hash.c revision 1.27
1 /* $NetBSD: hash.c,v 1.27 2007/02/03 23:46:09 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. 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 1.27 2007/02/03 23:46:09 christos 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 #include <assert.h> 55 56 #include <db.h> 57 #include "hash.h" 58 #include "page.h" 59 #include "extern.h" 60 61 static int alloc_segs(HTAB *, int); 62 static int flush_meta(HTAB *); 63 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 64 static int hash_close(DB *); 65 static int hash_delete(const DB *, const DBT *, u_int32_t); 66 static int hash_fd(const DB *); 67 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 68 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 69 static void *hash_realloc(SEGMENT **, size_t, size_t); 70 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 71 static int hash_sync(const DB *, u_int32_t); 72 static int hdestroy(HTAB *); 73 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 74 static int init_htab(HTAB *, size_t); 75 #if BYTE_ORDER == LITTLE_ENDIAN 76 static void swap_header(HTAB *); 77 static void swap_header_copy(HASHHDR *, HASHHDR *); 78 #endif 79 80 /* Fast arithmetic, relying on powers of 2, */ 81 #define MOD(x, y) ((x) & ((y) - 1)) 82 83 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 84 85 /* Return values */ 86 #define SUCCESS (0) 87 #define ERROR (-1) 88 #define ABNORMAL (1) 89 90 #ifdef HASH_STATISTICS 91 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 92 #endif 93 94 /************************** INTERFACE ROUTINES ***************************/ 95 /* OPEN/CLOSE */ 96 97 /* ARGSUSED */ 98 DB * 99 __hash_open(const char *file, int flags, mode_t mode, const HASHINFO *info, 100 int dflags) 101 { 102 HTAB *hashp; 103 struct stat statbuf; 104 DB *dbp; 105 int bpages, new_table, nsegs, save_errno; 106 ssize_t hdrsize; 107 108 if ((flags & O_ACCMODE) == O_WRONLY) { 109 errno = EINVAL; 110 return (NULL); 111 } 112 113 if (!(hashp = calloc(1, sizeof(HTAB)))) 114 return (NULL); 115 hashp->fp = -1; 116 117 /* 118 * Even if user wants write only, we need to be able to read 119 * the actual file, so we need to open it read/write. But, the 120 * field in the hashp structure needs to be accurate so that 121 * we can check accesses. 122 */ 123 hashp->flags = flags; 124 125 new_table = 0; 126 if (!file || (flags & O_TRUNC) || 127 (stat(file, &statbuf) && (errno == ENOENT))) { 128 if (errno == ENOENT) 129 errno = 0; /* Just in case someone looks at errno */ 130 new_table = 1; 131 } 132 if (file) { 133 if ((hashp->fp = open(file, flags, mode)) == -1) 134 RETURN_ERROR(errno, error0); 135 if (fcntl(hashp->fp, F_SETFD, FD_CLOEXEC) == -1) 136 RETURN_ERROR(errno, error1); 137 if (fstat(hashp->fp, &statbuf) == -1) 138 RETURN_ERROR(errno, error1); 139 new_table |= statbuf.st_size == 0; 140 } 141 if (new_table) { 142 if (!(hashp = init_hash(hashp, file, info))) 143 RETURN_ERROR(errno, error1); 144 } else { 145 /* Table already exists */ 146 if (info && info->hash) 147 hashp->hash = info->hash; 148 else 149 hashp->hash = __default_hash; 150 151 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 152 #if BYTE_ORDER == LITTLE_ENDIAN 153 swap_header(hashp); 154 #endif 155 if (hdrsize == -1) 156 RETURN_ERROR(errno, error1); 157 if (hdrsize != sizeof(HASHHDR)) 158 RETURN_ERROR(EFTYPE, error1); 159 /* Verify file type, versions and hash function */ 160 if (hashp->MAGIC != HASHMAGIC) 161 RETURN_ERROR(EFTYPE, error1); 162 #define OLDHASHVERSION 1 163 if (hashp->VERSION != HASHVERSION && 164 hashp->VERSION != OLDHASHVERSION) 165 RETURN_ERROR(EFTYPE, error1); 166 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 167 RETURN_ERROR(EFTYPE, error1); 168 /* 169 * Figure out how many segments we need. Max_Bucket is the 170 * maximum bucket number, so the number of buckets is 171 * max_bucket + 1. 172 */ 173 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 174 hashp->SGSIZE; 175 hashp->nsegs = 0; 176 if (alloc_segs(hashp, nsegs)) 177 /* 178 * If alloc_segs fails, table will have been destroyed 179 * and errno will have been set. 180 */ 181 return (NULL); 182 /* Read in bitmaps */ 183 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 184 (unsigned int)(hashp->BSIZE << BYTE_SHIFT) - 1) >> 185 (hashp->BSHIFT + BYTE_SHIFT); 186 187 hashp->nmaps = bpages; 188 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 189 } 190 191 /* Initialize Buffer Manager */ 192 if (info && info->cachesize) 193 __buf_init(hashp, info->cachesize); 194 else 195 __buf_init(hashp, DEF_BUFSIZE); 196 197 hashp->new_file = new_table; 198 hashp->save_file = file && (hashp->flags & O_RDWR); 199 hashp->cbucket = -1; 200 if (!(dbp = malloc(sizeof(DB)))) { 201 save_errno = errno; 202 hdestroy(hashp); 203 errno = save_errno; 204 return (NULL); 205 } 206 dbp->internal = hashp; 207 dbp->close = hash_close; 208 dbp->del = hash_delete; 209 dbp->fd = hash_fd; 210 dbp->get = hash_get; 211 dbp->put = hash_put; 212 dbp->seq = hash_seq; 213 dbp->sync = hash_sync; 214 dbp->type = DB_HASH; 215 216 #ifdef DEBUG 217 (void)fprintf(stderr, 218 "%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", 219 "init_htab:", 220 "TABLE POINTER ", hashp, 221 "BUCKET SIZE ", hashp->BSIZE, 222 "BUCKET SHIFT ", hashp->BSHIFT, 223 "DIRECTORY SIZE ", hashp->DSIZE, 224 "SEGMENT SIZE ", hashp->SGSIZE, 225 "SEGMENT SHIFT ", hashp->SSHIFT, 226 "FILL FACTOR ", hashp->FFACTOR, 227 "MAX BUCKET ", hashp->MAX_BUCKET, 228 "OVFL POINT ", hashp->OVFL_POINT, 229 "LAST FREED ", hashp->LAST_FREED, 230 "HIGH MASK ", hashp->HIGH_MASK, 231 "LOW MASK ", hashp->LOW_MASK, 232 "NSEGS ", hashp->nsegs, 233 "NKEYS ", hashp->NKEYS); 234 #endif 235 #ifdef HASH_STATISTICS 236 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 237 #endif 238 return (dbp); 239 240 error1: 241 if (hashp != NULL) 242 (void)close(hashp->fp); 243 244 error0: 245 free(hashp); 246 errno = save_errno; 247 return (NULL); 248 } 249 250 static int 251 hash_close(DB *dbp) 252 { 253 HTAB *hashp; 254 int retval; 255 256 if (!dbp) 257 return (ERROR); 258 259 hashp = dbp->internal; 260 retval = hdestroy(hashp); 261 free(dbp); 262 return (retval); 263 } 264 265 static int 266 hash_fd(const DB *dbp) 267 { 268 HTAB *hashp; 269 270 if (!dbp) 271 return (ERROR); 272 273 hashp = dbp->internal; 274 if (hashp->fp == -1) { 275 errno = ENOENT; 276 return (-1); 277 } 278 return (hashp->fp); 279 } 280 281 /************************** LOCAL CREATION ROUTINES **********************/ 282 static HTAB * 283 init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 284 { 285 struct stat statbuf; 286 int nelem; 287 288 nelem = 1; 289 hashp->NKEYS = 0; 290 hashp->LORDER = BYTE_ORDER; 291 hashp->BSIZE = DEF_BUCKET_SIZE; 292 hashp->BSHIFT = DEF_BUCKET_SHIFT; 293 hashp->SGSIZE = DEF_SEGSIZE; 294 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 295 hashp->DSIZE = DEF_DIRSIZE; 296 hashp->FFACTOR = DEF_FFACTOR; 297 hashp->hash = __default_hash; 298 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 299 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 300 301 /* Fix bucket size to be optimal for file system */ 302 if (file != NULL) { 303 if (stat(file, &statbuf)) 304 return (NULL); 305 hashp->BSIZE = MIN(statbuf.st_blksize, MAX_BSIZE); 306 hashp->BSHIFT = __log2((u_int32_t)hashp->BSIZE); 307 } 308 309 if (info) { 310 if (info->bsize) { 311 /* Round pagesize up to power of 2 */ 312 hashp->BSHIFT = __log2(info->bsize); 313 hashp->BSIZE = 1 << hashp->BSHIFT; 314 if (hashp->BSIZE > MAX_BSIZE) { 315 errno = EINVAL; 316 return (NULL); 317 } 318 } 319 if (info->ffactor) 320 hashp->FFACTOR = info->ffactor; 321 if (info->hash) 322 hashp->hash = info->hash; 323 if (info->nelem) 324 nelem = info->nelem; 325 if (info->lorder) { 326 if (info->lorder != BIG_ENDIAN && 327 info->lorder != LITTLE_ENDIAN) { 328 errno = EINVAL; 329 return (NULL); 330 } 331 hashp->LORDER = info->lorder; 332 } 333 } 334 /* init_htab should destroy the table and set errno if it fails */ 335 if (init_htab(hashp, (size_t)nelem)) 336 return (NULL); 337 else 338 return (hashp); 339 } 340 /* 341 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 342 * the table and set errno, so we just pass the error information along. 343 * 344 * Returns 0 on No Error 345 */ 346 static int 347 init_htab(HTAB *hashp, size_t nelem) 348 { 349 int nbuckets; 350 u_int32_t 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 _DBFIT(nelem, u_int32_t); 361 l2 = __log2(MAX((u_int32_t)nelem, 2)); 362 nbuckets = 1 << l2; 363 364 hashp->SPARES[l2] = l2 + 1; 365 hashp->SPARES[l2 + 1] = l2 + 1; 366 hashp->OVFL_POINT = l2; 367 hashp->LAST_FREED = 2; 368 369 /* First bitmap page is at: splitpoint l2 page offset 1 */ 370 if (__ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0)) 371 return (-1); 372 373 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 374 hashp->HIGH_MASK = (nbuckets << 1) - 1; 375 /* LINTED constant in conditional context */ 376 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 377 hashp->BSHIFT) + 1; 378 379 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 380 nsegs = 1 << __log2(nsegs); 381 382 if (nsegs > hashp->DSIZE) 383 hashp->DSIZE = nsegs; 384 return (alloc_segs(hashp, (int)nsegs)); 385 } 386 387 /********************** DESTROY/CLOSE ROUTINES ************************/ 388 389 /* 390 * Flushes any changes to the file if necessary and destroys the hashp 391 * structure, freeing all allocated space. 392 */ 393 static int 394 hdestroy(HTAB *hashp) 395 { 396 int i, save_errno; 397 398 save_errno = 0; 399 400 #ifdef HASH_STATISTICS 401 (void)fprintf(stderr, "hdestroy: accesses %d collisions %d\n", 402 hash_accesses, hash_collisions); 403 (void)fprintf(stderr, "hdestroy: expansions %d\n", 404 hash_expansions); 405 (void)fprintf(stderr, "hdestroy: overflows %d\n", 406 hash_overflows); 407 (void)fprintf(stderr, "keys %d maxp %d segmentcount %d\n", 408 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 409 410 for (i = 0; i < NCACHED; i++) 411 (void)fprintf(stderr, 412 "spares[%d] = %d\n", i, hashp->SPARES[i]); 413 #endif 414 /* 415 * Call on buffer manager to free buffers, and if required, 416 * write them to disk. 417 */ 418 if (__buf_free(hashp, 1, hashp->save_file)) 419 save_errno = errno; 420 if (hashp->dir) { 421 free(*hashp->dir); /* Free initial segments */ 422 /* Free extra segments */ 423 while (hashp->exsegs--) 424 free(hashp->dir[--hashp->nsegs]); 425 free(hashp->dir); 426 } 427 if (flush_meta(hashp) && !save_errno) 428 save_errno = errno; 429 /* Free Bigmaps */ 430 for (i = 0; i < hashp->nmaps; i++) 431 if (hashp->mapp[i]) 432 free(hashp->mapp[i]); 433 434 if (hashp->fp != -1) 435 (void)close(hashp->fp); 436 437 free(hashp); 438 439 if (save_errno) { 440 errno = save_errno; 441 return (ERROR); 442 } 443 return (SUCCESS); 444 } 445 /* 446 * Write modified pages to disk 447 * 448 * Returns: 449 * 0 == OK 450 * -1 ERROR 451 */ 452 static int 453 hash_sync(const DB *dbp, u_int32_t flags) 454 { 455 HTAB *hashp; 456 457 if (flags != 0) { 458 errno = EINVAL; 459 return (ERROR); 460 } 461 462 if (!dbp) 463 return (ERROR); 464 465 hashp = dbp->internal; 466 if (!hashp->save_file) 467 return (0); 468 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 469 return (ERROR); 470 hashp->new_file = 0; 471 return (0); 472 } 473 474 /* 475 * Returns: 476 * 0 == OK 477 * -1 indicates that errno should be set 478 */ 479 static int 480 flush_meta(HTAB *hashp) 481 { 482 HASHHDR *whdrp; 483 #if BYTE_ORDER == LITTLE_ENDIAN 484 HASHHDR whdr; 485 #endif 486 int fp, i; 487 ssize_t wsize; 488 489 if (!hashp->save_file) 490 return (0); 491 hashp->MAGIC = HASHMAGIC; 492 hashp->VERSION = HASHVERSION; 493 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 494 495 fp = hashp->fp; 496 whdrp = &hashp->hdr; 497 #if BYTE_ORDER == LITTLE_ENDIAN 498 whdrp = &whdr; 499 swap_header_copy(&hashp->hdr, whdrp); 500 #endif 501 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 502 return (-1); 503 else 504 if (wsize != sizeof(HASHHDR)) { 505 errno = EFTYPE; 506 hashp->err = errno; 507 return (-1); 508 } 509 for (i = 0; i < NCACHED; i++) 510 if (hashp->mapp[i]) 511 if (__put_page(hashp, (char *)(void *)hashp->mapp[i], 512 (u_int)hashp->BITMAPS[i], 0, 1)) 513 return (-1); 514 return (0); 515 } 516 517 /*******************************SEARCH ROUTINES *****************************/ 518 /* 519 * All the access routines return 520 * 521 * Returns: 522 * 0 on SUCCESS 523 * 1 to indicate an external ERROR (i.e. key not found, etc) 524 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 525 */ 526 static int 527 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 528 { 529 HTAB *hashp; 530 531 hashp = dbp->internal; 532 if (flag) { 533 hashp->err = errno = EINVAL; 534 return (ERROR); 535 } 536 return (hash_access(hashp, HASH_GET, __UNCONST(key), data)); 537 } 538 539 static int 540 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 541 { 542 HTAB *hashp; 543 544 hashp = dbp->internal; 545 if (flag && flag != R_NOOVERWRITE) { 546 hashp->err = errno = EINVAL; 547 return (ERROR); 548 } 549 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 550 hashp->err = errno = EPERM; 551 return (ERROR); 552 } 553 /* LINTED const castaway */ 554 return (hash_access(hashp, flag == R_NOOVERWRITE ? 555 HASH_PUTNEW : HASH_PUT, __UNCONST(key), __UNCONST(data))); 556 } 557 558 static int 559 hash_delete(const DB *dbp, const DBT *key, u_int32_t flag) 560 { 561 HTAB *hashp; 562 563 hashp = dbp->internal; 564 if (flag && flag != R_CURSOR) { 565 hashp->err = errno = EINVAL; 566 return (ERROR); 567 } 568 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 569 hashp->err = errno = EPERM; 570 return (ERROR); 571 } 572 return hash_access(hashp, HASH_DELETE, __UNCONST(key), NULL); 573 } 574 575 /* 576 * Assume that hashp has been set in wrapper routine. 577 */ 578 static int 579 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 580 { 581 BUFHEAD *rbufp; 582 BUFHEAD *bufp, *save_bufp; 583 u_int16_t *bp; 584 int n, ndx, off; 585 size_t size; 586 char *kp; 587 u_int16_t pageno; 588 589 #ifdef HASH_STATISTICS 590 hash_accesses++; 591 #endif 592 593 off = hashp->BSIZE; 594 size = key->size; 595 kp = (char *)key->data; 596 rbufp = __get_buf(hashp, __call_hash(hashp, kp, (int)size), NULL, 0); 597 if (!rbufp) 598 return (ERROR); 599 save_bufp = rbufp; 600 601 /* Pin the bucket chain */ 602 rbufp->flags |= BUF_PIN; 603 for (bp = (u_int16_t *)(void *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 604 if (bp[1] >= REAL_KEY) { 605 /* Real key/data pair */ 606 if (size == off - *bp && 607 memcmp(kp, rbufp->page + *bp, size) == 0) 608 goto found; 609 off = bp[1]; 610 #ifdef HASH_STATISTICS 611 hash_collisions++; 612 #endif 613 bp += 2; 614 ndx += 2; 615 } else if (bp[1] == OVFLPAGE) { 616 rbufp = __get_buf(hashp, (u_int32_t)*bp, rbufp, 0); 617 if (!rbufp) { 618 save_bufp->flags &= ~BUF_PIN; 619 return (ERROR); 620 } 621 /* FOR LOOP INIT */ 622 bp = (u_int16_t *)(void *)rbufp->page; 623 n = *bp++; 624 ndx = 1; 625 off = hashp->BSIZE; 626 } else if (bp[1] < REAL_KEY) { 627 if ((ndx = 628 __find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0) 629 goto found; 630 if (ndx == -2) { 631 bufp = rbufp; 632 if (!(pageno = 633 __find_last_page(hashp, &bufp))) { 634 ndx = 0; 635 rbufp = bufp; 636 break; /* FOR */ 637 } 638 rbufp = __get_buf(hashp, (u_int32_t)pageno, 639 bufp, 0); 640 if (!rbufp) { 641 save_bufp->flags &= ~BUF_PIN; 642 return (ERROR); 643 } 644 /* FOR LOOP INIT */ 645 bp = (u_int16_t *)(void *)rbufp->page; 646 n = *bp++; 647 ndx = 1; 648 off = hashp->BSIZE; 649 } else { 650 save_bufp->flags &= ~BUF_PIN; 651 return (ERROR); 652 } 653 } 654 655 /* Not found */ 656 switch (action) { 657 case HASH_PUT: 658 case HASH_PUTNEW: 659 if (__addel(hashp, rbufp, key, val)) { 660 save_bufp->flags &= ~BUF_PIN; 661 return (ERROR); 662 } else { 663 save_bufp->flags &= ~BUF_PIN; 664 return (SUCCESS); 665 } 666 case HASH_GET: 667 case HASH_DELETE: 668 default: 669 save_bufp->flags &= ~BUF_PIN; 670 return (ABNORMAL); 671 } 672 673 found: 674 switch (action) { 675 case HASH_PUTNEW: 676 save_bufp->flags &= ~BUF_PIN; 677 return (ABNORMAL); 678 case HASH_GET: 679 bp = (u_int16_t *)(void *)rbufp->page; 680 if (bp[ndx + 1] < REAL_KEY) { 681 if (__big_return(hashp, rbufp, ndx, val, 0)) 682 return (ERROR); 683 } else { 684 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 685 val->size = bp[ndx] - bp[ndx + 1]; 686 } 687 break; 688 case HASH_PUT: 689 if ((__delpair(hashp, rbufp, ndx)) || 690 (__addel(hashp, rbufp, key, val))) { 691 save_bufp->flags &= ~BUF_PIN; 692 return (ERROR); 693 } 694 break; 695 case HASH_DELETE: 696 if (__delpair(hashp, rbufp, ndx)) 697 return (ERROR); 698 break; 699 default: 700 abort(); 701 } 702 save_bufp->flags &= ~BUF_PIN; 703 return (SUCCESS); 704 } 705 706 static int 707 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 708 { 709 u_int32_t bucket; 710 BUFHEAD *bufp = NULL; /* XXX: gcc */ 711 HTAB *hashp; 712 u_int16_t *bp, ndx; 713 714 hashp = dbp->internal; 715 if (flag && flag != R_FIRST && flag != R_NEXT) { 716 hashp->err = errno = EINVAL; 717 return (ERROR); 718 } 719 #ifdef HASH_STATISTICS 720 hash_accesses++; 721 #endif 722 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 723 hashp->cbucket = 0; 724 hashp->cndx = 1; 725 hashp->cpage = NULL; 726 } 727 728 for (bp = NULL; !bp || !bp[0]; ) { 729 if (!(bufp = hashp->cpage)) { 730 for (bucket = hashp->cbucket; 731 bucket <= hashp->MAX_BUCKET; 732 bucket++, hashp->cndx = 1) { 733 bufp = __get_buf(hashp, bucket, NULL, 0); 734 if (!bufp) 735 return (ERROR); 736 hashp->cpage = bufp; 737 bp = (u_int16_t *)(void *)bufp->page; 738 if (bp[0]) 739 break; 740 } 741 hashp->cbucket = bucket; 742 if (hashp->cbucket > hashp->MAX_BUCKET) { 743 hashp->cbucket = -1; 744 return (ABNORMAL); 745 } 746 } else 747 bp = (u_int16_t *)(void *)hashp->cpage->page; 748 749 _DIAGASSERT(bp != NULL); 750 _DIAGASSERT(bufp != NULL); 751 while (bp[hashp->cndx + 1] == OVFLPAGE) { 752 bufp = hashp->cpage = 753 __get_buf(hashp, (u_int32_t)bp[hashp->cndx], bufp, 754 0); 755 if (!bufp) 756 return (ERROR); 757 bp = (u_int16_t *)(void *)(bufp->page); 758 hashp->cndx = 1; 759 } 760 if (!bp[0]) { 761 hashp->cpage = NULL; 762 ++hashp->cbucket; 763 } 764 } 765 ndx = hashp->cndx; 766 if (bp[ndx + 1] < REAL_KEY) { 767 if (__big_keydata(hashp, bufp, key, data, 1)) 768 return (ERROR); 769 } else { 770 if (hashp->cpage == NULL) 771 return (ERROR); 772 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 773 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 774 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 775 data->size = bp[ndx] - bp[ndx + 1]; 776 ndx += 2; 777 if (ndx > bp[0]) { 778 hashp->cpage = NULL; 779 hashp->cbucket++; 780 hashp->cndx = 1; 781 } else 782 hashp->cndx = ndx; 783 } 784 return (SUCCESS); 785 } 786 787 /********************************* UTILITIES ************************/ 788 789 /* 790 * Returns: 791 * 0 ==> OK 792 * -1 ==> Error 793 */ 794 int 795 __expand_table(HTAB *hashp) 796 { 797 u_int32_t old_bucket, new_bucket; 798 int new_segnum, spare_ndx; 799 size_t dirsize; 800 801 #ifdef HASH_STATISTICS 802 hash_expansions++; 803 #endif 804 new_bucket = ++hashp->MAX_BUCKET; 805 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 806 807 new_segnum = new_bucket >> hashp->SSHIFT; 808 809 /* Check if we need a new segment */ 810 if (new_segnum >= hashp->nsegs) { 811 /* Check if we need to expand directory */ 812 if (new_segnum >= hashp->DSIZE) { 813 /* Reallocate directory */ 814 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 815 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 816 return (-1); 817 hashp->DSIZE = dirsize << 1; 818 } 819 if ((hashp->dir[new_segnum] = 820 calloc((size_t)hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 821 return (-1); 822 hashp->exsegs++; 823 hashp->nsegs++; 824 } 825 /* 826 * If the split point is increasing (MAX_BUCKET's log base 2 827 * * increases), we need to copy the current contents of the spare 828 * split bucket to the next bucket. 829 */ 830 spare_ndx = __log2((u_int32_t)(hashp->MAX_BUCKET + 1)); 831 if (spare_ndx > hashp->OVFL_POINT) { 832 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 833 hashp->OVFL_POINT = spare_ndx; 834 } 835 836 if (new_bucket > hashp->HIGH_MASK) { 837 /* Starting a new doubling */ 838 hashp->LOW_MASK = hashp->HIGH_MASK; 839 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 840 } 841 /* Relocate records to the new bucket */ 842 return (__split_page(hashp, old_bucket, new_bucket)); 843 } 844 845 /* 846 * If realloc guarantees that the pointer is not destroyed if the realloc 847 * fails, then this routine can go away. 848 */ 849 static void * 850 hash_realloc(SEGMENT **p_ptr, size_t oldsize, size_t newsize) 851 { 852 void *p; 853 854 if ((p = malloc(newsize)) != NULL) { 855 memmove(p, *p_ptr, oldsize); 856 memset((char *)p + oldsize, 0, newsize - oldsize); 857 free(*p_ptr); 858 *p_ptr = p; 859 } 860 return (p); 861 } 862 863 u_int32_t 864 __call_hash(HTAB *hashp, char *k, int len) 865 { 866 int n, bucket; 867 868 n = hashp->hash(k, (size_t)len); 869 bucket = n & hashp->HIGH_MASK; 870 if (bucket > hashp->MAX_BUCKET) 871 bucket = bucket & hashp->LOW_MASK; 872 return (bucket); 873 } 874 875 /* 876 * Allocate segment table. On error, destroy the table and set errno. 877 * 878 * Returns 0 on success 879 */ 880 static int 881 alloc_segs(HTAB *hashp, int nsegs) 882 { 883 int i; 884 SEGMENT store; 885 886 int save_errno; 887 888 hashp->dir = calloc((size_t)hashp->DSIZE, sizeof(SEGMENT *)); 889 if (hashp->dir == NULL) { 890 save_errno = errno; 891 (void)hdestroy(hashp); 892 errno = save_errno; 893 return (-1); 894 } 895 hashp->nsegs = nsegs; 896 if (nsegs == 0) 897 return 0; 898 /* Allocate segments */ 899 store = calloc((size_t)(nsegs << hashp->SSHIFT), sizeof(SEGMENT)); 900 if (store == NULL) { 901 save_errno = errno; 902 (void)hdestroy(hashp); 903 errno = save_errno; 904 return (-1); 905 } 906 for (i = 0; i < nsegs; i++) 907 hashp->dir[i] = &store[i << hashp->SSHIFT]; 908 return (0); 909 } 910 911 #if BYTE_ORDER == LITTLE_ENDIAN 912 /* 913 * Hashp->hdr needs to be byteswapped. 914 */ 915 static void 916 swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 917 { 918 size_t i; 919 920 P_32_COPY(srcp->magic, destp->magic); 921 P_32_COPY(srcp->version, destp->version); 922 P_32_COPY(srcp->lorder, destp->lorder); 923 P_32_COPY(srcp->bsize, destp->bsize); 924 P_32_COPY(srcp->bshift, destp->bshift); 925 P_32_COPY(srcp->dsize, destp->dsize); 926 P_32_COPY(srcp->ssize, destp->ssize); 927 P_32_COPY(srcp->sshift, destp->sshift); 928 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 929 P_32_COPY(srcp->last_freed, destp->last_freed); 930 P_32_COPY(srcp->max_bucket, destp->max_bucket); 931 P_32_COPY(srcp->high_mask, destp->high_mask); 932 P_32_COPY(srcp->low_mask, destp->low_mask); 933 P_32_COPY(srcp->ffactor, destp->ffactor); 934 P_32_COPY(srcp->nkeys, destp->nkeys); 935 P_32_COPY(srcp->hdrpages, destp->hdrpages); 936 P_32_COPY(srcp->h_charkey, destp->h_charkey); 937 for (i = 0; i < NCACHED; i++) { 938 P_32_COPY(srcp->spares[i], destp->spares[i]); 939 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 940 } 941 } 942 943 static void 944 swap_header(HTAB *hashp) 945 { 946 HASHHDR *hdrp; 947 size_t i; 948 949 hdrp = &hashp->hdr; 950 951 M_32_SWAP(hdrp->magic); 952 M_32_SWAP(hdrp->version); 953 M_32_SWAP(hdrp->lorder); 954 M_32_SWAP(hdrp->bsize); 955 M_32_SWAP(hdrp->bshift); 956 M_32_SWAP(hdrp->dsize); 957 M_32_SWAP(hdrp->ssize); 958 M_32_SWAP(hdrp->sshift); 959 M_32_SWAP(hdrp->ovfl_point); 960 M_32_SWAP(hdrp->last_freed); 961 M_32_SWAP(hdrp->max_bucket); 962 M_32_SWAP(hdrp->high_mask); 963 M_32_SWAP(hdrp->low_mask); 964 M_32_SWAP(hdrp->ffactor); 965 M_32_SWAP(hdrp->nkeys); 966 M_32_SWAP(hdrp->hdrpages); 967 M_32_SWAP(hdrp->h_charkey); 968 for (i = 0; i < NCACHED; i++) { 969 M_32_SWAP(hdrp->spares[i]); 970 M_16_SWAP(hdrp->bitmaps[i]); 971 } 972 } 973 #endif 974
Indexes created Tue Sep 30 07:10:03 GMT 2025