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 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)hash.c 8.1 (Berkeley) 6/6/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #ifdef DEBUG 51 #include <assert.h> 52 #endif 53 54 #include <db.h> 55 #include "hash.h" 56 #include "page.h" 57 #include "extern.h" 58 59 static int alloc_segs __P((HTAB *, int)); 60 static int flush_meta __P((HTAB *)); 61 static int hash_access __P((HTAB *, ACTION, DBT *, DBT *)); 62 static int hash_close __P((DB *)); 63 static int hash_delete __P((const DB *, const DBT *, u_int)); 64 static int hash_fd __P((const DB *)); 65 static int hash_get __P((const DB *, const DBT *, DBT *, u_int)); 66 static int hash_put __P((const DB *, DBT *, const DBT *, u_int)); 67 static void *hash_realloc __P((SEGMENT **, int, int)); 68 static int hash_seq __P((const DB *, DBT *, DBT *, u_int)); 69 static int hash_sync __P((const DB *, u_int)); 70 static int hdestroy __P((HTAB *)); 71 static HTAB *init_hash __P((HTAB *, const char *, HASHINFO *)); 72 static int init_htab __P((HTAB *, int)); 73 #if BYTE_ORDER == LITTLE_ENDIAN 74 static void swap_header __P((HTAB *)); 75 static void swap_header_copy __P((HASHHDR *, HASHHDR *)); 76 #endif 77 78 /* Fast arithmetic, relying on powers of 2, */ 79 #define MOD(x, y) ((x) & ((y) - 1)) 80 81 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 82 83 /* Return values */ 84 #define SUCCESS (0) 85 #define ERROR (-1) 86 #define ABNORMAL (1) 87 88 #ifdef HASH_STATISTICS 89 long hash_accesses, hash_collisions, hash_expansions, hash_overflows; 90 #endif 91 92 /************************** INTERFACE ROUTINES ***************************/ 93 /* OPEN/CLOSE */ 94 95 extern DB * 96 __hash_open(file, flags, mode, info) 97 const char *file; 98 int flags, mode; 99 const HASHINFO *info; /* Special directives for create */ 100 { 101 HTAB *hashp; 102 struct stat statbuf; 103 DB *dbp; 104 int bpages, hdrsize, new_table, nsegs, save_errno; 105 106 if ((flags & O_ACCMODE) == O_WRONLY) { 107 errno = EINVAL; 108 return (NULL); 109 } 110 111 if (!(hashp = calloc(1, sizeof(HTAB)))) 112 return (NULL); 113 hashp->fp = -1; 114 /* 115 * Select flags relevant to us. Even if user wants write only, we need 116 * to be able to read the actual file, so we need to open it read/write. 117 * But, the field in the hashp structure needs to be accurate so that 118 * we can check accesses. 119 */ 120 hashp->flags = flags = flags & __USE_OPEN_FLAGS; 121 122 new_table = 0; 123 if (!file || (flags & O_TRUNC) || 124 (stat(file, &statbuf) && (errno == ENOENT))) { 125 if (errno == ENOENT) 126 errno = 0; /* Just in case someone looks at errno */ 127 new_table = 1; 128 } 129 if (file) { 130 if ((hashp->fp = open(file, flags, mode)) == -1) 131 RETURN_ERROR(errno, error0); 132 (void)fcntl(hashp->fp, F_SETFD, 1); 133 } 134 if (new_table) { 135 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 136 RETURN_ERROR(errno, error1); 137 } else { 138 /* Table already exists */ 139 if (info && info->hash) 140 hashp->hash = info->hash; 141 else 142 hashp->hash = __default_hash; 143 144 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 145 #if BYTE_ORDER == LITTLE_ENDIAN 146 swap_header(hashp); 147 #endif 148 if (hdrsize == -1) 149 RETURN_ERROR(errno, error1); 150 if (hdrsize != sizeof(HASHHDR)) 151 RETURN_ERROR(EFTYPE, error1); 152 /* Verify file type, versions and hash function */ 153 if (hashp->MAGIC != HASHMAGIC) 154 RETURN_ERROR(EFTYPE, error1); 155 if (hashp->VERSION != HASHVERSION) 156 RETURN_ERROR(EFTYPE, error1); 157 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 158 RETURN_ERROR(EFTYPE, error1); 159 /* 160 * Figure out how many segments we need. Max_Bucket is the 161 * maximum bucket number, so the number of buckets is 162 * max_bucket + 1. 163 */ 164 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 165 hashp->SGSIZE; 166 hashp->nsegs = 0; 167 if (alloc_segs(hashp, nsegs)) 168 /* 169 * If alloc_segs fails, table will have been destroyed 170 * and errno will have been set. 171 */ 172 return (NULL); 173 /* Read in bitmaps */ 174 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 175 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 176 (hashp->BSHIFT + BYTE_SHIFT); 177 178 hashp->nmaps = bpages; 179 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_long *)); 180 } 181 182 /* Initialize Buffer Manager */ 183 if (info && info->cachesize) 184 __buf_init(hashp, info->cachesize); 185 else 186 __buf_init(hashp, DEF_BUFSIZE); 187 188 hashp->new_file = new_table; 189 hashp->save_file = file && (hashp->flags & O_RDWR); 190 hashp->cbucket = -1; 191 if (!(dbp = malloc(sizeof(DB)))) { 192 save_errno = errno; 193 hdestroy(hashp); 194 errno = save_errno; 195 return (NULL); 196 } 197 dbp->internal = hashp; 198 dbp->close = hash_close; 199 dbp->del = hash_delete; 200 dbp->fd = hash_fd; 201 dbp->get = hash_get; 202 dbp->put = hash_put; 203 dbp->seq = hash_seq; 204 dbp->sync = hash_sync; 205 dbp->type = DB_HASH; 206 207 #ifdef DEBUG 208 (void)fprintf(stderr, 209 "%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", 210 "init_htab:", 211 "TABLE POINTER ", hashp, 212 "BUCKET SIZE ", hashp->BSIZE, 213 "BUCKET SHIFT ", hashp->BSHIFT, 214 "DIRECTORY SIZE ", hashp->DSIZE, 215 "SEGMENT SIZE ", hashp->SGSIZE, 216 "SEGMENT SHIFT ", hashp->SSHIFT, 217 "FILL FACTOR ", hashp->FFACTOR, 218 "MAX BUCKET ", hashp->MAX_BUCKET, 219 "OVFL POINT ", hashp->OVFL_POINT, 220 "LAST FREED ", hashp->LAST_FREED, 221 "HIGH MASK ", hashp->HIGH_MASK, 222 "LOW MASK ", hashp->LOW_MASK, 223 "NSEGS ", hashp->nsegs, 224 "NKEYS ", hashp->NKEYS); 225 #endif 226 #ifdef HASH_STATISTICS 227 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 228 #endif 229 return (dbp); 230 231 error1: 232 if (hashp != NULL) 233 (void)close(hashp->fp); 234 235 error0: 236 free(hashp); 237 errno = save_errno; 238 return (NULL); 239 } 240 241 static int 242 hash_close(dbp) 243 DB *dbp; 244 { 245 HTAB *hashp; 246 int retval; 247 248 if (!dbp) 249 return (ERROR); 250 251 hashp = (HTAB *)dbp->internal; 252 retval = hdestroy(hashp); 253 free(dbp); 254 return (retval); 255 } 256 257 static int 258 hash_fd(dbp) 259 const DB *dbp; 260 { 261 HTAB *hashp; 262 263 if (!dbp) 264 return (ERROR); 265 266 hashp = (HTAB *)dbp->internal; 267 if (hashp->fp == -1) { 268 errno = ENOENT; 269 return (-1); 270 } 271 return (hashp->fp); 272 } 273 274 /************************** LOCAL CREATION ROUTINES **********************/ 275 static HTAB * 276 init_hash(hashp, file, info) 277 HTAB *hashp; 278 const char *file; 279 HASHINFO *info; 280 { 281 struct stat statbuf; 282 int nelem; 283 284 nelem = 1; 285 hashp->NKEYS = 0; 286 hashp->LORDER = BYTE_ORDER; 287 hashp->BSIZE = DEF_BUCKET_SIZE; 288 hashp->BSHIFT = DEF_BUCKET_SHIFT; 289 hashp->SGSIZE = DEF_SEGSIZE; 290 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 291 hashp->DSIZE = DEF_DIRSIZE; 292 hashp->FFACTOR = DEF_FFACTOR; 293 hashp->hash = __default_hash; 294 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 295 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 296 297 /* Fix bucket size to be optimal for file system */ 298 if (file != NULL) { 299 if (stat(file, &statbuf)) 300 return (NULL); 301 hashp->BSIZE = statbuf.st_blksize; 302 hashp->BSHIFT = __log2(hashp->BSIZE); 303 } 304 305 if (info) { 306 if (info->bsize) { 307 /* Round pagesize up to power of 2 */ 308 hashp->BSHIFT = __log2(info->bsize); 309 hashp->BSIZE = 1 << hashp->BSHIFT; 310 if (hashp->BSIZE > MAX_BSIZE) { 311 errno = EINVAL; 312 return (NULL); 313 } 314 } 315 if (info->ffactor) 316 hashp->FFACTOR = info->ffactor; 317 if (info->hash) 318 hashp->hash = info->hash; 319 if (info->nelem) 320 nelem = info->nelem; 321 if (info->lorder) { 322 if (info->lorder != BIG_ENDIAN && 323 info->lorder != LITTLE_ENDIAN) { 324 errno = EINVAL; 325 return (NULL); 326 } 327 hashp->LORDER = info->lorder; 328 } 329 } 330 /* init_htab should destroy the table and set errno if it fails */ 331 if (init_htab(hashp, nelem)) 332 return (NULL); 333 else 334 return (hashp); 335 } 336 /* 337 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 338 * the table and set errno, so we just pass the error information along. 339 * 340 * Returns 0 on No Error 341 */ 342 static int 343 init_htab(hashp, nelem) 344 HTAB *hashp; 345 int nelem; 346 { 347 register int nbuckets, nsegs; 348 int l2; 349 350 /* 351 * Divide number of elements by the fill factor and determine a 352 * desired number of buckets. Allocate space for the next greater 353 * power of two number of buckets. 354 */ 355 nelem = (nelem - 1) / hashp->FFACTOR + 1; 356 357 l2 = __log2(MAX(nelem, 2)); 358 nbuckets = 1 << l2; 359 360 hashp->SPARES[l2] = l2 + 1; 361 hashp->SPARES[l2 + 1] = l2 + 1; 362 hashp->OVFL_POINT = l2; 363 hashp->LAST_FREED = 2; 364 365 /* First bitmap page is at: splitpoint l2 page offset 1 */ 366 if (__init_bitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 367 return (-1); 368 369 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 370 hashp->HIGH_MASK = (nbuckets << 1) - 1; 371 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 372 hashp->BSHIFT) + 1; 373 374 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 375 nsegs = 1 << __log2(nsegs); 376 377 if (nsegs > hashp->DSIZE) 378 hashp->DSIZE = nsegs; 379 return (alloc_segs(hashp, nsegs)); 380 } 381 382 /********************** DESTROY/CLOSE ROUTINES ************************/ 383 384 /* 385 * Flushes any changes to the file if necessary and destroys the hashp 386 * structure, freeing all allocated space. 387 */ 388 static int 389 hdestroy(hashp) 390 HTAB *hashp; 391 { 392 int i, save_errno; 393 394 save_errno = 0; 395 396 #ifdef HASH_STATISTICS 397 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 398 hash_accesses, hash_collisions); 399 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 400 hash_expansions); 401 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 402 hash_overflows); 403 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 404 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 405 406 for (i = 0; i < NCACHED; i++) 407 (void)fprintf(stderr, 408 "spares[%d] = %d\n", i, hashp->SPARES[i]); 409 #endif 410 /* 411 * Call on buffer manager to free buffers, and if required, 412 * write them to disk. 413 */ 414 if (__buf_free(hashp, 1, hashp->save_file)) 415 save_errno = errno; 416 if (hashp->dir) { 417 free(*hashp->dir); /* Free initial segments */ 418 /* Free extra segments */ 419 while (hashp->exsegs--) 420 free(hashp->dir[--hashp->nsegs]); 421 free(hashp->dir); 422 } 423 if (flush_meta(hashp) && !save_errno) 424 save_errno = errno; 425 /* Free Bigmaps */ 426 for (i = 0; i < hashp->nmaps; i++) 427 if (hashp->mapp[i]) 428 free(hashp->mapp[i]); 429 430 if (hashp->fp != -1) 431 (void)close(hashp->fp); 432 433 if (save_errno) { 434 errno = save_errno; 435 return (ERROR); 436 } 437 return (SUCCESS); 438 } 439 /* 440 * Write modified pages to disk 441 * 442 * Returns: 443 * 0 == OK 444 * -1 ERROR 445 */ 446 static int 447 hash_sync(dbp, flags) 448 const DB *dbp; 449 u_int flags; 450 { 451 HTAB *hashp; 452 453 if (flags != 0) { 454 errno = EINVAL; 455 return (ERROR); 456 } 457 458 if (!dbp) 459 return (ERROR); 460 461 hashp = (HTAB *)dbp->internal; 462 if (!hashp->save_file) 463 return (0); 464 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 465 return (ERROR); 466 hashp->new_file = 0; 467 return (0); 468 } 469 470 /* 471 * Returns: 472 * 0 == OK 473 * -1 indicates that errno should be set 474 */ 475 static int 476 flush_meta(hashp) 477 HTAB *hashp; 478 { 479 HASHHDR *whdrp; 480 #if BYTE_ORDER == LITTLE_ENDIAN 481 HASHHDR whdr; 482 #endif 483 int fp, i, wsize; 484 485 if (!hashp->save_file) 486 return (0); 487 hashp->MAGIC = HASHMAGIC; 488 hashp->VERSION = HASHVERSION; 489 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 490 491 fp = hashp->fp; 492 whdrp = &hashp->hdr; 493 #if BYTE_ORDER == LITTLE_ENDIAN 494 whdrp = &whdr; 495 swap_header_copy(&hashp->hdr, whdrp); 496 #endif 497 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 498 ((wsize = write(fp, whdrp, sizeof(HASHHDR))) == -1)) 499 return (-1); 500 else 501 if (wsize != sizeof(HASHHDR)) { 502 errno = EFTYPE; 503 hashp->errno = errno; 504 return (-1); 505 } 506 for (i = 0; i < NCACHED; i++) 507 if (hashp->mapp[i]) 508 if (__put_page(hashp, (char *)hashp->mapp[i], 509 hashp->BITMAPS[i], 0, 1)) 510 return (-1); 511 return (0); 512 } 513 514 /*******************************SEARCH ROUTINES *****************************/ 515 /* 516 * All the access routines return 517 * 518 * Returns: 519 * 0 on SUCCESS 520 * 1 to indicate an external ERROR (i.e. key not found, etc) 521 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 522 */ 523 static int 524 hash_get(dbp, key, data, flag) 525 const DB *dbp; 526 const DBT *key; 527 DBT *data; 528 u_int flag; 529 { 530 HTAB *hashp; 531 532 hashp = (HTAB *)dbp->internal; 533 if (flag) { 534 hashp->errno = errno = EINVAL; 535 return (ERROR); 536 } 537 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 538 } 539 540 static int 541 hash_put(dbp, key, data, flag) 542 const DB *dbp; 543 DBT *key; 544 const DBT *data; 545 u_int flag; 546 { 547 HTAB *hashp; 548 549 hashp = (HTAB *)dbp->internal; 550 if (flag && flag != R_NOOVERWRITE) { 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, flag == R_NOOVERWRITE ? 559 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 560 } 561 562 static int 563 hash_delete(dbp, key, flag) 564 const DB *dbp; 565 const DBT *key; 566 u_int flag; /* Ignored */ 567 { 568 HTAB *hashp; 569 570 hashp = (HTAB *)dbp->internal; 571 if (flag && flag != R_CURSOR) { 572 hashp->errno = errno = EINVAL; 573 return (ERROR); 574 } 575 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 576 hashp->errno = errno = EPERM; 577 return (ERROR); 578 } 579 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 580 } 581 582 /* 583 * Assume that hashp has been set in wrapper routine. 584 */ 585 static int 586 hash_access(hashp, action, key, val) 587 HTAB *hashp; 588 ACTION action; 589 DBT *key, *val; 590 { 591 register BUFHEAD *rbufp; 592 BUFHEAD *bufp, *save_bufp; 593 register u_short *bp; 594 register int n, ndx, off, size; 595 register char *kp; 596 u_short pageno; 597 598 #ifdef HASH_STATISTICS 599 hash_accesses++; 600 #endif 601 602 off = hashp->BSIZE; 603 size = key->size; 604 kp = (char *)key->data; 605 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 606 if (!rbufp) 607 return (ERROR); 608 save_bufp = rbufp; 609 610 /* Pin the bucket chain */ 611 rbufp->flags |= BUF_PIN; 612 for (bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 613 if (bp[1] >= REAL_KEY) { 614 /* Real key/data pair */ 615 if (size == off - *bp && 616 memcmp(kp, rbufp->page + *bp, size) == 0) 617 goto found; 618 off = bp[1]; 619 #ifdef HASH_STATISTICS 620 hash_collisions++; 621 #endif 622 bp += 2; 623 ndx += 2; 624 } else if (bp[1] == OVFLPAGE) { 625 rbufp = __get_buf(hashp, *bp, rbufp, 0); 626 if (!rbufp) { 627 save_bufp->flags &= ~BUF_PIN; 628 return (ERROR); 629 } 630 /* FOR LOOP INIT */ 631 bp = (u_short *)rbufp->page; 632 n = *bp++; 633 ndx = 1; 634 off = hashp->BSIZE; 635 } else if (bp[1] < REAL_KEY) { 636 if ((ndx = 637 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 638 goto found; 639 if (ndx == -2) { 640 bufp = rbufp; 641 if (!(pageno = 642 __find_last_page(hashp, &bufp))) { 643 ndx = 0; 644 rbufp = bufp; 645 break; /* FOR */ 646 } 647 rbufp = __get_buf(hashp, pageno, bufp, 0); 648 if (!rbufp) { 649 save_bufp->flags &= ~BUF_PIN; 650 return (ERROR); 651 } 652 /* FOR LOOP INIT */ 653 bp = (u_short *)rbufp->page; 654 n = *bp++; 655 ndx = 1; 656 off = hashp->BSIZE; 657 } else { 658 save_bufp->flags &= ~BUF_PIN; 659 return (ERROR); 660 } 661 } 662 663 /* Not found */ 664 switch (action) { 665 case HASH_PUT: 666 case HASH_PUTNEW: 667 if (__addel(hashp, rbufp, key, val)) { 668 save_bufp->flags &= ~BUF_PIN; 669 return (ERROR); 670 } else { 671 save_bufp->flags &= ~BUF_PIN; 672 return (SUCCESS); 673 } 674 case HASH_GET: 675 case HASH_DELETE: 676 default: 677 save_bufp->flags &= ~BUF_PIN; 678 return (ABNORMAL); 679 } 680 681 found: 682 switch (action) { 683 case HASH_PUTNEW: 684 save_bufp->flags &= ~BUF_PIN; 685 return (ABNORMAL); 686 case HASH_GET: 687 bp = (u_short *)rbufp->page; 688 if (bp[ndx + 1] < REAL_KEY) { 689 if (__big_return(hashp, rbufp, ndx, val, 0)) 690 return (ERROR); 691 } else { 692 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 693 val->size = bp[ndx] - bp[ndx + 1]; 694 } 695 break; 696 case HASH_PUT: 697 if ((__delpair(hashp, rbufp, ndx)) || 698 (__addel(hashp, rbufp, key, val))) { 699 save_bufp->flags &= ~BUF_PIN; 700 return (ERROR); 701 } 702 break; 703 case HASH_DELETE: 704 if (__delpair(hashp, rbufp, ndx)) 705 return (ERROR); 706 break; 707 default: 708 abort(); 709 } 710 save_bufp->flags &= ~BUF_PIN; 711 return (SUCCESS); 712 } 713 714 static int 715 hash_seq(dbp, key, data, flag) 716 const DB *dbp; 717 DBT *key, *data; 718 u_int flag; 719 { 720 register u_int bucket; 721 register BUFHEAD *bufp; 722 HTAB *hashp; 723 u_short *bp, ndx; 724 725 hashp = (HTAB *)dbp->internal; 726 if (flag && flag != R_FIRST && flag != R_NEXT) { 727 hashp->errno = errno = EINVAL; 728 return (ERROR); 729 } 730 #ifdef HASH_STATISTICS 731 hash_accesses++; 732 #endif 733 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 734 hashp->cbucket = 0; 735 hashp->cndx = 1; 736 hashp->cpage = NULL; 737 } 738 739 for (bp = NULL; !bp || !bp[0]; ) { 740 if (!(bufp = hashp->cpage)) { 741 for (bucket = hashp->cbucket; 742 bucket <= hashp->MAX_BUCKET; 743 bucket++, hashp->cndx = 1) { 744 bufp = __get_buf(hashp, bucket, NULL, 0); 745 if (!bufp) 746 return (ERROR); 747 hashp->cpage = bufp; 748 bp = (u_short *)bufp->page; 749 if (bp[0]) 750 break; 751 } 752 hashp->cbucket = bucket; 753 if (hashp->cbucket > hashp->MAX_BUCKET) { 754 hashp->cbucket = -1; 755 return (ABNORMAL); 756 } 757 } else 758 bp = (u_short *)hashp->cpage->page; 759 760 #ifdef DEBUG 761 assert(bp); 762 assert(bufp); 763 #endif 764 while (bp[hashp->cndx + 1] == OVFLPAGE) { 765 bufp = hashp->cpage = 766 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 767 if (!bufp) 768 return (ERROR); 769 bp = (u_short *)(bufp->page); 770 hashp->cndx = 1; 771 } 772 if (!bp[0]) { 773 hashp->cpage = NULL; 774 ++hashp->cbucket; 775 } 776 } 777 ndx = hashp->cndx; 778 if (bp[ndx + 1] < REAL_KEY) { 779 if (__big_keydata(hashp, bufp, key, data, 1)) 780 return (ERROR); 781 } else { 782 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 783 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 784 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 785 data->size = bp[ndx] - bp[ndx + 1]; 786 ndx += 2; 787 if (ndx > bp[0]) { 788 hashp->cpage = NULL; 789 hashp->cbucket++; 790 hashp->cndx = 1; 791 } else 792 hashp->cndx = ndx; 793 } 794 return (SUCCESS); 795 } 796 797 /********************************* UTILITIES ************************/ 798 799 /* 800 * Returns: 801 * 0 ==> OK 802 * -1 ==> Error 803 */ 804 extern int 805 __expand_table(hashp) 806 HTAB *hashp; 807 { 808 u_int old_bucket, new_bucket; 809 int dirsize, new_segnum, spare_ndx; 810 811 #ifdef HASH_STATISTICS 812 hash_expansions++; 813 #endif 814 new_bucket = ++hashp->MAX_BUCKET; 815 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 816 817 new_segnum = new_bucket >> hashp->SSHIFT; 818 819 /* Check if we need a new segment */ 820 if (new_segnum >= hashp->nsegs) { 821 /* Check if we need to expand directory */ 822 if (new_segnum >= hashp->DSIZE) { 823 /* Reallocate directory */ 824 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 825 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 826 return (-1); 827 hashp->DSIZE = dirsize << 1; 828 } 829 if (!(hashp->dir[new_segnum] = 830 calloc(hashp->SGSIZE, sizeof(SEGMENT)))) 831 return (-1); 832 hashp->exsegs++; 833 hashp->nsegs++; 834 } 835 /* 836 * If the split point is increasing (MAX_BUCKET's log base 2 837 * * increases), we need to copy the current contents of the spare 838 * split bucket to the next bucket. 839 */ 840 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 841 if (spare_ndx > hashp->OVFL_POINT) { 842 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 843 hashp->OVFL_POINT = spare_ndx; 844 } 845 846 if (new_bucket > hashp->HIGH_MASK) { 847 /* Starting a new doubling */ 848 hashp->LOW_MASK = hashp->HIGH_MASK; 849 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 850 } 851 /* Relocate records to the new bucket */ 852 return (__split_page(hashp, old_bucket, new_bucket)); 853 } 854 855 /* 856 * If realloc guarantees that the pointer is not destroyed if the realloc 857 * fails, then this routine can go away. 858 */ 859 static void * 860 hash_realloc(p_ptr, oldsize, newsize) 861 SEGMENT **p_ptr; 862 int oldsize, newsize; 863 { 864 register void *p; 865 866 if (p = malloc(newsize)) { 867 memmove(p, *p_ptr, oldsize); 868 memset(p + oldsize, 0, newsize - oldsize); 869 free(*p_ptr); 870 *p_ptr = p; 871 } 872 return (p); 873 } 874 875 extern u_int 876 __call_hash(hashp, k, len) 877 HTAB *hashp; 878 char *k; 879 int len; 880 { 881 int n, bucket; 882 883 n = hashp->hash(k, len); 884 bucket = n & hashp->HIGH_MASK; 885 if (bucket > hashp->MAX_BUCKET) 886 bucket = bucket & hashp->LOW_MASK; 887 return (bucket); 888 } 889 890 /* 891 * Allocate segment table. On error, destroy the table and set errno. 892 * 893 * Returns 0 on success 894 */ 895 static int 896 alloc_segs(hashp, nsegs) 897 HTAB *hashp; 898 int nsegs; 899 { 900 register int i; 901 register SEGMENT store; 902 903 int save_errno; 904 905 if (!(hashp->dir = calloc(hashp->DSIZE, sizeof(SEGMENT *)))) { 906 save_errno = errno; 907 (void)hdestroy(hashp); 908 errno = save_errno; 909 return (-1); 910 } 911 /* Allocate segments */ 912 store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT)); 913 if (!store) { 914 save_errno = errno; 915 (void)hdestroy(hashp); 916 errno = save_errno; 917 return (-1); 918 } 919 for (i = 0; i < nsegs; i++, hashp->nsegs++) 920 hashp->dir[i] = &store[i << hashp->SSHIFT]; 921 return (0); 922 } 923 924 #if BYTE_ORDER == LITTLE_ENDIAN 925 /* 926 * Hashp->hdr needs to be byteswapped. 927 */ 928 static void 929 swap_header_copy(srcp, destp) 930 HASHHDR *srcp, *destp; 931 { 932 int i; 933 934 BLSWAP_COPY(srcp->magic, destp->magic); 935 BLSWAP_COPY(srcp->version, destp->version); 936 BLSWAP_COPY(srcp->lorder, destp->lorder); 937 BLSWAP_COPY(srcp->bsize, destp->bsize); 938 BLSWAP_COPY(srcp->bshift, destp->bshift); 939 BLSWAP_COPY(srcp->dsize, destp->dsize); 940 BLSWAP_COPY(srcp->ssize, destp->ssize); 941 BLSWAP_COPY(srcp->sshift, destp->sshift); 942 BLSWAP_COPY(srcp->ovfl_point, destp->ovfl_point); 943 BLSWAP_COPY(srcp->last_freed, destp->last_freed); 944 BLSWAP_COPY(srcp->max_bucket, destp->max_bucket); 945 BLSWAP_COPY(srcp->high_mask, destp->high_mask); 946 BLSWAP_COPY(srcp->low_mask, destp->low_mask); 947 BLSWAP_COPY(srcp->ffactor, destp->ffactor); 948 BLSWAP_COPY(srcp->nkeys, destp->nkeys); 949 BLSWAP_COPY(srcp->hdrpages, destp->hdrpages); 950 BLSWAP_COPY(srcp->h_charkey, destp->h_charkey); 951 for (i = 0; i < NCACHED; i++) { 952 BLSWAP_COPY(srcp->spares[i], destp->spares[i]); 953 BSSWAP_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 954 } 955 } 956 957 static void 958 swap_header(hashp) 959 HTAB *hashp; 960 { 961 HASHHDR *hdrp; 962 int i; 963 964 hdrp = &hashp->hdr; 965 966 BLSWAP(hdrp->magic); 967 BLSWAP(hdrp->version); 968 BLSWAP(hdrp->lorder); 969 BLSWAP(hdrp->bsize); 970 BLSWAP(hdrp->bshift); 971 BLSWAP(hdrp->dsize); 972 BLSWAP(hdrp->ssize); 973 BLSWAP(hdrp->sshift); 974 BLSWAP(hdrp->ovfl_point); 975 BLSWAP(hdrp->last_freed); 976 BLSWAP(hdrp->max_bucket); 977 BLSWAP(hdrp->high_mask); 978 BLSWAP(hdrp->low_mask); 979 BLSWAP(hdrp->ffactor); 980 BLSWAP(hdrp->nkeys); 981 BLSWAP(hdrp->hdrpages); 982 BLSWAP(hdrp->h_charkey); 983 for (i = 0; i < NCACHED; i++) { 984 BLSWAP(hdrp->spares[i]); 985 BSSWAP(hdrp->bitmaps[i]); 986 } 987 } 988 #endif 989