1 /*- 2 * Copyright (c) 1990, 1993, 1994 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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <sys/param.h> 41 #include <sys/stat.h> 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #ifdef DEBUG 50 #include <assert.h> 51 #endif 52 #include "un-namespace.h" 53 54 #include <db.h> 55 #include "hash.h" 56 #include "page.h" 57 #include "extern.h" 58 59 static int alloc_segs(HTAB *, int); 60 static int flush_meta(HTAB *); 61 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 62 static int hash_close(DB *); 63 static int hash_delete(const DB *, const DBT *, u_int32_t); 64 static int hash_fd(const DB *); 65 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 66 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 67 static void *hash_realloc(SEGMENT **, int, int); 68 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 69 static int hash_sync(const DB *, u_int32_t); 70 static int hdestroy(HTAB *); 71 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 72 static int init_htab(HTAB *, int); 73 #if BYTE_ORDER == LITTLE_ENDIAN 74 static void swap_header(HTAB *); 75 static void swap_header_copy(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 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 90 #endif 91 92 /************************** INTERFACE ROUTINES ***************************/ 93 /* OPEN/CLOSE */ 94 95 /* ARGSUSED */ 96 DB * 97 __hash_open(const char *file, int flags, int mode, 98 const HASHINFO *info, /* Special directives for create */ 99 int dflags) 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 = (HTAB *)calloc(1, sizeof(HTAB)))) 112 return (NULL); 113 hashp->fp = -1; 114 115 /* 116 * Even if user wants write only, we need to be able to read 117 * the actual file, so we need to open it read/write. But, the 118 * field in the hashp structure needs to be accurate so that 119 * we can check accesses. 120 */ 121 hashp->flags = flags; 122 123 if (file) { 124 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1) 125 RETURN_ERROR(errno, error0); 126 new_table = _fstat(hashp->fp, &statbuf) == 0 && 127 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 128 } else 129 new_table = 1; 130 131 if (new_table) { 132 if (!(hashp = init_hash(hashp, file, info))) 133 RETURN_ERROR(errno, error1); 134 } else { 135 /* Table already exists */ 136 if (info && info->hash) 137 hashp->hash = info->hash; 138 else 139 hashp->hash = __default_hash; 140 141 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 142 #if BYTE_ORDER == LITTLE_ENDIAN 143 swap_header(hashp); 144 #endif 145 if (hdrsize == -1) 146 RETURN_ERROR(errno, error1); 147 if (hdrsize != sizeof(HASHHDR)) 148 RETURN_ERROR(EFTYPE, error1); 149 /* Verify file type, versions and hash function */ 150 if (hashp->MAGIC != HASHMAGIC) 151 RETURN_ERROR(EFTYPE, error1); 152 #define OLDHASHVERSION 1 153 if (hashp->VERSION != HASHVERSION && 154 hashp->VERSION != OLDHASHVERSION) 155 RETURN_ERROR(EFTYPE, error1); 156 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 157 RETURN_ERROR(EFTYPE, error1); 158 /* 159 * Figure out how many segments we need. Max_Bucket is the 160 * maximum bucket number, so the number of buckets is 161 * max_bucket + 1. 162 */ 163 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 164 hashp->SGSIZE; 165 if (alloc_segs(hashp, nsegs)) 166 /* 167 * If alloc_segs fails, table will have been destroyed 168 * and errno will have been set. 169 */ 170 return (NULL); 171 /* Read in bitmaps */ 172 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 173 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 174 (hashp->BSHIFT + BYTE_SHIFT); 175 176 hashp->nmaps = bpages; 177 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 178 } 179 180 /* Initialize Buffer Manager */ 181 if (info && info->cachesize) 182 __buf_init(hashp, info->cachesize); 183 else 184 __buf_init(hashp, DEF_BUFSIZE); 185 186 hashp->new_file = new_table; 187 hashp->save_file = file && (hashp->flags & O_RDWR); 188 hashp->cbucket = -1; 189 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 190 save_errno = errno; 191 hdestroy(hashp); 192 errno = save_errno; 193 return (NULL); 194 } 195 dbp->internal = hashp; 196 dbp->close = hash_close; 197 dbp->del = hash_delete; 198 dbp->fd = hash_fd; 199 dbp->get = hash_get; 200 dbp->put = hash_put; 201 dbp->seq = hash_seq; 202 dbp->sync = hash_sync; 203 dbp->type = DB_HASH; 204 205 #ifdef DEBUG 206 (void)fprintf(stderr, 207 "%s\n%s%p\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", 208 "init_htab:", 209 "TABLE POINTER ", hashp, 210 "BUCKET SIZE ", hashp->BSIZE, 211 "BUCKET SHIFT ", hashp->BSHIFT, 212 "DIRECTORY SIZE ", hashp->DSIZE, 213 "SEGMENT SIZE ", hashp->SGSIZE, 214 "SEGMENT SHIFT ", hashp->SSHIFT, 215 "FILL FACTOR ", hashp->FFACTOR, 216 "MAX BUCKET ", hashp->MAX_BUCKET, 217 "OVFL POINT ", hashp->OVFL_POINT, 218 "LAST FREED ", hashp->LAST_FREED, 219 "HIGH MASK ", hashp->HIGH_MASK, 220 "LOW MASK ", hashp->LOW_MASK, 221 "NSEGS ", hashp->nsegs, 222 "NKEYS ", hashp->NKEYS); 223 #endif 224 #ifdef HASH_STATISTICS 225 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 226 #endif 227 return (dbp); 228 229 error1: 230 if (hashp != NULL) 231 (void)_close(hashp->fp); 232 233 error0: 234 free(hashp); 235 errno = save_errno; 236 return (NULL); 237 } 238 239 static int 240 hash_close(DB *dbp) 241 { 242 HTAB *hashp; 243 int retval; 244 245 if (!dbp) 246 return (ERROR); 247 248 hashp = (HTAB *)dbp->internal; 249 retval = hdestroy(hashp); 250 free(dbp); 251 return (retval); 252 } 253 254 static int 255 hash_fd(const DB *dbp) 256 { 257 HTAB *hashp; 258 259 if (!dbp) 260 return (ERROR); 261 262 hashp = (HTAB *)dbp->internal; 263 if (hashp->fp == -1) { 264 errno = ENOENT; 265 return (-1); 266 } 267 return (hashp->fp); 268 } 269 270 /************************** LOCAL CREATION ROUTINES **********************/ 271 static HTAB * 272 init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 273 { 274 struct stat statbuf; 275 int nelem; 276 277 nelem = 1; 278 hashp->NKEYS = 0; 279 hashp->LORDER = BYTE_ORDER; 280 hashp->BSIZE = DEF_BUCKET_SIZE; 281 hashp->BSHIFT = DEF_BUCKET_SHIFT; 282 hashp->SGSIZE = DEF_SEGSIZE; 283 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 284 hashp->DSIZE = DEF_DIRSIZE; 285 hashp->FFACTOR = DEF_FFACTOR; 286 hashp->hash = __default_hash; 287 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 288 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 289 290 /* Fix bucket size to be optimal for file system */ 291 if (file != NULL) { 292 if (stat(file, &statbuf)) 293 return (NULL); 294 hashp->BSIZE = statbuf.st_blksize; 295 if (hashp->BSIZE > MAX_BSIZE) 296 hashp->BSIZE = MAX_BSIZE; 297 hashp->BSHIFT = __log2(hashp->BSIZE); 298 } 299 300 if (info) { 301 if (info->bsize) { 302 /* Round pagesize up to power of 2 */ 303 hashp->BSHIFT = __log2(info->bsize); 304 hashp->BSIZE = 1 << hashp->BSHIFT; 305 if (hashp->BSIZE > MAX_BSIZE) { 306 errno = EINVAL; 307 return (NULL); 308 } 309 } 310 if (info->ffactor) 311 hashp->FFACTOR = info->ffactor; 312 if (info->hash) 313 hashp->hash = info->hash; 314 if (info->nelem) 315 nelem = info->nelem; 316 if (info->lorder) { 317 if (info->lorder != BIG_ENDIAN && 318 info->lorder != LITTLE_ENDIAN) { 319 errno = EINVAL; 320 return (NULL); 321 } 322 hashp->LORDER = info->lorder; 323 } 324 } 325 /* init_htab should destroy the table and set errno if it fails */ 326 if (init_htab(hashp, nelem)) 327 return (NULL); 328 else 329 return (hashp); 330 } 331 /* 332 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 333 * the table and set errno, so we just pass the error information along. 334 * 335 * Returns 0 on No Error 336 */ 337 static int 338 init_htab(HTAB *hashp, int nelem) 339 { 340 int nbuckets, nsegs, l2; 341 342 /* 343 * Divide number of elements by the fill factor and determine a 344 * desired number of buckets. Allocate space for the next greater 345 * power of two number of buckets. 346 */ 347 nelem = (nelem - 1) / hashp->FFACTOR + 1; 348 349 l2 = __log2(MAX(nelem, 2)); 350 nbuckets = 1 << l2; 351 352 hashp->SPARES[l2] = l2 + 1; 353 hashp->SPARES[l2 + 1] = l2 + 1; 354 hashp->OVFL_POINT = l2; 355 hashp->LAST_FREED = 2; 356 357 /* First bitmap page is at: splitpoint l2 page offset 1 */ 358 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 359 return (-1); 360 361 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 362 hashp->HIGH_MASK = (nbuckets << 1) - 1; 363 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 364 hashp->BSHIFT) + 1; 365 366 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 367 nsegs = 1 << __log2(nsegs); 368 369 if (nsegs > hashp->DSIZE) 370 hashp->DSIZE = nsegs; 371 return (alloc_segs(hashp, nsegs)); 372 } 373 374 /********************** DESTROY/CLOSE ROUTINES ************************/ 375 376 /* 377 * Flushes any changes to the file if necessary and destroys the hashp 378 * structure, freeing all allocated space. 379 */ 380 static int 381 hdestroy(HTAB *hashp) 382 { 383 int i, save_errno; 384 385 save_errno = 0; 386 387 #ifdef HASH_STATISTICS 388 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 389 hash_accesses, hash_collisions); 390 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 391 hash_expansions); 392 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 393 hash_overflows); 394 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 395 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 396 397 for (i = 0; i < NCACHED; i++) 398 (void)fprintf(stderr, 399 "spares[%d] = %d\n", i, hashp->SPARES[i]); 400 #endif 401 /* 402 * Call on buffer manager to free buffers, and if required, 403 * write them to disk. 404 */ 405 if (__buf_free(hashp, 1, hashp->save_file)) 406 save_errno = errno; 407 if (hashp->dir) { 408 free(*hashp->dir); /* Free initial segments */ 409 /* Free extra segments */ 410 while (hashp->exsegs--) 411 free(hashp->dir[--hashp->nsegs]); 412 free(hashp->dir); 413 } 414 if (flush_meta(hashp) && !save_errno) 415 save_errno = errno; 416 /* Free Bigmaps */ 417 for (i = 0; i < hashp->nmaps; i++) 418 if (hashp->mapp[i]) 419 free(hashp->mapp[i]); 420 if (hashp->tmp_key) 421 free(hashp->tmp_key); 422 if (hashp->tmp_buf) 423 free(hashp->tmp_buf); 424 425 if (hashp->fp != -1) 426 (void)_close(hashp->fp); 427 428 free(hashp); 429 430 if (save_errno) { 431 errno = save_errno; 432 return (ERROR); 433 } 434 return (SUCCESS); 435 } 436 /* 437 * Write modified pages to disk 438 * 439 * Returns: 440 * 0 == OK 441 * -1 ERROR 442 */ 443 static int 444 hash_sync(const DB *dbp, u_int32_t flags) 445 { 446 HTAB *hashp; 447 448 if (flags != 0) { 449 errno = EINVAL; 450 return (ERROR); 451 } 452 453 if (!dbp) 454 return (ERROR); 455 456 hashp = (HTAB *)dbp->internal; 457 if (!hashp->save_file) 458 return (0); 459 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 460 return (ERROR); 461 hashp->new_file = 0; 462 return (0); 463 } 464 465 /* 466 * Returns: 467 * 0 == OK 468 * -1 indicates that errno should be set 469 */ 470 static int 471 flush_meta(HTAB *hashp) 472 { 473 HASHHDR *whdrp; 474 #if BYTE_ORDER == LITTLE_ENDIAN 475 HASHHDR whdr; 476 #endif 477 int fp, i, wsize; 478 479 if (!hashp->save_file) 480 return (0); 481 hashp->MAGIC = HASHMAGIC; 482 hashp->VERSION = HASHVERSION; 483 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 484 485 fp = hashp->fp; 486 whdrp = &hashp->hdr; 487 #if BYTE_ORDER == LITTLE_ENDIAN 488 whdrp = &whdr; 489 swap_header_copy(&hashp->hdr, whdrp); 490 #endif 491 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 492 return (-1); 493 else 494 if (wsize != sizeof(HASHHDR)) { 495 errno = EFTYPE; 496 hashp->error = errno; 497 return (-1); 498 } 499 for (i = 0; i < NCACHED; i++) 500 if (hashp->mapp[i]) 501 if (__put_page(hashp, (char *)hashp->mapp[i], 502 hashp->BITMAPS[i], 0, 1)) 503 return (-1); 504 return (0); 505 } 506 507 /*******************************SEARCH ROUTINES *****************************/ 508 /* 509 * All the access routines return 510 * 511 * Returns: 512 * 0 on SUCCESS 513 * 1 to indicate an external ERROR (i.e. key not found, etc) 514 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 515 */ 516 static int 517 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 518 { 519 HTAB *hashp; 520 521 hashp = (HTAB *)dbp->internal; 522 if (flag) { 523 hashp->error = errno = EINVAL; 524 return (ERROR); 525 } 526 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 527 } 528 529 static int 530 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 531 { 532 HTAB *hashp; 533 534 hashp = (HTAB *)dbp->internal; 535 if (flag && flag != R_NOOVERWRITE) { 536 hashp->error = errno = EINVAL; 537 return (ERROR); 538 } 539 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 540 hashp->error = errno = EPERM; 541 return (ERROR); 542 } 543 return (hash_access(hashp, flag == R_NOOVERWRITE ? 544 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 545 } 546 547 static int 548 hash_delete(const DB *dbp, const DBT *key, 549 u_int32_t flag) /* Ignored */ 550 { 551 HTAB *hashp; 552 553 hashp = (HTAB *)dbp->internal; 554 if (flag && flag != R_CURSOR) { 555 hashp->error = errno = EINVAL; 556 return (ERROR); 557 } 558 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 559 hashp->error = errno = EPERM; 560 return (ERROR); 561 } 562 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 563 } 564 565 /* 566 * Assume that hashp has been set in wrapper routine. 567 */ 568 static int 569 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 570 { 571 BUFHEAD *rbufp; 572 BUFHEAD *bufp, *save_bufp; 573 u_int16_t *bp; 574 int n, ndx, off, size; 575 char *kp; 576 u_int16_t pageno; 577 578 #ifdef HASH_STATISTICS 579 hash_accesses++; 580 #endif 581 582 off = hashp->BSIZE; 583 size = key->size; 584 kp = (char *)key->data; 585 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 586 if (!rbufp) 587 return (ERROR); 588 save_bufp = rbufp; 589 590 /* Pin the bucket chain */ 591 rbufp->flags |= BUF_PIN; 592 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 593 if (bp[1] >= REAL_KEY) { 594 /* Real key/data pair */ 595 if (size == off - *bp && 596 memcmp(kp, rbufp->page + *bp, size) == 0) 597 goto found; 598 off = bp[1]; 599 #ifdef HASH_STATISTICS 600 hash_collisions++; 601 #endif 602 bp += 2; 603 ndx += 2; 604 } else if (bp[1] == OVFLPAGE) { 605 rbufp = __get_buf(hashp, *bp, rbufp, 0); 606 if (!rbufp) { 607 save_bufp->flags &= ~BUF_PIN; 608 return (ERROR); 609 } 610 /* FOR LOOP INIT */ 611 bp = (u_int16_t *)rbufp->page; 612 n = *bp++; 613 ndx = 1; 614 off = hashp->BSIZE; 615 } else if (bp[1] < REAL_KEY) { 616 if ((ndx = 617 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 618 goto found; 619 if (ndx == -2) { 620 bufp = rbufp; 621 if (!(pageno = 622 __find_last_page(hashp, &bufp))) { 623 ndx = 0; 624 rbufp = bufp; 625 break; /* FOR */ 626 } 627 rbufp = __get_buf(hashp, pageno, bufp, 0); 628 if (!rbufp) { 629 save_bufp->flags &= ~BUF_PIN; 630 return (ERROR); 631 } 632 /* FOR LOOP INIT */ 633 bp = (u_int16_t *)rbufp->page; 634 n = *bp++; 635 ndx = 1; 636 off = hashp->BSIZE; 637 } else { 638 save_bufp->flags &= ~BUF_PIN; 639 return (ERROR); 640 } 641 } 642 643 /* Not found */ 644 switch (action) { 645 case HASH_PUT: 646 case HASH_PUTNEW: 647 if (__addel(hashp, rbufp, key, val)) { 648 save_bufp->flags &= ~BUF_PIN; 649 return (ERROR); 650 } else { 651 save_bufp->flags &= ~BUF_PIN; 652 return (SUCCESS); 653 } 654 case HASH_GET: 655 case HASH_DELETE: 656 default: 657 save_bufp->flags &= ~BUF_PIN; 658 return (ABNORMAL); 659 } 660 661 found: 662 switch (action) { 663 case HASH_PUTNEW: 664 save_bufp->flags &= ~BUF_PIN; 665 return (ABNORMAL); 666 case HASH_GET: 667 bp = (u_int16_t *)rbufp->page; 668 if (bp[ndx + 1] < REAL_KEY) { 669 if (__big_return(hashp, rbufp, ndx, val, 0)) 670 return (ERROR); 671 } else { 672 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 673 val->size = bp[ndx] - bp[ndx + 1]; 674 } 675 break; 676 case HASH_PUT: 677 if ((__delpair(hashp, rbufp, ndx)) || 678 (__addel(hashp, rbufp, key, val))) { 679 save_bufp->flags &= ~BUF_PIN; 680 return (ERROR); 681 } 682 break; 683 case HASH_DELETE: 684 if (__delpair(hashp, rbufp, ndx)) 685 return (ERROR); 686 break; 687 default: 688 abort(); 689 } 690 save_bufp->flags &= ~BUF_PIN; 691 return (SUCCESS); 692 } 693 694 static int 695 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 696 { 697 u_int32_t bucket; 698 BUFHEAD *bufp; 699 HTAB *hashp; 700 u_int16_t *bp, ndx; 701 702 hashp = (HTAB *)dbp->internal; 703 if (flag && flag != R_FIRST && flag != R_NEXT) { 704 hashp->error = errno = EINVAL; 705 return (ERROR); 706 } 707 #ifdef HASH_STATISTICS 708 hash_accesses++; 709 #endif 710 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 711 hashp->cbucket = 0; 712 hashp->cndx = 1; 713 hashp->cpage = NULL; 714 } 715 next_bucket: 716 for (bp = NULL; !bp || !bp[0]; ) { 717 if (!(bufp = hashp->cpage)) { 718 for (bucket = hashp->cbucket; 719 bucket <= hashp->MAX_BUCKET; 720 bucket++, hashp->cndx = 1) { 721 bufp = __get_buf(hashp, bucket, NULL, 0); 722 if (!bufp) 723 return (ERROR); 724 hashp->cpage = bufp; 725 bp = (u_int16_t *)bufp->page; 726 if (bp[0]) 727 break; 728 } 729 hashp->cbucket = bucket; 730 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 731 hashp->cbucket = -1; 732 return (ABNORMAL); 733 } 734 } else { 735 bp = (u_int16_t *)hashp->cpage->page; 736 if (flag == R_NEXT || flag == 0) { 737 hashp->cndx += 2; 738 if (hashp->cndx > bp[0]) { 739 hashp->cpage = NULL; 740 hashp->cbucket++; 741 hashp->cndx = 1; 742 goto next_bucket; 743 } 744 } 745 } 746 747 #ifdef DEBUG 748 assert(bp); 749 assert(bufp); 750 #endif 751 while (bp[hashp->cndx + 1] == OVFLPAGE) { 752 bufp = hashp->cpage = 753 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 754 if (!bufp) 755 return (ERROR); 756 bp = (u_int16_t *)(bufp->page); 757 hashp->cndx = 1; 758 } 759 if (!bp[0]) { 760 hashp->cpage = NULL; 761 ++hashp->cbucket; 762 } 763 } 764 ndx = hashp->cndx; 765 if (bp[ndx + 1] < REAL_KEY) { 766 if (__big_keydata(hashp, bufp, key, data, 1)) 767 return (ERROR); 768 } else { 769 if (hashp->cpage == 0) 770 return (ERROR); 771 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 772 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 773 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 774 data->size = bp[ndx] - bp[ndx + 1]; 775 } 776 return (SUCCESS); 777 } 778 779 /********************************* UTILITIES ************************/ 780 781 /* 782 * Returns: 783 * 0 ==> OK 784 * -1 ==> Error 785 */ 786 int 787 __expand_table(HTAB *hashp) 788 { 789 u_int32_t old_bucket, new_bucket; 790 int dirsize, new_segnum, spare_ndx; 791 792 #ifdef HASH_STATISTICS 793 hash_expansions++; 794 #endif 795 new_bucket = ++hashp->MAX_BUCKET; 796 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 797 798 new_segnum = new_bucket >> hashp->SSHIFT; 799 800 /* Check if we need a new segment */ 801 if (new_segnum >= hashp->nsegs) { 802 /* Check if we need to expand directory */ 803 if (new_segnum >= hashp->DSIZE) { 804 /* Reallocate directory */ 805 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 806 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 807 return (-1); 808 hashp->DSIZE = dirsize << 1; 809 } 810 if ((hashp->dir[new_segnum] = 811 calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 812 return (-1); 813 hashp->exsegs++; 814 hashp->nsegs++; 815 } 816 /* 817 * If the split point is increasing (MAX_BUCKET's log base 2 818 * * increases), we need to copy the current contents of the spare 819 * split bucket to the next bucket. 820 */ 821 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 822 if (spare_ndx > hashp->OVFL_POINT) { 823 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 824 hashp->OVFL_POINT = spare_ndx; 825 } 826 827 if (new_bucket > hashp->HIGH_MASK) { 828 /* Starting a new doubling */ 829 hashp->LOW_MASK = hashp->HIGH_MASK; 830 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 831 } 832 /* Relocate records to the new bucket */ 833 return (__split_page(hashp, old_bucket, new_bucket)); 834 } 835 836 /* 837 * If realloc guarantees that the pointer is not destroyed if the realloc 838 * fails, then this routine can go away. 839 */ 840 static void * 841 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 842 { 843 void *p; 844 845 if ( (p = malloc(newsize)) ) { 846 memmove(p, *p_ptr, oldsize); 847 memset((char *)p + oldsize, 0, newsize - oldsize); 848 free(*p_ptr); 849 *p_ptr = p; 850 } 851 return (p); 852 } 853 854 u_int32_t 855 __call_hash(HTAB *hashp, char *k, int len) 856 { 857 unsigned int n, bucket; 858 859 n = hashp->hash(k, len); 860 bucket = n & hashp->HIGH_MASK; 861 if (bucket > hashp->MAX_BUCKET) 862 bucket = bucket & hashp->LOW_MASK; 863 return (bucket); 864 } 865 866 /* 867 * Allocate segment table. On error, destroy the table and set errno. 868 * 869 * Returns 0 on success 870 */ 871 static int 872 alloc_segs(HTAB *hashp, int nsegs) 873 { 874 int i; 875 SEGMENT store; 876 877 int save_errno; 878 879 if ((hashp->dir = 880 calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 881 save_errno = errno; 882 (void)hdestroy(hashp); 883 errno = save_errno; 884 return (-1); 885 } 886 hashp->nsegs = nsegs; 887 if (nsegs == 0) 888 return (0); 889 /* Allocate segments */ 890 if ((store = calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 891 save_errno = errno; 892 (void)hdestroy(hashp); 893 errno = save_errno; 894 return (-1); 895 } 896 for (i = 0; i < nsegs; i++) 897 hashp->dir[i] = &store[i << hashp->SSHIFT]; 898 return (0); 899 } 900 901 #if BYTE_ORDER == LITTLE_ENDIAN 902 /* 903 * Hashp->hdr needs to be byteswapped. 904 */ 905 static void 906 swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 907 { 908 int i; 909 910 P_32_COPY(srcp->magic, destp->magic); 911 P_32_COPY(srcp->version, destp->version); 912 P_32_COPY(srcp->lorder, destp->lorder); 913 P_32_COPY(srcp->bsize, destp->bsize); 914 P_32_COPY(srcp->bshift, destp->bshift); 915 P_32_COPY(srcp->dsize, destp->dsize); 916 P_32_COPY(srcp->ssize, destp->ssize); 917 P_32_COPY(srcp->sshift, destp->sshift); 918 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 919 P_32_COPY(srcp->last_freed, destp->last_freed); 920 P_32_COPY(srcp->max_bucket, destp->max_bucket); 921 P_32_COPY(srcp->high_mask, destp->high_mask); 922 P_32_COPY(srcp->low_mask, destp->low_mask); 923 P_32_COPY(srcp->ffactor, destp->ffactor); 924 P_32_COPY(srcp->nkeys, destp->nkeys); 925 P_32_COPY(srcp->hdrpages, destp->hdrpages); 926 P_32_COPY(srcp->h_charkey, destp->h_charkey); 927 for (i = 0; i < NCACHED; i++) { 928 P_32_COPY(srcp->spares[i], destp->spares[i]); 929 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 930 } 931 } 932 933 static void 934 swap_header(HTAB *hashp) 935 { 936 HASHHDR *hdrp; 937 int i; 938 939 hdrp = &hashp->hdr; 940 941 M_32_SWAP(hdrp->magic); 942 M_32_SWAP(hdrp->version); 943 M_32_SWAP(hdrp->lorder); 944 M_32_SWAP(hdrp->bsize); 945 M_32_SWAP(hdrp->bshift); 946 M_32_SWAP(hdrp->dsize); 947 M_32_SWAP(hdrp->ssize); 948 M_32_SWAP(hdrp->sshift); 949 M_32_SWAP(hdrp->ovfl_point); 950 M_32_SWAP(hdrp->last_freed); 951 M_32_SWAP(hdrp->max_bucket); 952 M_32_SWAP(hdrp->high_mask); 953 M_32_SWAP(hdrp->low_mask); 954 M_32_SWAP(hdrp->ffactor); 955 M_32_SWAP(hdrp->nkeys); 956 M_32_SWAP(hdrp->hdrpages); 957 M_32_SWAP(hdrp->h_charkey); 958 for (i = 0; i < NCACHED; i++) { 959 M_32_SWAP(hdrp->spares[i]); 960 M_16_SWAP(hdrp->bitmaps[i]); 961 } 962 } 963 #endif 964