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 8.1 (Berkeley) 06/06/93"; 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) 71 const char *file; 72 int flags, mode; 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 * Select flags relevant to us. Even if user wants write only, we need 90 * to be able to read the actual file, so we need to open it read/write. 91 * But, the field in the hashp structure needs to be accurate so that 92 * we can check accesses. 93 */ 94 hashp->flags = flags = flags & __USE_OPEN_FLAGS; 95 96 new_table = 0; 97 if (!file || (flags & O_TRUNC) || 98 (stat(file, &statbuf) && (errno == ENOENT))) { 99 if (errno == ENOENT) 100 errno = 0; /* Just in case someone looks at errno */ 101 new_table = 1; 102 } 103 if (file) { 104 if ((hashp->fp = open(file, flags, mode)) == -1) 105 RETURN_ERROR(errno, error0); 106 (void)fcntl(hashp->fp, F_SETFD, 1); 107 } 108 if (new_table) { 109 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 110 RETURN_ERROR(errno, error1); 111 } else { 112 /* Table already exists */ 113 if (info && info->hash) 114 hashp->hash = info->hash; 115 else 116 hashp->hash = __default_hash; 117 118 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 119 #if BYTE_ORDER == LITTLE_ENDIAN 120 swap_header(hashp); 121 #endif 122 if (hdrsize == -1) 123 RETURN_ERROR(errno, error1); 124 if (hdrsize != sizeof(HASHHDR)) 125 RETURN_ERROR(EFTYPE, error1); 126 /* Verify file type, versions and hash function */ 127 if (hashp->MAGIC != HASHMAGIC) 128 RETURN_ERROR(EFTYPE, error1); 129 if (hashp->VERSION != HASHVERSION) 130 RETURN_ERROR(EFTYPE, error1); 131 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 132 RETURN_ERROR(EFTYPE, error1); 133 /* 134 * Figure out how many segments we need. Max_Bucket is the 135 * maximum bucket number, so the number of buckets is 136 * max_bucket + 1. 137 */ 138 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 139 hashp->SGSIZE; 140 hashp->nsegs = 0; 141 if (alloc_segs(hashp, nsegs)) 142 /* 143 * If alloc_segs fails, table will have been destroyed 144 * and errno will have been set. 145 */ 146 return (NULL); 147 /* Read in bitmaps */ 148 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 149 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 150 (hashp->BSHIFT + BYTE_SHIFT); 151 152 hashp->nmaps = bpages; 153 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_long *)); 154 } 155 156 /* Initialize Buffer Manager */ 157 if (info && info->cachesize) 158 __buf_init(hashp, info->cachesize); 159 else 160 __buf_init(hashp, DEF_BUFSIZE); 161 162 hashp->new_file = new_table; 163 hashp->save_file = file && (hashp->flags & O_RDWR); 164 hashp->cbucket = -1; 165 if (!(dbp = malloc(sizeof(DB)))) { 166 save_errno = errno; 167 hdestroy(hashp); 168 errno = save_errno; 169 return (NULL); 170 } 171 dbp->internal = hashp; 172 dbp->close = hash_close; 173 dbp->del = hash_delete; 174 dbp->fd = hash_fd; 175 dbp->get = hash_get; 176 dbp->put = hash_put; 177 dbp->seq = hash_seq; 178 dbp->sync = hash_sync; 179 dbp->type = DB_HASH; 180 181 #ifdef DEBUG 182 (void)fprintf(stderr, 183 "%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", 184 "init_htab:", 185 "TABLE POINTER ", hashp, 186 "BUCKET SIZE ", hashp->BSIZE, 187 "BUCKET SHIFT ", hashp->BSHIFT, 188 "DIRECTORY SIZE ", hashp->DSIZE, 189 "SEGMENT SIZE ", hashp->SGSIZE, 190 "SEGMENT SHIFT ", hashp->SSHIFT, 191 "FILL FACTOR ", hashp->FFACTOR, 192 "MAX BUCKET ", hashp->MAX_BUCKET, 193 "OVFL POINT ", hashp->OVFL_POINT, 194 "LAST FREED ", hashp->LAST_FREED, 195 "HIGH MASK ", hashp->HIGH_MASK, 196 "LOW MASK ", hashp->LOW_MASK, 197 "NSEGS ", hashp->nsegs, 198 "NKEYS ", hashp->NKEYS); 199 #endif 200 #ifdef HASH_STATISTICS 201 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 202 #endif 203 return (dbp); 204 205 error1: 206 if (hashp != NULL) 207 (void)close(hashp->fp); 208 209 error0: 210 free(hashp); 211 errno = save_errno; 212 return (NULL); 213 } 214 215 static int 216 hash_close(dbp) 217 DB *dbp; 218 { 219 HTAB *hashp; 220 int retval; 221 222 if (!dbp) 223 return (ERROR); 224 225 hashp = (HTAB *)dbp->internal; 226 retval = hdestroy(hashp); 227 free(dbp); 228 return (retval); 229 } 230 231 static int 232 hash_fd(dbp) 233 const DB *dbp; 234 { 235 HTAB *hashp; 236 237 if (!dbp) 238 return (ERROR); 239 240 hashp = (HTAB *)dbp->internal; 241 if (hashp->fp == -1) { 242 errno = ENOENT; 243 return (-1); 244 } 245 return (hashp->fp); 246 } 247 248 /************************** LOCAL CREATION ROUTINES **********************/ 249 static HTAB * 250 init_hash(hashp, file, info) 251 HTAB *hashp; 252 const char *file; 253 HASHINFO *info; 254 { 255 struct stat statbuf; 256 int nelem; 257 258 nelem = 1; 259 hashp->NKEYS = 0; 260 hashp->LORDER = BYTE_ORDER; 261 hashp->BSIZE = DEF_BUCKET_SIZE; 262 hashp->BSHIFT = DEF_BUCKET_SHIFT; 263 hashp->SGSIZE = DEF_SEGSIZE; 264 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 265 hashp->DSIZE = DEF_DIRSIZE; 266 hashp->FFACTOR = DEF_FFACTOR; 267 hashp->hash = __default_hash; 268 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 269 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 270 271 /* Fix bucket size to be optimal for file system */ 272 if (file != NULL) { 273 if (stat(file, &statbuf)) 274 return (NULL); 275 hashp->BSIZE = statbuf.st_blksize; 276 hashp->BSHIFT = __log2(hashp->BSIZE); 277 } 278 279 if (info) { 280 if (info->bsize) { 281 /* Round pagesize up to power of 2 */ 282 hashp->BSHIFT = __log2(info->bsize); 283 hashp->BSIZE = 1 << hashp->BSHIFT; 284 if (hashp->BSIZE > MAX_BSIZE) { 285 errno = EINVAL; 286 return (NULL); 287 } 288 } 289 if (info->ffactor) 290 hashp->FFACTOR = info->ffactor; 291 if (info->hash) 292 hashp->hash = info->hash; 293 if (info->nelem) 294 nelem = info->nelem; 295 if (info->lorder) { 296 if (info->lorder != BIG_ENDIAN && 297 info->lorder != LITTLE_ENDIAN) { 298 errno = EINVAL; 299 return (NULL); 300 } 301 hashp->LORDER = info->lorder; 302 } 303 } 304 /* init_htab should destroy the table and set errno if it fails */ 305 if (init_htab(hashp, nelem)) 306 return (NULL); 307 else 308 return (hashp); 309 } 310 /* 311 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 312 * the table and set errno, so we just pass the error information along. 313 * 314 * Returns 0 on No Error 315 */ 316 static int 317 init_htab(hashp, nelem) 318 HTAB *hashp; 319 int nelem; 320 { 321 register int nbuckets, nsegs; 322 int l2; 323 324 /* 325 * Divide number of elements by the fill factor and determine a 326 * desired number of buckets. Allocate space for the next greater 327 * power of two number of buckets. 328 */ 329 nelem = (nelem - 1) / hashp->FFACTOR + 1; 330 331 l2 = __log2(MAX(nelem, 2)); 332 nbuckets = 1 << l2; 333 334 hashp->SPARES[l2] = l2 + 1; 335 hashp->SPARES[l2 + 1] = l2 + 1; 336 hashp->OVFL_POINT = l2; 337 hashp->LAST_FREED = 2; 338 339 /* First bitmap page is at: splitpoint l2 page offset 1 */ 340 if (__init_bitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 341 return (-1); 342 343 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 344 hashp->HIGH_MASK = (nbuckets << 1) - 1; 345 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 346 hashp->BSHIFT) + 1; 347 348 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 349 nsegs = 1 << __log2(nsegs); 350 351 if (nsegs > hashp->DSIZE) 352 hashp->DSIZE = nsegs; 353 return (alloc_segs(hashp, nsegs)); 354 } 355 356 /********************** DESTROY/CLOSE ROUTINES ************************/ 357 358 /* 359 * Flushes any changes to the file if necessary and destroys the hashp 360 * structure, freeing all allocated space. 361 */ 362 static int 363 hdestroy(hashp) 364 HTAB *hashp; 365 { 366 int i, save_errno; 367 368 save_errno = 0; 369 370 #ifdef HASH_STATISTICS 371 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 372 hash_accesses, hash_collisions); 373 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 374 hash_expansions); 375 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 376 hash_overflows); 377 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 378 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 379 380 for (i = 0; i < NCACHED; i++) 381 (void)fprintf(stderr, 382 "spares[%d] = %d\n", i, hashp->SPARES[i]); 383 #endif 384 /* 385 * Call on buffer manager to free buffers, and if required, 386 * write them to disk. 387 */ 388 if (__buf_free(hashp, 1, hashp->save_file)) 389 save_errno = errno; 390 if (hashp->dir) { 391 free(*hashp->dir); /* Free initial segments */ 392 /* Free extra segments */ 393 while (hashp->exsegs--) 394 free(hashp->dir[--hashp->nsegs]); 395 free(hashp->dir); 396 } 397 if (flush_meta(hashp) && !save_errno) 398 save_errno = errno; 399 /* Free Bigmaps */ 400 for (i = 0; i < hashp->nmaps; i++) 401 if (hashp->mapp[i]) 402 free(hashp->mapp[i]); 403 404 if (hashp->fp != -1) 405 (void)close(hashp->fp); 406 407 if (save_errno) { 408 errno = save_errno; 409 return (ERROR); 410 } 411 return (SUCCESS); 412 } 413 /* 414 * Write modified pages to disk 415 * 416 * Returns: 417 * 0 == OK 418 * -1 ERROR 419 */ 420 static int 421 hash_sync(dbp, flags) 422 const DB *dbp; 423 u_int flags; 424 { 425 HTAB *hashp; 426 427 if (flags != 0) { 428 errno = EINVAL; 429 return (ERROR); 430 } 431 432 if (!dbp) 433 return (ERROR); 434 435 hashp = (HTAB *)dbp->internal; 436 if (!hashp->save_file) 437 return (0); 438 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 439 return (ERROR); 440 hashp->new_file = 0; 441 return (0); 442 } 443 444 /* 445 * Returns: 446 * 0 == OK 447 * -1 indicates that errno should be set 448 */ 449 static int 450 flush_meta(hashp) 451 HTAB *hashp; 452 { 453 HASHHDR *whdrp; 454 #if BYTE_ORDER == LITTLE_ENDIAN 455 HASHHDR whdr; 456 #endif 457 int fp, i, wsize; 458 459 if (!hashp->save_file) 460 return (0); 461 hashp->MAGIC = HASHMAGIC; 462 hashp->VERSION = HASHVERSION; 463 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 464 465 fp = hashp->fp; 466 whdrp = &hashp->hdr; 467 #if BYTE_ORDER == LITTLE_ENDIAN 468 whdrp = &whdr; 469 swap_header_copy(&hashp->hdr, whdrp); 470 #endif 471 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 472 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 473 return (-1); 474 else 475 if (wsize != sizeof(HASHHDR)) { 476 errno = EFTYPE; 477 hashp->errno = errno; 478 return (-1); 479 } 480 for (i = 0; i < NCACHED; i++) 481 if (hashp->mapp[i]) 482 if (__put_page(hashp, (char *)hashp->mapp[i], 483 hashp->BITMAPS[i], 0, 1)) 484 return (-1); 485 return (0); 486 } 487 488 /*******************************SEARCH ROUTINES *****************************/ 489 /* 490 * All the access routines return 491 * 492 * Returns: 493 * 0 on SUCCESS 494 * 1 to indicate an external ERROR (i.e. key not found, etc) 495 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 496 */ 497 static int 498 hash_get(dbp, key, data, flag) 499 const DB *dbp; 500 const DBT *key; 501 DBT *data; 502 u_int flag; 503 { 504 HTAB *hashp; 505 506 hashp = (HTAB *)dbp->internal; 507 if (flag) { 508 hashp->errno = errno = EINVAL; 509 return (ERROR); 510 } 511 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 512 } 513 514 static int 515 hash_put(dbp, key, data, flag) 516 const DB *dbp; 517 DBT *key; 518 const DBT *data; 519 u_int flag; 520 { 521 HTAB *hashp; 522 523 hashp = (HTAB *)dbp->internal; 524 if (flag && flag != R_NOOVERWRITE) { 525 hashp->errno = errno = EINVAL; 526 return (ERROR); 527 } 528 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 529 hashp->errno = errno = EPERM; 530 return (ERROR); 531 } 532 return (hash_access(hashp, flag == R_NOOVERWRITE ? 533 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 534 } 535 536 static int 537 hash_delete(dbp, key, flag) 538 const DB *dbp; 539 const DBT *key; 540 u_int flag; /* Ignored */ 541 { 542 HTAB *hashp; 543 544 hashp = (HTAB *)dbp->internal; 545 if (flag && flag != R_CURSOR) { 546 hashp->errno = errno = EINVAL; 547 return (ERROR); 548 } 549 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 550 hashp->errno = errno = EPERM; 551 return (ERROR); 552 } 553 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 554 } 555 556 /* 557 * Assume that hashp has been set in wrapper routine. 558 */ 559 static int 560 hash_access(hashp, action, key, val) 561 HTAB *hashp; 562 ACTION action; 563 DBT *key, *val; 564 { 565 register BUFHEAD *rbufp; 566 BUFHEAD *bufp, *save_bufp; 567 register u_short *bp; 568 register int n, ndx, off, size; 569 register char *kp; 570 u_short pageno; 571 572 #ifdef HASH_STATISTICS 573 hash_accesses++; 574 #endif 575 576 off = hashp->BSIZE; 577 size = key->size; 578 kp = (char *)key->data; 579 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 580 if (!rbufp) 581 return (ERROR); 582 save_bufp = rbufp; 583 584 /* Pin the bucket chain */ 585 rbufp->flags |= BUF_PIN; 586 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 587 if (bp[1] >= REAL_KEY) { 588 /* Real key/data pair */ 589 if (size == off - *bp && 590 memcmp(kp, rbufp->page + *bp, size) == 0) 591 goto found; 592 off = bp[1]; 593 #ifdef HASH_STATISTICS 594 hash_collisions++; 595 #endif 596 bp += 2; 597 ndx += 2; 598 } else if (bp[1] == OVFLPAGE) { 599 rbufp = __get_buf(hashp, *bp, rbufp, 0); 600 if (!rbufp) { 601 save_bufp->flags &= ~BUF_PIN; 602 return (ERROR); 603 } 604 /* FOR LOOP INIT */ 605 bp = (u_short *)rbufp->page; 606 n = *bp++; 607 ndx = 1; 608 off = hashp->BSIZE; 609 } else if (bp[1] < REAL_KEY) { 610 if ((ndx = 611 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 612 goto found; 613 if (ndx == -2) { 614 bufp = rbufp; 615 if (!(pageno = 616 __find_last_page(hashp, &bufp))) { 617 ndx = 0; 618 rbufp = bufp; 619 break; /* FOR */ 620 } 621 rbufp = __get_buf(hashp, pageno, bufp, 0); 622 if (!rbufp) { 623 save_bufp->flags &= ~BUF_PIN; 624 return (ERROR); 625 } 626 /* FOR LOOP INIT */ 627 bp = (u_short *)rbufp->page; 628 n = *bp++; 629 ndx = 1; 630 off = hashp->BSIZE; 631 } else { 632 save_bufp->flags &= ~BUF_PIN; 633 return (ERROR); 634 } 635 } 636 637 /* Not found */ 638 switch (action) { 639 case HASH_PUT: 640 case HASH_PUTNEW: 641 if (__addel(hashp, rbufp, key, val)) { 642 save_bufp->flags &= ~BUF_PIN; 643 return (ERROR); 644 } else { 645 save_bufp->flags &= ~BUF_PIN; 646 return (SUCCESS); 647 } 648 case HASH_GET: 649 case HASH_DELETE: 650 default: 651 save_bufp->flags &= ~BUF_PIN; 652 return (ABNORMAL); 653 } 654 655 found: 656 switch (action) { 657 case HASH_PUTNEW: 658 save_bufp->flags &= ~BUF_PIN; 659 return (ABNORMAL); 660 case HASH_GET: 661 bp = (u_short *)rbufp->page; 662 if (bp[ndx + 1] < REAL_KEY) { 663 if (__big_return(hashp, rbufp, ndx, val, 0)) 664 return (ERROR); 665 } else { 666 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 667 val->size = bp[ndx] - bp[ndx + 1]; 668 } 669 break; 670 case HASH_PUT: 671 if ((__delpair(hashp, rbufp, ndx)) || 672 (__addel(hashp, rbufp, key, val))) { 673 save_bufp->flags &= ~BUF_PIN; 674 return (ERROR); 675 } 676 break; 677 case HASH_DELETE: 678 if (__delpair(hashp, rbufp, ndx)) 679 return (ERROR); 680 break; 681 default: 682 abort(); 683 } 684 save_bufp->flags &= ~BUF_PIN; 685 return (SUCCESS); 686 } 687 688 static int 689 hash_seq(dbp, key, data, flag) 690 const DB *dbp; 691 DBT *key, *data; 692 u_int flag; 693 { 694 register u_int bucket; 695 register BUFHEAD *bufp; 696 HTAB *hashp; 697 u_short *bp, ndx; 698 699 hashp = (HTAB *)dbp->internal; 700 if (flag && flag != R_FIRST && flag != R_NEXT) { 701 hashp->errno = errno = EINVAL; 702 return (ERROR); 703 } 704 #ifdef HASH_STATISTICS 705 hash_accesses++; 706 #endif 707 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 708 hashp->cbucket = 0; 709 hashp->cndx = 1; 710 hashp->cpage = NULL; 711 } 712 713 for (bp = NULL; !bp || !bp[0]; ) { 714 if (!(bufp = hashp->cpage)) { 715 for (bucket = hashp->cbucket; 716 bucket <= hashp->MAX_BUCKET; 717 bucket++, hashp->cndx = 1) { 718 bufp = __get_buf(hashp, bucket, NULL, 0); 719 if (!bufp) 720 return (ERROR); 721 hashp->cpage = bufp; 722 bp = (u_short *)bufp->page; 723 if (bp[0]) 724 break; 725 } 726 hashp->cbucket = bucket; 727 if (hashp->cbucket > hashp->MAX_BUCKET) { 728 hashp->cbucket = -1; 729 return (ABNORMAL); 730 } 731 } else 732 bp = (u_short *)hashp->cpage->page; 733 734 #ifdef DEBUG 735 assert(bp); 736 assert(bufp); 737 #endif 738 while (bp[hashp->cndx + 1] == OVFLPAGE) { 739 bufp = hashp->cpage = 740 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 741 if (!bufp) 742 return (ERROR); 743 bp = (u_short *)(bufp->page); 744 hashp->cndx = 1; 745 } 746 if (!bp[0]) { 747 hashp->cpage = NULL; 748 ++hashp->cbucket; 749 } 750 } 751 ndx = hashp->cndx; 752 if (bp[ndx + 1] < REAL_KEY) { 753 if (__big_keydata(hashp, bufp, key, data, 1)) 754 return (ERROR); 755 } else { 756 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 757 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 758 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 759 data->size = bp[ndx] - bp[ndx + 1]; 760 ndx += 2; 761 if (ndx > bp[0]) { 762 hashp->cpage = NULL; 763 hashp->cbucket++; 764 hashp->cndx = 1; 765 } else 766 hashp->cndx = ndx; 767 } 768 return (SUCCESS); 769 } 770 771 /********************************* UTILITIES ************************/ 772 773 /* 774 * Returns: 775 * 0 ==> OK 776 * -1 ==> Error 777 */ 778 extern int 779 __expand_table(hashp) 780 HTAB *hashp; 781 { 782 u_int old_bucket, new_bucket; 783 int dirsize, new_segnum, spare_ndx; 784 785 #ifdef HASH_STATISTICS 786 hash_expansions++; 787 #endif 788 new_bucket = ++hashp->MAX_BUCKET; 789 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 790 791 new_segnum = new_bucket >> hashp->SSHIFT; 792 793 /* Check if we need a new segment */ 794 if (new_segnum >= hashp->nsegs) { 795 /* Check if we need to expand directory */ 796 if (new_segnum >= hashp->DSIZE) { 797 /* Reallocate directory */ 798 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 799 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 800 return (-1); 801 hashp->DSIZE = dirsize << 1; 802 } 803 if (!(hashp->dir[new_segnum] = 804 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 805 return (-1); 806 hashp->exsegs++; 807 hashp->nsegs++; 808 } 809 /* 810 * If the split point is increasing (MAX_BUCKET's log base 2 811 * * increases), we need to copy the current contents of the spare 812 * split bucket to the next bucket. 813 */ 814 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 815 if (spare_ndx > hashp->OVFL_POINT) { 816 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 817 hashp->OVFL_POINT = spare_ndx; 818 } 819 820 if (new_bucket > hashp->HIGH_MASK) { 821 /* Starting a new doubling */ 822 hashp->LOW_MASK = hashp->HIGH_MASK; 823 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 824 } 825 /* Relocate records to the new bucket */ 826 return (__split_page(hashp, old_bucket, new_bucket)); 827 } 828 829 /* 830 * If realloc guarantees that the pointer is not destroyed if the realloc 831 * fails, then this routine can go away. 832 */ 833 static void * 834 hash_realloc(p_ptr, oldsize, newsize) 835 SEGMENT **p_ptr; 836 int oldsize, newsize; 837 { 838 register void *p; 839 840 if (p = malloc(newsize)) { 841 memmove(p, *p_ptr, oldsize); 842 memset(p + oldsize, 0, newsize - oldsize); 843 free(*p_ptr); 844 *p_ptr = p; 845 } 846 return (p); 847 } 848 849 extern u_int 850 __call_hash(hashp, k, len) 851 HTAB *hashp; 852 char *k; 853 int len; 854 { 855 int n, bucket; 856 857 n = hashp->hash(k, len); 858 bucket = n & hashp->HIGH_MASK; 859 if (bucket > hashp->MAX_BUCKET) 860 bucket = bucket & hashp->LOW_MASK; 861 return (bucket); 862 } 863 864 /* 865 * Allocate segment table. On error, destroy the table and set errno. 866 * 867 * Returns 0 on success 868 */ 869 static int 870 alloc_segs(hashp, nsegs) 871 HTAB *hashp; 872 int nsegs; 873 { 874 register int i; 875 register SEGMENT store; 876 877 int save_errno; 878 879 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 880 save_errno = errno; 881 (void)hdestroy(hashp); 882 errno = save_errno; 883 return (-1); 884 } 885 /* Allocate segments */ 886 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 887 if (!store) { 888 save_errno = errno; 889 (void)hdestroy(hashp); 890 errno = save_errno; 891 return (-1); 892 } 893 for (i = 0; i < nsegs; i++, hashp->nsegs++) 894 hashp->dir[i] = &store[i << hashp->SSHIFT]; 895 return (0); 896 } 897 898 #if BYTE_ORDER == LITTLE_ENDIAN 899 /* 900 * Hashp->hdr needs to be byteswapped. 901 */ 902 static void 903 swap_header_copy(srcp, destp) 904 HASHHDR *srcp, *destp; 905 { 906 int i; 907 908 BLSWAP_COPY(srcp->magic, destp->magic); 909 BLSWAP_COPY(srcp->version, destp->version); 910 BLSWAP_COPY(srcp->lorder, destp->lorder); 911 BLSWAP_COPY(srcp->bsize, destp->bsize); 912 BLSWAP_COPY(srcp->bshift, destp->bshift); 913 BLSWAP_COPY(srcp->dsize, destp->dsize); 914 BLSWAP_COPY(srcp->ssize, destp->ssize); 915 BLSWAP_COPY(srcp->sshift, destp->sshift); 916 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 917 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 918 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 919 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 920 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 921 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 922 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 923 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 924 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 925 for (i = 0; i < NCACHED; i++) { 926 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 927 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 928 } 929 } 930 931 static void 932 swap_header(hashp) 933 HTAB *hashp; 934 { 935 HASHHDR *hdrp; 936 int i; 937 938 hdrp = &hashp->hdr; 939 940 BLSWAP(hdrp->magic); 941 BLSWAP(hdrp->version); 942 BLSWAP(hdrp->lorder); 943 BLSWAP(hdrp->bsize); 944 BLSWAP(hdrp->bshift); 945 BLSWAP(hdrp->dsize); 946 BLSWAP(hdrp->ssize); 947 BLSWAP(hdrp->sshift); 948 BLSWAP(hdrp->ovfl_point); 949 BLSWAP(hdrp->last_freed); 950 BLSWAP(hdrp->max_bucket); 951 BLSWAP(hdrp->high_mask); 952 BLSWAP(hdrp->low_mask); 953 BLSWAP(hdrp->ffactor); 954 BLSWAP(hdrp->nkeys); 955 BLSWAP(hdrp->hdrpages); 956 BLSWAP(hdrp->h_charkey); 957 for (i = 0; i < NCACHED; i++) { 958 BLSWAP(hdrp->spares[i]); 959 BSSWAP(hdrp->bitmaps[i]); 960 } 961 } 962 #endif 963