1 /*- 2 * Copyright (c) 1990, 1993 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 * %sccs.include.redist.c% 9 */ 10 11 #if defined(LIBC_SCCS) && !defined(lint) 12 static char sccsid[] = "@(#)hash.c 8.4 (Berkeley) 10/12/93"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <sys/param.h> 16 #include <sys/stat.h> 17 18 #include <errno.h> 19 #include <fcntl.h> 20 #include <stdio.h> 21 #include <stdlib.h> 22 #include <string.h> 23 #include <unistd.h> 24 #ifdef DEBUG 25 #include <assert.h> 26 #endif 27 28 #include <db.h> 29 #include "hash.h" 30 #include "page.h" 31 #include "extern.h" 32 33 static int alloc_segs __P((HTAB *, int)); 34 static int flush_meta __P((HTAB *)); 35 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 36 static int hash_close __P((DB *)); 37 static int hash_delete __P((const DB *, const DBT *, u_int)); 38 static int hash_fd __P((const DB *)); 39 static int hash_get __P((const DB *, const DBT *, DBT *, u_int)); 40 static int hash_put __P((const DB *, DBT *, const DBT *, u_int)); 41 static void *hash_realloc __P((SEGMENT **, int, int)); 42 static int hash_seq __P((const DB *, DBT *, DBT *, u_int)); 43 static int hash_sync __P((const DB *, u_int)); 44 static int hdestroy __P((HTAB *)); 45 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *)); 46 static int init_htab __P((HTAB *, int)); 47 #if BYTE_ORDER == LITTLE_ENDIAN 48 static void swap_header __P((HTAB *)); 49 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 50 #endif 51 52 /* Fast arithmetic, relying on powers of 2, */ 53 #define MOD(x, y) ((x) & ((y) - 1)) 54 55 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 56 57 /* Return values */ 58 #define SUCCESS (0) 59 #define ERROR (-1) 60 #define ABNORMAL (1) 61 62 #ifdef HASH_STATISTICS 63 long hash_accesses, hash_collisions, hash_expansions, hash_overflows; 64 #endif 65 66 /************************** INTERFACE ROUTINES ***************************/ 67 /* OPEN/CLOSE */ 68 69 extern DB * 70 __hash_open(file, flags, mode, info, dflags) 71 const char *file; 72 int flags, mode, dflags; 73 const HASHINFO *info; /* Special directives for create */ 74 { 75 HTAB *hashp; 76 struct stat statbuf; 77 DB *dbp; 78 int bpages, hdrsize, new_table, nsegs, save_errno; 79 80 if ((flags & O_ACCMODE) == O_WRONLY) { 81 errno = EINVAL; 82 return (NULL); 83 } 84 85 if (!(hashp = calloc(1, sizeof(HTAB)))) 86 return (NULL); 87 hashp->fp = -1; 88 89 /* 90 * Even if user wants write only, we need to be able to read 91 * the actual file, so we need to open it read/write. But, the 92 * field in the hashp structure needs to be accurate so that 93 * we can check accesses. 94 */ 95 hashp->flags = flags; 96 97 new_table = 0; 98 if (!file || (flags & O_TRUNC) || 99 (stat(file, &statbuf) && (errno == ENOENT))) { 100 if (errno == ENOENT) 101 errno = 0; /* Just in case someone looks at errno */ 102 new_table = 1; 103 } 104 if (file) { 105 if ((hashp->fp = open(file, flags, mode)) == -1) 106 RETURN_ERROR(errno, error0); 107 (void)fcntl(hashp->fp, F_SETFD, 1); 108 } 109 if (new_table) { 110 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 111 RETURN_ERROR(errno, error1); 112 } else { 113 /* Table already exists */ 114 if (info && info->hash) 115 hashp->hash = info->hash; 116 else 117 hashp->hash = __default_hash; 118 119 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 120 #if BYTE_ORDER == LITTLE_ENDIAN 121 swap_header(hashp); 122 #endif 123 if (hdrsize == -1) 124 RETURN_ERROR(errno, error1); 125 if (hdrsize != sizeof(HASHHDR)) 126 RETURN_ERROR(EFTYPE, error1); 127 /* Verify file type, versions and hash function */ 128 if (hashp->MAGIC != HASHMAGIC) 129 RETURN_ERROR(EFTYPE, error1); 130 #define OLDHASHVERSION 1 131 if (hashp->VERSION != HASHVERSION && 132 hashp->VERSION != OLDHASHVERSION) 133 RETURN_ERROR(EFTYPE, error1); 134 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 135 RETURN_ERROR(EFTYPE, error1); 136 /* 137 * Figure out how many segments we need. Max_Bucket is the 138 * maximum bucket number, so the number of buckets is 139 * max_bucket + 1. 140 */ 141 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 142 hashp->SGSIZE; 143 hashp->nsegs = 0; 144 if (alloc_segs(hashp, nsegs)) 145 /* 146 * If alloc_segs fails, table will have been destroyed 147 * and errno will have been set. 148 */ 149 return (NULL); 150 /* Read in bitmaps */ 151 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 152 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 153 (hashp->BSHIFT + BYTE_SHIFT); 154 155 hashp->nmaps = bpages; 156 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_long *)); 157 } 158 159 /* Initialize Buffer Manager */ 160 if (info && info->cachesize) 161 __buf_init(hashp, info->cachesize); 162 else 163 __buf_init(hashp, DEF_BUFSIZE); 164 165 hashp->new_file = new_table; 166 hashp->save_file = file && (hashp->flags & O_RDWR); 167 hashp->cbucket = -1; 168 if (!(dbp = malloc(sizeof(DB)))) { 169 save_errno = errno; 170 hdestroy(hashp); 171 errno = save_errno; 172 return (NULL); 173 } 174 dbp->internal = hashp; 175 dbp->close = hash_close; 176 dbp->del = hash_delete; 177 dbp->fd = hash_fd; 178 dbp->get = hash_get; 179 dbp->put = hash_put; 180 dbp->seq = hash_seq; 181 dbp->sync = hash_sync; 182 dbp->type = DB_HASH; 183 184 #ifdef DEBUG 185 (void)fprintf(stderr, 186 "%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", 187 "init_htab:", 188 "TABLE POINTER ", hashp, 189 "BUCKET SIZE ", hashp->BSIZE, 190 "BUCKET SHIFT ", hashp->BSHIFT, 191 "DIRECTORY SIZE ", hashp->DSIZE, 192 "SEGMENT SIZE ", hashp->SGSIZE, 193 "SEGMENT SHIFT ", hashp->SSHIFT, 194 "FILL FACTOR ", hashp->FFACTOR, 195 "MAX BUCKET ", hashp->MAX_BUCKET, 196 "OVFL POINT ", hashp->OVFL_POINT, 197 "LAST FREED ", hashp->LAST_FREED, 198 "HIGH MASK ", hashp->HIGH_MASK, 199 "LOW MASK ", hashp->LOW_MASK, 200 "NSEGS ", hashp->nsegs, 201 "NKEYS ", hashp->NKEYS); 202 #endif 203 #ifdef HASH_STATISTICS 204 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 205 #endif 206 return (dbp); 207 208 error1: 209 if (hashp != NULL) 210 (void)close(hashp->fp); 211 212 error0: 213 free(hashp); 214 errno = save_errno; 215 return (NULL); 216 } 217 218 static int 219 hash_close(dbp) 220 DB *dbp; 221 { 222 HTAB *hashp; 223 int retval; 224 225 if (!dbp) 226 return (ERROR); 227 228 hashp = (HTAB *)dbp->internal; 229 retval = hdestroy(hashp); 230 free(dbp); 231 return (retval); 232 } 233 234 static int 235 hash_fd(dbp) 236 const DB *dbp; 237 { 238 HTAB *hashp; 239 240 if (!dbp) 241 return (ERROR); 242 243 hashp = (HTAB *)dbp->internal; 244 if (hashp->fp == -1) { 245 errno = ENOENT; 246 return (-1); 247 } 248 return (hashp->fp); 249 } 250 251 /************************** LOCAL CREATION ROUTINES **********************/ 252 static HTAB * 253 init_hash(hashp, file, info) 254 HTAB *hashp; 255 const char *file; 256 HASHINFO *info; 257 { 258 struct stat statbuf; 259 int nelem; 260 261 nelem = 1; 262 hashp->NKEYS = 0; 263 hashp->LORDER = BYTE_ORDER; 264 hashp->BSIZE = DEF_BUCKET_SIZE; 265 hashp->BSHIFT = DEF_BUCKET_SHIFT; 266 hashp->SGSIZE = DEF_SEGSIZE; 267 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 268 hashp->DSIZE = DEF_DIRSIZE; 269 hashp->FFACTOR = DEF_FFACTOR; 270 hashp->hash = __default_hash; 271 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 272 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 273 274 /* Fix bucket size to be optimal for file system */ 275 if (file != NULL) { 276 if (stat(file, &statbuf)) 277 return (NULL); 278 hashp->BSIZE = statbuf.st_blksize; 279 hashp->BSHIFT = __log2(hashp->BSIZE); 280 } 281 282 if (info) { 283 if (info->bsize) { 284 /* Round pagesize up to power of 2 */ 285 hashp->BSHIFT = __log2(info->bsize); 286 hashp->BSIZE = 1 << hashp->BSHIFT; 287 if (hashp->BSIZE > MAX_BSIZE) { 288 errno = EINVAL; 289 return (NULL); 290 } 291 } 292 if (info->ffactor) 293 hashp->FFACTOR = info->ffactor; 294 if (info->hash) 295 hashp->hash = info->hash; 296 if (info->nelem) 297 nelem = info->nelem; 298 if (info->lorder) { 299 if (info->lorder != BIG_ENDIAN && 300 info->lorder != LITTLE_ENDIAN) { 301 errno = EINVAL; 302 return (NULL); 303 } 304 hashp->LORDER = info->lorder; 305 } 306 } 307 /* init_htab should destroy the table and set errno if it fails */ 308 if (init_htab(hashp, nelem)) 309 return (NULL); 310 else 311 return (hashp); 312 } 313 /* 314 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 315 * the table and set errno, so we just pass the error information along. 316 * 317 * Returns 0 on No Error 318 */ 319 static int 320 init_htab(hashp, nelem) 321 HTAB *hashp; 322 int nelem; 323 { 324 register int nbuckets, nsegs; 325 int l2; 326 327 /* 328 * Divide number of elements by the fill factor and determine a 329 * desired number of buckets. Allocate space for the next greater 330 * power of two number of buckets. 331 */ 332 nelem = (nelem - 1) / hashp->FFACTOR + 1; 333 334 l2 = __log2(MAX(nelem, 2)); 335 nbuckets = 1 << l2; 336 337 hashp->SPARES[l2] = l2 + 1; 338 hashp->SPARES[l2 + 1] = l2 + 1; 339 hashp->OVFL_POINT = l2; 340 hashp->LAST_FREED = 2; 341 342 /* First bitmap page is at: splitpoint l2 page offset 1 */ 343 if (__init_bitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 344 return (-1); 345 346 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 347 hashp->HIGH_MASK = (nbuckets << 1) - 1; 348 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 349 hashp->BSHIFT) + 1; 350 351 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 352 nsegs = 1 << __log2(nsegs); 353 354 if (nsegs > hashp->DSIZE) 355 hashp->DSIZE = nsegs; 356 return (alloc_segs(hashp, nsegs)); 357 } 358 359 /********************** DESTROY/CLOSE ROUTINES ************************/ 360 361 /* 362 * Flushes any changes to the file if necessary and destroys the hashp 363 * structure, freeing all allocated space. 364 */ 365 static int 366 hdestroy(hashp) 367 HTAB *hashp; 368 { 369 int i, save_errno; 370 371 save_errno = 0; 372 373 #ifdef HASH_STATISTICS 374 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 375 hash_accesses, hash_collisions); 376 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 377 hash_expansions); 378 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 379 hash_overflows); 380 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 381 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 382 383 for (i = 0; i < NCACHED; i++) 384 (void)fprintf(stderr, 385 "spares[%d] = %d\n", i, hashp->SPARES[i]); 386 #endif 387 /* 388 * Call on buffer manager to free buffers, and if required, 389 * write them to disk. 390 */ 391 if (__buf_free(hashp, 1, hashp->save_file)) 392 save_errno = errno; 393 if (hashp->dir) { 394 free(*hashp->dir); /* Free initial segments */ 395 /* Free extra segments */ 396 while (hashp->exsegs--) 397 free(hashp->dir[--hashp->nsegs]); 398 free(hashp->dir); 399 } 400 if (flush_meta(hashp) && !save_errno) 401 save_errno = errno; 402 /* Free Bigmaps */ 403 for (i = 0; i < hashp->nmaps; i++) 404 if (hashp->mapp[i]) 405 free(hashp->mapp[i]); 406 407 if (hashp->fp != -1) 408 (void)close(hashp->fp); 409 410 if (save_errno) { 411 errno = save_errno; 412 return (ERROR); 413 } 414 return (SUCCESS); 415 } 416 /* 417 * Write modified pages to disk 418 * 419 * Returns: 420 * 0 == OK 421 * -1 ERROR 422 */ 423 static int 424 hash_sync(dbp, flags) 425 const DB *dbp; 426 u_int flags; 427 { 428 HTAB *hashp; 429 430 if (flags != 0) { 431 errno = EINVAL; 432 return (ERROR); 433 } 434 435 if (!dbp) 436 return (ERROR); 437 438 hashp = (HTAB *)dbp->internal; 439 if (!hashp->save_file) 440 return (0); 441 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 442 return (ERROR); 443 hashp->new_file = 0; 444 return (0); 445 } 446 447 /* 448 * Returns: 449 * 0 == OK 450 * -1 indicates that errno should be set 451 */ 452 static int 453 flush_meta(hashp) 454 HTAB *hashp; 455 { 456 HASHHDR *whdrp; 457 #if BYTE_ORDER == LITTLE_ENDIAN 458 HASHHDR whdr; 459 #endif 460 int fp, i, wsize; 461 462 if (!hashp->save_file) 463 return (0); 464 hashp->MAGIC = HASHMAGIC; 465 hashp->VERSION = HASHVERSION; 466 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 467 468 fp = hashp->fp; 469 whdrp = &hashp->hdr; 470 #if BYTE_ORDER == LITTLE_ENDIAN 471 whdrp = &whdr; 472 swap_header_copy(&hashp->hdr, whdrp); 473 #endif 474 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 475 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 476 return (-1); 477 else 478 if (wsize != sizeof(HASHHDR)) { 479 errno = EFTYPE; 480 hashp->errno = errno; 481 return (-1); 482 } 483 for (i = 0; i < NCACHED; i++) 484 if (hashp->mapp[i]) 485 if (__put_page(hashp, (char *)hashp->mapp[i], 486 hashp->BITMAPS[i], 0, 1)) 487 return (-1); 488 return (0); 489 } 490 491 /*******************************SEARCH ROUTINES *****************************/ 492 /* 493 * All the access routines return 494 * 495 * Returns: 496 * 0 on SUCCESS 497 * 1 to indicate an external ERROR (i.e. key not found, etc) 498 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 499 */ 500 static int 501 hash_get(dbp, key, data, flag) 502 const DB *dbp; 503 const DBT *key; 504 DBT *data; 505 u_int flag; 506 { 507 HTAB *hashp; 508 509 hashp = (HTAB *)dbp->internal; 510 if (flag) { 511 hashp->errno = errno = EINVAL; 512 return (ERROR); 513 } 514 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 515 } 516 517 static int 518 hash_put(dbp, key, data, flag) 519 const DB *dbp; 520 DBT *key; 521 const DBT *data; 522 u_int flag; 523 { 524 HTAB *hashp; 525 526 hashp = (HTAB *)dbp->internal; 527 if (flag && flag != R_NOOVERWRITE) { 528 hashp->errno = errno = EINVAL; 529 return (ERROR); 530 } 531 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 532 hashp->errno = errno = EPERM; 533 return (ERROR); 534 } 535 return (hash_access(hashp, flag == R_NOOVERWRITE ? 536 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 537 } 538 539 static int 540 hash_delete(dbp, key, flag) 541 const DB *dbp; 542 const DBT *key; 543 u_int flag; /* Ignored */ 544 { 545 HTAB *hashp; 546 547 hashp = (HTAB *)dbp->internal; 548 if (flag && flag != R_CURSOR) { 549 hashp->errno = errno = EINVAL; 550 return (ERROR); 551 } 552 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 553 hashp->errno = errno = EPERM; 554 return (ERROR); 555 } 556 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 557 } 558 559 /* 560 * Assume that hashp has been set in wrapper routine. 561 */ 562 static int 563 hash_access(hashp, action, key, val) 564 HTAB *hashp; 565 ACTION action; 566 DBT *key, *val; 567 { 568 register BUFHEAD *rbufp; 569 BUFHEAD *bufp, *save_bufp; 570 register u_short *bp; 571 register int n, ndx, off, size; 572 register char *kp; 573 u_short pageno; 574 575 #ifdef HASH_STATISTICS 576 hash_accesses++; 577 #endif 578 579 off = hashp->BSIZE; 580 size = key->size; 581 kp = (char *)key->data; 582 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 583 if (!rbufp) 584 return (ERROR); 585 save_bufp = rbufp; 586 587 /* Pin the bucket chain */ 588 rbufp->flags |= BUF_PIN; 589 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 590 if (bp[1] >= REAL_KEY) { 591 /* Real key/data pair */ 592 if (size == off - *bp && 593 memcmp(kp, rbufp->page + *bp, size) == 0) 594 goto found; 595 off = bp[1]; 596 #ifdef HASH_STATISTICS 597 hash_collisions++; 598 #endif 599 bp += 2; 600 ndx += 2; 601 } else if (bp[1] == OVFLPAGE) { 602 rbufp = __get_buf(hashp, *bp, rbufp, 0); 603 if (!rbufp) { 604 save_bufp->flags &= ~BUF_PIN; 605 return (ERROR); 606 } 607 /* FOR LOOP INIT */ 608 bp = (u_short *)rbufp->page; 609 n = *bp++; 610 ndx = 1; 611 off = hashp->BSIZE; 612 } else if (bp[1] < REAL_KEY) { 613 if ((ndx = 614 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 615 goto found; 616 if (ndx == -2) { 617 bufp = rbufp; 618 if (!(pageno = 619 __find_last_page(hashp, &bufp))) { 620 ndx = 0; 621 rbufp = bufp; 622 break; /* FOR */ 623 } 624 rbufp = __get_buf(hashp, pageno, bufp, 0); 625 if (!rbufp) { 626 save_bufp->flags &= ~BUF_PIN; 627 return (ERROR); 628 } 629 /* FOR LOOP INIT */ 630 bp = (u_short *)rbufp->page; 631 n = *bp++; 632 ndx = 1; 633 off = hashp->BSIZE; 634 } else { 635 save_bufp->flags &= ~BUF_PIN; 636 return (ERROR); 637 } 638 } 639 640 /* Not found */ 641 switch (action) { 642 case HASH_PUT: 643 case HASH_PUTNEW: 644 if (__addel(hashp, rbufp, key, val)) { 645 save_bufp->flags &= ~BUF_PIN; 646 return (ERROR); 647 } else { 648 save_bufp->flags &= ~BUF_PIN; 649 return (SUCCESS); 650 } 651 case HASH_GET: 652 case HASH_DELETE: 653 default: 654 save_bufp->flags &= ~BUF_PIN; 655 return (ABNORMAL); 656 } 657 658 found: 659 switch (action) { 660 case HASH_PUTNEW: 661 save_bufp->flags &= ~BUF_PIN; 662 return (ABNORMAL); 663 case HASH_GET: 664 bp = (u_short *)rbufp->page; 665 if (bp[ndx + 1] < REAL_KEY) { 666 if (__big_return(hashp, rbufp, ndx, val, 0)) 667 return (ERROR); 668 } else { 669 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 670 val->size = bp[ndx] - bp[ndx + 1]; 671 } 672 break; 673 case HASH_PUT: 674 if ((__delpair(hashp, rbufp, ndx)) || 675 (__addel(hashp, rbufp, key, val))) { 676 save_bufp->flags &= ~BUF_PIN; 677 return (ERROR); 678 } 679 break; 680 case HASH_DELETE: 681 if (__delpair(hashp, rbufp, ndx)) 682 return (ERROR); 683 break; 684 default: 685 abort(); 686 } 687 save_bufp->flags &= ~BUF_PIN; 688 return (SUCCESS); 689 } 690 691 static int 692 hash_seq(dbp, key, data, flag) 693 const DB *dbp; 694 DBT *key, *data; 695 u_int flag; 696 { 697 register u_int bucket; 698 register BUFHEAD *bufp; 699 HTAB *hashp; 700 u_short *bp, ndx; 701 702 hashp = (HTAB *)dbp->internal; 703 if (flag && flag != R_FIRST && flag != R_NEXT) { 704 hashp->errno = errno = EINVAL; 705 return (ERROR); 706 } 707 #ifdef HASH_STATISTICS 708 hash_accesses++; 709 #endif 710 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 711 hashp->cbucket = 0; 712 hashp->cndx = 1; 713 hashp->cpage = NULL; 714 } 715 716 for (bp = NULL; !bp || !bp[0]; ) { 717 if (!(bufp = hashp->cpage)) { 718 for (bucket = hashp->cbucket; 719 bucket <= hashp->MAX_BUCKET; 720 bucket++, hashp->cndx = 1) { 721 bufp = __get_buf(hashp, bucket, NULL, 0); 722 if (!bufp) 723 return (ERROR); 724 hashp->cpage = bufp; 725 bp = (u_short *)bufp->page; 726 if (bp[0]) 727 break; 728 } 729 hashp->cbucket = bucket; 730 if (hashp->cbucket > hashp->MAX_BUCKET) { 731 hashp->cbucket = -1; 732 return (ABNORMAL); 733 } 734 } else 735 bp = (u_short *)hashp->cpage->page; 736 737 #ifdef DEBUG 738 assert(bp); 739 assert(bufp); 740 #endif 741 while (bp[hashp->cndx + 1] == OVFLPAGE) { 742 bufp = hashp->cpage = 743 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 744 if (!bufp) 745 return (ERROR); 746 bp = (u_short *)(bufp->page); 747 hashp->cndx = 1; 748 } 749 if (!bp[0]) { 750 hashp->cpage = NULL; 751 ++hashp->cbucket; 752 } 753 } 754 ndx = hashp->cndx; 755 if (bp[ndx + 1] < REAL_KEY) { 756 if (__big_keydata(hashp, bufp, key, data, 1)) 757 return (ERROR); 758 } else { 759 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 760 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 761 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 762 data->size = bp[ndx] - bp[ndx + 1]; 763 ndx += 2; 764 if (ndx > bp[0]) { 765 hashp->cpage = NULL; 766 hashp->cbucket++; 767 hashp->cndx = 1; 768 } else 769 hashp->cndx = ndx; 770 } 771 return (SUCCESS); 772 } 773 774 /********************************* UTILITIES ************************/ 775 776 /* 777 * Returns: 778 * 0 ==> OK 779 * -1 ==> Error 780 */ 781 extern int 782 __expand_table(hashp) 783 HTAB *hashp; 784 { 785 u_int old_bucket, new_bucket; 786 int dirsize, new_segnum, spare_ndx; 787 788 #ifdef HASH_STATISTICS 789 hash_expansions++; 790 #endif 791 new_bucket = ++hashp->MAX_BUCKET; 792 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 793 794 new_segnum = new_bucket >> hashp->SSHIFT; 795 796 /* Check if we need a new segment */ 797 if (new_segnum >= hashp->nsegs) { 798 /* Check if we need to expand directory */ 799 if (new_segnum >= hashp->DSIZE) { 800 /* Reallocate directory */ 801 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 802 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 803 return (-1); 804 hashp->DSIZE = dirsize << 1; 805 } 806 if (!(hashp->dir[new_segnum] = 807 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 808 return (-1); 809 hashp->exsegs++; 810 hashp->nsegs++; 811 } 812 /* 813 * If the split point is increasing (MAX_BUCKET's log base 2 814 * * increases), we need to copy the current contents of the spare 815 * split bucket to the next bucket. 816 */ 817 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 818 if (spare_ndx > hashp->OVFL_POINT) { 819 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 820 hashp->OVFL_POINT = spare_ndx; 821 } 822 823 if (new_bucket > hashp->HIGH_MASK) { 824 /* Starting a new doubling */ 825 hashp->LOW_MASK = hashp->HIGH_MASK; 826 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 827 } 828 /* Relocate records to the new bucket */ 829 return (__split_page(hashp, old_bucket, new_bucket)); 830 } 831 832 /* 833 * If realloc guarantees that the pointer is not destroyed if the realloc 834 * fails, then this routine can go away. 835 */ 836 static void * 837 hash_realloc(p_ptr, oldsize, newsize) 838 SEGMENT **p_ptr; 839 int oldsize, newsize; 840 { 841 register void *p; 842 843 if (p = malloc(newsize)) { 844 memmove(p, *p_ptr, oldsize); 845 memset((char *)p + oldsize, 0, newsize - oldsize); 846 free(*p_ptr); 847 *p_ptr = p; 848 } 849 return (p); 850 } 851 852 extern u_int 853 __call_hash(hashp, k, len) 854 HTAB *hashp; 855 char *k; 856 int len; 857 { 858 int n, bucket; 859 860 n = hashp->hash(k, len); 861 bucket = n & hashp->HIGH_MASK; 862 if (bucket > hashp->MAX_BUCKET) 863 bucket = bucket & hashp->LOW_MASK; 864 return (bucket); 865 } 866 867 /* 868 * Allocate segment table. On error, destroy the table and set errno. 869 * 870 * Returns 0 on success 871 */ 872 static int 873 alloc_segs(hashp, nsegs) 874 HTAB *hashp; 875 int nsegs; 876 { 877 register int i; 878 register SEGMENT store; 879 880 int save_errno; 881 882 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 883 save_errno = errno; 884 (void)hdestroy(hashp); 885 errno = save_errno; 886 return (-1); 887 } 888 /* Allocate segments */ 889 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 890 if (!store) { 891 save_errno = errno; 892 (void)hdestroy(hashp); 893 errno = save_errno; 894 return (-1); 895 } 896 for (i = 0; i < nsegs; i++, hashp->nsegs++) 897 hashp->dir[i] = &store[i << hashp->SSHIFT]; 898 return (0); 899 } 900 901 #if BYTE_ORDER == LITTLE_ENDIAN 902 /* 903 * Hashp->hdr needs to be byteswapped. 904 */ 905 static void 906 swap_header_copy(srcp, destp) 907 HASHHDR *srcp, *destp; 908 { 909 int i; 910 911 BLSWAP_COPY(srcp->magic, destp->magic); 912 BLSWAP_COPY(srcp->version, destp->version); 913 BLSWAP_COPY(srcp->lorder, destp->lorder); 914 BLSWAP_COPY(srcp->bsize, destp->bsize); 915 BLSWAP_COPY(srcp->bshift, destp->bshift); 916 BLSWAP_COPY(srcp->dsize, destp->dsize); 917 BLSWAP_COPY(srcp->ssize, destp->ssize); 918 BLSWAP_COPY(srcp->sshift, destp->sshift); 919 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 920 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 921 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 922 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 923 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 924 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 925 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 926 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 927 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 928 for (i = 0; i < NCACHED; i++) { 929 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 930 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 931 } 932 } 933 934 static void 935 swap_header(hashp) 936 HTAB *hashp; 937 { 938 HASHHDR *hdrp; 939 int i; 940 941 hdrp = &hashp->hdr; 942 943 BLSWAP(hdrp->magic); 944 BLSWAP(hdrp->version); 945 BLSWAP(hdrp->lorder); 946 BLSWAP(hdrp->bsize); 947 BLSWAP(hdrp->bshift); 948 BLSWAP(hdrp->dsize); 949 BLSWAP(hdrp->ssize); 950 BLSWAP(hdrp->sshift); 951 BLSWAP(hdrp->ovfl_point); 952 BLSWAP(hdrp->last_freed); 953 BLSWAP(hdrp->max_bucket); 954 BLSWAP(hdrp->high_mask); 955 BLSWAP(hdrp->low_mask); 956 BLSWAP(hdrp->ffactor); 957 BLSWAP(hdrp->nkeys); 958 BLSWAP(hdrp->hdrpages); 959 BLSWAP(hdrp->h_charkey); 960 for (i = 0; i < NCACHED; i++) { 961 BLSWAP(hdrp->spares[i]); 962 BSSWAP(hdrp->bitmaps[i]); 963 } 964 } 965 #endif 966