 252 static int 253 hash_close(dbp) 254 DB *dbp; 255 { 256 HTAB *hashp; 257 int retval; 258 259 if (!dbp) 260 return (ERROR); 261 262 hashp = (HTAB *)dbp->internal; 263 retval = hdestroy(hashp); 264 free(dbp); 265 return (retval); 266 } 267 268 static int 269 hash_fd(dbp) 270 const DB *dbp; 271 { 272 HTAB *hashp; 273 274 if (!dbp) 275 return (ERROR); 276 277 hashp = (HTAB *)dbp->internal; 278 if (hashp->fp == -1) { 279 errno = ENOENT; 280 return (-1); 281 } 282 return (hashp->fp); 283 } 284 285 /************************** LOCAL CREATION ROUTINES **********************/ 286 static HTAB * 287 init_hash(hashp, file, info) 288 HTAB *hashp; 289 const char *file; 290 const HASHINFO *info; 291 { 292 struct stat statbuf; 293 int nelem; 294 295 nelem = 1; 296 hashp->NKEYS = 0; 297 hashp->LORDER = BYTE_ORDER; 298 hashp->BSIZE = DEF_BUCKET_SIZE; 299 hashp->BSHIFT = DEF_BUCKET_SHIFT; 300 hashp->SGSIZE = DEF_SEGSIZE; 301 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 302 hashp->DSIZE = DEF_DIRSIZE; 303 hashp->FFACTOR = DEF_FFACTOR; 304 hashp->hash = __default_hash; 305 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 306 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 307 308 /* Fix bucket size to be optimal for file system */ 309 if (file != NULL) { 310 if (stat(file, &statbuf)) 311 return (NULL); 312 hashp->BSIZE = MIN(statbuf.st_blksize, MAX_BSIZE - 1); 313 hashp->BSHIFT = __log2((u_int32_t)hashp->BSIZE); 314 } 315 316 if (info) { 317 if (info->bsize) { 318 /* Round pagesize up to power of 2 */ 319 hashp->BSHIFT = __log2(info->bsize); 320 hashp->BSIZE = 1 << hashp->BSHIFT; 321 if (hashp->BSIZE >= MAX_BSIZE) { 322 errno = EINVAL; 323 return (NULL); 324 } 325 } 326 if (info->ffactor) 327 hashp->FFACTOR = info->ffactor; 328 if (info->hash) 329 hashp->hash = info->hash; 330 if (info->nelem) 331 nelem = info->nelem; 332 if (info->lorder) { 333 if (info->lorder != BIG_ENDIAN && 334 info->lorder != LITTLE_ENDIAN) { 335 errno = EINVAL; 336 return (NULL); 337 } 338 hashp->LORDER = info->lorder; 339 } 340 } 341 /* init_htab should destroy the table and set errno if it fails */ 342 if (init_htab(hashp, (size_t)nelem)) 343 return (NULL); 344 else 345 return (hashp); 346 } 347 /* 348 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 349 * the table and set errno, so we just pass the error information along. 350 * 351 * Returns 0 on No Error 352 */ 353 static int 354 init_htab(hashp, nelem) 355 HTAB *hashp; 356 size_t nelem; 357 { 358 register int nbuckets; 359 u_int32_t nsegs; 360 int l2; 361 362 /* 363 * Divide number of elements by the fill factor and determine a 364 * desired number of buckets. Allocate space for the next greater 365 * power of two number of buckets. 366 */ 367 nelem = (nelem - 1) / hashp->FFACTOR + 1; 368 369 l2 = __log2(MAX(nelem, 2)); 370 nbuckets = 1 << l2; 371 372 hashp->SPARES[l2] = l2 + 1; 373 hashp->SPARES[l2 + 1] = l2 + 1; 374 hashp->OVFL_POINT = l2; 375 hashp->LAST_FREED = 2; 376 377 /* First bitmap page is at: splitpoint l2 page offset 1 */ 378 if (__ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0)) 379 return (-1); 380 381 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 382 hashp->HIGH_MASK = (nbuckets << 1) - 1; 383 /* LINTED constant in conditional context */ 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, (int)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 ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 513 return (-1); 514 else 515 if (wsize != sizeof(HASHHDR)) { 516 errno = EFTYPE; 517 hashp->err = errno; 518 return (-1); 519 } 520 for (i = 0; i < NCACHED; i++) 521 if (hashp->mapp[i]) 522 if (__put_page(hashp, (char *)(void *)hashp->mapp[i], 523 (u_int)hashp->BITMAPS[i], 0, 1)) 524 return (-1); 525 return (0); 526 } 527 528 /*******************************SEARCH ROUTINES *****************************/ 529 /* 530 * All the access routines return 531 * 532 * Returns: 533 * 0 on SUCCESS 534 * 1 to indicate an external ERROR (i.e. key not found, etc) 535 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 536 */ 537 static int 538 hash_get(dbp, key, data, flag) 539 const DB *dbp; 540 const DBT *key; 541 DBT *data; 542 u_int32_t flag; 543 { 544 HTAB *hashp; 545 546 hashp = (HTAB *)dbp->internal; 547 if (flag) { 548 hashp->err = errno = EINVAL; 549 return (ERROR); 550 } 551 /* LINTED const castaway */ 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->err = errno = EINVAL; 567 return (ERROR); 568 } 569 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 570 hashp->err = errno = EPERM; 571 return (ERROR); 572 } 573 /* LINTED const castaway */ 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->err = errno = EINVAL; 589 return (ERROR); 590 } 591 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 592 hashp->err = errno = EPERM; 593 return (ERROR); 594 } 595 /* LINTED const castaway */ 596 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 597 } 598 599 /* 600 * Assume that hashp has been set in wrapper routine. 601 */ 602 static int 603 hash_access(hashp, action, key, val) 604 HTAB *hashp; 605 ACTION action; 606 DBT *key, *val; 607 { 608 register BUFHEAD *rbufp; 609 BUFHEAD *bufp, *save_bufp; 610 register u_int16_t *bp; 611 register int n, ndx, off; 612 size_t 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, (int)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 *)(void *)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, (u_int32_t)*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 *)(void *)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, (int)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, (u_int32_t)pageno, 666 bufp, 0); 667 if (!rbufp) { 668 save_bufp->flags &= ~BUF_PIN; 669 return (ERROR); 670 } 671 /* FOR LOOP INIT */ 672 bp = (u_int16_t *)(void *)rbufp->page; 673 n = *bp++; 674 ndx = 1; 675 off = hashp->BSIZE; 676 } else { 677 save_bufp->flags &= ~BUF_PIN; 678 return (ERROR); 679 } 680 } 681 682 /* Not found */ 683 switch (action) { 684 case HASH_PUT: 685 case HASH_PUTNEW: 686 if (__addel(hashp, rbufp, key, val)) { 687 save_bufp->flags &= ~BUF_PIN; 688 return (ERROR); 689 } else { 690 save_bufp->flags &= ~BUF_PIN; 691 return (SUCCESS); 692 } 693 case HASH_GET: 694 case HASH_DELETE: 695 default: 696 save_bufp->flags &= ~BUF_PIN; 697 return (ABNORMAL); 698 } 699 700 found: 701 switch (action) { 702 case HASH_PUTNEW: 703 save_bufp->flags &= ~BUF_PIN; 704 return (ABNORMAL); 705 case HASH_GET: 706 bp = (u_int16_t *)(void *)rbufp->page; 707 if (bp[ndx + 1] < REAL_KEY) { 708 if (__big_return(hashp, rbufp, ndx, val, 0)) 709 return (ERROR); 710 } else { 711 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 712 val->size = bp[ndx] - bp[ndx + 1]; 713 } 714 break; 715 case HASH_PUT: 716 if ((__delpair(hashp, rbufp, ndx)) || 717 (__addel(hashp, rbufp, key, val))) { 718 save_bufp->flags &= ~BUF_PIN; 719 return (ERROR); 720 } 721 break; 722 case HASH_DELETE: 723 if (__delpair(hashp, rbufp, ndx)) 724 return (ERROR); 725 break; 726 default: 727 abort(); 728 } 729 save_bufp->flags &= ~BUF_PIN; 730 return (SUCCESS); 731 } 732 733 static int 734 hash_seq(dbp, key, data, flag) 735 const DB *dbp; 736 DBT *key, *data; 737 u_int32_t flag; 738 { 739 register u_int32_t bucket; 740 register BUFHEAD *bufp; 741 HTAB *hashp; 742 u_int16_t *bp, ndx; 743 744 hashp = (HTAB *)dbp->internal; 745 if (flag && flag != R_FIRST && flag != R_NEXT) { 746 hashp->err = errno = EINVAL; 747 return (ERROR); 748 } 749 #ifdef HASH_STATISTICS 750 hash_accesses++; 751 #endif 752 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 753 hashp->cbucket = 0; 754 hashp->cndx = 1; 755 hashp->cpage = NULL; 756 } 757 758 for (bp = NULL; !bp || !bp[0]; ) { 759 if (!(bufp = hashp->cpage)) { 760 for (bucket = hashp->cbucket; 761 bucket <= hashp->MAX_BUCKET; 762 bucket++, hashp->cndx = 1) { 763 bufp = __get_buf(hashp, bucket, NULL, 0); 764 if (!bufp) 765 return (ERROR); 766 hashp->cpage = bufp; 767 bp = (u_int16_t *)(void *)bufp->page; 768 if (bp[0]) 769 break; 770 } 771 hashp->cbucket = bucket; 772 if (hashp->cbucket > hashp->MAX_BUCKET) { 773 hashp->cbucket = -1; 774 return (ABNORMAL); 775 } 776 } else 777 bp = (u_int16_t *)(void *)hashp->cpage->page; 778 779 #ifdef DEBUG 780 assert(bp); 781 assert(bufp); 782 #endif 783 while (bp[hashp->cndx + 1] == OVFLPAGE) { 784 bufp = hashp->cpage = 785 __get_buf(hashp, (u_int32_t)bp[hashp->cndx], bufp, 786 0); 787 if (!bufp) 788 return (ERROR); 789 bp = (u_int16_t *)(void *)(bufp->page); 790 hashp->cndx = 1; 791 } 792 if (!bp[0]) { 793 hashp->cpage = NULL; 794 ++hashp->cbucket; 795 } 796 } 797 ndx = hashp->cndx; 798 if (bp[ndx + 1] < REAL_KEY) { 799 if (__big_keydata(hashp, bufp, key, data, 1)) 800 return (ERROR); 801 } else { 802 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 803 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 804 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 805 data->size = bp[ndx] - bp[ndx + 1]; 806 ndx += 2; 807 if (ndx > bp[0]) { 808 hashp->cpage = NULL; 809 hashp->cbucket++; 810 hashp->cndx = 1; 811 } else 812 hashp->cndx = ndx; 813 } 814 return (SUCCESS); 815 } 816 817 /********************************* UTILITIES ************************/ 818 819 /* 820 * Returns: 821 * 0 ==> OK 822 * -1 ==> Error 823 */ 824 extern int 825 __expand_table(hashp) 826 HTAB *hashp; 827 { 828 u_int32_t old_bucket, new_bucket; 829 int dirsize, new_segnum, spare_ndx; 830 831 #ifdef HASH_STATISTICS 832 hash_expansions++; 833 #endif 834 new_bucket = ++hashp->MAX_BUCKET; 835 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 836 837 new_segnum = new_bucket >> hashp->SSHIFT; 838 839 /* Check if we need a new segment */ 840 if (new_segnum >= hashp->nsegs) { 841 /* Check if we need to expand directory */ 842 if (new_segnum >= hashp->DSIZE) { 843 /* Reallocate directory */ 844 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 845 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 846 return (-1); 847 hashp->DSIZE = dirsize << 1; 848 } 849 if ((hashp->dir[new_segnum] = 850 (SEGMENT)calloc((size_t)hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 851 return (-1); 852 hashp->exsegs++; 853 hashp->nsegs++; 854 } 855 /* 856 * If the split point is increasing (MAX_BUCKET's log base 2 857 * * increases), we need to copy the current contents of the spare 858 * split bucket to the next bucket. 859 */ 860 spare_ndx = __log2((u_int32_t)(hashp->MAX_BUCKET + 1)); 861 if (spare_ndx > hashp->OVFL_POINT) { 862 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 863 hashp->OVFL_POINT = spare_ndx; 864 } 865 866 if (new_bucket > hashp->HIGH_MASK) { 867 /* Starting a new doubling */ 868 hashp->LOW_MASK = hashp->HIGH_MASK; 869 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 870 } 871 /* Relocate records to the new bucket */ 872 return (__split_page(hashp, old_bucket, new_bucket)); 873 } 874 875 /* 876 * If realloc guarantees that the pointer is not destroyed if the realloc 877 * fails, then this routine can go away. 878 */ 879 static void * 880 hash_realloc(p_ptr, oldsize, newsize) 881 SEGMENT **p_ptr; 882 int oldsize, newsize; 883 { 884 register void *p; 885 886 if ((p = malloc((size_t)newsize)) != NULL) { 887 memmove(p, *p_ptr, (size_t)oldsize); 888 memset((char *)p + oldsize, 0, (size_t)(newsize - oldsize)); 889 free(*p_ptr); 890 *p_ptr = p; 891 } 892 return (p); 893 } 894 895 extern u_int32_t 896 __call_hash(hashp, k, len) 897 HTAB *hashp; 898 char *k; 899 int len; 900 { 901 int n, bucket; 902 903 n = hashp->hash(k, (size_t)len); 904 bucket = n & hashp->HIGH_MASK; 905 if (bucket > hashp->MAX_BUCKET) 906 bucket = bucket & hashp->LOW_MASK; 907 return (bucket); 908 } 909 910 /* 911 * Allocate segment table. On error, destroy the table and set errno. 912 * 913 * Returns 0 on success 914 */ 915 static int 916 alloc_segs(hashp, nsegs) 917 HTAB *hashp; 918 int nsegs; 919 { 920 register int i; 921 register SEGMENT store; 922 923 int save_errno; 924 925 if ((hashp->dir = 926 (SEGMENT *)calloc((size_t)hashp->DSIZE, 927 sizeof(SEGMENT *))) == NULL) { 928 save_errno = errno; 929 (void)hdestroy(hashp); 930 errno = save_errno; 931 return (-1); 932 } 933 /* Allocate segments */ 934 if ((store = 935 (SEGMENT)calloc((size_t)(nsegs << hashp->SSHIFT), 936 sizeof(SEGMENT))) == NULL) { 937 save_errno = errno; 938 (void)hdestroy(hashp); 939 errno = save_errno; 940 return (-1); 941 } 942 for (i = 0; i < nsegs; i++, hashp->nsegs++) 943 hashp->dir[i] = &store[i << hashp->SSHIFT]; 944 return (0); 945 } 946 947 #if BYTE_ORDER == LITTLE_ENDIAN 948 /* 949 * Hashp->hdr needs to be byteswapped. 950 */ 951 static void 952 swap_header_copy(srcp, destp) 953 HASHHDR *srcp, *destp; 954 { 955 int i; 956 957 P_32_COPY(srcp->magic, destp->magic); 958 P_32_COPY(srcp->version, destp->version); 959 P_32_COPY(srcp->lorder, destp->lorder); 960 P_32_COPY(srcp->bsize, destp->bsize); 961 P_32_COPY(srcp->bshift, destp->bshift); 962 P_32_COPY(srcp->dsize, destp->dsize); 963 P_32_COPY(srcp->ssize, destp->ssize); 964 P_32_COPY(srcp->sshift, destp->sshift); 965 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 966 P_32_COPY(srcp->last_freed, destp->last_freed); 967 P_32_COPY(srcp->max_bucket, destp->max_bucket); 968 P_32_COPY(srcp->high_mask, destp->high_mask); 969 P_32_COPY(srcp->low_mask, destp->low_mask); 970 P_32_COPY(srcp->ffactor, destp->ffactor); 971 P_32_COPY(srcp->nkeys, destp->nkeys); 972 P_32_COPY(srcp->hdrpages, destp->hdrpages); 973 P_32_COPY(srcp->h_charkey, destp->h_charkey); 974 for (i = 0; i < NCACHED; i++) { 975 P_32_COPY(srcp->spares[i], destp->spares[i]); 976 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 977 } 978 } 979 980 static void 981 swap_header(hashp) 982 HTAB *hashp; 983 { 984 HASHHDR *hdrp; 985 int i; 986 987 hdrp = &hashp->hdr; 988 989 M_32_SWAP(hdrp->magic); 990 M_32_SWAP(hdrp->version); 991 M_32_SWAP(hdrp->lorder); 992 M_32_SWAP(hdrp->bsize); 993 M_32_SWAP(hdrp->bshift); 994 M_32_SWAP(hdrp->dsize); 995 M_32_SWAP(hdrp->ssize); 996 M_32_SWAP(hdrp->sshift); 997 M_32_SWAP(hdrp->ovfl_point); 998 M_32_SWAP(hdrp->last_freed); 999 M_32_SWAP(hdrp->max_bucket); 1000 M_32_SWAP(hdrp->high_mask); 1001 M_32_SWAP(hdrp->low_mask); 1002 M_32_SWAP(hdrp->ffactor); 1003 M_32_SWAP(hdrp->nkeys); 1004 M_32_SWAP(hdrp->hdrpages); 1005 M_32_SWAP(hdrp->h_charkey); 1006 for (i = 0; i < NCACHED; i++) { 1007 M_32_SWAP(hdrp->spares[i]); 1008 M_16_SWAP(hdrp->bitmaps[i]); 1009 } 1010 } 1011 #endif 1012
Indexes created Fri Sep 26 20:09:58 GMT 2025