hash.c revision 1.12
1 /* $NetBSD: hash.c,v 1.12 1998/05/07 19:24:21 kleink Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Margo Seltzer. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 43 #else 44 __RCSID("$NetBSD: hash.c,v 1.12 1998/05/07 19:24:21 kleink Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include <sys/param.h> 49 #include <sys/stat.h> 50 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 #ifdef DEBUG 58 #include <assert.h> 59 #endif 60 61 #include <db.h> 62 #include "hash.h" 63 #include "page.h" 64 #include "extern.h" 65 66 static int alloc_segs __P((HTAB *, int)); 67 static int flush_meta __P((HTAB *)); 68 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 69 static int hash_close __P((DB *)); 70 static int hash_delete __P((const DB *, const DBT *, u_int32_t)); 71 static int hash_fd __P((const DB *)); 72 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); 73 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); 74 static void *hash_realloc __P((SEGMENT **, int, int)); 75 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); 76 static int hash_sync __P((const DB *, u_int32_t)); 77 static int hdestroy __P((HTAB *)); 78 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *)); 79 static int init_htab __P((HTAB *, int)); 80 #if BYTE_ORDER == LITTLE_ENDIAN 81 static void swap_header __P((HTAB *)); 82 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 83 #endif 84 85 /* Fast arithmetic, relying on powers of 2, */ 86 #define MOD(x, y) ((x) & ((y) - 1)) 87 88 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 89 90 /* Return values */ 91 #define SUCCESS (0) 92 #define ERROR (-1) 93 #define ABNORMAL (1) 94 95 #ifdef HASH_STATISTICS 96 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 97 #endif 98 99 /************************** INTERFACE ROUTINES ***************************/ 100 /* OPEN/CLOSE */ 101 102 extern DB * 103 __hash_open(file, flags, mode, info, dflags) 104 const char *file; 105 int flags; 106 mode_t mode; 107 const HASHINFO *info; /* Special directives for create */ 108 int dflags; 109 { 110 HTAB *hashp; 111 struct stat statbuf; 112 DB *dbp; 113 int bpages, hdrsize, new_table, nsegs, save_errno; 114 115 if ((flags & O_ACCMODE) == O_WRONLY) { 116 errno = EINVAL; 117 return (NULL); 118 } 119 120 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 121 return (NULL); 122 hashp->fp = -1; 123 124 /* 125 * Even if user wants write only, we need to be able to read 126 * the actual file, so we need to open it read/write. But, the 127 * field in the hashp structure needs to be accurate so that 128 * we can check accesses. 129 */ 130 hashp->flags = flags; 131 132 new_table = 0; 133 if (!file || (flags & O_TRUNC) || 134 (stat(file, &statbuf) && (errno == ENOENT))) { 135 if (errno == ENOENT) 136 errno = 0; /* Just in case someone looks at errno */ 137 new_table = 1; 138 } 139 if (file) { 140 if ((hashp->fp = open(file, flags, mode)) == -1) 141 RETURN_ERROR(errno, error0); 142 (void)fcntl(hashp->fp, F_SETFD, 1); 143 } 144 if (new_table) { 145 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 146 RETURN_ERROR(errno, error1); 147 } else { 148 /* Table already exists */ 149 if (info && info->hash) 150 hashp->hash = info->hash; 151 else 152 hashp->hash = __default_hash; 153 154 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 155 #if BYTE_ORDER == LITTLE_ENDIAN 156 swap_header(hashp); 157 #endif 158 if (hdrsize == -1) 159 RETURN_ERROR(errno, error1); 160 if (hdrsize != sizeof(HASHHDR)) 161 RETURN_ERROR(EFTYPE, error1); 162 /* Verify file type, versions and hash function */ 163 if (hashp->MAGIC != HASHMAGIC) 164 RETURN_ERROR(EFTYPE, error1); 165 #define OLDHASHVERSION 1 166 if (hashp->VERSION != HASHVERSION && 167 hashp->VERSION != OLDHASHVERSION) 168 RETURN_ERROR(EFTYPE, error1); 169 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 170 RETURN_ERROR(EFTYPE, error1); 171 /* 172 * Figure out how many segments we need. Max_Bucket is the 173 * maximum bucket number, so the number of buckets is 174 * max_bucket + 1. 175 */ 176 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 177 hashp->SGSIZE; 178 hashp->nsegs = 0; 179 if (alloc_segs(hashp, nsegs)) 180 /* 181 * If alloc_segs fails, table will have been destroyed 182 * and errno will have been set. 183 */ 184 return (NULL); 185 /* Read in bitmaps */ 186 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 187 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 188 (hashp->BSHIFT + BYTE_SHIFT); 189 190 hashp->nmaps = bpages; 191 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 192 } 193 194 /* Initialize Buffer Manager */ 195 if (info && info->cachesize) 196 __buf_init(hashp, info->cachesize); 197 else 198 __buf_init(hashp, DEF_BUFSIZE); 199 200 hashp->new_file = new_table; 201 hashp->save_file = file && (hashp->flags & O_RDWR); 202 hashp->cbucket = -1; 203 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 204 save_errno = errno; 205 hdestroy(hashp); 206 errno = save_errno; 207 return (NULL); 208 } 209 dbp->internal = hashp; 210 dbp->close = hash_close; 211 dbp->del = hash_delete; 212 dbp->fd = hash_fd; 213 dbp->get = hash_get; 214 dbp->put = hash_put; 215 dbp->seq = hash_seq; 216 dbp->sync = hash_sync; 217 dbp->type = DB_HASH; 218 219 #ifdef DEBUG 220 (void)fprintf(stderr, 221 "%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", 222 "init_htab:", 223 "TABLE POINTER ", hashp, 224 "BUCKET SIZE ", hashp->BSIZE, 225 "BUCKET SHIFT ", hashp->BSHIFT, 226 "DIRECTORY SIZE ", hashp->DSIZE, 227 "SEGMENT SIZE ", hashp->SGSIZE, 228 "SEGMENT SHIFT ", hashp->SSHIFT, 229 "FILL FACTOR ", hashp->FFACTOR, 230 "MAX BUCKET ", hashp->MAX_BUCKET, 231 "OVFL POINT ", hashp->OVFL_POINT, 232 "LAST FREED ", hashp->LAST_FREED, 233 "HIGH MASK ", hashp->HIGH_MASK, 234 "LOW MASK ", hashp->LOW_MASK, 235 "NSEGS ", hashp->nsegs, 236 "NKEYS ", hashp->NKEYS); 237 #endif 238 #ifdef HASH_STATISTICS 239 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 240 #endif 241 return (dbp); 242 243 error1: 244 if (hashp != NULL) 245 (void)close(hashp->fp); 246 247 error0: 248 free(hashp); 249 errno = save_errno; 250 return (NULL); 251 } 252 253 static int 254 hash_close(dbp) 255 DB *dbp; 256 { 257 HTAB *hashp; 258 int retval; 259 260 if (!dbp) 261 return (ERROR); 262 263 hashp = (HTAB *)dbp->internal; 264 retval = hdestroy(hashp); 265 free(dbp); 266 return (retval); 267 } 268 269 static int 270 hash_fd(dbp) 271 const DB *dbp; 272 { 273 HTAB *hashp; 274 275 if (!dbp) 276 return (ERROR); 277 278 hashp = (HTAB *)dbp->internal; 279 if (hashp->fp == -1) { 280 errno = ENOENT; 281 return (-1); 282 } 283 return (hashp->fp); 284 } 285 286 /************************** LOCAL CREATION ROUTINES **********************/ 287 static HTAB * 288 init_hash(hashp, file, info) 289 HTAB *hashp; 290 const char *file; 291 HASHINFO *info; 292 { 293 struct stat statbuf; 294 int nelem; 295 296 nelem = 1; 297 hashp->NKEYS = 0; 298 hashp->LORDER = BYTE_ORDER; 299 hashp->BSIZE = DEF_BUCKET_SIZE; 300 hashp->BSHIFT = DEF_BUCKET_SHIFT; 301 hashp->SGSIZE = DEF_SEGSIZE; 302 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 303 hashp->DSIZE = DEF_DIRSIZE; 304 hashp->FFACTOR = DEF_FFACTOR; 305 hashp->hash = __default_hash; 306 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 307 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 308 309 /* Fix bucket size to be optimal for file system */ 310 if (file != NULL) { 311 if (stat(file, &statbuf)) 312 return (NULL); 313 hashp->BSIZE = statbuf.st_blksize; 314 hashp->BSHIFT = __log2(hashp->BSIZE); 315 } 316 317 if (info) { 318 if (info->bsize) { 319 /* Round pagesize up to power of 2 */ 320 hashp->BSHIFT = __log2(info->bsize); 321 hashp->BSIZE = 1 << hashp->BSHIFT; 322 if (hashp->BSIZE > MAX_BSIZE) { 323 errno = EINVAL; 324 return (NULL); 325 } 326 } 327 if (info->ffactor) 328 hashp->FFACTOR = info->ffactor; 329 if (info->hash) 330 hashp->hash = info->hash; 331 if (info->nelem) 332 nelem = info->nelem; 333 if (info->lorder) { 334 if (info->lorder != BIG_ENDIAN && 335 info->lorder != LITTLE_ENDIAN) { 336 errno = EINVAL; 337 return (NULL); 338 } 339 hashp->LORDER = info->lorder; 340 } 341 } 342 /* init_htab should destroy the table and set errno if it fails */ 343 if (init_htab(hashp, nelem)) 344 return (NULL); 345 else 346 return (hashp); 347 } 348 /* 349 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 350 * the table and set errno, so we just pass the error information along. 351 * 352 * Returns 0 on No Error 353 */ 354 static int 355 init_htab(hashp, nelem) 356 HTAB *hashp; 357 int nelem; 358 { 359 register int nbuckets, 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, 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 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, 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 ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 512 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -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 *)hashp->mapp[i], 523 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 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 return (hash_access(hashp, flag == R_NOOVERWRITE ? 573 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 574 } 575 576 static int 577 hash_delete(dbp, key, flag) 578 const DB *dbp; 579 const DBT *key; 580 u_int32_t flag; /* Ignored */ 581 { 582 HTAB *hashp; 583 584 hashp = (HTAB *)dbp->internal; 585 if (flag && flag != R_CURSOR) { 586 hashp->err = errno = EINVAL; 587 return (ERROR); 588 } 589 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 590 hashp->err = errno = EPERM; 591 return (ERROR); 592 } 593 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 594 } 595 596 /* 597 * Assume that hashp has been set in wrapper routine. 598 */ 599 static int 600 hash_access(hashp, action, key, val) 601 HTAB *hashp; 602 ACTION action; 603 DBT *key, *val; 604 { 605 register BUFHEAD *rbufp; 606 BUFHEAD *bufp, *save_bufp; 607 register u_int16_t *bp; 608 register int n, ndx, off, size; 609 register char *kp; 610 u_int16_t pageno; 611 612 #ifdef HASH_STATISTICS 613 hash_accesses++; 614 #endif 615 616 off = hashp->BSIZE; 617 size = key->size; 618 kp = (char *)key->data; 619 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 620 if (!rbufp) 621 return (ERROR); 622 save_bufp = rbufp; 623 624 /* Pin the bucket chain */ 625 rbufp->flags |= BUF_PIN; 626 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 627 if (bp[1] >= REAL_KEY) { 628 /* Real key/data pair */ 629 if (size == off - *bp && 630 memcmp(kp, rbufp->page + *bp, size) == 0) 631 goto found; 632 off = bp[1]; 633 #ifdef HASH_STATISTICS 634 hash_collisions++; 635 #endif 636 bp += 2; 637 ndx += 2; 638 } else if (bp[1] == OVFLPAGE) { 639 rbufp = __get_buf(hashp, *bp, rbufp, 0); 640 if (!rbufp) { 641 save_bufp->flags &= ~BUF_PIN; 642 return (ERROR); 643 } 644 /* FOR LOOP INIT */ 645 bp = (u_int16_t *)rbufp->page; 646 n = *bp++; 647 ndx = 1; 648 off = hashp->BSIZE; 649 } else if (bp[1] < REAL_KEY) { 650 if ((ndx = 651 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 652 goto found; 653 if (ndx == -2) { 654 bufp = rbufp; 655 if (!(pageno = 656 __find_last_page(hashp, &bufp))) { 657 ndx = 0; 658 rbufp = bufp; 659 break; /* FOR */ 660 } 661 rbufp = __get_buf(hashp, pageno, bufp, 0); 662 if (!rbufp) { 663 save_bufp->flags &= ~BUF_PIN; 664 return (ERROR); 665 } 666 /* FOR LOOP INIT */ 667 bp = (u_int16_t *)rbufp->page; 668 n = *bp++; 669 ndx = 1; 670 off = hashp->BSIZE; 671 } else { 672 save_bufp->flags &= ~BUF_PIN; 673 return (ERROR); 674 } 675 } 676 677 /* Not found */ 678 switch (action) { 679 case HASH_PUT: 680 case HASH_PUTNEW: 681 if (__addel(hashp, rbufp, key, val)) { 682 save_bufp->flags &= ~BUF_PIN; 683 return (ERROR); 684 } else { 685 save_bufp->flags &= ~BUF_PIN; 686 return (SUCCESS); 687 } 688 case HASH_GET: 689 case HASH_DELETE: 690 default: 691 save_bufp->flags &= ~BUF_PIN; 692 return (ABNORMAL); 693 } 694 695 found: 696 switch (action) { 697 case HASH_PUTNEW: 698 save_bufp->flags &= ~BUF_PIN; 699 return (ABNORMAL); 700 case HASH_GET: 701 bp = (u_int16_t *)rbufp->page; 702 if (bp[ndx + 1] < REAL_KEY) { 703 if (__big_return(hashp, rbufp, ndx, val, 0)) 704 return (ERROR); 705 } else { 706 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 707 val->size = bp[ndx] - bp[ndx + 1]; 708 } 709 break; 710 case HASH_PUT: 711 if ((__delpair(hashp, rbufp, ndx)) || 712 (__addel(hashp, rbufp, key, val))) { 713 save_bufp->flags &= ~BUF_PIN; 714 return (ERROR); 715 } 716 break; 717 case HASH_DELETE: 718 if (__delpair(hashp, rbufp, ndx)) 719 return (ERROR); 720 break; 721 default: 722 abort(); 723 } 724 save_bufp->flags &= ~BUF_PIN; 725 return (SUCCESS); 726 } 727 728 static int 729 hash_seq(dbp, key, data, flag) 730 const DB *dbp; 731 DBT *key, *data; 732 u_int32_t flag; 733 { 734 register u_int32_t bucket; 735 register BUFHEAD *bufp; 736 HTAB *hashp; 737 u_int16_t *bp, ndx; 738 739 hashp = (HTAB *)dbp->internal; 740 if (flag && flag != R_FIRST && flag != R_NEXT) { 741 hashp->err = errno = EINVAL; 742 return (ERROR); 743 } 744 #ifdef HASH_STATISTICS 745 hash_accesses++; 746 #endif 747 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 748 hashp->cbucket = 0; 749 hashp->cndx = 1; 750 hashp->cpage = NULL; 751 } 752 753 for (bp = NULL; !bp || !bp[0]; ) { 754 if (!(bufp = hashp->cpage)) { 755 for (bucket = hashp->cbucket; 756 bucket <= hashp->MAX_BUCKET; 757 bucket++, hashp->cndx = 1) { 758 bufp = __get_buf(hashp, bucket, NULL, 0); 759 if (!bufp) 760 return (ERROR); 761 hashp->cpage = bufp; 762 bp = (u_int16_t *)bufp->page; 763 if (bp[0]) 764 break; 765 } 766 hashp->cbucket = bucket; 767 if (hashp->cbucket > hashp->MAX_BUCKET) { 768 hashp->cbucket = -1; 769 return (ABNORMAL); 770 } 771 } else 772 bp = (u_int16_t *)hashp->cpage->page; 773 774 #ifdef DEBUG 775 assert(bp); 776 assert(bufp); 777 #endif 778 while (bp[hashp->cndx + 1] == OVFLPAGE) { 779 bufp = hashp->cpage = 780 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 781 if (!bufp) 782 return (ERROR); 783 bp = (u_int16_t *)(bufp->page); 784 hashp->cndx = 1; 785 } 786 if (!bp[0]) { 787 hashp->cpage = NULL; 788 ++hashp->cbucket; 789 } 790 } 791 ndx = hashp->cndx; 792 if (bp[ndx + 1] < REAL_KEY) { 793 if (__big_keydata(hashp, bufp, key, data, 1)) 794 return (ERROR); 795 } else { 796 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 797 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 798 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 799 data->size = bp[ndx] - bp[ndx + 1]; 800 ndx += 2; 801 if (ndx > bp[0]) { 802 hashp->cpage = NULL; 803 hashp->cbucket++; 804 hashp->cndx = 1; 805 } else 806 hashp->cndx = ndx; 807 } 808 return (SUCCESS); 809 } 810 811 /********************************* UTILITIES ************************/ 812 813 /* 814 * Returns: 815 * 0 ==> OK 816 * -1 ==> Error 817 */ 818 extern int 819 __expand_table(hashp) 820 HTAB *hashp; 821 { 822 u_int32_t old_bucket, new_bucket; 823 int dirsize, new_segnum, spare_ndx; 824 825 #ifdef HASH_STATISTICS 826 hash_expansions++; 827 #endif 828 new_bucket = ++hashp->MAX_BUCKET; 829 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 830 831 new_segnum = new_bucket >> hashp->SSHIFT; 832 833 /* Check if we need a new segment */ 834 if (new_segnum >= hashp->nsegs) { 835 /* Check if we need to expand directory */ 836 if (new_segnum >= hashp->DSIZE) { 837 /* Reallocate directory */ 838 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 839 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 840 return (-1); 841 hashp->DSIZE = dirsize << 1; 842 } 843 if ((hashp->dir[new_segnum] = 844 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 845 return (-1); 846 hashp->exsegs++; 847 hashp->nsegs++; 848 } 849 /* 850 * If the split point is increasing (MAX_BUCKET's log base 2 851 * * increases), we need to copy the current contents of the spare 852 * split bucket to the next bucket. 853 */ 854 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 855 if (spare_ndx > hashp->OVFL_POINT) { 856 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 857 hashp->OVFL_POINT = spare_ndx; 858 } 859 860 if (new_bucket > hashp->HIGH_MASK) { 861 /* Starting a new doubling */ 862 hashp->LOW_MASK = hashp->HIGH_MASK; 863 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 864 } 865 /* Relocate records to the new bucket */ 866 return (__split_page(hashp, old_bucket, new_bucket)); 867 } 868 869 /* 870 * If realloc guarantees that the pointer is not destroyed if the realloc 871 * fails, then this routine can go away. 872 */ 873 static void * 874 hash_realloc(p_ptr, oldsize, newsize) 875 SEGMENT **p_ptr; 876 int oldsize, newsize; 877 { 878 register void *p; 879 880 if ((p = malloc(newsize)) != NULL) { 881 memmove(p, *p_ptr, oldsize); 882 memset((char *)p + oldsize, 0, newsize - oldsize); 883 free(*p_ptr); 884 *p_ptr = p; 885 } 886 return (p); 887 } 888 889 extern u_int32_t 890 __call_hash(hashp, k, len) 891 HTAB *hashp; 892 char *k; 893 int len; 894 { 895 int n, bucket; 896 897 n = hashp->hash(k, len); 898 bucket = n & hashp->HIGH_MASK; 899 if (bucket > hashp->MAX_BUCKET) 900 bucket = bucket & hashp->LOW_MASK; 901 return (bucket); 902 } 903 904 /* 905 * Allocate segment table. On error, destroy the table and set errno. 906 * 907 * Returns 0 on success 908 */ 909 static int 910 alloc_segs(hashp, nsegs) 911 HTAB *hashp; 912 int nsegs; 913 { 914 register int i; 915 register SEGMENT store; 916 917 int save_errno; 918 919 if ((hashp->dir = 920 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 921 save_errno = errno; 922 (void)hdestroy(hashp); 923 errno = save_errno; 924 return (-1); 925 } 926 /* Allocate segments */ 927 if ((store = 928 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 929 save_errno = errno; 930 (void)hdestroy(hashp); 931 errno = save_errno; 932 return (-1); 933 } 934 for (i = 0; i < nsegs; i++, hashp->nsegs++) 935 hashp->dir[i] = &store[i << hashp->SSHIFT]; 936 return (0); 937 } 938 939 #if BYTE_ORDER == LITTLE_ENDIAN 940 /* 941 * Hashp->hdr needs to be byteswapped. 942 */ 943 static void 944 swap_header_copy(srcp, destp) 945 HASHHDR *srcp, *destp; 946 { 947 int i; 948 949 P_32_COPY(srcp->magic, destp->magic); 950 P_32_COPY(srcp->version, destp->version); 951 P_32_COPY(srcp->lorder, destp->lorder); 952 P_32_COPY(srcp->bsize, destp->bsize); 953 P_32_COPY(srcp->bshift, destp->bshift); 954 P_32_COPY(srcp->dsize, destp->dsize); 955 P_32_COPY(srcp->ssize, destp->ssize); 956 P_32_COPY(srcp->sshift, destp->sshift); 957 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 958 P_32_COPY(srcp->last_freed, destp->last_freed); 959 P_32_COPY(srcp->max_bucket, destp->max_bucket); 960 P_32_COPY(srcp->high_mask, destp->high_mask); 961 P_32_COPY(srcp->low_mask, destp->low_mask); 962 P_32_COPY(srcp->ffactor, destp->ffactor); 963 P_32_COPY(srcp->nkeys, destp->nkeys); 964 P_32_COPY(srcp->hdrpages, destp->hdrpages); 965 P_32_COPY(srcp->h_charkey, destp->h_charkey); 966 for (i = 0; i < NCACHED; i++) { 967 P_32_COPY(srcp->spares[i], destp->spares[i]); 968 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 969 } 970 } 971 972 static void 973 swap_header(hashp) 974 HTAB *hashp; 975 { 976 HASHHDR *hdrp; 977 int i; 978 979 hdrp = &hashp->hdr; 980 981 M_32_SWAP(hdrp->magic); 982 M_32_SWAP(hdrp->version); 983 M_32_SWAP(hdrp->lorder); 984 M_32_SWAP(hdrp->bsize); 985 M_32_SWAP(hdrp->bshift); 986 M_32_SWAP(hdrp->dsize); 987 M_32_SWAP(hdrp->ssize); 988 M_32_SWAP(hdrp->sshift); 989 M_32_SWAP(hdrp->ovfl_point); 990 M_32_SWAP(hdrp->last_freed); 991 M_32_SWAP(hdrp->max_bucket); 992 M_32_SWAP(hdrp->high_mask); 993 M_32_SWAP(hdrp->low_mask); 994 M_32_SWAP(hdrp->ffactor); 995 M_32_SWAP(hdrp->nkeys); 996 M_32_SWAP(hdrp->hdrpages); 997 M_32_SWAP(hdrp->h_charkey); 998 for (i = 0; i < NCACHED; i++) { 999 M_32_SWAP(hdrp->spares[i]); 1000 M_16_SWAP(hdrp->bitmaps[i]); 1001 } 1002 } 1003 #endif 1004
Indexes created Thu Oct 30 16:09:53 GMT 2025