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 5.33 (Berkeley) 02/21/93"; 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 *)); 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) 393 const DB *dbp; 394 { 395 HTAB *hashp; 396 397 if (!dbp) 398 return (ERROR); 399 400 hashp = (HTAB *)dbp->internal; 401 if (!hashp->save_file) 402 return (0); 403 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 404 return (ERROR); 405 hashp->new_file = 0; 406 return (0); 407 } 408 409 /* 410 * Returns: 411 * 0 == OK 412 * -1 indicates that errno should be set 413 */ 414 static int 415 flush_meta(hashp) 416 HTAB *hashp; 417 { 418 HASHHDR *whdrp; 419 #if BYTE_ORDER == LITTLE_ENDIAN 420 HASHHDR whdr; 421 #endif 422 int fp, i, wsize; 423 424 if (!hashp->save_file) 425 return (0); 426 hashp->MAGIC = HASHMAGIC; 427 hashp->VERSION = HASHVERSION; 428 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 429 430 fp = hashp->fp; 431 whdrp = &hashp->hdr; 432 #if BYTE_ORDER == LITTLE_ENDIAN 433 whdrp = &whdr; 434 swap_header_copy(&hashp->hdr, whdrp); 435 #endif 436 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 437 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 438 return (-1); 439 else 440 if (wsize != sizeof(HASHHDR)) { 441 errno = EFTYPE; 442 hashp->errno = errno; 443 return (-1); 444 } 445 for (i = 0; i < NCACHED; i++) 446 if (hashp->mapp[i]) 447 if (__put_page(hashp, (char *)hashp->mapp[i], 448 hashp->BITMAPS[i], 0, 1)) 449 return (-1); 450 return (0); 451 } 452 453 /*******************************SEARCH ROUTINES *****************************/ 454 /* 455 * All the access routines return 456 * 457 * Returns: 458 * 0 on SUCCESS 459 * 1 to indicate an external ERROR (i.e. key not found, etc) 460 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 461 */ 462 static int 463 hash_get(dbp, key, data, flag) 464 const DB *dbp; 465 const DBT *key; 466 DBT *data; 467 u_int flag; 468 { 469 HTAB *hashp; 470 471 hashp = (HTAB *)dbp->internal; 472 if (flag) { 473 hashp->errno = errno = EINVAL; 474 return (ERROR); 475 } 476 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 477 } 478 479 static int 480 hash_put(dbp, key, data, flag) 481 const DB *dbp; 482 DBT *key; 483 const DBT *data; 484 u_int flag; 485 { 486 HTAB *hashp; 487 488 hashp = (HTAB *)dbp->internal; 489 if (flag && flag != R_NOOVERWRITE) { 490 hashp->errno = errno = EINVAL; 491 return (ERROR); 492 } 493 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 494 hashp->errno = errno = EPERM; 495 return (ERROR); 496 } 497 return (hash_access(hashp, flag == R_NOOVERWRITE ? 498 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 499 } 500 501 static int 502 hash_delete(dbp, key, flag) 503 const DB *dbp; 504 const DBT *key; 505 u_int flag; /* Ignored */ 506 { 507 HTAB *hashp; 508 509 hashp = (HTAB *)dbp->internal; 510 if (flag && flag != R_CURSOR) { 511 hashp->errno = errno = EINVAL; 512 return (ERROR); 513 } 514 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 515 hashp->errno = errno = EPERM; 516 return (ERROR); 517 } 518 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 519 } 520 521 /* 522 * Assume that hashp has been set in wrapper routine. 523 */ 524 static int 525 hash_access(hashp, action, key, val) 526 HTAB *hashp; 527 ACTION action; 528 DBT *key, *val; 529 { 530 register BUFHEAD *rbufp; 531 BUFHEAD *bufp, *save_bufp; 532 register u_short *bp; 533 register int n, ndx, off, size; 534 register char *kp; 535 u_short pageno; 536 537 #ifdef HASH_STATISTICS 538 hash_accesses++; 539 #endif 540 541 off = hashp->BSIZE; 542 size = key->size; 543 kp = (char *)key->data; 544 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 545 if (!rbufp) 546 return (ERROR); 547 save_bufp = rbufp; 548 549 /* Pin the bucket chain */ 550 rbufp->flags |= BUF_PIN; 551 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 552 if (bp[1] >= REAL_KEY) { 553 /* Real key/data pair */ 554 if (size == off - *bp && 555 memcmp(kp, rbufp->page + *bp, size) == 0) 556 goto found; 557 off = bp[1]; 558 #ifdef HASH_STATISTICS 559 hash_collisions++; 560 #endif 561 bp += 2; 562 ndx += 2; 563 } else if (bp[1] == OVFLPAGE) { 564 rbufp = __get_buf(hashp, *bp, rbufp, 0); 565 if (!rbufp) { 566 save_bufp->flags &= ~BUF_PIN; 567 return (ERROR); 568 } 569 /* FOR LOOP INIT */ 570 bp = (u_short *)rbufp->page; 571 n = *bp++; 572 ndx = 1; 573 off = hashp->BSIZE; 574 } else if (bp[1] < REAL_KEY) { 575 if ((ndx = 576 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 577 goto found; 578 if (ndx == -2) { 579 bufp = rbufp; 580 if (!(pageno = 581 __find_last_page(hashp, &bufp))) { 582 ndx = 0; 583 rbufp = bufp; 584 break; /* FOR */ 585 } 586 rbufp = __get_buf(hashp, pageno, bufp, 0); 587 if (!rbufp) { 588 save_bufp->flags &= ~BUF_PIN; 589 return (ERROR); 590 } 591 /* FOR LOOP INIT */ 592 bp = (u_short *)rbufp->page; 593 n = *bp++; 594 ndx = 1; 595 off = hashp->BSIZE; 596 } else { 597 save_bufp->flags &= ~BUF_PIN; 598 return (ERROR); 599 } 600 } 601 602 /* Not found */ 603 switch (action) { 604 case HASH_PUT: 605 case HASH_PUTNEW: 606 if (__addel(hashp, rbufp, key, val)) { 607 save_bufp->flags &= ~BUF_PIN; 608 return (ERROR); 609 } else { 610 save_bufp->flags &= ~BUF_PIN; 611 return (SUCCESS); 612 } 613 case HASH_GET: 614 case HASH_DELETE: 615 default: 616 save_bufp->flags &= ~BUF_PIN; 617 return (ABNORMAL); 618 } 619 620 found: 621 switch (action) { 622 case HASH_PUTNEW: 623 save_bufp->flags &= ~BUF_PIN; 624 return (ABNORMAL); 625 case HASH_GET: 626 bp = (u_short *)rbufp->page; 627 if (bp[ndx + 1] < REAL_KEY) { 628 if (__big_return(hashp, rbufp, ndx, val, 0)) 629 return (ERROR); 630 } else { 631 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 632 val->size = bp[ndx] - bp[ndx + 1]; 633 } 634 break; 635 case HASH_PUT: 636 if ((__delpair(hashp, rbufp, ndx)) || 637 (__addel(hashp, rbufp, key, val))) { 638 save_bufp->flags &= ~BUF_PIN; 639 return (ERROR); 640 } 641 break; 642 case HASH_DELETE: 643 if (__delpair(hashp, rbufp, ndx)) 644 return (ERROR); 645 break; 646 default: 647 abort(); 648 } 649 save_bufp->flags &= ~BUF_PIN; 650 return (SUCCESS); 651 } 652 653 static int 654 hash_seq(dbp, key, data, flag) 655 const DB *dbp; 656 DBT *key, *data; 657 u_int flag; 658 { 659 register u_int bucket; 660 register BUFHEAD *bufp; 661 HTAB *hashp; 662 u_short *bp, ndx; 663 664 hashp = (HTAB *)dbp->internal; 665 if (flag && flag != R_FIRST && flag != R_NEXT) { 666 hashp->errno = errno = EINVAL; 667 return (ERROR); 668 } 669 #ifdef HASH_STATISTICS 670 hash_accesses++; 671 #endif 672 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 673 hashp->cbucket = 0; 674 hashp->cndx = 1; 675 hashp->cpage = NULL; 676 } 677 678 for (bp = NULL; !bp || !bp[0]; ) { 679 if (!(bufp = hashp->cpage)) { 680 for (bucket = hashp->cbucket; 681 bucket <= hashp->MAX_BUCKET; 682 bucket++, hashp->cndx = 1) { 683 bufp = __get_buf(hashp, bucket, NULL, 0); 684 if (!bufp) 685 return (ERROR); 686 hashp->cpage = bufp; 687 bp = (u_short *)bufp->page; 688 if (bp[0]) 689 break; 690 } 691 hashp->cbucket = bucket; 692 if (hashp->cbucket > hashp->MAX_BUCKET) { 693 hashp->cbucket = -1; 694 return (ABNORMAL); 695 } 696 } else 697 bp = (u_short *)hashp->cpage->page; 698 699 #ifdef DEBUG 700 assert(bp); 701 assert(bufp); 702 #endif 703 while (bp[hashp->cndx + 1] == OVFLPAGE) { 704 bufp = hashp->cpage = 705 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 706 if (!bufp) 707 return (ERROR); 708 bp = (u_short *)(bufp->page); 709 hashp->cndx = 1; 710 } 711 if (!bp[0]) { 712 hashp->cpage = NULL; 713 ++hashp->cbucket; 714 } 715 } 716 ndx = hashp->cndx; 717 if (bp[ndx + 1] < REAL_KEY) { 718 if (__big_keydata(hashp, bufp, key, data, 1)) 719 return (ERROR); 720 } else { 721 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 722 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 723 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 724 data->size = bp[ndx] - bp[ndx + 1]; 725 ndx += 2; 726 if (ndx > bp[0]) { 727 hashp->cpage = NULL; 728 hashp->cbucket++; 729 hashp->cndx = 1; 730 } else 731 hashp->cndx = ndx; 732 } 733 return (SUCCESS); 734 } 735 736 /********************************* UTILITIES ************************/ 737 738 /* 739 * Returns: 740 * 0 ==> OK 741 * -1 ==> Error 742 */ 743 extern int 744 __expand_table(hashp) 745 HTAB *hashp; 746 { 747 u_int old_bucket, new_bucket; 748 int dirsize, new_segnum, spare_ndx; 749 750 #ifdef HASH_STATISTICS 751 hash_expansions++; 752 #endif 753 new_bucket = ++hashp->MAX_BUCKET; 754 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 755 756 new_segnum = new_bucket >> hashp->SSHIFT; 757 758 /* Check if we need a new segment */ 759 if (new_segnum >= hashp->nsegs) { 760 /* Check if we need to expand directory */ 761 if (new_segnum >= hashp->DSIZE) { 762 /* Reallocate directory */ 763 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 764 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 765 return (-1); 766 hashp->DSIZE = dirsize << 1; 767 } 768 if (!(hashp->dir[new_segnum] = 769 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 770 return (-1); 771 hashp->exsegs++; 772 hashp->nsegs++; 773 } 774 /* 775 * If the split point is increasing (MAX_BUCKET's log base 2 776 * * increases), we need to copy the current contents of the spare 777 * split bucket to the next bucket. 778 */ 779 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 780 if (spare_ndx > hashp->OVFL_POINT) { 781 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 782 hashp->OVFL_POINT = spare_ndx; 783 } 784 785 if (new_bucket > hashp->HIGH_MASK) { 786 /* Starting a new doubling */ 787 hashp->LOW_MASK = hashp->HIGH_MASK; 788 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 789 } 790 /* Relocate records to the new bucket */ 791 return (__split_page(hashp, old_bucket, new_bucket)); 792 } 793 794 /* 795 * If realloc guarantees that the pointer is not destroyed if the realloc 796 * fails, then this routine can go away. 797 */ 798 static void * 799 hash_realloc(p_ptr, oldsize, newsize) 800 SEGMENT **p_ptr; 801 int oldsize, newsize; 802 { 803 register void *p; 804 805 if (p = malloc(newsize)) { 806 memmove(p, *p_ptr, oldsize); 807 memset(*p_ptr + oldsize, 0, newsize - oldsize); 808 free(*p_ptr); 809 *p_ptr = p; 810 } 811 return (p); 812 } 813 814 extern u_int 815 __call_hash(hashp, k, len) 816 HTAB *hashp; 817 char *k; 818 int len; 819 { 820 int n, bucket; 821 822 n = hashp->hash(k, len); 823 bucket = n & hashp->HIGH_MASK; 824 if (bucket > hashp->MAX_BUCKET) 825 bucket = bucket & hashp->LOW_MASK; 826 return (bucket); 827 } 828 829 /* 830 * Allocate segment table. On error, destroy the table and set errno. 831 * 832 * Returns 0 on success 833 */ 834 static int 835 alloc_segs(hashp, nsegs) 836 HTAB *hashp; 837 int nsegs; 838 { 839 register int i; 840 register SEGMENT store; 841 842 int save_errno; 843 844 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 845 save_errno = errno; 846 (void)hdestroy(hashp); 847 errno = save_errno; 848 return (-1); 849 } 850 /* Allocate segments */ 851 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 852 if (!store) { 853 save_errno = errno; 854 (void)hdestroy(hashp); 855 errno = save_errno; 856 return (-1); 857 } 858 for (i = 0; i < nsegs; i++, hashp->nsegs++) 859 hashp->dir[i] = &store[i << hashp->SSHIFT]; 860 return (0); 861 } 862 863 #if BYTE_ORDER == LITTLE_ENDIAN 864 /* 865 * Hashp->hdr needs to be byteswapped. 866 */ 867 static void 868 swap_header_copy(srcp, destp) 869 HASHHDR *srcp, *destp; 870 { 871 int i; 872 873 BLSWAP_COPY(srcp->magic, destp->magic); 874 BLSWAP_COPY(srcp->version, destp->version); 875 BLSWAP_COPY(srcp->lorder, destp->lorder); 876 BLSWAP_COPY(srcp->bsize, destp->bsize); 877 BLSWAP_COPY(srcp->bshift, destp->bshift); 878 BLSWAP_COPY(srcp->dsize, destp->dsize); 879 BLSWAP_COPY(srcp->ssize, destp->ssize); 880 BLSWAP_COPY(srcp->sshift, destp->sshift); 881 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 882 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 883 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 884 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 885 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 886 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 887 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 888 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 889 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 890 for (i = 0; i < NCACHED; i++) { 891 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 892 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 893 } 894 } 895 896 static void 897 swap_header(hashp) 898 HTAB *hashp; 899 { 900 HASHHDR *hdrp; 901 int i; 902 903 hdrp = &hashp->hdr; 904 905 BLSWAP(hdrp->magic); 906 BLSWAP(hdrp->version); 907 BLSWAP(hdrp->lorder); 908 BLSWAP(hdrp->bsize); 909 BLSWAP(hdrp->bshift); 910 BLSWAP(hdrp->dsize); 911 BLSWAP(hdrp->ssize); 912 BLSWAP(hdrp->sshift); 913 BLSWAP(hdrp->ovfl_point); 914 BLSWAP(hdrp->last_freed); 915 BLSWAP(hdrp->max_bucket); 916 BLSWAP(hdrp->high_mask); 917 BLSWAP(hdrp->low_mask); 918 BLSWAP(hdrp->ffactor); 919 BLSWAP(hdrp->nkeys); 920 BLSWAP(hdrp->hdrpages); 921 BLSWAP(hdrp->h_charkey); 922 for (i = 0; i < NCACHED; i++) { 923 BLSWAP(hdrp->spares[i]); 924 BSSWAP(hdrp->bitmaps[i]); 925 } 926 } 927 #endif 928