1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 5.34 (Berkeley) 05/16/93"; 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_get __P((const DB *, const DBT *, DBT *, u_int)); 39 static int hash_put __P((const DB *, DBT *, const DBT *, u_int)); 40 static void *hash_realloc __P((SEGMENT **, int, int)); 41 static int hash_seq __P((const DB *, DBT *, DBT *, u_int)); 42 static int hash_sync __P((const DB *, u_int)); 43 static int hdestroy __P((HTAB *)); 44 static HTAB *init_hash __P((HTAB *, HASHINFO *)); 45 static int init_htab __P((HTAB *, int)); 46 #if BYTE_ORDER == LITTLE_ENDIAN 47 static void swap_header __P((HTAB *)); 48 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 49 #endif 50 51 /* Fast arithmetic, relying on powers of 2, */ 52 #define MOD(x, y) ((x) & ((y) - 1)) 53 54 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 55 56 /* Return values */ 57 #define SUCCESS (0) 58 #define ERROR (-1) 59 #define ABNORMAL (1) 60 61 #ifdef HASH_STATISTICS 62 long hash_accesses, hash_collisions, hash_expansions, hash_overflows; 63 #endif 64 65 /************************** INTERFACE ROUTINES ***************************/ 66 /* OPEN/CLOSE */ 67 68 extern DB * 69 __hash_open(file, flags, mode, info) 70 const char *file; 71 int flags, mode; 72 const HASHINFO *info; /* Special directives for create */ 73 { 74 HTAB *hashp; 75 struct stat statbuf; 76 DB *dbp; 77 int bpages, hdrsize, new_table, nsegs, save_errno; 78 79 if ((flags & O_ACCMODE) == O_WRONLY) { 80 errno = EINVAL; 81 return (NULL); 82 } 83 84 if (!(hashp = calloc(1, sizeof(HTAB)))) 85 return (NULL); 86 hashp->fp = -1; 87 /* 88 * Select flags relevant to us. Even if user wants write only, we need 89 * to be able to read the actual file, so we need to open it read/write. 90 * But, the field in the hashp structure needs to be accurate so that 91 * we can check accesses. 92 */ 93 hashp->flags = flags = flags & __USE_OPEN_FLAGS; 94 95 new_table = 0; 96 if (!file || (flags & O_TRUNC) || 97 (stat(file, &statbuf) && (errno == ENOENT))) { 98 if (errno == ENOENT) 99 errno = 0; /* Just in case someone looks at errno */ 100 new_table = 1; 101 } 102 if (file) { 103 if ((hashp->fp = open(file, flags, mode)) == -1) 104 RETURN_ERROR(errno, error0); 105 (void)fcntl(hashp->fp, F_SETFD, 1); 106 } 107 if (new_table) { 108 if (!(hashp = init_hash(hashp, (HASHINFO *)info))) 109 RETURN_ERROR(errno, error1); 110 } else { 111 /* Table already exists */ 112 if (info && info->hash) 113 hashp->hash = info->hash; 114 else 115 hashp->hash = __default_hash; 116 117 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 118 #if BYTE_ORDER == LITTLE_ENDIAN 119 swap_header(hashp); 120 #endif 121 if (hdrsize == -1) 122 RETURN_ERROR(errno, error1); 123 if (hdrsize != sizeof(HASHHDR)) 124 RETURN_ERROR(EFTYPE, error1); 125 /* Verify file type, versions and hash function */ 126 if (hashp->MAGIC != HASHMAGIC) 127 RETURN_ERROR(EFTYPE, error1); 128 if (hashp->VERSION != HASHVERSION) 129 RETURN_ERROR(EFTYPE, error1); 130 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 131 RETURN_ERROR(EFTYPE, error1); 132 /* 133 * Figure out how many segments we need. Max_Bucket is the 134 * maximum bucket number, so the number of buckets is 135 * max_bucket + 1. 136 */ 137 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 138 hashp->SGSIZE; 139 hashp->nsegs = 0; 140 if (alloc_segs(hashp, nsegs)) 141 /* 142 * If alloc_segs fails, table will have been destroyed 143 * and errno will have been set. 144 */ 145 return (NULL); 146 /* Read in bitmaps */ 147 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 148 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 149 (hashp->BSHIFT + BYTE_SHIFT); 150 151 hashp->nmaps = bpages; 152 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_long *)); 153 } 154 155 /* Initialize Buffer Manager */ 156 if (info && info->cachesize) 157 __buf_init(hashp, info->cachesize); 158 else 159 __buf_init(hashp, DEF_BUFSIZE); 160 161 hashp->new_file = new_table; 162 hashp->save_file = file && (hashp->flags & O_RDWR); 163 hashp->cbucket = -1; 164 if (!(dbp = malloc(sizeof(DB)))) { 165 save_errno = errno; 166 hdestroy(hashp); 167 errno = save_errno; 168 return (NULL); 169 } 170 dbp->internal = hashp; 171 dbp->close = hash_close; 172 dbp->del = hash_delete; 173 dbp->get = hash_get; 174 dbp->put = hash_put; 175 dbp->seq = hash_seq; 176 dbp->sync = hash_sync; 177 dbp->type = DB_HASH; 178 179 #ifdef DEBUG 180 (void)fprintf(stderr, 181 "%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", 182 "init_htab:", 183 "TABLE POINTER ", hashp, 184 "BUCKET SIZE ", hashp->BSIZE, 185 "BUCKET SHIFT ", hashp->BSHIFT, 186 "DIRECTORY SIZE ", hashp->DSIZE, 187 "SEGMENT SIZE ", hashp->SGSIZE, 188 "SEGMENT SHIFT ", hashp->SSHIFT, 189 "FILL FACTOR ", hashp->FFACTOR, 190 "MAX BUCKET ", hashp->MAX_BUCKET, 191 "OVFL POINT ", hashp->OVFL_POINT, 192 "LAST FREED ", hashp->LAST_FREED, 193 "HIGH MASK ", hashp->HIGH_MASK, 194 "LOW MASK ", hashp->LOW_MASK, 195 "NSEGS ", hashp->nsegs, 196 "NKEYS ", hashp->NKEYS); 197 #endif 198 #ifdef HASH_STATISTICS 199 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 200 #endif 201 return (dbp); 202 203 error1: 204 if (hashp != NULL) 205 (void)close(hashp->fp); 206 207 error0: 208 free(hashp); 209 errno = save_errno; 210 return (NULL); 211 } 212 213 static int 214 hash_close(dbp) 215 DB *dbp; 216 { 217 HTAB *hashp; 218 int retval; 219 220 if (!dbp) 221 return (ERROR); 222 223 hashp = (HTAB *)dbp->internal; 224 retval = hdestroy(hashp); 225 free(dbp); 226 return (retval); 227 } 228 229 /************************** LOCAL CREATION ROUTINES **********************/ 230 static HTAB * 231 init_hash(hashp, info) 232 HTAB *hashp; 233 HASHINFO *info; 234 { 235 int nelem; 236 237 nelem = 1; 238 hashp->NKEYS = 0; 239 hashp->LORDER = BYTE_ORDER; 240 hashp->BSIZE = DEF_BUCKET_SIZE; 241 hashp->BSHIFT = DEF_BUCKET_SHIFT; 242 hashp->SGSIZE = DEF_SEGSIZE; 243 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 244 hashp->DSIZE = DEF_DIRSIZE; 245 hashp->FFACTOR = DEF_FFACTOR; 246 hashp->hash = __default_hash; 247 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 248 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 249 250 if (info) { 251 if (info->bsize) { 252 /* Round pagesize up to power of 2 */ 253 hashp->BSHIFT = __log2(info->bsize); 254 hashp->BSIZE = 1 << hashp->BSHIFT; 255 if (hashp->BSIZE > MAX_BSIZE) { 256 errno = EINVAL; 257 return (NULL); 258 } 259 } 260 if (info->ffactor) 261 hashp->FFACTOR = info->ffactor; 262 if (info->hash) 263 hashp->hash = info->hash; 264 if (info->nelem) 265 nelem = info->nelem; 266 if (info->lorder) { 267 if (info->lorder != BIG_ENDIAN && 268 info->lorder != LITTLE_ENDIAN) { 269 errno = EINVAL; 270 return (NULL); 271 } 272 hashp->LORDER = info->lorder; 273 } 274 } 275 /* init_htab should destroy the table and set errno if it fails */ 276 if (init_htab(hashp, nelem)) 277 return (NULL); 278 else 279 return (hashp); 280 } 281 /* 282 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 283 * the table and set errno, so we just pass the error information along. 284 * 285 * Returns 0 on No Error 286 */ 287 static int 288 init_htab(hashp, nelem) 289 HTAB *hashp; 290 int nelem; 291 { 292 register int nbuckets, nsegs; 293 int l2; 294 295 /* 296 * Divide number of elements by the fill factor and determine a 297 * desired number of buckets. Allocate space for the next greater 298 * power of two number of buckets. 299 */ 300 nelem = (nelem - 1) / hashp->FFACTOR + 1; 301 302 l2 = __log2(MAX(nelem, 2)); 303 nbuckets = 1 << l2; 304 305 hashp->SPARES[l2] = l2 + 1; 306 hashp->SPARES[l2 + 1] = l2 + 1; 307 hashp->OVFL_POINT = l2; 308 hashp->LAST_FREED = 2; 309 310 /* First bitmap page is at: splitpoint l2 page offset 1 */ 311 if (__init_bitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 312 return (-1); 313 314 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 315 hashp->HIGH_MASK = (nbuckets << 1) - 1; 316 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 317 hashp->BSHIFT) + 1; 318 319 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 320 nsegs = 1 << __log2(nsegs); 321 322 if (nsegs > hashp->DSIZE) 323 hashp->DSIZE = nsegs; 324 return (alloc_segs(hashp, nsegs)); 325 } 326 327 /********************** DESTROY/CLOSE ROUTINES ************************/ 328 329 /* 330 * Flushes any changes to the file if necessary and destroys the hashp 331 * structure, freeing all allocated space. 332 */ 333 static int 334 hdestroy(hashp) 335 HTAB *hashp; 336 { 337 int i, save_errno; 338 339 save_errno = 0; 340 341 #ifdef HASH_STATISTICS 342 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 343 hash_accesses, hash_collisions); 344 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 345 hash_expansions); 346 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 347 hash_overflows); 348 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 349 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 350 351 for (i = 0; i < NCACHED; i++) 352 (void)fprintf(stderr, 353 "spares[%d] = %d\n", i, hashp->SPARES[i]); 354 #endif 355 /* 356 * Call on buffer manager to free buffers, and if required, 357 * write them to disk. 358 */ 359 if (__buf_free(hashp, 1, hashp->save_file)) 360 save_errno = errno; 361 if (hashp->dir) { 362 free(*hashp->dir); /* Free initial segments */ 363 /* Free extra segments */ 364 while (hashp->exsegs--) 365 free(hashp->dir[--hashp->nsegs]); 366 free(hashp->dir); 367 } 368 if (flush_meta(hashp) && !save_errno) 369 save_errno = errno; 370 /* Free Bigmaps */ 371 for (i = 0; i < hashp->nmaps; i++) 372 if (hashp->mapp[i]) 373 free(hashp->mapp[i]); 374 375 if (hashp->fp != -1) 376 (void)close(hashp->fp); 377 378 if (save_errno) { 379 errno = save_errno; 380 return (ERROR); 381 } 382 return (SUCCESS); 383 } 384 /* 385 * Write modified pages to disk 386 * 387 * Returns: 388 * 0 == OK 389 * -1 ERROR 390 */ 391 static int 392 hash_sync(dbp, flags) 393 const DB *dbp; 394 u_int flags; 395 { 396 HTAB *hashp; 397 398 if (flags != 0) { 399 errno = EINVAL; 400 return (ERROR); 401 } 402 403 if (!dbp) 404 return (ERROR); 405 406 hashp = (HTAB *)dbp->internal; 407 if (!hashp->save_file) 408 return (0); 409 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 410 return (ERROR); 411 hashp->new_file = 0; 412 return (0); 413 } 414 415 /* 416 * Returns: 417 * 0 == OK 418 * -1 indicates that errno should be set 419 */ 420 static int 421 flush_meta(hashp) 422 HTAB *hashp; 423 { 424 HASHHDR *whdrp; 425 #if BYTE_ORDER == LITTLE_ENDIAN 426 HASHHDR whdr; 427 #endif 428 int fp, i, wsize; 429 430 if (!hashp->save_file) 431 return (0); 432 hashp->MAGIC = HASHMAGIC; 433 hashp->VERSION = HASHVERSION; 434 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 435 436 fp = hashp->fp; 437 whdrp = &hashp->hdr; 438 #if BYTE_ORDER == LITTLE_ENDIAN 439 whdrp = &whdr; 440 swap_header_copy(&hashp->hdr, whdrp); 441 #endif 442 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 443 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 444 return (-1); 445 else 446 if (wsize != sizeof(HASHHDR)) { 447 errno = EFTYPE; 448 hashp->errno = errno; 449 return (-1); 450 } 451 for (i = 0; i < NCACHED; i++) 452 if (hashp->mapp[i]) 453 if (__put_page(hashp, (char *)hashp->mapp[i], 454 hashp->BITMAPS[i], 0, 1)) 455 return (-1); 456 return (0); 457 } 458 459 /*******************************SEARCH ROUTINES *****************************/ 460 /* 461 * All the access routines return 462 * 463 * Returns: 464 * 0 on SUCCESS 465 * 1 to indicate an external ERROR (i.e. key not found, etc) 466 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 467 */ 468 static int 469 hash_get(dbp, key, data, flag) 470 const DB *dbp; 471 const DBT *key; 472 DBT *data; 473 u_int flag; 474 { 475 HTAB *hashp; 476 477 hashp = (HTAB *)dbp->internal; 478 if (flag) { 479 hashp->errno = errno = EINVAL; 480 return (ERROR); 481 } 482 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 483 } 484 485 static int 486 hash_put(dbp, key, data, flag) 487 const DB *dbp; 488 DBT *key; 489 const DBT *data; 490 u_int flag; 491 { 492 HTAB *hashp; 493 494 hashp = (HTAB *)dbp->internal; 495 if (flag && flag != R_NOOVERWRITE) { 496 hashp->errno = errno = EINVAL; 497 return (ERROR); 498 } 499 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 500 hashp->errno = errno = EPERM; 501 return (ERROR); 502 } 503 return (hash_access(hashp, flag == R_NOOVERWRITE ? 504 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 505 } 506 507 static int 508 hash_delete(dbp, key, flag) 509 const DB *dbp; 510 const DBT *key; 511 u_int flag; /* Ignored */ 512 { 513 HTAB *hashp; 514 515 hashp = (HTAB *)dbp->internal; 516 if (flag && flag != R_CURSOR) { 517 hashp->errno = errno = EINVAL; 518 return (ERROR); 519 } 520 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 521 hashp->errno = errno = EPERM; 522 return (ERROR); 523 } 524 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 525 } 526 527 /* 528 * Assume that hashp has been set in wrapper routine. 529 */ 530 static int 531 hash_access(hashp, action, key, val) 532 HTAB *hashp; 533 ACTION action; 534 DBT *key, *val; 535 { 536 register BUFHEAD *rbufp; 537 BUFHEAD *bufp, *save_bufp; 538 register u_short *bp; 539 register int n, ndx, off, size; 540 register char *kp; 541 u_short pageno; 542 543 #ifdef HASH_STATISTICS 544 hash_accesses++; 545 #endif 546 547 off = hashp->BSIZE; 548 size = key->size; 549 kp = (char *)key->data; 550 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 551 if (!rbufp) 552 return (ERROR); 553 save_bufp = rbufp; 554 555 /* Pin the bucket chain */ 556 rbufp->flags |= BUF_PIN; 557 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 558 if (bp[1] >= REAL_KEY) { 559 /* Real key/data pair */ 560 if (size == off - *bp && 561 memcmp(kp, rbufp->page + *bp, size) == 0) 562 goto found; 563 off = bp[1]; 564 #ifdef HASH_STATISTICS 565 hash_collisions++; 566 #endif 567 bp += 2; 568 ndx += 2; 569 } else if (bp[1] == OVFLPAGE) { 570 rbufp = __get_buf(hashp, *bp, rbufp, 0); 571 if (!rbufp) { 572 save_bufp->flags &= ~BUF_PIN; 573 return (ERROR); 574 } 575 /* FOR LOOP INIT */ 576 bp = (u_short *)rbufp->page; 577 n = *bp++; 578 ndx = 1; 579 off = hashp->BSIZE; 580 } else if (bp[1] < REAL_KEY) { 581 if ((ndx = 582 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 583 goto found; 584 if (ndx == -2) { 585 bufp = rbufp; 586 if (!(pageno = 587 __find_last_page(hashp, &bufp))) { 588 ndx = 0; 589 rbufp = bufp; 590 break; /* FOR */ 591 } 592 rbufp = __get_buf(hashp, pageno, bufp, 0); 593 if (!rbufp) { 594 save_bufp->flags &= ~BUF_PIN; 595 return (ERROR); 596 } 597 /* FOR LOOP INIT */ 598 bp = (u_short *)rbufp->page; 599 n = *bp++; 600 ndx = 1; 601 off = hashp->BSIZE; 602 } else { 603 save_bufp->flags &= ~BUF_PIN; 604 return (ERROR); 605 } 606 } 607 608 /* Not found */ 609 switch (action) { 610 case HASH_PUT: 611 case HASH_PUTNEW: 612 if (__addel(hashp, rbufp, key, val)) { 613 save_bufp->flags &= ~BUF_PIN; 614 return (ERROR); 615 } else { 616 save_bufp->flags &= ~BUF_PIN; 617 return (SUCCESS); 618 } 619 case HASH_GET: 620 case HASH_DELETE: 621 default: 622 save_bufp->flags &= ~BUF_PIN; 623 return (ABNORMAL); 624 } 625 626 found: 627 switch (action) { 628 case HASH_PUTNEW: 629 save_bufp->flags &= ~BUF_PIN; 630 return (ABNORMAL); 631 case HASH_GET: 632 bp = (u_short *)rbufp->page; 633 if (bp[ndx + 1] < REAL_KEY) { 634 if (__big_return(hashp, rbufp, ndx, val, 0)) 635 return (ERROR); 636 } else { 637 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 638 val->size = bp[ndx] - bp[ndx + 1]; 639 } 640 break; 641 case HASH_PUT: 642 if ((__delpair(hashp, rbufp, ndx)) || 643 (__addel(hashp, rbufp, key, val))) { 644 save_bufp->flags &= ~BUF_PIN; 645 return (ERROR); 646 } 647 break; 648 case HASH_DELETE: 649 if (__delpair(hashp, rbufp, ndx)) 650 return (ERROR); 651 break; 652 default: 653 abort(); 654 } 655 save_bufp->flags &= ~BUF_PIN; 656 return (SUCCESS); 657 } 658 659 static int 660 hash_seq(dbp, key, data, flag) 661 const DB *dbp; 662 DBT *key, *data; 663 u_int flag; 664 { 665 register u_int bucket; 666 register BUFHEAD *bufp; 667 HTAB *hashp; 668 u_short *bp, ndx; 669 670 hashp = (HTAB *)dbp->internal; 671 if (flag && flag != R_FIRST && flag != R_NEXT) { 672 hashp->errno = errno = EINVAL; 673 return (ERROR); 674 } 675 #ifdef HASH_STATISTICS 676 hash_accesses++; 677 #endif 678 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 679 hashp->cbucket = 0; 680 hashp->cndx = 1; 681 hashp->cpage = NULL; 682 } 683 684 for (bp = NULL; !bp || !bp[0]; ) { 685 if (!(bufp = hashp->cpage)) { 686 for (bucket = hashp->cbucket; 687 bucket <= hashp->MAX_BUCKET; 688 bucket++, hashp->cndx = 1) { 689 bufp = __get_buf(hashp, bucket, NULL, 0); 690 if (!bufp) 691 return (ERROR); 692 hashp->cpage = bufp; 693 bp = (u_short *)bufp->page; 694 if (bp[0]) 695 break; 696 } 697 hashp->cbucket = bucket; 698 if (hashp->cbucket > hashp->MAX_BUCKET) { 699 hashp->cbucket = -1; 700 return (ABNORMAL); 701 } 702 } else 703 bp = (u_short *)hashp->cpage->page; 704 705 #ifdef DEBUG 706 assert(bp); 707 assert(bufp); 708 #endif 709 while (bp[hashp->cndx + 1] == OVFLPAGE) { 710 bufp = hashp->cpage = 711 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 712 if (!bufp) 713 return (ERROR); 714 bp = (u_short *)(bufp->page); 715 hashp->cndx = 1; 716 } 717 if (!bp[0]) { 718 hashp->cpage = NULL; 719 ++hashp->cbucket; 720 } 721 } 722 ndx = hashp->cndx; 723 if (bp[ndx + 1] < REAL_KEY) { 724 if (__big_keydata(hashp, bufp, key, data, 1)) 725 return (ERROR); 726 } else { 727 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 728 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 729 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 730 data->size = bp[ndx] - bp[ndx + 1]; 731 ndx += 2; 732 if (ndx > bp[0]) { 733 hashp->cpage = NULL; 734 hashp->cbucket++; 735 hashp->cndx = 1; 736 } else 737 hashp->cndx = ndx; 738 } 739 return (SUCCESS); 740 } 741 742 /********************************* UTILITIES ************************/ 743 744 /* 745 * Returns: 746 * 0 ==> OK 747 * -1 ==> Error 748 */ 749 extern int 750 __expand_table(hashp) 751 HTAB *hashp; 752 { 753 u_int old_bucket, new_bucket; 754 int dirsize, new_segnum, spare_ndx; 755 756 #ifdef HASH_STATISTICS 757 hash_expansions++; 758 #endif 759 new_bucket = ++hashp->MAX_BUCKET; 760 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 761 762 new_segnum = new_bucket >> hashp->SSHIFT; 763 764 /* Check if we need a new segment */ 765 if (new_segnum >= hashp->nsegs) { 766 /* Check if we need to expand directory */ 767 if (new_segnum >= hashp->DSIZE) { 768 /* Reallocate directory */ 769 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 770 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 771 return (-1); 772 hashp->DSIZE = dirsize << 1; 773 } 774 if (!(hashp->dir[new_segnum] = 775 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 776 return (-1); 777 hashp->exsegs++; 778 hashp->nsegs++; 779 } 780 /* 781 * If the split point is increasing (MAX_BUCKET's log base 2 782 * * increases), we need to copy the current contents of the spare 783 * split bucket to the next bucket. 784 */ 785 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 786 if (spare_ndx > hashp->OVFL_POINT) { 787 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 788 hashp->OVFL_POINT = spare_ndx; 789 } 790 791 if (new_bucket > hashp->HIGH_MASK) { 792 /* Starting a new doubling */ 793 hashp->LOW_MASK = hashp->HIGH_MASK; 794 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 795 } 796 /* Relocate records to the new bucket */ 797 return (__split_page(hashp, old_bucket, new_bucket)); 798 } 799 800 /* 801 * If realloc guarantees that the pointer is not destroyed if the realloc 802 * fails, then this routine can go away. 803 */ 804 static void * 805 hash_realloc(p_ptr, oldsize, newsize) 806 SEGMENT **p_ptr; 807 int oldsize, newsize; 808 { 809 register void *p; 810 811 if (p = malloc(newsize)) { 812 memmove(p, *p_ptr, oldsize); 813 memset(*p_ptr + oldsize, 0, newsize - oldsize); 814 free(*p_ptr); 815 *p_ptr = p; 816 } 817 return (p); 818 } 819 820 extern u_int 821 __call_hash(hashp, k, len) 822 HTAB *hashp; 823 char *k; 824 int len; 825 { 826 int n, bucket; 827 828 n = hashp->hash(k, len); 829 bucket = n & hashp->HIGH_MASK; 830 if (bucket > hashp->MAX_BUCKET) 831 bucket = bucket & hashp->LOW_MASK; 832 return (bucket); 833 } 834 835 /* 836 * Allocate segment table. On error, destroy the table and set errno. 837 * 838 * Returns 0 on success 839 */ 840 static int 841 alloc_segs(hashp, nsegs) 842 HTAB *hashp; 843 int nsegs; 844 { 845 register int i; 846 register SEGMENT store; 847 848 int save_errno; 849 850 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 851 save_errno = errno; 852 (void)hdestroy(hashp); 853 errno = save_errno; 854 return (-1); 855 } 856 /* Allocate segments */ 857 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 858 if (!store) { 859 save_errno = errno; 860 (void)hdestroy(hashp); 861 errno = save_errno; 862 return (-1); 863 } 864 for (i = 0; i < nsegs; i++, hashp->nsegs++) 865 hashp->dir[i] = &store[i << hashp->SSHIFT]; 866 return (0); 867 } 868 869 #if BYTE_ORDER == LITTLE_ENDIAN 870 /* 871 * Hashp->hdr needs to be byteswapped. 872 */ 873 static void 874 swap_header_copy(srcp, destp) 875 HASHHDR *srcp, *destp; 876 { 877 int i; 878 879 BLSWAP_COPY(srcp->magic, destp->magic); 880 BLSWAP_COPY(srcp->version, destp->version); 881 BLSWAP_COPY(srcp->lorder, destp->lorder); 882 BLSWAP_COPY(srcp->bsize, destp->bsize); 883 BLSWAP_COPY(srcp->bshift, destp->bshift); 884 BLSWAP_COPY(srcp->dsize, destp->dsize); 885 BLSWAP_COPY(srcp->ssize, destp->ssize); 886 BLSWAP_COPY(srcp->sshift, destp->sshift); 887 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 888 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 889 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 890 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 891 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 892 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 893 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 894 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 895 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 896 for (i = 0; i < NCACHED; i++) { 897 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 898 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 899 } 900 } 901 902 static void 903 swap_header(hashp) 904 HTAB *hashp; 905 { 906 HASHHDR *hdrp; 907 int i; 908 909 hdrp = &hashp->hdr; 910 911 BLSWAP(hdrp->magic); 912 BLSWAP(hdrp->version); 913 BLSWAP(hdrp->lorder); 914 BLSWAP(hdrp->bsize); 915 BLSWAP(hdrp->bshift); 916 BLSWAP(hdrp->dsize); 917 BLSWAP(hdrp->ssize); 918 BLSWAP(hdrp->sshift); 919 BLSWAP(hdrp->ovfl_point); 920 BLSWAP(hdrp->last_freed); 921 BLSWAP(hdrp->max_bucket); 922 BLSWAP(hdrp->high_mask); 923 BLSWAP(hdrp->low_mask); 924 BLSWAP(hdrp->ffactor); 925 BLSWAP(hdrp->nkeys); 926 BLSWAP(hdrp->hdrpages); 927 BLSWAP(hdrp->h_charkey); 928 for (i = 0; i < NCACHED; i++) { 929 BLSWAP(hdrp->spares[i]); 930 BSSWAP(hdrp->bitmaps[i]); 931 } 932 } 933 #endif 934