hash.c revision 1.18
1 /* $NetBSD: hash.c,v 1.18 2003/08/07 16:42:42 agc 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 1.18 2003/08/07 16:42:42 agc 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 (void)fcntl(hashp->fp, F_SETFD, 1); 141 } 142 if (new_table) { 143 if (!(hashp = init_hash(hashp, file, info))) 144 RETURN_ERROR(errno, error1); 145 } else { 146 /* Table already exists */ 147 if (info && info->hash) 148 hashp->hash = info->hash; 149 else 150 hashp->hash = __default_hash; 151 152 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 153 #if BYTE_ORDER == LITTLE_ENDIAN 154 swap_header(hashp); 155 #endif 156 if (hdrsize == -1) 157 RETURN_ERROR(errno, error1); 158 if (hdrsize != sizeof(HASHHDR)) 159 RETURN_ERROR(EFTYPE, error1); 160 /* Verify file type, versions and hash function */ 161 if (hashp->MAGIC != HASHMAGIC) 162 RETURN_ERROR(EFTYPE, error1); 163 #define OLDHASHVERSION 1 164 if (hashp->VERSION != HASHVERSION && 165 hashp->VERSION != OLDHASHVERSION) 166 RETURN_ERROR(EFTYPE, error1); 167 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 168 RETURN_ERROR(EFTYPE, error1); 169 /* 170 * Figure out how many segments we need. Max_Bucket is the 171 * maximum bucket number, so the number of buckets is 172 * max_bucket + 1. 173 */ 174 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 175 hashp->SGSIZE; 176 hashp->nsegs = 0; 177 if (alloc_segs(hashp, nsegs)) 178 /* 179 * If alloc_segs fails, table will have been destroyed 180 * and errno will have been set. 181 */ 182 return (NULL); 183 /* Read in bitmaps */ 184 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 185 (unsigned int)(hashp->BSIZE << BYTE_SHIFT) - 1) >> 186 (hashp->BSHIFT + BYTE_SHIFT); 187 188 hashp->nmaps = bpages; 189 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 190 } 191 192 /* Initialize Buffer Manager */ 193 if (info && info->cachesize) 194 __buf_init(hashp, info->cachesize); 195 else 196 __buf_init(hashp, DEF_BUFSIZE); 197 198 hashp->new_file = new_table; 199 hashp->save_file = file && (hashp->flags & O_RDWR); 200 hashp->cbucket = -1; 201 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 202 save_errno = errno; 203 hdestroy(hashp); 204 errno = save_errno; 205 return (NULL); 206 } 207 dbp->internal = hashp; 208 dbp->close = hash_close; 209 dbp->del = hash_delete; 210 dbp->fd = hash_fd; 211 dbp->get = hash_get; 212 dbp->put = hash_put; 213 dbp->seq = hash_seq; 214 dbp->sync = hash_sync; 215 dbp->type = DB_HASH; 216 217 #ifdef DEBUG 218 (void)fprintf(stderr, 219 "%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", 220 "init_htab:", 221 "TABLE POINTER ", hashp, 222 "BUCKET SIZE ", hashp->BSIZE, 223 "BUCKET SHIFT ", hashp->BSHIFT, 224 "DIRECTORY SIZE ", hashp->DSIZE, 225 "SEGMENT SIZE ", hashp->SGSIZE, 226 "SEGMENT SHIFT ", hashp->SSHIFT, 227 "FILL FACTOR ", hashp->FFACTOR, 228 "MAX BUCKET ", hashp->MAX_BUCKET, 229 "OVFL POINT ", hashp->OVFL_POINT, 230 "LAST FREED ", hashp->LAST_FREED, 231 "HIGH MASK ", hashp->HIGH_MASK, 232 "LOW MASK ", hashp->LOW_MASK, 233 "NSEGS ", hashp->nsegs, 234 "NKEYS ", hashp->NKEYS); 235 #endif 236 #ifdef HASH_STATISTICS 237 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 238 #endif 239 return (dbp); 240 241 error1: 242 if (hashp != NULL) 243 (void)close(hashp->fp); 244 245 error0: 246 free(hashp); 247 errno = save_errno; 248 return (NULL); 249 } 250 251 static int 252 hash_close(dbp) 253 DB *dbp; 254 { 255 HTAB *hashp; 256 int retval; 257 258 if (!dbp) 259 return (ERROR); 260 261 hashp = (HTAB *)dbp->internal; 262 retval = hdestroy(hashp); 263 free(dbp); 264 return (retval); 265 } 266 267 static int 268 hash_fd(dbp) 269 const DB *dbp; 270 { 271 HTAB *hashp; 272 273 if (!dbp) 274 return (ERROR); 275 276 hashp = (HTAB *)dbp->internal; 277 if (hashp->fp == -1) { 278 errno = ENOENT; 279 return (-1); 280 } 281 return (hashp->fp); 282 } 283 284 /************************** LOCAL CREATION ROUTINES **********************/ 285 static HTAB * 286 init_hash(hashp, file, info) 287 HTAB *hashp; 288 const char *file; 289 const HASHINFO *info; 290 { 291 struct stat statbuf; 292 int nelem; 293 294 nelem = 1; 295 hashp->NKEYS = 0; 296 hashp->LORDER = BYTE_ORDER; 297 hashp->BSIZE = DEF_BUCKET_SIZE; 298 hashp->BSHIFT = DEF_BUCKET_SHIFT; 299 hashp->SGSIZE = DEF_SEGSIZE; 300 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 301 hashp->DSIZE = DEF_DIRSIZE; 302 hashp->FFACTOR = DEF_FFACTOR; 303 hashp->hash = __default_hash; 304 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 305 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 306 307 /* Fix bucket size to be optimal for file system */ 308 if (file != NULL) { 309 if (stat(file, &statbuf)) 310 return (NULL); 311 hashp->BSIZE = MIN(statbuf.st_blksize, MAX_BSIZE - 1); 312 hashp->BSHIFT = __log2((u_int32_t)hashp->BSIZE); 313 } 314 315 if (info) { 316 if (info->bsize) { 317 /* Round pagesize up to power of 2 */ 318 hashp->BSHIFT = __log2(info->bsize); 319 hashp->BSIZE = 1 << hashp->BSHIFT; 320 if (hashp->BSIZE >= MAX_BSIZE) { 321 errno = EINVAL; 322 return (NULL); 323 } 324 } 325 if (info->ffactor) 326 hashp->FFACTOR = info->ffactor; 327 if (info->hash) 328 hashp->hash = info->hash; 329 if (info->nelem) 330 nelem = info->nelem; 331 if (info->lorder) { 332 if (info->lorder != BIG_ENDIAN && 333 info->lorder != LITTLE_ENDIAN) { 334 errno = EINVAL; 335 return (NULL); 336 } 337 hashp->LORDER = info->lorder; 338 } 339 } 340 /* init_htab should destroy the table and set errno if it fails */ 341 if (init_htab(hashp, (size_t)nelem)) 342 return (NULL); 343 else 344 return (hashp); 345 } 346 /* 347 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 348 * the table and set errno, so we just pass the error information along. 349 * 350 * Returns 0 on No Error 351 */ 352 static int 353 init_htab(hashp, nelem) 354 HTAB *hashp; 355 size_t nelem; 356 { 357 register int nbuckets; 358 u_int32_t nsegs; 359 int l2; 360 361 /* 362 * Divide number of elements by the fill factor and determine a 363 * desired number of buckets. Allocate space for the next greater 364 * power of two number of buckets. 365 */ 366 nelem = (nelem - 1) / hashp->FFACTOR + 1; 367 368 l2 = __log2(MAX(nelem, 2)); 369 nbuckets = 1 << l2; 370 371 hashp->SPARES[l2] = l2 + 1; 372 hashp->SPARES[l2 + 1] = l2 + 1; 373 hashp->OVFL_POINT = l2; 374 hashp->LAST_FREED = 2; 375 376 /* First bitmap page is at: splitpoint l2 page offset 1 */ 377 if (__ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0)) 378 return (-1); 379 380 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 381 hashp->HIGH_MASK = (nbuckets << 1) - 1; 382 /* LINTED constant in conditional context */ 383 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 384 hashp->BSHIFT) + 1; 385 386 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 387 nsegs = 1 << __log2(nsegs); 388 389 if (nsegs > hashp->DSIZE) 390 hashp->DSIZE = nsegs; 391 return (alloc_segs(hashp, (int)nsegs)); 392 } 393 394 /********************** DESTROY/CLOSE ROUTINES ************************/ 395 396 /* 397 * Flushes any changes to the file if necessary and destroys the hashp 398 * structure, freeing all allocated space. 399 */ 400 static int 401 hdestroy(hashp) 402 HTAB *hashp; 403 { 404 int i, save_errno; 405 406 save_errno = 0; 407 408 #ifdef HASH_STATISTICS 409 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 410 hash_accesses, hash_collisions); 411 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 412 hash_expansions); 413 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 414 hash_overflows); 415 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 416 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 417 418 for (i = 0; i < NCACHED; i++) 419 (void)fprintf(stderr, 420 "spares[%d] = %d\n", i, hashp->SPARES[i]); 421 #endif 422 /* 423 * Call on buffer manager to free buffers, and if required, 424 * write them to disk. 425 */ 426 if (__buf_free(hashp, 1, hashp->save_file)) 427 save_errno = errno; 428 if (hashp->dir) { 429 free(*hashp->dir); /* Free initial segments */ 430 /* Free extra segments */ 431 while (hashp->exsegs--) 432 free(hashp->dir[--hashp->nsegs]); 433 free(hashp->dir); 434 } 435 if (flush_meta(hashp) && !save_errno) 436 save_errno = errno; 437 /* Free Bigmaps */ 438 for (i = 0; i < hashp->nmaps; i++) 439 if (hashp->mapp[i]) 440 free(hashp->mapp[i]); 441 442 if (hashp->fp != -1) 443 (void)close(hashp->fp); 444 445 free(hashp); 446 447 if (save_errno) { 448 errno = save_errno; 449 return (ERROR); 450 } 451 return (SUCCESS); 452 } 453 /* 454 * Write modified pages to disk 455 * 456 * Returns: 457 * 0 == OK 458 * -1 ERROR 459 */ 460 static int 461 hash_sync(dbp, flags) 462 const DB *dbp; 463 u_int32_t flags; 464 { 465 HTAB *hashp; 466 467 if (flags != 0) { 468 errno = EINVAL; 469 return (ERROR); 470 } 471 472 if (!dbp) 473 return (ERROR); 474 475 hashp = (HTAB *)dbp->internal; 476 if (!hashp->save_file) 477 return (0); 478 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 479 return (ERROR); 480 hashp->new_file = 0; 481 return (0); 482 } 483 484 /* 485 * Returns: 486 * 0 == OK 487 * -1 indicates that errno should be set 488 */ 489 static int 490 flush_meta(hashp) 491 HTAB *hashp; 492 { 493 HASHHDR *whdrp; 494 #if BYTE_ORDER == LITTLE_ENDIAN 495 HASHHDR whdr; 496 #endif 497 int fp, i, wsize; 498 499 if (!hashp->save_file) 500 return (0); 501 hashp->MAGIC = HASHMAGIC; 502 hashp->VERSION = HASHVERSION; 503 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 504 505 fp = hashp->fp; 506 whdrp = &hashp->hdr; 507 #if BYTE_ORDER == LITTLE_ENDIAN 508 whdrp = &whdr; 509 swap_header_copy(&hashp->hdr, whdrp); 510 #endif 511 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 512 return (-1); 513 else 514 if (wsize != sizeof(HASHHDR)) { 515 errno = EFTYPE; 516 hashp->err = errno; 517 return (-1); 518 } 519 for (i = 0; i < NCACHED; i++) 520 if (hashp->mapp[i]) 521 if (__put_page(hashp, (char *)(void *)hashp->mapp[i], 522 (u_int)hashp->BITMAPS[i], 0, 1)) 523 return (-1); 524 return (0); 525 } 526 527 /*******************************SEARCH ROUTINES *****************************/ 528 /* 529 * All the access routines return 530 * 531 * Returns: 532 * 0 on SUCCESS 533 * 1 to indicate an external ERROR (i.e. key not found, etc) 534 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 535 */ 536 static int 537 hash_get(dbp, key, data, flag) 538 const DB *dbp; 539 const DBT *key; 540 DBT *data; 541 u_int32_t flag; 542 { 543 HTAB *hashp; 544 545 hashp = (HTAB *)dbp->internal; 546 if (flag) { 547 hashp->err = errno = EINVAL; 548 return (ERROR); 549 } 550 /* LINTED const castaway */ 551 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 552 } 553 554 static int 555 hash_put(dbp, key, data, flag) 556 const DB *dbp; 557 DBT *key; 558 const DBT *data; 559 u_int32_t flag; 560 { 561 HTAB *hashp; 562 563 hashp = (HTAB *)dbp->internal; 564 if (flag && flag != R_NOOVERWRITE) { 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 /* LINTED const castaway */ 573 return (hash_access(hashp, flag == R_NOOVERWRITE ? 574 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 575 } 576 577 static int 578 hash_delete(dbp, key, flag) 579 const DB *dbp; 580 const DBT *key; 581 u_int32_t flag; /* Ignored */ 582 { 583 HTAB *hashp; 584 585 hashp = (HTAB *)dbp->internal; 586 if (flag && flag != R_CURSOR) { 587 hashp->err = errno = EINVAL; 588 return (ERROR); 589 } 590 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 591 hashp->err = errno = EPERM; 592 return (ERROR); 593 } 594 /* LINTED const castaway */ 595 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 596 } 597 598 /* 599 * Assume that hashp has been set in wrapper routine. 600 */ 601 static int 602 hash_access(hashp, action, key, val) 603 HTAB *hashp; 604 ACTION action; 605 DBT *key, *val; 606 { 607 register BUFHEAD *rbufp; 608 BUFHEAD *bufp, *save_bufp; 609 register u_int16_t *bp; 610 register int n, ndx, off; 611 size_t size; 612 register char *kp; 613 u_int16_t pageno; 614 615 #ifdef HASH_STATISTICS 616 hash_accesses++; 617 #endif 618 619 off = hashp->BSIZE; 620 size = key->size; 621 kp = (char *)key->data; 622 rbufp = __get_buf(hashp, __call_hash(hashp, kp, (int)size), NULL, 0); 623 if (!rbufp) 624 return (ERROR); 625 save_bufp = rbufp; 626 627 /* Pin the bucket chain */ 628 rbufp->flags |= BUF_PIN; 629 for (bp = (u_int16_t *)(void *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 630 if (bp[1] >= REAL_KEY) { 631 /* Real key/data pair */ 632 if (size == off - *bp && 633 memcmp(kp, rbufp->page + *bp, size) == 0) 634 goto found; 635 off = bp[1]; 636 #ifdef HASH_STATISTICS 637 hash_collisions++; 638 #endif 639 bp += 2; 640 ndx += 2; 641 } else if (bp[1] == OVFLPAGE) { 642 rbufp = __get_buf(hashp, (u_int32_t)*bp, rbufp, 0); 643 if (!rbufp) { 644 save_bufp->flags &= ~BUF_PIN; 645 return (ERROR); 646 } 647 /* FOR LOOP INIT */ 648 bp = (u_int16_t *)(void *)rbufp->page; 649 n = *bp++; 650 ndx = 1; 651 off = hashp->BSIZE; 652 } else if (bp[1] < REAL_KEY) { 653 if ((ndx = 654 __find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0) 655 goto found; 656 if (ndx == -2) { 657 bufp = rbufp; 658 if (!(pageno = 659 __find_last_page(hashp, &bufp))) { 660 ndx = 0; 661 rbufp = bufp; 662 break; /* FOR */ 663 } 664 rbufp = __get_buf(hashp, (u_int32_t)pageno, 665 bufp, 0); 666 if (!rbufp) { 667 save_bufp->flags &= ~BUF_PIN; 668 return (ERROR); 669 } 670 /* FOR LOOP INIT */ 671 bp = (u_int16_t *)(void *)rbufp->page; 672 n = *bp++; 673 ndx = 1; 674 off = hashp->BSIZE; 675 } else { 676 save_bufp->flags &= ~BUF_PIN; 677 return (ERROR); 678 } 679 } 680 681 /* Not found */ 682 switch (action) { 683 case HASH_PUT: 684 case HASH_PUTNEW: 685 if (__addel(hashp, rbufp, key, val)) { 686 save_bufp->flags &= ~BUF_PIN; 687 return (ERROR); 688 } else { 689 save_bufp->flags &= ~BUF_PIN; 690 return (SUCCESS); 691 } 692 case HASH_GET: 693 case HASH_DELETE: 694 default: 695 save_bufp->flags &= ~BUF_PIN; 696 return (ABNORMAL); 697 } 698 699 found: 700 switch (action) { 701 case HASH_PUTNEW: 702 save_bufp->flags &= ~BUF_PIN; 703 return (ABNORMAL); 704 case HASH_GET: 705 bp = (u_int16_t *)(void *)rbufp->page; 706 if (bp[ndx + 1] < REAL_KEY) { 707 if (__big_return(hashp, rbufp, ndx, val, 0)) 708 return (ERROR); 709 } else { 710 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 711 val->size = bp[ndx] - bp[ndx + 1]; 712 } 713 break; 714 case HASH_PUT: 715 if ((__delpair(hashp, rbufp, ndx)) || 716 (__addel(hashp, rbufp, key, val))) { 717 save_bufp->flags &= ~BUF_PIN; 718 return (ERROR); 719 } 720 break; 721 case HASH_DELETE: 722 if (__delpair(hashp, rbufp, ndx)) 723 return (ERROR); 724 break; 725 default: 726 abort(); 727 } 728 save_bufp->flags &= ~BUF_PIN; 729 return (SUCCESS); 730 } 731 732 static int 733 hash_seq(dbp, key, data, flag) 734 const DB *dbp; 735 DBT *key, *data; 736 u_int32_t flag; 737 { 738 register u_int32_t bucket; 739 register BUFHEAD *bufp; 740 HTAB *hashp; 741 u_int16_t *bp, ndx; 742 743 hashp = (HTAB *)dbp->internal; 744 if (flag && flag != R_FIRST && flag != R_NEXT) { 745 hashp->err = errno = EINVAL; 746 return (ERROR); 747 } 748 #ifdef HASH_STATISTICS 749 hash_accesses++; 750 #endif 751 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 752 hashp->cbucket = 0; 753 hashp->cndx = 1; 754 hashp->cpage = NULL; 755 } 756 757 for (bp = NULL; !bp || !bp[0]; ) { 758 if (!(bufp = hashp->cpage)) { 759 for (bucket = hashp->cbucket; 760 bucket <= hashp->MAX_BUCKET; 761 bucket++, hashp->cndx = 1) { 762 bufp = __get_buf(hashp, bucket, NULL, 0); 763 if (!bufp) 764 return (ERROR); 765 hashp->cpage = bufp; 766 bp = (u_int16_t *)(void *)bufp->page; 767 if (bp[0]) 768 break; 769 } 770 hashp->cbucket = bucket; 771 if (hashp->cbucket > hashp->MAX_BUCKET) { 772 hashp->cbucket = -1; 773 return (ABNORMAL); 774 } 775 } else 776 bp = (u_int16_t *)(void *)hashp->cpage->page; 777 778 #ifdef DEBUG 779 assert(bp); 780 assert(bufp); 781 #endif 782 while (bp[hashp->cndx + 1] == OVFLPAGE) { 783 bufp = hashp->cpage = 784 __get_buf(hashp, (u_int32_t)bp[hashp->cndx], bufp, 785 0); 786 if (!bufp) 787 return (ERROR); 788 bp = (u_int16_t *)(void *)(bufp->page); 789 hashp->cndx = 1; 790 } 791 if (!bp[0]) { 792 hashp->cpage = NULL; 793 ++hashp->cbucket; 794 } 795 } 796 ndx = hashp->cndx; 797 if (bp[ndx + 1] < REAL_KEY) { 798 if (__big_keydata(hashp, bufp, key, data, 1)) 799 return (ERROR); 800 } else { 801 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 802 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 803 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 804 data->size = bp[ndx] - bp[ndx + 1]; 805 ndx += 2; 806 if (ndx > bp[0]) { 807 hashp->cpage = NULL; 808 hashp->cbucket++; 809 hashp->cndx = 1; 810 } else 811 hashp->cndx = ndx; 812 } 813 return (SUCCESS); 814 } 815 816 /********************************* UTILITIES ************************/ 817 818 /* 819 * Returns: 820 * 0 ==> OK 821 * -1 ==> Error 822 */ 823 extern int 824 __expand_table(hashp) 825 HTAB *hashp; 826 { 827 u_int32_t old_bucket, new_bucket; 828 int dirsize, new_segnum, spare_ndx; 829 830 #ifdef HASH_STATISTICS 831 hash_expansions++; 832 #endif 833 new_bucket = ++hashp->MAX_BUCKET; 834 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 835 836 new_segnum = new_bucket >> hashp->SSHIFT; 837 838 /* Check if we need a new segment */ 839 if (new_segnum >= hashp->nsegs) { 840 /* Check if we need to expand directory */ 841 if (new_segnum >= hashp->DSIZE) { 842 /* Reallocate directory */ 843 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 844 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 845 return (-1); 846 hashp->DSIZE = dirsize << 1; 847 } 848 if ((hashp->dir[new_segnum] = 849 (SEGMENT)calloc((size_t)hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 850 return (-1); 851 hashp->exsegs++; 852 hashp->nsegs++; 853 } 854 /* 855 * If the split point is increasing (MAX_BUCKET's log base 2 856 * * increases), we need to copy the current contents of the spare 857 * split bucket to the next bucket. 858 */ 859 spare_ndx = __log2((u_int32_t)(hashp->MAX_BUCKET + 1)); 860 if (spare_ndx > hashp->OVFL_POINT) { 861 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 862 hashp->OVFL_POINT = spare_ndx; 863 } 864 865 if (new_bucket > hashp->HIGH_MASK) { 866 /* Starting a new doubling */ 867 hashp->LOW_MASK = hashp->HIGH_MASK; 868 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 869 } 870 /* Relocate records to the new bucket */ 871 return (__split_page(hashp, old_bucket, new_bucket)); 872 } 873 874 /* 875 * If realloc guarantees that the pointer is not destroyed if the realloc 876 * fails, then this routine can go away. 877 */ 878 static void * 879 hash_realloc(p_ptr, oldsize, newsize) 880 SEGMENT **p_ptr; 881 int oldsize, newsize; 882 { 883 register void *p; 884 885 if ((p = malloc((size_t)newsize)) != NULL) { 886 memmove(p, *p_ptr, (size_t)oldsize); 887 memset((char *)p + oldsize, 0, (size_t)(newsize - oldsize)); 888 free(*p_ptr); 889 *p_ptr = p; 890 } 891 return (p); 892 } 893 894 extern u_int32_t 895 __call_hash(hashp, k, len) 896 HTAB *hashp; 897 char *k; 898 int len; 899 { 900 int n, bucket; 901 902 n = hashp->hash(k, (size_t)len); 903 bucket = n & hashp->HIGH_MASK; 904 if (bucket > hashp->MAX_BUCKET) 905 bucket = bucket & hashp->LOW_MASK; 906 return (bucket); 907 } 908 909 /* 910 * Allocate segment table. On error, destroy the table and set errno. 911 * 912 * Returns 0 on success 913 */ 914 static int 915 alloc_segs(hashp, nsegs) 916 HTAB *hashp; 917 int nsegs; 918 { 919 register int i; 920 register SEGMENT store; 921 922 int save_errno; 923 924 if ((hashp->dir = 925 (SEGMENT *)calloc((size_t)hashp->DSIZE, 926 sizeof(SEGMENT *))) == NULL) { 927 save_errno = errno; 928 (void)hdestroy(hashp); 929 errno = save_errno; 930 return (-1); 931 } 932 /* Allocate segments */ 933 if ((store = 934 (SEGMENT)calloc((size_t)(nsegs << hashp->SSHIFT), 935 sizeof(SEGMENT))) == NULL) { 936 save_errno = errno; 937 (void)hdestroy(hashp); 938 errno = save_errno; 939 return (-1); 940 } 941 for (i = 0; i < nsegs; i++, hashp->nsegs++) 942 hashp->dir[i] = &store[i << hashp->SSHIFT]; 943 return (0); 944 } 945 946 #if BYTE_ORDER == LITTLE_ENDIAN 947 /* 948 * Hashp->hdr needs to be byteswapped. 949 */ 950 static void 951 swap_header_copy(srcp, destp) 952 HASHHDR *srcp, *destp; 953 { 954 int i; 955 956 P_32_COPY(srcp->magic, destp->magic); 957 P_32_COPY(srcp->version, destp->version); 958 P_32_COPY(srcp->lorder, destp->lorder); 959 P_32_COPY(srcp->bsize, destp->bsize); 960 P_32_COPY(srcp->bshift, destp->bshift); 961 P_32_COPY(srcp->dsize, destp->dsize); 962 P_32_COPY(srcp->ssize, destp->ssize); 963 P_32_COPY(srcp->sshift, destp->sshift); 964 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 965 P_32_COPY(srcp->last_freed, destp->last_freed); 966 P_32_COPY(srcp->max_bucket, destp->max_bucket); 967 P_32_COPY(srcp->high_mask, destp->high_mask); 968 P_32_COPY(srcp->low_mask, destp->low_mask); 969 P_32_COPY(srcp->ffactor, destp->ffactor); 970 P_32_COPY(srcp->nkeys, destp->nkeys); 971 P_32_COPY(srcp->hdrpages, destp->hdrpages); 972 P_32_COPY(srcp->h_charkey, destp->h_charkey); 973 for (i = 0; i < NCACHED; i++) { 974 P_32_COPY(srcp->spares[i], destp->spares[i]); 975 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 976 } 977 } 978 979 static void 980 swap_header(hashp) 981 HTAB *hashp; 982 { 983 HASHHDR *hdrp; 984 int i; 985 986 hdrp = &hashp->hdr; 987 988 M_32_SWAP(hdrp->magic); 989 M_32_SWAP(hdrp->version); 990 M_32_SWAP(hdrp->lorder); 991 M_32_SWAP(hdrp->bsize); 992 M_32_SWAP(hdrp->bshift); 993 M_32_SWAP(hdrp->dsize); 994 M_32_SWAP(hdrp->ssize); 995 M_32_SWAP(hdrp->sshift); 996 M_32_SWAP(hdrp->ovfl_point); 997 M_32_SWAP(hdrp->last_freed); 998 M_32_SWAP(hdrp->max_bucket); 999 M_32_SWAP(hdrp->high_mask); 1000 M_32_SWAP(hdrp->low_mask); 1001 M_32_SWAP(hdrp->ffactor); 1002 M_32_SWAP(hdrp->nkeys); 1003 M_32_SWAP(hdrp->hdrpages); 1004 M_32_SWAP(hdrp->h_charkey); 1005 for (i = 0; i < NCACHED; i++) { 1006 M_32_SWAP(hdrp->spares[i]); 1007 M_16_SWAP(hdrp->bitmaps[i]); 1008 } 1009 } 1010 #endif 1011
Indexes created Fri Sep 26 20:09:58 GMT 2025