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 8.5 (Berkeley) 01/13/94"; 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 free(hashp); 411 412 if (save_errno) { 413 errno = save_errno; 414 return (ERROR); 415 } 416 return (SUCCESS); 417 } 418 /* 419 * Write modified pages to disk 420 * 421 * Returns: 422 * 0 == OK 423 * -1 ERROR 424 */ 425 static int 426 hash_sync(dbp, flags) 427 const DB *dbp; 428 u_int flags; 429 { 430 HTAB *hashp; 431 432 if (flags != 0) { 433 errno = EINVAL; 434 return (ERROR); 435 } 436 437 if (!dbp) 438 return (ERROR); 439 440 hashp = (HTAB *)dbp->internal; 441 if (!hashp->save_file) 442 return (0); 443 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 444 return (ERROR); 445 hashp->new_file = 0; 446 return (0); 447 } 448 449 /* 450 * Returns: 451 * 0 == OK 452 * -1 indicates that errno should be set 453 */ 454 static int 455 flush_meta(hashp) 456 HTAB *hashp; 457 { 458 HASHHDR *whdrp; 459 #if BYTE_ORDER == LITTLE_ENDIAN 460 HASHHDR whdr; 461 #endif 462 int fp, i, wsize; 463 464 if (!hashp->save_file) 465 return (0); 466 hashp->MAGIC = HASHMAGIC; 467 hashp->VERSION = HASHVERSION; 468 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 469 470 fp = hashp->fp; 471 whdrp = &hashp->hdr; 472 #if BYTE_ORDER == LITTLE_ENDIAN 473 whdrp = &whdr; 474 swap_header_copy(&hashp->hdr, whdrp); 475 #endif 476 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 477 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 478 return (-1); 479 else 480 if (wsize != sizeof(HASHHDR)) { 481 errno = EFTYPE; 482 hashp->errno = errno; 483 return (-1); 484 } 485 for (i = 0; i < NCACHED; i++) 486 if (hashp->mapp[i]) 487 if (__put_page(hashp, (char *)hashp->mapp[i], 488 hashp->BITMAPS[i], 0, 1)) 489 return (-1); 490 return (0); 491 } 492 493 /*******************************SEARCH ROUTINES *****************************/ 494 /* 495 * All the access routines return 496 * 497 * Returns: 498 * 0 on SUCCESS 499 * 1 to indicate an external ERROR (i.e. key not found, etc) 500 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 501 */ 502 static int 503 hash_get(dbp, key, data, flag) 504 const DB *dbp; 505 const DBT *key; 506 DBT *data; 507 u_int flag; 508 { 509 HTAB *hashp; 510 511 hashp = (HTAB *)dbp->internal; 512 if (flag) { 513 hashp->errno = errno = EINVAL; 514 return (ERROR); 515 } 516 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 517 } 518 519 static int 520 hash_put(dbp, key, data, flag) 521 const DB *dbp; 522 DBT *key; 523 const DBT *data; 524 u_int flag; 525 { 526 HTAB *hashp; 527 528 hashp = (HTAB *)dbp->internal; 529 if (flag && flag != R_NOOVERWRITE) { 530 hashp->errno = errno = EINVAL; 531 return (ERROR); 532 } 533 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 534 hashp->errno = errno = EPERM; 535 return (ERROR); 536 } 537 return (hash_access(hashp, flag == R_NOOVERWRITE ? 538 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 539 } 540 541 static int 542 hash_delete(dbp, key, flag) 543 const DB *dbp; 544 const DBT *key; 545 u_int flag; /* Ignored */ 546 { 547 HTAB *hashp; 548 549 hashp = (HTAB *)dbp->internal; 550 if (flag && flag != R_CURSOR) { 551 hashp->errno = errno = EINVAL; 552 return (ERROR); 553 } 554 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 555 hashp->errno = errno = EPERM; 556 return (ERROR); 557 } 558 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 559 } 560 561 /* 562 * Assume that hashp has been set in wrapper routine. 563 */ 564 static int 565 hash_access(hashp, action, key, val) 566 HTAB *hashp; 567 ACTION action; 568 DBT *key, *val; 569 { 570 register BUFHEAD *rbufp; 571 BUFHEAD *bufp, *save_bufp; 572 register u_short *bp; 573 register int n, ndx, off, size; 574 register char *kp; 575 u_short pageno; 576 577 #ifdef HASH_STATISTICS 578 hash_accesses++; 579 #endif 580 581 off = hashp->BSIZE; 582 size = key->size; 583 kp = (char *)key->data; 584 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 585 if (!rbufp) 586 return (ERROR); 587 save_bufp = rbufp; 588 589 /* Pin the bucket chain */ 590 rbufp->flags |= BUF_PIN; 591 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 592 if (bp[1] >= REAL_KEY) { 593 /* Real key/data pair */ 594 if (size == off - *bp && 595 memcmp(kp, rbufp->page + *bp, size) == 0) 596 goto found; 597 off = bp[1]; 598 #ifdef HASH_STATISTICS 599 hash_collisions++; 600 #endif 601 bp += 2; 602 ndx += 2; 603 } else if (bp[1] == OVFLPAGE) { 604 rbufp = __get_buf(hashp, *bp, rbufp, 0); 605 if (!rbufp) { 606 save_bufp->flags &= ~BUF_PIN; 607 return (ERROR); 608 } 609 /* FOR LOOP INIT */ 610 bp = (u_short *)rbufp->page; 611 n = *bp++; 612 ndx = 1; 613 off = hashp->BSIZE; 614 } else if (bp[1] < REAL_KEY) { 615 if ((ndx = 616 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 617 goto found; 618 if (ndx == -2) { 619 bufp = rbufp; 620 if (!(pageno = 621 __find_last_page(hashp, &bufp))) { 622 ndx = 0; 623 rbufp = bufp; 624 break; /* FOR */ 625 } 626 rbufp = __get_buf(hashp, pageno, bufp, 0); 627 if (!rbufp) { 628 save_bufp->flags &= ~BUF_PIN; 629 return (ERROR); 630 } 631 /* FOR LOOP INIT */ 632 bp = (u_short *)rbufp->page; 633 n = *bp++; 634 ndx = 1; 635 off = hashp->BSIZE; 636 } else { 637 save_bufp->flags &= ~BUF_PIN; 638 return (ERROR); 639 } 640 } 641 642 /* Not found */ 643 switch (action) { 644 case HASH_PUT: 645 case HASH_PUTNEW: 646 if (__addel(hashp, rbufp, key, val)) { 647 save_bufp->flags &= ~BUF_PIN; 648 return (ERROR); 649 } else { 650 save_bufp->flags &= ~BUF_PIN; 651 return (SUCCESS); 652 } 653 case HASH_GET: 654 case HASH_DELETE: 655 default: 656 save_bufp->flags &= ~BUF_PIN; 657 return (ABNORMAL); 658 } 659 660 found: 661 switch (action) { 662 case HASH_PUTNEW: 663 save_bufp->flags &= ~BUF_PIN; 664 return (ABNORMAL); 665 case HASH_GET: 666 bp = (u_short *)rbufp->page; 667 if (bp[ndx + 1] < REAL_KEY) { 668 if (__big_return(hashp, rbufp, ndx, val, 0)) 669 return (ERROR); 670 } else { 671 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 672 val->size = bp[ndx] - bp[ndx + 1]; 673 } 674 break; 675 case HASH_PUT: 676 if ((__delpair(hashp, rbufp, ndx)) || 677 (__addel(hashp, rbufp, key, val))) { 678 save_bufp->flags &= ~BUF_PIN; 679 return (ERROR); 680 } 681 break; 682 case HASH_DELETE: 683 if (__delpair(hashp, rbufp, ndx)) 684 return (ERROR); 685 break; 686 default: 687 abort(); 688 } 689 save_bufp->flags &= ~BUF_PIN; 690 return (SUCCESS); 691 } 692 693 static int 694 hash_seq(dbp, key, data, flag) 695 const DB *dbp; 696 DBT *key, *data; 697 u_int flag; 698 { 699 register u_int bucket; 700 register BUFHEAD *bufp; 701 HTAB *hashp; 702 u_short *bp, ndx; 703 704 hashp = (HTAB *)dbp->internal; 705 if (flag && flag != R_FIRST && flag != R_NEXT) { 706 hashp->errno = errno = EINVAL; 707 return (ERROR); 708 } 709 #ifdef HASH_STATISTICS 710 hash_accesses++; 711 #endif 712 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 713 hashp->cbucket = 0; 714 hashp->cndx = 1; 715 hashp->cpage = NULL; 716 } 717 718 for (bp = NULL; !bp || !bp[0]; ) { 719 if (!(bufp = hashp->cpage)) { 720 for (bucket = hashp->cbucket; 721 bucket <= hashp->MAX_BUCKET; 722 bucket++, hashp->cndx = 1) { 723 bufp = __get_buf(hashp, bucket, NULL, 0); 724 if (!bufp) 725 return (ERROR); 726 hashp->cpage = bufp; 727 bp = (u_short *)bufp->page; 728 if (bp[0]) 729 break; 730 } 731 hashp->cbucket = bucket; 732 if (hashp->cbucket > hashp->MAX_BUCKET) { 733 hashp->cbucket = -1; 734 return (ABNORMAL); 735 } 736 } else 737 bp = (u_short *)hashp->cpage->page; 738 739 #ifdef DEBUG 740 assert(bp); 741 assert(bufp); 742 #endif 743 while (bp[hashp->cndx + 1] == OVFLPAGE) { 744 bufp = hashp->cpage = 745 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 746 if (!bufp) 747 return (ERROR); 748 bp = (u_short *)(bufp->page); 749 hashp->cndx = 1; 750 } 751 if (!bp[0]) { 752 hashp->cpage = NULL; 753 ++hashp->cbucket; 754 } 755 } 756 ndx = hashp->cndx; 757 if (bp[ndx + 1] < REAL_KEY) { 758 if (__big_keydata(hashp, bufp, key, data, 1)) 759 return (ERROR); 760 } else { 761 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 762 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 763 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 764 data->size = bp[ndx] - bp[ndx + 1]; 765 ndx += 2; 766 if (ndx > bp[0]) { 767 hashp->cpage = NULL; 768 hashp->cbucket++; 769 hashp->cndx = 1; 770 } else 771 hashp->cndx = ndx; 772 } 773 return (SUCCESS); 774 } 775 776 /********************************* UTILITIES ************************/ 777 778 /* 779 * Returns: 780 * 0 ==> OK 781 * -1 ==> Error 782 */ 783 extern int 784 __expand_table(hashp) 785 HTAB *hashp; 786 { 787 u_int old_bucket, new_bucket; 788 int dirsize, new_segnum, spare_ndx; 789 790 #ifdef HASH_STATISTICS 791 hash_expansions++; 792 #endif 793 new_bucket = ++hashp->MAX_BUCKET; 794 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 795 796 new_segnum = new_bucket >> hashp->SSHIFT; 797 798 /* Check if we need a new segment */ 799 if (new_segnum >= hashp->nsegs) { 800 /* Check if we need to expand directory */ 801 if (new_segnum >= hashp->DSIZE) { 802 /* Reallocate directory */ 803 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 804 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 805 return (-1); 806 hashp->DSIZE = dirsize << 1; 807 } 808 if (!(hashp->dir[new_segnum] = 809 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 810 return (-1); 811 hashp->exsegs++; 812 hashp->nsegs++; 813 } 814 /* 815 * If the split point is increasing (MAX_BUCKET's log base 2 816 * * increases), we need to copy the current contents of the spare 817 * split bucket to the next bucket. 818 */ 819 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 820 if (spare_ndx > hashp->OVFL_POINT) { 821 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 822 hashp->OVFL_POINT = spare_ndx; 823 } 824 825 if (new_bucket > hashp->HIGH_MASK) { 826 /* Starting a new doubling */ 827 hashp->LOW_MASK = hashp->HIGH_MASK; 828 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 829 } 830 /* Relocate records to the new bucket */ 831 return (__split_page(hashp, old_bucket, new_bucket)); 832 } 833 834 /* 835 * If realloc guarantees that the pointer is not destroyed if the realloc 836 * fails, then this routine can go away. 837 */ 838 static void * 839 hash_realloc(p_ptr, oldsize, newsize) 840 SEGMENT **p_ptr; 841 int oldsize, newsize; 842 { 843 register void *p; 844 845 if (p = malloc(newsize)) { 846 memmove(p, *p_ptr, oldsize); 847 memset((char *)p + oldsize, 0, newsize - oldsize); 848 free(*p_ptr); 849 *p_ptr = p; 850 } 851 return (p); 852 } 853 854 extern u_int 855 __call_hash(hashp, k, len) 856 HTAB *hashp; 857 char *k; 858 int len; 859 { 860 int n, bucket; 861 862 n = hashp->hash(k, len); 863 bucket = n & hashp->HIGH_MASK; 864 if (bucket > hashp->MAX_BUCKET) 865 bucket = bucket & hashp->LOW_MASK; 866 return (bucket); 867 } 868 869 /* 870 * Allocate segment table. On error, destroy the table and set errno. 871 * 872 * Returns 0 on success 873 */ 874 static int 875 alloc_segs(hashp, nsegs) 876 HTAB *hashp; 877 int nsegs; 878 { 879 register int i; 880 register SEGMENT store; 881 882 int save_errno; 883 884 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 885 save_errno = errno; 886 (void)hdestroy(hashp); 887 errno = save_errno; 888 return (-1); 889 } 890 /* Allocate segments */ 891 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 892 if (!store) { 893 save_errno = errno; 894 (void)hdestroy(hashp); 895 errno = save_errno; 896 return (-1); 897 } 898 for (i = 0; i < nsegs; i++, hashp->nsegs++) 899 hashp->dir[i] = &store[i << hashp->SSHIFT]; 900 return (0); 901 } 902 903 #if BYTE_ORDER == LITTLE_ENDIAN 904 /* 905 * Hashp->hdr needs to be byteswapped. 906 */ 907 static void 908 swap_header_copy(srcp, destp) 909 HASHHDR *srcp, *destp; 910 { 911 int i; 912 913 BLSWAP_COPY(srcp->magic, destp->magic); 914 BLSWAP_COPY(srcp->version, destp->version); 915 BLSWAP_COPY(srcp->lorder, destp->lorder); 916 BLSWAP_COPY(srcp->bsize, destp->bsize); 917 BLSWAP_COPY(srcp->bshift, destp->bshift); 918 BLSWAP_COPY(srcp->dsize, destp->dsize); 919 BLSWAP_COPY(srcp->ssize, destp->ssize); 920 BLSWAP_COPY(srcp->sshift, destp->sshift); 921 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 922 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 923 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 924 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 925 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 926 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 927 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 928 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 929 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 930 for (i = 0; i < NCACHED; i++) { 931 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 932 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 933 } 934 } 935 936 static void 937 swap_header(hashp) 938 HTAB *hashp; 939 { 940 HASHHDR *hdrp; 941 int i; 942 943 hdrp = &hashp->hdr; 944 945 BLSWAP(hdrp->magic); 946 BLSWAP(hdrp->version); 947 BLSWAP(hdrp->lorder); 948 BLSWAP(hdrp->bsize); 949 BLSWAP(hdrp->bshift); 950 BLSWAP(hdrp->dsize); 951 BLSWAP(hdrp->ssize); 952 BLSWAP(hdrp->sshift); 953 BLSWAP(hdrp->ovfl_point); 954 BLSWAP(hdrp->last_freed); 955 BLSWAP(hdrp->max_bucket); 956 BLSWAP(hdrp->high_mask); 957 BLSWAP(hdrp->low_mask); 958 BLSWAP(hdrp->ffactor); 959 BLSWAP(hdrp->nkeys); 960 BLSWAP(hdrp->hdrpages); 961 BLSWAP(hdrp->h_charkey); 962 for (i = 0; i < NCACHED; i++) { 963 BLSWAP(hdrp->spares[i]); 964 BSSWAP(hdrp->bitmaps[i]); 965 } 966 } 967 #endif 968