hash.c revision 1.7
1 /*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Margo Seltzer. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #ifdef DEBUG 51 #include <assert.h> 52 #endif 53 54 #include <db.h> 55 #include "hash.h" 56 #include "page.h" 57 #include "extern.h" 58 59 static int alloc_segs __P((HTAB *, int)); 60 static int flush_meta __P((HTAB *)); 61 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 62 static int hash_close __P((DB *)); 63 static int hash_delete __P((const DB *, const DBT *, u_int32_t)); 64 static int hash_fd __P((const DB *)); 65 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); 66 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); 67 static void *hash_realloc __P((SEGMENT **, int, int)); 68 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); 69 static int hash_sync __P((const DB *, u_int32_t)); 70 static int hdestroy __P((HTAB *)); 71 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *)); 72 static int init_htab __P((HTAB *, int)); 73 #if BYTE_ORDER == LITTLE_ENDIAN 74 static void swap_header __P((HTAB *)); 75 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 76 #endif 77 78 /* Fast arithmetic, relying on powers of 2, */ 79 #define MOD(x, y) ((x) & ((y) - 1)) 80 81 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 82 83 /* Return values */ 84 #define SUCCESS (0) 85 #define ERROR (-1) 86 #define ABNORMAL (1) 87 88 #ifdef HASH_STATISTICS 89 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 90 #endif 91 92 /************************** INTERFACE ROUTINES ***************************/ 93 /* OPEN/CLOSE */ 94 95 extern DB * 96 __hash_open(file, flags, mode, info, dflags) 97 const char *file; 98 int flags, mode, dflags; 99 const HASHINFO *info; /* Special directives for create */ 100 { 101 HTAB *hashp; 102 struct stat statbuf; 103 DB *dbp; 104 int bpages, hdrsize, new_table, nsegs, save_errno; 105 106 if ((flags & O_ACCMODE) == O_WRONLY) { 107 errno = EINVAL; 108 return (NULL); 109 } 110 111 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 112 return (NULL); 113 hashp->fp = -1; 114 115 /* 116 * Even if user wants write only, we need to be able to read 117 * the actual file, so we need to open it read/write. But, the 118 * field in the hashp structure needs to be accurate so that 119 * we can check accesses. 120 */ 121 hashp->flags = flags; 122 123 new_table = 0; 124 if (!file || (flags & O_TRUNC) || 125 (stat(file, &statbuf) && (errno == ENOENT))) { 126 if (errno == ENOENT) 127 errno = 0; /* Just in case someone looks at errno */ 128 new_table = 1; 129 } 130 if (file) { 131 if ((hashp->fp = open(file, flags, mode)) == -1) 132 RETURN_ERROR(errno, error0); 133 (void)fcntl(hashp->fp, F_SETFD, 1); 134 } 135 if (new_table) { 136 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 137 RETURN_ERROR(errno, error1); 138 } else { 139 /* Table already exists */ 140 if (info && info->hash) 141 hashp->hash = info->hash; 142 else 143 hashp->hash = __default_hash; 144 145 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 146 #if BYTE_ORDER == LITTLE_ENDIAN 147 swap_header(hashp); 148 #endif 149 if (hdrsize == -1) 150 RETURN_ERROR(errno, error1); 151 if (hdrsize != sizeof(HASHHDR)) 152 RETURN_ERROR(EFTYPE, error1); 153 /* Verify file type, versions and hash function */ 154 if (hashp->MAGIC != HASHMAGIC) 155 RETURN_ERROR(EFTYPE, error1); 156 #define OLDHASHVERSION 1 157 if (hashp->VERSION != HASHVERSION && 158 hashp->VERSION != OLDHASHVERSION) 159 RETURN_ERROR(EFTYPE, error1); 160 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 161 RETURN_ERROR(EFTYPE, error1); 162 /* 163 * Figure out how many segments we need. Max_Bucket is the 164 * maximum bucket number, so the number of buckets is 165 * max_bucket + 1. 166 */ 167 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 168 hashp->SGSIZE; 169 hashp->nsegs = 0; 170 if (alloc_segs(hashp, nsegs)) 171 /* 172 * If alloc_segs fails, table will have been destroyed 173 * and errno will have been set. 174 */ 175 return (NULL); 176 /* Read in bitmaps */ 177 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 178 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 179 (hashp->BSHIFT + BYTE_SHIFT); 180 181 hashp->nmaps = bpages; 182 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 183 } 184 185 /* Initialize Buffer Manager */ 186 if (info && info->cachesize) 187 __buf_init(hashp, info->cachesize); 188 else 189 __buf_init(hashp, DEF_BUFSIZE); 190 191 hashp->new_file = new_table; 192 hashp->save_file = file && (hashp->flags & O_RDWR); 193 hashp->cbucket = -1; 194 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 195 save_errno = errno; 196 hdestroy(hashp); 197 errno = save_errno; 198 return (NULL); 199 } 200 dbp->internal = hashp; 201 dbp->close = hash_close; 202 dbp->del = hash_delete; 203 dbp->fd = hash_fd; 204 dbp->get = hash_get; 205 dbp->put = hash_put; 206 dbp->seq = hash_seq; 207 dbp->sync = hash_sync; 208 dbp->type = DB_HASH; 209 210 #ifdef DEBUG 211 (void)fprintf(stderr, 212 "%s\n%s%x\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n", 213 "init_htab:", 214 "TABLE POINTER ", hashp, 215 "BUCKET SIZE ", hashp->BSIZE, 216 "BUCKET SHIFT ", hashp->BSHIFT, 217 "DIRECTORY SIZE ", hashp->DSIZE, 218 "SEGMENT SIZE ", hashp->SGSIZE, 219 "SEGMENT SHIFT ", hashp->SSHIFT, 220 "FILL FACTOR ", hashp->FFACTOR, 221 "MAX BUCKET ", hashp->MAX_BUCKET, 222 "OVFL POINT ", hashp->OVFL_POINT, 223 "LAST FREED ", hashp->LAST_FREED, 224 "HIGH MASK ", hashp->HIGH_MASK, 225 "LOW MASK ", hashp->LOW_MASK, 226 "NSEGS ", hashp->nsegs, 227 "NKEYS ", hashp->NKEYS); 228 #endif 229 #ifdef HASH_STATISTICS 230 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 231 #endif 232 return (dbp); 233 234 error1: 235 if (hashp != NULL) 236 (void)close(hashp->fp); 237 238 error0: 239 free(hashp); 240 errno = save_errno; 241 return (NULL); 242 } 243 244 static int 245 hash_close(dbp) 246 DB *dbp; 247 { 248 HTAB *hashp; 249 int retval; 250 251 if (!dbp) 252 return (ERROR); 253 254 hashp = (HTAB *)dbp->internal; 255 retval = hdestroy(hashp); 256 free(dbp); 257 return (retval); 258 } 259 260 static int 261 hash_fd(dbp) 262 const DB *dbp; 263 { 264 HTAB *hashp; 265 266 if (!dbp) 267 return (ERROR); 268 269 hashp = (HTAB *)dbp->internal; 270 if (hashp->fp == -1) { 271 errno = ENOENT; 272 return (-1); 273 } 274 return (hashp->fp); 275 } 276 277 /************************** LOCAL CREATION ROUTINES **********************/ 278 static HTAB * 279 init_hash(hashp, file, info) 280 HTAB *hashp; 281 const char *file; 282 HASHINFO *info; 283 { 284 struct stat statbuf; 285 int nelem; 286 287 nelem = 1; 288 hashp->NKEYS = 0; 289 hashp->LORDER = BYTE_ORDER; 290 hashp->BSIZE = DEF_BUCKET_SIZE; 291 hashp->BSHIFT = DEF_BUCKET_SHIFT; 292 hashp->SGSIZE = DEF_SEGSIZE; 293 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 294 hashp->DSIZE = DEF_DIRSIZE; 295 hashp->FFACTOR = DEF_FFACTOR; 296 hashp->hash = __default_hash; 297 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 298 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 299 300 /* Fix bucket size to be optimal for file system */ 301 if (file != NULL) { 302 if (stat(file, &statbuf)) 303 return (NULL); 304 hashp->BSIZE = statbuf.st_blksize; 305 hashp->BSHIFT = __log2(hashp->BSIZE); 306 } 307 308 if (info) { 309 if (info->bsize) { 310 /* Round pagesize up to power of 2 */ 311 hashp->BSHIFT = __log2(info->bsize); 312 hashp->BSIZE = 1 << hashp->BSHIFT; 313 if (hashp->BSIZE > MAX_BSIZE) { 314 errno = EINVAL; 315 return (NULL); 316 } 317 } 318 if (info->ffactor) 319 hashp->FFACTOR = info->ffactor; 320 if (info->hash) 321 hashp->hash = info->hash; 322 if (info->nelem) 323 nelem = info->nelem; 324 if (info->lorder) { 325 if (info->lorder != BIG_ENDIAN && 326 info->lorder != LITTLE_ENDIAN) { 327 errno = EINVAL; 328 return (NULL); 329 } 330 hashp->LORDER = info->lorder; 331 } 332 } 333 /* init_htab should destroy the table and set errno if it fails */ 334 if (init_htab(hashp, nelem)) 335 return (NULL); 336 else 337 return (hashp); 338 } 339 /* 340 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 341 * the table and set errno, so we just pass the error information along. 342 * 343 * Returns 0 on No Error 344 */ 345 static int 346 init_htab(hashp, nelem) 347 HTAB *hashp; 348 int nelem; 349 { 350 register int nbuckets, nsegs; 351 int l2; 352 353 /* 354 * Divide number of elements by the fill factor and determine a 355 * desired number of buckets. Allocate space for the next greater 356 * power of two number of buckets. 357 */ 358 nelem = (nelem - 1) / hashp->FFACTOR + 1; 359 360 l2 = __log2(MAX(nelem, 2)); 361 nbuckets = 1 << l2; 362 363 hashp->SPARES[l2] = l2 + 1; 364 hashp->SPARES[l2 + 1] = l2 + 1; 365 hashp->OVFL_POINT = l2; 366 hashp->LAST_FREED = 2; 367 368 /* First bitmap page is at: splitpoint l2 page offset 1 */ 369 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 370 return (-1); 371 372 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 373 hashp->HIGH_MASK = (nbuckets << 1) - 1; 374 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 375 hashp->BSHIFT) + 1; 376 377 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 378 nsegs = 1 << __log2(nsegs); 379 380 if (nsegs > hashp->DSIZE) 381 hashp->DSIZE = nsegs; 382 return (alloc_segs(hashp, nsegs)); 383 } 384 385 /********************** DESTROY/CLOSE ROUTINES ************************/ 386 387 /* 388 * Flushes any changes to the file if necessary and destroys the hashp 389 * structure, freeing all allocated space. 390 */ 391 static int 392 hdestroy(hashp) 393 HTAB *hashp; 394 { 395 int i, save_errno; 396 397 save_errno = 0; 398 399 #ifdef HASH_STATISTICS 400 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 401 hash_accesses, hash_collisions); 402 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 403 hash_expansions); 404 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 405 hash_overflows); 406 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 407 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 408 409 for (i = 0; i < NCACHED; i++) 410 (void)fprintf(stderr, 411 "spares[%d] = %d\n", i, hashp->SPARES[i]); 412 #endif 413 /* 414 * Call on buffer manager to free buffers, and if required, 415 * write them to disk. 416 */ 417 if (__buf_free(hashp, 1, hashp->save_file)) 418 save_errno = errno; 419 if (hashp->dir) { 420 free(*hashp->dir); /* Free initial segments */ 421 /* Free extra segments */ 422 while (hashp->exsegs--) 423 free(hashp->dir[--hashp->nsegs]); 424 free(hashp->dir); 425 } 426 if (flush_meta(hashp) && !save_errno) 427 save_errno = errno; 428 /* Free Bigmaps */ 429 for (i = 0; i < hashp->nmaps; i++) 430 if (hashp->mapp[i]) 431 free(hashp->mapp[i]); 432 433 if (hashp->fp != -1) 434 (void)close(hashp->fp); 435 436 free(hashp); 437 438 if (save_errno) { 439 errno = save_errno; 440 return (ERROR); 441 } 442 return (SUCCESS); 443 } 444 /* 445 * Write modified pages to disk 446 * 447 * Returns: 448 * 0 == OK 449 * -1 ERROR 450 */ 451 static int 452 hash_sync(dbp, flags) 453 const DB *dbp; 454 u_int32_t flags; 455 { 456 HTAB *hashp; 457 458 if (flags != 0) { 459 errno = EINVAL; 460 return (ERROR); 461 } 462 463 if (!dbp) 464 return (ERROR); 465 466 hashp = (HTAB *)dbp->internal; 467 if (!hashp->save_file) 468 return (0); 469 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 470 return (ERROR); 471 hashp->new_file = 0; 472 return (0); 473 } 474 475 /* 476 * Returns: 477 * 0 == OK 478 * -1 indicates that errno should be set 479 */ 480 static int 481 flush_meta(hashp) 482 HTAB *hashp; 483 { 484 HASHHDR *whdrp; 485 #if BYTE_ORDER == LITTLE_ENDIAN 486 HASHHDR whdr; 487 #endif 488 int fp, i, wsize; 489 490 if (!hashp->save_file) 491 return (0); 492 hashp->MAGIC = HASHMAGIC; 493 hashp->VERSION = HASHVERSION; 494 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 495 496 fp = hashp->fp; 497 whdrp = &hashp->hdr; 498 #if BYTE_ORDER == LITTLE_ENDIAN 499 whdrp = &whdr; 500 swap_header_copy(&hashp->hdr, whdrp); 501 #endif 502 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 503 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 504 return (-1); 505 else 506 if (wsize != sizeof(HASHHDR)) { 507 errno = EFTYPE; 508 hashp->errno = errno; 509 return (-1); 510 } 511 for (i = 0; i < NCACHED; i++) 512 if (hashp->mapp[i]) 513 if (__put_page(hashp, (char *)hashp->mapp[i], 514 hashp->BITMAPS[i], 0, 1)) 515 return (-1); 516 return (0); 517 } 518 519 /*******************************SEARCH ROUTINES *****************************/ 520 /* 521 * All the access routines return 522 * 523 * Returns: 524 * 0 on SUCCESS 525 * 1 to indicate an external ERROR (i.e. key not found, etc) 526 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 527 */ 528 static int 529 hash_get(dbp, key, data, flag) 530 const DB *dbp; 531 const DBT *key; 532 DBT *data; 533 u_int32_t flag; 534 { 535 HTAB *hashp; 536 537 hashp = (HTAB *)dbp->internal; 538 if (flag) { 539 hashp->errno = errno = EINVAL; 540 return (ERROR); 541 } 542 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 543 } 544 545 static int 546 hash_put(dbp, key, data, flag) 547 const DB *dbp; 548 DBT *key; 549 const DBT *data; 550 u_int32_t flag; 551 { 552 HTAB *hashp; 553 554 hashp = (HTAB *)dbp->internal; 555 if (flag && flag != R_NOOVERWRITE) { 556 hashp->errno = errno = EINVAL; 557 return (ERROR); 558 } 559 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 560 hashp->errno = errno = EPERM; 561 return (ERROR); 562 } 563 return (hash_access(hashp, flag == R_NOOVERWRITE ? 564 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 565 } 566 567 static int 568 hash_delete(dbp, key, flag) 569 const DB *dbp; 570 const DBT *key; 571 u_int32_t flag; /* Ignored */ 572 { 573 HTAB *hashp; 574 575 hashp = (HTAB *)dbp->internal; 576 if (flag && flag != R_CURSOR) { 577 hashp->errno = errno = EINVAL; 578 return (ERROR); 579 } 580 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 581 hashp->errno = errno = EPERM; 582 return (ERROR); 583 } 584 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 585 } 586 587 /* 588 * Assume that hashp has been set in wrapper routine. 589 */ 590 static int 591 hash_access(hashp, action, key, val) 592 HTAB *hashp; 593 ACTION action; 594 DBT *key, *val; 595 { 596 register BUFHEAD *rbufp; 597 BUFHEAD *bufp, *save_bufp; 598 register u_int16_t *bp; 599 register int n, ndx, off, size; 600 register char *kp; 601 u_int16_t pageno; 602 603 #ifdef HASH_STATISTICS 604 hash_accesses++; 605 #endif 606 607 off = hashp->BSIZE; 608 size = key->size; 609 kp = (char *)key->data; 610 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 611 if (!rbufp) 612 return (ERROR); 613 save_bufp = rbufp; 614 615 /* Pin the bucket chain */ 616 rbufp->flags |= BUF_PIN; 617 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 618 if (bp[1] >= REAL_KEY) { 619 /* Real key/data pair */ 620 if (size == off - *bp && 621 memcmp(kp, rbufp->page + *bp, size) == 0) 622 goto found; 623 off = bp[1]; 624 #ifdef HASH_STATISTICS 625 hash_collisions++; 626 #endif 627 bp += 2; 628 ndx += 2; 629 } else if (bp[1] == OVFLPAGE) { 630 rbufp = __get_buf(hashp, *bp, rbufp, 0); 631 if (!rbufp) { 632 save_bufp->flags &= ~BUF_PIN; 633 return (ERROR); 634 } 635 /* FOR LOOP INIT */ 636 bp = (u_int16_t *)rbufp->page; 637 n = *bp++; 638 ndx = 1; 639 off = hashp->BSIZE; 640 } else if (bp[1] < REAL_KEY) { 641 if ((ndx = 642 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 643 goto found; 644 if (ndx == -2) { 645 bufp = rbufp; 646 if (!(pageno = 647 __find_last_page(hashp, &bufp))) { 648 ndx = 0; 649 rbufp = bufp; 650 break; /* FOR */ 651 } 652 rbufp = __get_buf(hashp, pageno, bufp, 0); 653 if (!rbufp) { 654 save_bufp->flags &= ~BUF_PIN; 655 return (ERROR); 656 } 657 /* FOR LOOP INIT */ 658 bp = (u_int16_t *)rbufp->page; 659 n = *bp++; 660 ndx = 1; 661 off = hashp->BSIZE; 662 } else { 663 save_bufp->flags &= ~BUF_PIN; 664 return (ERROR); 665 } 666 } 667 668 /* Not found */ 669 switch (action) { 670 case HASH_PUT: 671 case HASH_PUTNEW: 672 if (__addel(hashp, rbufp, key, val)) { 673 save_bufp->flags &= ~BUF_PIN; 674 return (ERROR); 675 } else { 676 save_bufp->flags &= ~BUF_PIN; 677 return (SUCCESS); 678 } 679 case HASH_GET: 680 case HASH_DELETE: 681 default: 682 save_bufp->flags &= ~BUF_PIN; 683 return (ABNORMAL); 684 } 685 686 found: 687 switch (action) { 688 case HASH_PUTNEW: 689 save_bufp->flags &= ~BUF_PIN; 690 return (ABNORMAL); 691 case HASH_GET: 692 bp = (u_int16_t *)rbufp->page; 693 if (bp[ndx + 1] < REAL_KEY) { 694 if (__big_return(hashp, rbufp, ndx, val, 0)) 695 return (ERROR); 696 } else { 697 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 698 val->size = bp[ndx] - bp[ndx + 1]; 699 } 700 break; 701 case HASH_PUT: 702 if ((__delpair(hashp, rbufp, ndx)) || 703 (__addel(hashp, rbufp, key, val))) { 704 save_bufp->flags &= ~BUF_PIN; 705 return (ERROR); 706 } 707 break; 708 case HASH_DELETE: 709 if (__delpair(hashp, rbufp, ndx)) 710 return (ERROR); 711 break; 712 default: 713 abort(); 714 } 715 save_bufp->flags &= ~BUF_PIN; 716 return (SUCCESS); 717 } 718 719 static int 720 hash_seq(dbp, key, data, flag) 721 const DB *dbp; 722 DBT *key, *data; 723 u_int32_t flag; 724 { 725 register u_int32_t bucket; 726 register BUFHEAD *bufp; 727 HTAB *hashp; 728 u_int16_t *bp, ndx; 729 730 hashp = (HTAB *)dbp->internal; 731 if (flag && flag != R_FIRST && flag != R_NEXT) { 732 hashp->errno = errno = EINVAL; 733 return (ERROR); 734 } 735 #ifdef HASH_STATISTICS 736 hash_accesses++; 737 #endif 738 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 739 hashp->cbucket = 0; 740 hashp->cndx = 1; 741 hashp->cpage = NULL; 742 } 743 744 for (bp = NULL; !bp || !bp[0]; ) { 745 if (!(bufp = hashp->cpage)) { 746 for (bucket = hashp->cbucket; 747 bucket <= hashp->MAX_BUCKET; 748 bucket++, hashp->cndx = 1) { 749 bufp = __get_buf(hashp, bucket, NULL, 0); 750 if (!bufp) 751 return (ERROR); 752 hashp->cpage = bufp; 753 bp = (u_int16_t *)bufp->page; 754 if (bp[0]) 755 break; 756 } 757 hashp->cbucket = bucket; 758 if (hashp->cbucket > hashp->MAX_BUCKET) { 759 hashp->cbucket = -1; 760 return (ABNORMAL); 761 } 762 } else 763 bp = (u_int16_t *)hashp->cpage->page; 764 765 #ifdef DEBUG 766 assert(bp); 767 assert(bufp); 768 #endif 769 while (bp[hashp->cndx + 1] == OVFLPAGE) { 770 bufp = hashp->cpage = 771 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 772 if (!bufp) 773 return (ERROR); 774 bp = (u_int16_t *)(bufp->page); 775 hashp->cndx = 1; 776 } 777 if (!bp[0]) { 778 hashp->cpage = NULL; 779 ++hashp->cbucket; 780 } 781 } 782 ndx = hashp->cndx; 783 if (bp[ndx + 1] < REAL_KEY) { 784 if (__big_keydata(hashp, bufp, key, data, 1)) 785 return (ERROR); 786 } else { 787 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 788 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 789 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 790 data->size = bp[ndx] - bp[ndx + 1]; 791 ndx += 2; 792 if (ndx > bp[0]) { 793 hashp->cpage = NULL; 794 hashp->cbucket++; 795 hashp->cndx = 1; 796 } else 797 hashp->cndx = ndx; 798 } 799 return (SUCCESS); 800 } 801 802 /********************************* UTILITIES ************************/ 803 804 /* 805 * Returns: 806 * 0 ==> OK 807 * -1 ==> Error 808 */ 809 extern int 810 __expand_table(hashp) 811 HTAB *hashp; 812 { 813 u_int32_t old_bucket, new_bucket; 814 int dirsize, new_segnum, spare_ndx; 815 816 #ifdef HASH_STATISTICS 817 hash_expansions++; 818 #endif 819 new_bucket = ++hashp->MAX_BUCKET; 820 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 821 822 new_segnum = new_bucket >> hashp->SSHIFT; 823 824 /* Check if we need a new segment */ 825 if (new_segnum >= hashp->nsegs) { 826 /* Check if we need to expand directory */ 827 if (new_segnum >= hashp->DSIZE) { 828 /* Reallocate directory */ 829 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 830 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 831 return (-1); 832 hashp->DSIZE = dirsize << 1; 833 } 834 if ((hashp->dir[new_segnum] = 835 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 836 return (-1); 837 hashp->exsegs++; 838 hashp->nsegs++; 839 } 840 /* 841 * If the split point is increasing (MAX_BUCKET's log base 2 842 * * increases), we need to copy the current contents of the spare 843 * split bucket to the next bucket. 844 */ 845 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 846 if (spare_ndx > hashp->OVFL_POINT) { 847 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 848 hashp->OVFL_POINT = spare_ndx; 849 } 850 851 if (new_bucket > hashp->HIGH_MASK) { 852 /* Starting a new doubling */ 853 hashp->LOW_MASK = hashp->HIGH_MASK; 854 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 855 } 856 /* Relocate records to the new bucket */ 857 return (__split_page(hashp, old_bucket, new_bucket)); 858 } 859 860 /* 861 * If realloc guarantees that the pointer is not destroyed if the realloc 862 * fails, then this routine can go away. 863 */ 864 static void * 865 hash_realloc(p_ptr, oldsize, newsize) 866 SEGMENT **p_ptr; 867 int oldsize, newsize; 868 { 869 register void *p; 870 871 if (p = malloc(newsize)) { 872 memmove(p, *p_ptr, oldsize); 873 memset((char *)p + oldsize, 0, newsize - oldsize); 874 free(*p_ptr); 875 *p_ptr = p; 876 } 877 return (p); 878 } 879 880 extern u_int32_t 881 __call_hash(hashp, k, len) 882 HTAB *hashp; 883 char *k; 884 int len; 885 { 886 int n, bucket; 887 888 n = hashp->hash(k, len); 889 bucket = n & hashp->HIGH_MASK; 890 if (bucket > hashp->MAX_BUCKET) 891 bucket = bucket & hashp->LOW_MASK; 892 return (bucket); 893 } 894 895 /* 896 * Allocate segment table. On error, destroy the table and set errno. 897 * 898 * Returns 0 on success 899 */ 900 static int 901 alloc_segs(hashp, nsegs) 902 HTAB *hashp; 903 int nsegs; 904 { 905 register int i; 906 register SEGMENT store; 907 908 int save_errno; 909 910 if ((hashp->dir = 911 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 912 save_errno = errno; 913 (void)hdestroy(hashp); 914 errno = save_errno; 915 return (-1); 916 } 917 /* Allocate segments */ 918 if ((store = 919 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 920 save_errno = errno; 921 (void)hdestroy(hashp); 922 errno = save_errno; 923 return (-1); 924 } 925 for (i = 0; i < nsegs; i++, hashp->nsegs++) 926 hashp->dir[i] = &store[i << hashp->SSHIFT]; 927 return (0); 928 } 929 930 #if BYTE_ORDER == LITTLE_ENDIAN 931 /* 932 * Hashp->hdr needs to be byteswapped. 933 */ 934 static void 935 swap_header_copy(srcp, destp) 936 HASHHDR *srcp, *destp; 937 { 938 int i; 939 940 P_32_COPY(srcp->magic, destp->magic); 941 P_32_COPY(srcp->version, destp->version); 942 P_32_COPY(srcp->lorder, destp->lorder); 943 P_32_COPY(srcp->bsize, destp->bsize); 944 P_32_COPY(srcp->bshift, destp->bshift); 945 P_32_COPY(srcp->dsize, destp->dsize); 946 P_32_COPY(srcp->ssize, destp->ssize); 947 P_32_COPY(srcp->sshift, destp->sshift); 948 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 949 P_32_COPY(srcp->last_freed, destp->last_freed); 950 P_32_COPY(srcp->max_bucket, destp->max_bucket); 951 P_32_COPY(srcp->high_mask, destp->high_mask); 952 P_32_COPY(srcp->low_mask, destp->low_mask); 953 P_32_COPY(srcp->ffactor, destp->ffactor); 954 P_32_COPY(srcp->nkeys, destp->nkeys); 955 P_32_COPY(srcp->hdrpages, destp->hdrpages); 956 P_32_COPY(srcp->h_charkey, destp->h_charkey); 957 for (i = 0; i < NCACHED; i++) { 958 P_32_COPY(srcp->spares[i], destp->spares[i]); 959 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 960 } 961 } 962 963 static void 964 swap_header(hashp) 965 HTAB *hashp; 966 { 967 HASHHDR *hdrp; 968 int i; 969 970 hdrp = &hashp->hdr; 971 972 M_32_SWAP(hdrp->magic); 973 M_32_SWAP(hdrp->version); 974 M_32_SWAP(hdrp->lorder); 975 M_32_SWAP(hdrp->bsize); 976 M_32_SWAP(hdrp->bshift); 977 M_32_SWAP(hdrp->dsize); 978 M_32_SWAP(hdrp->ssize); 979 M_32_SWAP(hdrp->sshift); 980 M_32_SWAP(hdrp->ovfl_point); 981 M_32_SWAP(hdrp->last_freed); 982 M_32_SWAP(hdrp->max_bucket); 983 M_32_SWAP(hdrp->high_mask); 984 M_32_SWAP(hdrp->low_mask); 985 M_32_SWAP(hdrp->ffactor); 986 M_32_SWAP(hdrp->nkeys); 987 M_32_SWAP(hdrp->hdrpages); 988 M_32_SWAP(hdrp->h_charkey); 989 for (i = 0; i < NCACHED; i++) { 990 M_32_SWAP(hdrp->spares[i]); 991 M_16_SWAP(hdrp->bitmaps[i]); 992 } 993 } 994 #endif 995
Indexes created Fri Sep 26 20:09:58 GMT 2025