hash.c revision 1.8
1 /* $NetBSD: hash.c,v 1.8 1995/02/27 13:21:59 cgd 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 #if defined(LIBC_SCCS) && !defined(lint) 40 #if 0 41 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 42 #else 43 static char rcsid[] = "$NetBSD: hash.c,v 1.8 1995/02/27 13:21:59 cgd Exp $"; 44 #endif 45 #endif /* LIBC_SCCS and not lint */ 46 47 #include <sys/param.h> 48 #include <sys/stat.h> 49 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 #ifdef DEBUG 57 #include <assert.h> 58 #endif 59 60 #include <db.h> 61 #include "hash.h" 62 #include "page.h" 63 #include "extern.h" 64 65 static int alloc_segs __P((HTAB *, int)); 66 static int flush_meta __P((HTAB *)); 67 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 68 static int hash_close __P((DB *)); 69 static int hash_delete __P((const DB *, const DBT *, u_int32_t)); 70 static int hash_fd __P((const DB *)); 71 static int hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); 72 static int hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); 73 static void *hash_realloc __P((SEGMENT **, int, int)); 74 static int hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); 75 static int hash_sync __P((const DB *, u_int32_t)); 76 static int hdestroy __P((HTAB *)); 77 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *)); 78 static int init_htab __P((HTAB *, int)); 79 #if BYTE_ORDER == LITTLE_ENDIAN 80 static void swap_header __P((HTAB *)); 81 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 82 #endif 83 84 /* Fast arithmetic, relying on powers of 2, */ 85 #define MOD(x, y) ((x) & ((y) - 1)) 86 87 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 88 89 /* Return values */ 90 #define SUCCESS (0) 91 #define ERROR (-1) 92 #define ABNORMAL (1) 93 94 #ifdef HASH_STATISTICS 95 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 96 #endif 97 98 /************************** INTERFACE ROUTINES ***************************/ 99 /* OPEN/CLOSE */ 100 101 extern DB * 102 __hash_open(file, flags, mode, info, dflags) 103 const char *file; 104 int flags, mode, dflags; 105 const HASHINFO *info; /* Special directives for create */ 106 { 107 HTAB *hashp; 108 struct stat statbuf; 109 DB *dbp; 110 int bpages, hdrsize, new_table, nsegs, save_errno; 111 112 if ((flags & O_ACCMODE) == O_WRONLY) { 113 errno = EINVAL; 114 return (NULL); 115 } 116 117 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 118 return (NULL); 119 hashp->fp = -1; 120 121 /* 122 * Even if user wants write only, we need to be able to read 123 * the actual file, so we need to open it read/write. But, the 124 * field in the hashp structure needs to be accurate so that 125 * we can check accesses. 126 */ 127 hashp->flags = flags; 128 129 new_table = 0; 130 if (!file || (flags & O_TRUNC) || 131 (stat(file, &statbuf) && (errno == ENOENT))) { 132 if (errno == ENOENT) 133 errno = 0; /* Just in case someone looks at errno */ 134 new_table = 1; 135 } 136 if (file) { 137 if ((hashp->fp = open(file, flags, mode)) == -1) 138 RETURN_ERROR(errno, error0); 139 (void)fcntl(hashp->fp, F_SETFD, 1); 140 } 141 if (new_table) { 142 if (!(hashp = init_hash(hashp, file, (HASHINFO *)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 (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 = (DB *)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%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", 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(dbp) 252 DB *dbp; 253 { 254 HTAB *hashp; 255 int retval; 256 257 if (!dbp) 258 return (ERROR); 259 260 hashp = (HTAB *)dbp->internal; 261 retval = hdestroy(hashp); 262 free(dbp); 263 return (retval); 264 } 265 266 static int 267 hash_fd(dbp) 268 const DB *dbp; 269 { 270 HTAB *hashp; 271 272 if (!dbp) 273 return (ERROR); 274 275 hashp = (HTAB *)dbp->internal; 276 if (hashp->fp == -1) { 277 errno = ENOENT; 278 return (-1); 279 } 280 return (hashp->fp); 281 } 282 283 /************************** LOCAL CREATION ROUTINES **********************/ 284 static HTAB * 285 init_hash(hashp, file, info) 286 HTAB *hashp; 287 const char *file; 288 HASHINFO *info; 289 { 290 struct stat statbuf; 291 int nelem; 292 293 nelem = 1; 294 hashp->NKEYS = 0; 295 hashp->LORDER = BYTE_ORDER; 296 hashp->BSIZE = DEF_BUCKET_SIZE; 297 hashp->BSHIFT = DEF_BUCKET_SHIFT; 298 hashp->SGSIZE = DEF_SEGSIZE; 299 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 300 hashp->DSIZE = DEF_DIRSIZE; 301 hashp->FFACTOR = DEF_FFACTOR; 302 hashp->hash = __default_hash; 303 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 304 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 305 306 /* Fix bucket size to be optimal for file system */ 307 if (file != NULL) { 308 if (stat(file, &statbuf)) 309 return (NULL); 310 hashp->BSIZE = statbuf.st_blksize; 311 hashp->BSHIFT = __log2(hashp->BSIZE); 312 } 313 314 if (info) { 315 if (info->bsize) { 316 /* Round pagesize up to power of 2 */ 317 hashp->BSHIFT = __log2(info->bsize); 318 hashp->BSIZE = 1 << hashp->BSHIFT; 319 if (hashp->BSIZE > MAX_BSIZE) { 320 errno = EINVAL; 321 return (NULL); 322 } 323 } 324 if (info->ffactor) 325 hashp->FFACTOR = info->ffactor; 326 if (info->hash) 327 hashp->hash = info->hash; 328 if (info->nelem) 329 nelem = info->nelem; 330 if (info->lorder) { 331 if (info->lorder != BIG_ENDIAN && 332 info->lorder != LITTLE_ENDIAN) { 333 errno = EINVAL; 334 return (NULL); 335 } 336 hashp->LORDER = info->lorder; 337 } 338 } 339 /* init_htab should destroy the table and set errno if it fails */ 340 if (init_htab(hashp, nelem)) 341 return (NULL); 342 else 343 return (hashp); 344 } 345 /* 346 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 347 * the table and set errno, so we just pass the error information along. 348 * 349 * Returns 0 on No Error 350 */ 351 static int 352 init_htab(hashp, nelem) 353 HTAB *hashp; 354 int nelem; 355 { 356 register int nbuckets, nsegs; 357 int l2; 358 359 /* 360 * Divide number of elements by the fill factor and determine a 361 * desired number of buckets. Allocate space for the next greater 362 * power of two number of buckets. 363 */ 364 nelem = (nelem - 1) / hashp->FFACTOR + 1; 365 366 l2 = __log2(MAX(nelem, 2)); 367 nbuckets = 1 << l2; 368 369 hashp->SPARES[l2] = l2 + 1; 370 hashp->SPARES[l2 + 1] = l2 + 1; 371 hashp->OVFL_POINT = l2; 372 hashp->LAST_FREED = 2; 373 374 /* First bitmap page is at: splitpoint l2 page offset 1 */ 375 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 376 return (-1); 377 378 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 379 hashp->HIGH_MASK = (nbuckets << 1) - 1; 380 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 381 hashp->BSHIFT) + 1; 382 383 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 384 nsegs = 1 << __log2(nsegs); 385 386 if (nsegs > hashp->DSIZE) 387 hashp->DSIZE = nsegs; 388 return (alloc_segs(hashp, nsegs)); 389 } 390 391 /********************** DESTROY/CLOSE ROUTINES ************************/ 392 393 /* 394 * Flushes any changes to the file if necessary and destroys the hashp 395 * structure, freeing all allocated space. 396 */ 397 static int 398 hdestroy(hashp) 399 HTAB *hashp; 400 { 401 int i, save_errno; 402 403 save_errno = 0; 404 405 #ifdef HASH_STATISTICS 406 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 407 hash_accesses, hash_collisions); 408 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 409 hash_expansions); 410 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 411 hash_overflows); 412 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 413 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 414 415 for (i = 0; i < NCACHED; i++) 416 (void)fprintf(stderr, 417 "spares[%d] = %d\n", i, hashp->SPARES[i]); 418 #endif 419 /* 420 * Call on buffer manager to free buffers, and if required, 421 * write them to disk. 422 */ 423 if (__buf_free(hashp, 1, hashp->save_file)) 424 save_errno = errno; 425 if (hashp->dir) { 426 free(*hashp->dir); /* Free initial segments */ 427 /* Free extra segments */ 428 while (hashp->exsegs--) 429 free(hashp->dir[--hashp->nsegs]); 430 free(hashp->dir); 431 } 432 if (flush_meta(hashp) && !save_errno) 433 save_errno = errno; 434 /* Free Bigmaps */ 435 for (i = 0; i < hashp->nmaps; i++) 436 if (hashp->mapp[i]) 437 free(hashp->mapp[i]); 438 439 if (hashp->fp != -1) 440 (void)close(hashp->fp); 441 442 free(hashp); 443 444 if (save_errno) { 445 errno = save_errno; 446 return (ERROR); 447 } 448 return (SUCCESS); 449 } 450 /* 451 * Write modified pages to disk 452 * 453 * Returns: 454 * 0 == OK 455 * -1 ERROR 456 */ 457 static int 458 hash_sync(dbp, flags) 459 const DB *dbp; 460 u_int32_t flags; 461 { 462 HTAB *hashp; 463 464 if (flags != 0) { 465 errno = EINVAL; 466 return (ERROR); 467 } 468 469 if (!dbp) 470 return (ERROR); 471 472 hashp = (HTAB *)dbp->internal; 473 if (!hashp->save_file) 474 return (0); 475 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 476 return (ERROR); 477 hashp->new_file = 0; 478 return (0); 479 } 480 481 /* 482 * Returns: 483 * 0 == OK 484 * -1 indicates that errno should be set 485 */ 486 static int 487 flush_meta(hashp) 488 HTAB *hashp; 489 { 490 HASHHDR *whdrp; 491 #if BYTE_ORDER == LITTLE_ENDIAN 492 HASHHDR whdr; 493 #endif 494 int fp, i, wsize; 495 496 if (!hashp->save_file) 497 return (0); 498 hashp->MAGIC = HASHMAGIC; 499 hashp->VERSION = HASHVERSION; 500 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 501 502 fp = hashp->fp; 503 whdrp = &hashp->hdr; 504 #if BYTE_ORDER == LITTLE_ENDIAN 505 whdrp = &whdr; 506 swap_header_copy(&hashp->hdr, whdrp); 507 #endif 508 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 509 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 510 return (-1); 511 else 512 if (wsize != sizeof(HASHHDR)) { 513 errno = EFTYPE; 514 hashp->errno = errno; 515 return (-1); 516 } 517 for (i = 0; i < NCACHED; i++) 518 if (hashp->mapp[i]) 519 if (__put_page(hashp, (char *)hashp->mapp[i], 520 hashp->BITMAPS[i], 0, 1)) 521 return (-1); 522 return (0); 523 } 524 525 /*******************************SEARCH ROUTINES *****************************/ 526 /* 527 * All the access routines return 528 * 529 * Returns: 530 * 0 on SUCCESS 531 * 1 to indicate an external ERROR (i.e. key not found, etc) 532 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 533 */ 534 static int 535 hash_get(dbp, key, data, flag) 536 const DB *dbp; 537 const DBT *key; 538 DBT *data; 539 u_int32_t flag; 540 { 541 HTAB *hashp; 542 543 hashp = (HTAB *)dbp->internal; 544 if (flag) { 545 hashp->errno = errno = EINVAL; 546 return (ERROR); 547 } 548 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 549 } 550 551 static int 552 hash_put(dbp, key, data, flag) 553 const DB *dbp; 554 DBT *key; 555 const DBT *data; 556 u_int32_t flag; 557 { 558 HTAB *hashp; 559 560 hashp = (HTAB *)dbp->internal; 561 if (flag && flag != R_NOOVERWRITE) { 562 hashp->errno = errno = EINVAL; 563 return (ERROR); 564 } 565 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 566 hashp->errno = errno = EPERM; 567 return (ERROR); 568 } 569 return (hash_access(hashp, flag == R_NOOVERWRITE ? 570 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 571 } 572 573 static int 574 hash_delete(dbp, key, flag) 575 const DB *dbp; 576 const DBT *key; 577 u_int32_t flag; /* Ignored */ 578 { 579 HTAB *hashp; 580 581 hashp = (HTAB *)dbp->internal; 582 if (flag && flag != R_CURSOR) { 583 hashp->errno = errno = EINVAL; 584 return (ERROR); 585 } 586 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 587 hashp->errno = errno = EPERM; 588 return (ERROR); 589 } 590 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 591 } 592 593 /* 594 * Assume that hashp has been set in wrapper routine. 595 */ 596 static int 597 hash_access(hashp, action, key, val) 598 HTAB *hashp; 599 ACTION action; 600 DBT *key, *val; 601 { 602 register BUFHEAD *rbufp; 603 BUFHEAD *bufp, *save_bufp; 604 register u_int16_t *bp; 605 register int n, ndx, off, size; 606 register char *kp; 607 u_int16_t pageno; 608 609 #ifdef HASH_STATISTICS 610 hash_accesses++; 611 #endif 612 613 off = hashp->BSIZE; 614 size = key->size; 615 kp = (char *)key->data; 616 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 617 if (!rbufp) 618 return (ERROR); 619 save_bufp = rbufp; 620 621 /* Pin the bucket chain */ 622 rbufp->flags |= BUF_PIN; 623 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 624 if (bp[1] >= REAL_KEY) { 625 /* Real key/data pair */ 626 if (size == off - *bp && 627 memcmp(kp, rbufp->page + *bp, size) == 0) 628 goto found; 629 off = bp[1]; 630 #ifdef HASH_STATISTICS 631 hash_collisions++; 632 #endif 633 bp += 2; 634 ndx += 2; 635 } else if (bp[1] == OVFLPAGE) { 636 rbufp = __get_buf(hashp, *bp, rbufp, 0); 637 if (!rbufp) { 638 save_bufp->flags &= ~BUF_PIN; 639 return (ERROR); 640 } 641 /* FOR LOOP INIT */ 642 bp = (u_int16_t *)rbufp->page; 643 n = *bp++; 644 ndx = 1; 645 off = hashp->BSIZE; 646 } else if (bp[1] < REAL_KEY) { 647 if ((ndx = 648 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 649 goto found; 650 if (ndx == -2) { 651 bufp = rbufp; 652 if (!(pageno = 653 __find_last_page(hashp, &bufp))) { 654 ndx = 0; 655 rbufp = bufp; 656 break; /* FOR */ 657 } 658 rbufp = __get_buf(hashp, pageno, bufp, 0); 659 if (!rbufp) { 660 save_bufp->flags &= ~BUF_PIN; 661 return (ERROR); 662 } 663 /* FOR LOOP INIT */ 664 bp = (u_int16_t *)rbufp->page; 665 n = *bp++; 666 ndx = 1; 667 off = hashp->BSIZE; 668 } else { 669 save_bufp->flags &= ~BUF_PIN; 670 return (ERROR); 671 } 672 } 673 674 /* Not found */ 675 switch (action) { 676 case HASH_PUT: 677 case HASH_PUTNEW: 678 if (__addel(hashp, rbufp, key, val)) { 679 save_bufp->flags &= ~BUF_PIN; 680 return (ERROR); 681 } else { 682 save_bufp->flags &= ~BUF_PIN; 683 return (SUCCESS); 684 } 685 case HASH_GET: 686 case HASH_DELETE: 687 default: 688 save_bufp->flags &= ~BUF_PIN; 689 return (ABNORMAL); 690 } 691 692 found: 693 switch (action) { 694 case HASH_PUTNEW: 695 save_bufp->flags &= ~BUF_PIN; 696 return (ABNORMAL); 697 case HASH_GET: 698 bp = (u_int16_t *)rbufp->page; 699 if (bp[ndx + 1] < REAL_KEY) { 700 if (__big_return(hashp, rbufp, ndx, val, 0)) 701 return (ERROR); 702 } else { 703 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 704 val->size = bp[ndx] - bp[ndx + 1]; 705 } 706 break; 707 case HASH_PUT: 708 if ((__delpair(hashp, rbufp, ndx)) || 709 (__addel(hashp, rbufp, key, val))) { 710 save_bufp->flags &= ~BUF_PIN; 711 return (ERROR); 712 } 713 break; 714 case HASH_DELETE: 715 if (__delpair(hashp, rbufp, ndx)) 716 return (ERROR); 717 break; 718 default: 719 abort(); 720 } 721 save_bufp->flags &= ~BUF_PIN; 722 return (SUCCESS); 723 } 724 725 static int 726 hash_seq(dbp, key, data, flag) 727 const DB *dbp; 728 DBT *key, *data; 729 u_int32_t flag; 730 { 731 register u_int32_t bucket; 732 register BUFHEAD *bufp; 733 HTAB *hashp; 734 u_int16_t *bp, ndx; 735 736 hashp = (HTAB *)dbp->internal; 737 if (flag && flag != R_FIRST && flag != R_NEXT) { 738 hashp->errno = errno = EINVAL; 739 return (ERROR); 740 } 741 #ifdef HASH_STATISTICS 742 hash_accesses++; 743 #endif 744 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 745 hashp->cbucket = 0; 746 hashp->cndx = 1; 747 hashp->cpage = NULL; 748 } 749 750 for (bp = NULL; !bp || !bp[0]; ) { 751 if (!(bufp = hashp->cpage)) { 752 for (bucket = hashp->cbucket; 753 bucket <= hashp->MAX_BUCKET; 754 bucket++, hashp->cndx = 1) { 755 bufp = __get_buf(hashp, bucket, NULL, 0); 756 if (!bufp) 757 return (ERROR); 758 hashp->cpage = bufp; 759 bp = (u_int16_t *)bufp->page; 760 if (bp[0]) 761 break; 762 } 763 hashp->cbucket = bucket; 764 if (hashp->cbucket > hashp->MAX_BUCKET) { 765 hashp->cbucket = -1; 766 return (ABNORMAL); 767 } 768 } else 769 bp = (u_int16_t *)hashp->cpage->page; 770 771 #ifdef DEBUG 772 assert(bp); 773 assert(bufp); 774 #endif 775 while (bp[hashp->cndx + 1] == OVFLPAGE) { 776 bufp = hashp->cpage = 777 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 778 if (!bufp) 779 return (ERROR); 780 bp = (u_int16_t *)(bufp->page); 781 hashp->cndx = 1; 782 } 783 if (!bp[0]) { 784 hashp->cpage = NULL; 785 ++hashp->cbucket; 786 } 787 } 788 ndx = hashp->cndx; 789 if (bp[ndx + 1] < REAL_KEY) { 790 if (__big_keydata(hashp, bufp, key, data, 1)) 791 return (ERROR); 792 } else { 793 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 794 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 795 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 796 data->size = bp[ndx] - bp[ndx + 1]; 797 ndx += 2; 798 if (ndx > bp[0]) { 799 hashp->cpage = NULL; 800 hashp->cbucket++; 801 hashp->cndx = 1; 802 } else 803 hashp->cndx = ndx; 804 } 805 return (SUCCESS); 806 } 807 808 /********************************* UTILITIES ************************/ 809 810 /* 811 * Returns: 812 * 0 ==> OK 813 * -1 ==> Error 814 */ 815 extern int 816 __expand_table(hashp) 817 HTAB *hashp; 818 { 819 u_int32_t old_bucket, new_bucket; 820 int dirsize, new_segnum, spare_ndx; 821 822 #ifdef HASH_STATISTICS 823 hash_expansions++; 824 #endif 825 new_bucket = ++hashp->MAX_BUCKET; 826 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 827 828 new_segnum = new_bucket >> hashp->SSHIFT; 829 830 /* Check if we need a new segment */ 831 if (new_segnum >= hashp->nsegs) { 832 /* Check if we need to expand directory */ 833 if (new_segnum >= hashp->DSIZE) { 834 /* Reallocate directory */ 835 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 836 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 837 return (-1); 838 hashp->DSIZE = dirsize << 1; 839 } 840 if ((hashp->dir[new_segnum] = 841 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 842 return (-1); 843 hashp->exsegs++; 844 hashp->nsegs++; 845 } 846 /* 847 * If the split point is increasing (MAX_BUCKET's log base 2 848 * * increases), we need to copy the current contents of the spare 849 * split bucket to the next bucket. 850 */ 851 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 852 if (spare_ndx > hashp->OVFL_POINT) { 853 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 854 hashp->OVFL_POINT = spare_ndx; 855 } 856 857 if (new_bucket > hashp->HIGH_MASK) { 858 /* Starting a new doubling */ 859 hashp->LOW_MASK = hashp->HIGH_MASK; 860 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 861 } 862 /* Relocate records to the new bucket */ 863 return (__split_page(hashp, old_bucket, new_bucket)); 864 } 865 866 /* 867 * If realloc guarantees that the pointer is not destroyed if the realloc 868 * fails, then this routine can go away. 869 */ 870 static void * 871 hash_realloc(p_ptr, oldsize, newsize) 872 SEGMENT **p_ptr; 873 int oldsize, newsize; 874 { 875 register void *p; 876 877 if (p = malloc(newsize)) { 878 memmove(p, *p_ptr, oldsize); 879 memset((char *)p + oldsize, 0, newsize - oldsize); 880 free(*p_ptr); 881 *p_ptr = p; 882 } 883 return (p); 884 } 885 886 extern u_int32_t 887 __call_hash(hashp, k, len) 888 HTAB *hashp; 889 char *k; 890 int len; 891 { 892 int n, bucket; 893 894 n = hashp->hash(k, len); 895 bucket = n & hashp->HIGH_MASK; 896 if (bucket > hashp->MAX_BUCKET) 897 bucket = bucket & hashp->LOW_MASK; 898 return (bucket); 899 } 900 901 /* 902 * Allocate segment table. On error, destroy the table and set errno. 903 * 904 * Returns 0 on success 905 */ 906 static int 907 alloc_segs(hashp, nsegs) 908 HTAB *hashp; 909 int nsegs; 910 { 911 register int i; 912 register SEGMENT store; 913 914 int save_errno; 915 916 if ((hashp->dir = 917 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 918 save_errno = errno; 919 (void)hdestroy(hashp); 920 errno = save_errno; 921 return (-1); 922 } 923 /* Allocate segments */ 924 if ((store = 925 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 926 save_errno = errno; 927 (void)hdestroy(hashp); 928 errno = save_errno; 929 return (-1); 930 } 931 for (i = 0; i < nsegs; i++, hashp->nsegs++) 932 hashp->dir[i] = &store[i << hashp->SSHIFT]; 933 return (0); 934 } 935 936 #if BYTE_ORDER == LITTLE_ENDIAN 937 /* 938 * Hashp->hdr needs to be byteswapped. 939 */ 940 static void 941 swap_header_copy(srcp, destp) 942 HASHHDR *srcp, *destp; 943 { 944 int i; 945 946 P_32_COPY(srcp->magic, destp->magic); 947 P_32_COPY(srcp->version, destp->version); 948 P_32_COPY(srcp->lorder, destp->lorder); 949 P_32_COPY(srcp->bsize, destp->bsize); 950 P_32_COPY(srcp->bshift, destp->bshift); 951 P_32_COPY(srcp->dsize, destp->dsize); 952 P_32_COPY(srcp->ssize, destp->ssize); 953 P_32_COPY(srcp->sshift, destp->sshift); 954 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 955 P_32_COPY(srcp->last_freed, destp->last_freed); 956 P_32_COPY(srcp->max_bucket, destp->max_bucket); 957 P_32_COPY(srcp->high_mask, destp->high_mask); 958 P_32_COPY(srcp->low_mask, destp->low_mask); 959 P_32_COPY(srcp->ffactor, destp->ffactor); 960 P_32_COPY(srcp->nkeys, destp->nkeys); 961 P_32_COPY(srcp->hdrpages, destp->hdrpages); 962 P_32_COPY(srcp->h_charkey, destp->h_charkey); 963 for (i = 0; i < NCACHED; i++) { 964 P_32_COPY(srcp->spares[i], destp->spares[i]); 965 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 966 } 967 } 968 969 static void 970 swap_header(hashp) 971 HTAB *hashp; 972 { 973 HASHHDR *hdrp; 974 int i; 975 976 hdrp = &hashp->hdr; 977 978 M_32_SWAP(hdrp->magic); 979 M_32_SWAP(hdrp->version); 980 M_32_SWAP(hdrp->lorder); 981 M_32_SWAP(hdrp->bsize); 982 M_32_SWAP(hdrp->bshift); 983 M_32_SWAP(hdrp->dsize); 984 M_32_SWAP(hdrp->ssize); 985 M_32_SWAP(hdrp->sshift); 986 M_32_SWAP(hdrp->ovfl_point); 987 M_32_SWAP(hdrp->last_freed); 988 M_32_SWAP(hdrp->max_bucket); 989 M_32_SWAP(hdrp->high_mask); 990 M_32_SWAP(hdrp->low_mask); 991 M_32_SWAP(hdrp->ffactor); 992 M_32_SWAP(hdrp->nkeys); 993 M_32_SWAP(hdrp->hdrpages); 994 M_32_SWAP(hdrp->h_charkey); 995 for (i = 0; i < NCACHED; i++) { 996 M_32_SWAP(hdrp->spares[i]); 997 M_16_SWAP(hdrp->bitmaps[i]); 998 } 999 } 1000 #endif 1001
Indexes created Fri Sep 26 20:09:58 GMT 2025