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, mode)) == -1) 125 RETURN_ERROR(errno, error0); 126 (void)_fcntl(hashp->fp, F_SETFD, 1); 127 new_table = _fstat(hashp->fp, &statbuf) == 0 && 128 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 129 } else 130 new_table = 1; 131 132 if (new_table) { 133 if (!(hashp = init_hash(hashp, file, info))) 134 RETURN_ERROR(errno, error1); 135 } else { 136 /* Table already exists */ 137 if (info && info->hash) 138 hashp->hash = info->hash; 139 else 140 hashp->hash = __default_hash; 141 142 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 143 #if BYTE_ORDER == LITTLE_ENDIAN 144 swap_header(hashp); 145 #endif 146 if (hdrsize == -1) 147 RETURN_ERROR(errno, error1); 148 if (hdrsize != sizeof(HASHHDR)) 149 RETURN_ERROR(EFTYPE, error1); 150 /* Verify file type, versions and hash function */ 151 if (hashp->MAGIC != HASHMAGIC) 152 RETURN_ERROR(EFTYPE, error1); 153 #define OLDHASHVERSION 1 154 if (hashp->VERSION != HASHVERSION && 155 hashp->VERSION != OLDHASHVERSION) 156 RETURN_ERROR(EFTYPE, error1); 157 if ((int32_t)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 if (alloc_segs(hashp, nsegs)) 167 /* 168 * If alloc_segs fails, table will have been destroyed 169 * and errno will have been set. 170 */ 171 return (NULL); 172 /* Read in bitmaps */ 173 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 174 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 175 (hashp->BSHIFT + BYTE_SHIFT); 176 177 hashp->nmaps = bpages; 178 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 179 } 180 181 /* Initialize Buffer Manager */ 182 if (info && info->cachesize) 183 __buf_init(hashp, info->cachesize); 184 else 185 __buf_init(hashp, DEF_BUFSIZE); 186 187 hashp->new_file = new_table; 188 hashp->save_file = file && (hashp->flags & O_RDWR); 189 hashp->cbucket = -1; 190 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 191 save_errno = errno; 192 hdestroy(hashp); 193 errno = save_errno; 194 return (NULL); 195 } 196 dbp->internal = hashp; 197 dbp->close = hash_close; 198 dbp->del = hash_delete; 199 dbp->fd = hash_fd; 200 dbp->get = hash_get; 201 dbp->put = hash_put; 202 dbp->seq = hash_seq; 203 dbp->sync = hash_sync; 204 dbp->type = DB_HASH; 205 206 #ifdef DEBUG 207 (void)fprintf(stderr, 208 "%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", 209 "init_htab:", 210 "TABLE POINTER ", hashp, 211 "BUCKET SIZE ", hashp->BSIZE, 212 "BUCKET SHIFT ", hashp->BSHIFT, 213 "DIRECTORY SIZE ", hashp->DSIZE, 214 "SEGMENT SIZE ", hashp->SGSIZE, 215 "SEGMENT SHIFT ", hashp->SSHIFT, 216 "FILL FACTOR ", hashp->FFACTOR, 217 "MAX BUCKET ", hashp->MAX_BUCKET, 218 "OVFL POINT ", hashp->OVFL_POINT, 219 "LAST FREED ", hashp->LAST_FREED, 220 "HIGH MASK ", hashp->HIGH_MASK, 221 "LOW MASK ", hashp->LOW_MASK, 222 "NSEGS ", hashp->nsegs, 223 "NKEYS ", hashp->NKEYS); 224 #endif 225 #ifdef HASH_STATISTICS 226 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 227 #endif 228 return (dbp); 229 230 error1: 231 if (hashp != NULL) 232 (void)_close(hashp->fp); 233 234 error0: 235 free(hashp); 236 errno = save_errno; 237 return (NULL); 238 } 239 240 static int 241 hash_close(DB *dbp) 242 { 243 HTAB *hashp; 244 int retval; 245 246 if (!dbp) 247 return (ERROR); 248 249 hashp = (HTAB *)dbp->internal; 250 retval = hdestroy(hashp); 251 free(dbp); 252 return (retval); 253 } 254 255 static int 256 hash_fd(const DB *dbp) 257 { 258 HTAB *hashp; 259 260 if (!dbp) 261 return (ERROR); 262 263 hashp = (HTAB *)dbp->internal; 264 if (hashp->fp == -1) { 265 errno = ENOENT; 266 return (-1); 267 } 268 return (hashp->fp); 269 } 270 271 /************************** LOCAL CREATION ROUTINES **********************/ 272 static HTAB * 273 init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 274 { 275 struct stat statbuf; 276 int nelem; 277 278 nelem = 1; 279 hashp->NKEYS = 0; 280 hashp->LORDER = BYTE_ORDER; 281 hashp->BSIZE = DEF_BUCKET_SIZE; 282 hashp->BSHIFT = DEF_BUCKET_SHIFT; 283 hashp->SGSIZE = DEF_SEGSIZE; 284 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 285 hashp->DSIZE = DEF_DIRSIZE; 286 hashp->FFACTOR = DEF_FFACTOR; 287 hashp->hash = __default_hash; 288 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 289 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 290 291 /* Fix bucket size to be optimal for file system */ 292 if (file != NULL) { 293 if (stat(file, &statbuf)) 294 return (NULL); 295 hashp->BSIZE = statbuf.st_blksize; 296 if (hashp->BSIZE > MAX_BSIZE) 297 hashp->BSIZE = MAX_BSIZE; 298 hashp->BSHIFT = __log2(hashp->BSIZE); 299 } 300 301 if (info) { 302 if (info->bsize) { 303 /* Round pagesize up to power of 2 */ 304 hashp->BSHIFT = __log2(info->bsize); 305 hashp->BSIZE = 1 << hashp->BSHIFT; 306 if (hashp->BSIZE > MAX_BSIZE) { 307 errno = EINVAL; 308 return (NULL); 309 } 310 } 311 if (info->ffactor) 312 hashp->FFACTOR = info->ffactor; 313 if (info->hash) 314 hashp->hash = info->hash; 315 if (info->nelem) 316 nelem = info->nelem; 317 if (info->lorder) { 318 if (info->lorder != BIG_ENDIAN && 319 info->lorder != LITTLE_ENDIAN) { 320 errno = EINVAL; 321 return (NULL); 322 } 323 hashp->LORDER = info->lorder; 324 } 325 } 326 /* init_htab should destroy the table and set errno if it fails */ 327 if (init_htab(hashp, nelem)) 328 return (NULL); 329 else 330 return (hashp); 331 } 332 /* 333 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 334 * the table and set errno, so we just pass the error information along. 335 * 336 * Returns 0 on No Error 337 */ 338 static int 339 init_htab(HTAB *hashp, int nelem) 340 { 341 int nbuckets, nsegs, l2; 342 343 /* 344 * Divide number of elements by the fill factor and determine a 345 * desired number of buckets. Allocate space for the next greater 346 * power of two number of buckets. 347 */ 348 nelem = (nelem - 1) / hashp->FFACTOR + 1; 349 350 l2 = __log2(MAX(nelem, 2)); 351 nbuckets = 1 << l2; 352 353 hashp->SPARES[l2] = l2 + 1; 354 hashp->SPARES[l2 + 1] = l2 + 1; 355 hashp->OVFL_POINT = l2; 356 hashp->LAST_FREED = 2; 357 358 /* First bitmap page is at: splitpoint l2 page offset 1 */ 359 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 360 return (-1); 361 362 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 363 hashp->HIGH_MASK = (nbuckets << 1) - 1; 364 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 365 hashp->BSHIFT) + 1; 366 367 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 368 nsegs = 1 << __log2(nsegs); 369 370 if (nsegs > hashp->DSIZE) 371 hashp->DSIZE = nsegs; 372 return (alloc_segs(hashp, nsegs)); 373 } 374 375 /********************** DESTROY/CLOSE ROUTINES ************************/ 376 377 /* 378 * Flushes any changes to the file if necessary and destroys the hashp 379 * structure, freeing all allocated space. 380 */ 381 static int 382 hdestroy(HTAB *hashp) 383 { 384 int i, save_errno; 385 386 save_errno = 0; 387 388 #ifdef HASH_STATISTICS 389 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 390 hash_accesses, hash_collisions); 391 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 392 hash_expansions); 393 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 394 hash_overflows); 395 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 396 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 397 398 for (i = 0; i < NCACHED; i++) 399 (void)fprintf(stderr, 400 "spares[%d] = %d\n", i, hashp->SPARES[i]); 401 #endif 402 /* 403 * Call on buffer manager to free buffers, and if required, 404 * write them to disk. 405 */ 406 if (__buf_free(hashp, 1, hashp->save_file)) 407 save_errno = errno; 408 if (hashp->dir) { 409 free(*hashp->dir); /* Free initial segments */ 410 /* Free extra segments */ 411 while (hashp->exsegs--) 412 free(hashp->dir[--hashp->nsegs]); 413 free(hashp->dir); 414 } 415 if (flush_meta(hashp) && !save_errno) 416 save_errno = errno; 417 /* Free Bigmaps */ 418 for (i = 0; i < hashp->nmaps; i++) 419 if (hashp->mapp[i]) 420 free(hashp->mapp[i]); 421 if (hashp->tmp_key) 422 free(hashp->tmp_key); 423 if (hashp->tmp_buf) 424 free(hashp->tmp_buf); 425 426 if (hashp->fp != -1) 427 (void)_close(hashp->fp); 428 429 free(hashp); 430 431 if (save_errno) { 432 errno = save_errno; 433 return (ERROR); 434 } 435 return (SUCCESS); 436 } 437 /* 438 * Write modified pages to disk 439 * 440 * Returns: 441 * 0 == OK 442 * -1 ERROR 443 */ 444 static int 445 hash_sync(const DB *dbp, u_int32_t flags) 446 { 447 HTAB *hashp; 448 449 if (flags != 0) { 450 errno = EINVAL; 451 return (ERROR); 452 } 453 454 if (!dbp) 455 return (ERROR); 456 457 hashp = (HTAB *)dbp->internal; 458 if (!hashp->save_file) 459 return (0); 460 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 461 return (ERROR); 462 hashp->new_file = 0; 463 return (0); 464 } 465 466 /* 467 * Returns: 468 * 0 == OK 469 * -1 indicates that errno should be set 470 */ 471 static int 472 flush_meta(HTAB *hashp) 473 { 474 HASHHDR *whdrp; 475 #if BYTE_ORDER == LITTLE_ENDIAN 476 HASHHDR whdr; 477 #endif 478 int fp, i, wsize; 479 480 if (!hashp->save_file) 481 return (0); 482 hashp->MAGIC = HASHMAGIC; 483 hashp->VERSION = HASHVERSION; 484 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 485 486 fp = hashp->fp; 487 whdrp = &hashp->hdr; 488 #if BYTE_ORDER == LITTLE_ENDIAN 489 whdrp = &whdr; 490 swap_header_copy(&hashp->hdr, whdrp); 491 #endif 492 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 493 return (-1); 494 else 495 if (wsize != sizeof(HASHHDR)) { 496 errno = EFTYPE; 497 hashp->error = errno; 498 return (-1); 499 } 500 for (i = 0; i < NCACHED; i++) 501 if (hashp->mapp[i]) 502 if (__put_page(hashp, (char *)hashp->mapp[i], 503 hashp->BITMAPS[i], 0, 1)) 504 return (-1); 505 return (0); 506 } 507 508 /*******************************SEARCH ROUTINES *****************************/ 509 /* 510 * All the access routines return 511 * 512 * Returns: 513 * 0 on SUCCESS 514 * 1 to indicate an external ERROR (i.e. key not found, etc) 515 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 516 */ 517 static int 518 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 519 { 520 HTAB *hashp; 521 522 hashp = (HTAB *)dbp->internal; 523 if (flag) { 524 hashp->error = errno = EINVAL; 525 return (ERROR); 526 } 527 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 528 } 529 530 static int 531 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 532 { 533 HTAB *hashp; 534 535 hashp = (HTAB *)dbp->internal; 536 if (flag && flag != R_NOOVERWRITE) { 537 hashp->error = errno = EINVAL; 538 return (ERROR); 539 } 540 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 541 hashp->error = errno = EPERM; 542 return (ERROR); 543 } 544 return (hash_access(hashp, flag == R_NOOVERWRITE ? 545 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 546 } 547 548 static int 549 hash_delete(const DB *dbp, const DBT *key, 550 u_int32_t flag) /* Ignored */ 551 { 552 HTAB *hashp; 553 554 hashp = (HTAB *)dbp->internal; 555 if (flag && flag != R_CURSOR) { 556 hashp->error = errno = EINVAL; 557 return (ERROR); 558 } 559 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 560 hashp->error = errno = EPERM; 561 return (ERROR); 562 } 563 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 564 } 565 566 /* 567 * Assume that hashp has been set in wrapper routine. 568 */ 569 static int 570 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 571 { 572 BUFHEAD *rbufp; 573 BUFHEAD *bufp, *save_bufp; 574 u_int16_t *bp; 575 int n, ndx, off, size; 576 char *kp; 577 u_int16_t pageno; 578 579 #ifdef HASH_STATISTICS 580 hash_accesses++; 581 #endif 582 583 off = hashp->BSIZE; 584 size = key->size; 585 kp = (char *)key->data; 586 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 587 if (!rbufp) 588 return (ERROR); 589 save_bufp = rbufp; 590 591 /* Pin the bucket chain */ 592 rbufp->flags |= BUF_PIN; 593 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 594 if (bp[1] >= REAL_KEY) { 595 /* Real key/data pair */ 596 if (size == off - *bp && 597 memcmp(kp, rbufp->page + *bp, size) == 0) 598 goto found; 599 off = bp[1]; 600 #ifdef HASH_STATISTICS 601 hash_collisions++; 602 #endif 603 bp += 2; 604 ndx += 2; 605 } else if (bp[1] == OVFLPAGE) { 606 rbufp = __get_buf(hashp, *bp, rbufp, 0); 607 if (!rbufp) { 608 save_bufp->flags &= ~BUF_PIN; 609 return (ERROR); 610 } 611 /* FOR LOOP INIT */ 612 bp = (u_int16_t *)rbufp->page; 613 n = *bp++; 614 ndx = 1; 615 off = hashp->BSIZE; 616 } else if (bp[1] < REAL_KEY) { 617 if ((ndx = 618 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 619 goto found; 620 if (ndx == -2) { 621 bufp = rbufp; 622 if (!(pageno = 623 __find_last_page(hashp, &bufp))) { 624 ndx = 0; 625 rbufp = bufp; 626 break; /* FOR */ 627 } 628 rbufp = __get_buf(hashp, pageno, bufp, 0); 629 if (!rbufp) { 630 save_bufp->flags &= ~BUF_PIN; 631 return (ERROR); 632 } 633 /* FOR LOOP INIT */ 634 bp = (u_int16_t *)rbufp->page; 635 n = *bp++; 636 ndx = 1; 637 off = hashp->BSIZE; 638 } else { 639 save_bufp->flags &= ~BUF_PIN; 640 return (ERROR); 641 } 642 } 643 644 /* Not found */ 645 switch (action) { 646 case HASH_PUT: 647 case HASH_PUTNEW: 648 if (__addel(hashp, rbufp, key, val)) { 649 save_bufp->flags &= ~BUF_PIN; 650 return (ERROR); 651 } else { 652 save_bufp->flags &= ~BUF_PIN; 653 return (SUCCESS); 654 } 655 case HASH_GET: 656 case HASH_DELETE: 657 default: 658 save_bufp->flags &= ~BUF_PIN; 659 return (ABNORMAL); 660 } 661 662 found: 663 switch (action) { 664 case HASH_PUTNEW: 665 save_bufp->flags &= ~BUF_PIN; 666 return (ABNORMAL); 667 case HASH_GET: 668 bp = (u_int16_t *)rbufp->page; 669 if (bp[ndx + 1] < REAL_KEY) { 670 if (__big_return(hashp, rbufp, ndx, val, 0)) 671 return (ERROR); 672 } else { 673 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 674 val->size = bp[ndx] - bp[ndx + 1]; 675 } 676 break; 677 case HASH_PUT: 678 if ((__delpair(hashp, rbufp, ndx)) || 679 (__addel(hashp, rbufp, key, val))) { 680 save_bufp->flags &= ~BUF_PIN; 681 return (ERROR); 682 } 683 break; 684 case HASH_DELETE: 685 if (__delpair(hashp, rbufp, ndx)) 686 return (ERROR); 687 break; 688 default: 689 abort(); 690 } 691 save_bufp->flags &= ~BUF_PIN; 692 return (SUCCESS); 693 } 694 695 static int 696 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 697 { 698 u_int32_t bucket; 699 BUFHEAD *bufp; 700 HTAB *hashp; 701 u_int16_t *bp, ndx; 702 703 hashp = (HTAB *)dbp->internal; 704 if (flag && flag != R_FIRST && flag != R_NEXT) { 705 hashp->error = errno = EINVAL; 706 return (ERROR); 707 } 708 #ifdef HASH_STATISTICS 709 hash_accesses++; 710 #endif 711 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 712 hashp->cbucket = 0; 713 hashp->cndx = 1; 714 hashp->cpage = NULL; 715 } 716 next_bucket: 717 for (bp = NULL; !bp || !bp[0]; ) { 718 if (!(bufp = hashp->cpage)) { 719 for (bucket = hashp->cbucket; 720 bucket <= hashp->MAX_BUCKET; 721 bucket++, hashp->cndx = 1) { 722 bufp = __get_buf(hashp, bucket, NULL, 0); 723 if (!bufp) 724 return (ERROR); 725 hashp->cpage = bufp; 726 bp = (u_int16_t *)bufp->page; 727 if (bp[0]) 728 break; 729 } 730 hashp->cbucket = bucket; 731 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 732 hashp->cbucket = -1; 733 return (ABNORMAL); 734 } 735 } else { 736 bp = (u_int16_t *)hashp->cpage->page; 737 if (flag == R_NEXT || flag == 0) { 738 hashp->cndx += 2; 739 if (hashp->cndx > bp[0]) { 740 hashp->cpage = NULL; 741 hashp->cbucket++; 742 hashp->cndx = 1; 743 goto next_bucket; 744 } 745 } 746 } 747 748 #ifdef DEBUG 749 assert(bp); 750 assert(bufp); 751 #endif 752 while (bp[hashp->cndx + 1] == OVFLPAGE) { 753 bufp = hashp->cpage = 754 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 755 if (!bufp) 756 return (ERROR); 757 bp = (u_int16_t *)(bufp->page); 758 hashp->cndx = 1; 759 } 760 if (!bp[0]) { 761 hashp->cpage = NULL; 762 ++hashp->cbucket; 763 } 764 } 765 ndx = hashp->cndx; 766 if (bp[ndx + 1] < REAL_KEY) { 767 if (__big_keydata(hashp, bufp, key, data, 1)) 768 return (ERROR); 769 } else { 770 if (hashp->cpage == 0) 771 return (ERROR); 772 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 773 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 774 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 775 data->size = bp[ndx] - bp[ndx + 1]; 776 } 777 return (SUCCESS); 778 } 779 780 /********************************* UTILITIES ************************/ 781 782 /* 783 * Returns: 784 * 0 ==> OK 785 * -1 ==> Error 786 */ 787 int 788 __expand_table(HTAB *hashp) 789 { 790 u_int32_t old_bucket, new_bucket; 791 int dirsize, new_segnum, spare_ndx; 792 793 #ifdef HASH_STATISTICS 794 hash_expansions++; 795 #endif 796 new_bucket = ++hashp->MAX_BUCKET; 797 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 798 799 new_segnum = new_bucket >> hashp->SSHIFT; 800 801 /* Check if we need a new segment */ 802 if (new_segnum >= hashp->nsegs) { 803 /* Check if we need to expand directory */ 804 if (new_segnum >= hashp->DSIZE) { 805 /* Reallocate directory */ 806 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 807 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 808 return (-1); 809 hashp->DSIZE = dirsize << 1; 810 } 811 if ((hashp->dir[new_segnum] = 812 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 813 return (-1); 814 hashp->exsegs++; 815 hashp->nsegs++; 816 } 817 /* 818 * If the split point is increasing (MAX_BUCKET's log base 2 819 * * increases), we need to copy the current contents of the spare 820 * split bucket to the next bucket. 821 */ 822 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 823 if (spare_ndx > hashp->OVFL_POINT) { 824 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 825 hashp->OVFL_POINT = spare_ndx; 826 } 827 828 if (new_bucket > hashp->HIGH_MASK) { 829 /* Starting a new doubling */ 830 hashp->LOW_MASK = hashp->HIGH_MASK; 831 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 832 } 833 /* Relocate records to the new bucket */ 834 return (__split_page(hashp, old_bucket, new_bucket)); 835 } 836 837 /* 838 * If realloc guarantees that the pointer is not destroyed if the realloc 839 * fails, then this routine can go away. 840 */ 841 static void * 842 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 843 { 844 void *p; 845 846 if ( (p = malloc(newsize)) ) { 847 memmove(p, *p_ptr, oldsize); 848 memset((char *)p + oldsize, 0, newsize - oldsize); 849 free(*p_ptr); 850 *p_ptr = p; 851 } 852 return (p); 853 } 854 855 u_int32_t 856 __call_hash(HTAB *hashp, char *k, int len) 857 { 858 unsigned int n, bucket; 859 860 n = hashp->hash(k, len); 861 bucket = n & hashp->HIGH_MASK; 862 if (bucket > hashp->MAX_BUCKET) 863 bucket = bucket & hashp->LOW_MASK; 864 return (bucket); 865 } 866 867 /* 868 * Allocate segment table. On error, destroy the table and set errno. 869 * 870 * Returns 0 on success 871 */ 872 static int 873 alloc_segs(HTAB *hashp, int nsegs) 874 { 875 int i; 876 SEGMENT store; 877 878 int save_errno; 879 880 if ((hashp->dir = 881 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 882 save_errno = errno; 883 (void)hdestroy(hashp); 884 errno = save_errno; 885 return (-1); 886 } 887 hashp->nsegs = nsegs; 888 if (nsegs == 0) 889 return (0); 890 /* Allocate segments */ 891 if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT, 892 sizeof(SEGMENT))) == NULL) { 893 save_errno = errno; 894 (void)hdestroy(hashp); 895 errno = save_errno; 896 return (-1); 897 } 898 for (i = 0; i < nsegs; i++) 899 hashp->dir[i] = &store[i << hashp->SSHIFT]; 900 return (0); 901 } 902 903 #if BYTE_ORDER == LITTLE_ENDIAN 904 /* 905 * Hashp->hdr needs to be byteswapped. 906 */ 907 static void 908 swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 909 { 910 int i; 911 912 P_32_COPY(srcp->magic, destp->magic); 913 P_32_COPY(srcp->version, destp->version); 914 P_32_COPY(srcp->lorder, destp->lorder); 915 P_32_COPY(srcp->bsize, destp->bsize); 916 P_32_COPY(srcp->bshift, destp->bshift); 917 P_32_COPY(srcp->dsize, destp->dsize); 918 P_32_COPY(srcp->ssize, destp->ssize); 919 P_32_COPY(srcp->sshift, destp->sshift); 920 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 921 P_32_COPY(srcp->last_freed, destp->last_freed); 922 P_32_COPY(srcp->max_bucket, destp->max_bucket); 923 P_32_COPY(srcp->high_mask, destp->high_mask); 924 P_32_COPY(srcp->low_mask, destp->low_mask); 925 P_32_COPY(srcp->ffactor, destp->ffactor); 926 P_32_COPY(srcp->nkeys, destp->nkeys); 927 P_32_COPY(srcp->hdrpages, destp->hdrpages); 928 P_32_COPY(srcp->h_charkey, destp->h_charkey); 929 for (i = 0; i < NCACHED; i++) { 930 P_32_COPY(srcp->spares[i], destp->spares[i]); 931 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 932 } 933 } 934 935 static void 936 swap_header(HTAB *hashp) 937 { 938 HASHHDR *hdrp; 939 int i; 940 941 hdrp = &hashp->hdr; 942 943 M_32_SWAP(hdrp->magic); 944 M_32_SWAP(hdrp->version); 945 M_32_SWAP(hdrp->lorder); 946 M_32_SWAP(hdrp->bsize); 947 M_32_SWAP(hdrp->bshift); 948 M_32_SWAP(hdrp->dsize); 949 M_32_SWAP(hdrp->ssize); 950 M_32_SWAP(hdrp->sshift); 951 M_32_SWAP(hdrp->ovfl_point); 952 M_32_SWAP(hdrp->last_freed); 953 M_32_SWAP(hdrp->max_bucket); 954 M_32_SWAP(hdrp->high_mask); 955 M_32_SWAP(hdrp->low_mask); 956 M_32_SWAP(hdrp->ffactor); 957 M_32_SWAP(hdrp->nkeys); 958 M_32_SWAP(hdrp->hdrpages); 959 M_32_SWAP(hdrp->h_charkey); 960 for (i = 0; i < NCACHED; i++) { 961 M_32_SWAP(hdrp->spares[i]); 962 M_16_SWAP(hdrp->bitmaps[i]); 963 } 964 } 965 #endif 966