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 * 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 8.9 (Berkeley) 6/16/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <sys/param.h> 45 #include <sys/stat.h> 46 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 #ifdef DEBUG 54 #include <assert.h> 55 #endif 56 #include "un-namespace.h" 57 58 #include <db.h> 59 #include "hash.h" 60 #include "page.h" 61 #include "extern.h" 62 63 static int alloc_segs(HTAB *, int); 64 static int flush_meta(HTAB *); 65 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 66 static int hash_close(DB *); 67 static int hash_delete(const DB *, const DBT *, u_int32_t); 68 static int hash_fd(const DB *); 69 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 70 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 71 static void *hash_realloc(SEGMENT **, int, int); 72 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 73 static int hash_sync(const DB *, u_int32_t); 74 static int hdestroy(HTAB *); 75 static HTAB *init_hash(HTAB *, const char *, HASHINFO *); 76 static int init_htab(HTAB *, int); 77 #if BYTE_ORDER == LITTLE_ENDIAN 78 static void swap_header(HTAB *); 79 static void swap_header_copy(HASHHDR *, HASHHDR *); 80 #endif 81 82 /* Fast arithmetic, relying on powers of 2, */ 83 #define MOD(x, y) ((x) & ((y) - 1)) 84 85 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 86 87 /* Return values */ 88 #define SUCCESS (0) 89 #define ERROR (-1) 90 #define ABNORMAL (1) 91 92 #ifdef HASH_STATISTICS 93 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 94 #endif 95 96 /************************** INTERFACE ROUTINES ***************************/ 97 /* OPEN/CLOSE */ 98 99 extern DB * 100 __hash_open(file, flags, mode, info, dflags) 101 const char *file; 102 int flags, mode, dflags; 103 const HASHINFO *info; /* Special directives for create */ 104 { 105 HTAB *hashp; 106 struct stat statbuf; 107 DB *dbp; 108 int bpages, hdrsize, new_table, nsegs, save_errno; 109 110 if ((flags & O_ACCMODE) == O_WRONLY) { 111 errno = EINVAL; 112 return (NULL); 113 } 114 115 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 116 return (NULL); 117 hashp->fp = -1; 118 119 /* 120 * Even if user wants write only, we need to be able to read 121 * the actual file, so we need to open it read/write. But, the 122 * field in the hashp structure needs to be accurate so that 123 * we can check accesses. 124 */ 125 hashp->flags = flags; 126 127 new_table = 0; 128 if (!file || (flags & O_TRUNC) || 129 (stat(file, &statbuf) && (errno == ENOENT))) { 130 if (errno == ENOENT) 131 errno = 0; /* Just in case someone looks at errno */ 132 new_table = 1; 133 } 134 if (file) { 135 if ((hashp->fp = _open(file, flags, mode)) == -1) 136 RETURN_ERROR(errno, error0); 137 138 /* if the .db file is empty, and we had permission to create 139 a new .db file, then reinitialize the database */ 140 if ((flags & O_CREAT) && 141 _fstat(hashp->fp, &statbuf) == 0 && statbuf.st_size == 0) 142 new_table = 1; 143 144 (void)_fcntl(hashp->fp, F_SETFD, 1); 145 } 146 if (new_table) { 147 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 148 RETURN_ERROR(errno, error1); 149 } else { 150 /* Table already exists */ 151 if (info && info->hash) 152 hashp->hash = info->hash; 153 else 154 hashp->hash = __default_hash; 155 156 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 157 #if BYTE_ORDER == LITTLE_ENDIAN 158 swap_header(hashp); 159 #endif 160 if (hdrsize == -1) 161 RETURN_ERROR(errno, error1); 162 if (hdrsize != sizeof(HASHHDR)) 163 RETURN_ERROR(EFTYPE, error1); 164 /* Verify file type, versions and hash function */ 165 if (hashp->MAGIC != HASHMAGIC) 166 RETURN_ERROR(EFTYPE, error1); 167 #define OLDHASHVERSION 1 168 if (hashp->VERSION != HASHVERSION && 169 hashp->VERSION != OLDHASHVERSION) 170 RETURN_ERROR(EFTYPE, error1); 171 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 172 RETURN_ERROR(EFTYPE, error1); 173 /* 174 * Figure out how many segments we need. Max_Bucket is the 175 * maximum bucket number, so the number of buckets is 176 * max_bucket + 1. 177 */ 178 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 179 hashp->SGSIZE; 180 hashp->nsegs = 0; 181 if (alloc_segs(hashp, nsegs)) 182 /* 183 * If alloc_segs fails, table will have been destroyed 184 * and errno will have been set. 185 */ 186 return (NULL); 187 /* Read in bitmaps */ 188 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 189 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 190 (hashp->BSHIFT + BYTE_SHIFT); 191 192 hashp->nmaps = bpages; 193 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 194 } 195 196 /* Initialize Buffer Manager */ 197 if (info && info->cachesize) 198 __buf_init(hashp, info->cachesize); 199 else 200 __buf_init(hashp, DEF_BUFSIZE); 201 202 hashp->new_file = new_table; 203 hashp->save_file = file && (hashp->flags & O_RDWR); 204 hashp->cbucket = -1; 205 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 206 save_errno = errno; 207 hdestroy(hashp); 208 errno = save_errno; 209 return (NULL); 210 } 211 dbp->internal = hashp; 212 dbp->close = hash_close; 213 dbp->del = hash_delete; 214 dbp->fd = hash_fd; 215 dbp->get = hash_get; 216 dbp->put = hash_put; 217 dbp->seq = hash_seq; 218 dbp->sync = hash_sync; 219 dbp->type = DB_HASH; 220 221 #ifdef DEBUG 222 (void)fprintf(stderr, 223 "%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", 224 "init_htab:", 225 "TABLE POINTER ", hashp, 226 "BUCKET SIZE ", hashp->BSIZE, 227 "BUCKET SHIFT ", hashp->BSHIFT, 228 "DIRECTORY SIZE ", hashp->DSIZE, 229 "SEGMENT SIZE ", hashp->SGSIZE, 230 "SEGMENT SHIFT ", hashp->SSHIFT, 231 "FILL FACTOR ", hashp->FFACTOR, 232 "MAX BUCKET ", hashp->MAX_BUCKET, 233 "OVFL POINT ", hashp->OVFL_POINT, 234 "LAST FREED ", hashp->LAST_FREED, 235 "HIGH MASK ", hashp->HIGH_MASK, 236 "LOW MASK ", hashp->LOW_MASK, 237 "NSEGS ", hashp->nsegs, 238 "NKEYS ", hashp->NKEYS); 239 #endif 240 #ifdef HASH_STATISTICS 241 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 242 #endif 243 return (dbp); 244 245 error1: 246 if (hashp != NULL) 247 (void)_close(hashp->fp); 248 249 error0: 250 free(hashp); 251 errno = save_errno; 252 return (NULL); 253 } 254 255 static int 256 hash_close(dbp) 257 DB *dbp; 258 { 259 HTAB *hashp; 260 int retval; 261 262 if (!dbp) 263 return (ERROR); 264 265 hashp = (HTAB *)dbp->internal; 266 retval = hdestroy(hashp); 267 free(dbp); 268 return (retval); 269 } 270 271 static int 272 hash_fd(dbp) 273 const DB *dbp; 274 { 275 HTAB *hashp; 276 277 if (!dbp) 278 return (ERROR); 279 280 hashp = (HTAB *)dbp->internal; 281 if (hashp->fp == -1) { 282 errno = ENOENT; 283 return (-1); 284 } 285 return (hashp->fp); 286 } 287 288 /************************** LOCAL CREATION ROUTINES **********************/ 289 static HTAB * 290 init_hash(hashp, file, info) 291 HTAB *hashp; 292 const char *file; 293 HASHINFO *info; 294 { 295 struct stat statbuf; 296 int nelem; 297 298 nelem = 1; 299 hashp->NKEYS = 0; 300 hashp->LORDER = BYTE_ORDER; 301 hashp->BSIZE = DEF_BUCKET_SIZE; 302 hashp->BSHIFT = DEF_BUCKET_SHIFT; 303 hashp->SGSIZE = DEF_SEGSIZE; 304 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 305 hashp->DSIZE = DEF_DIRSIZE; 306 hashp->FFACTOR = DEF_FFACTOR; 307 hashp->hash = __default_hash; 308 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 309 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 310 311 /* Fix bucket size to be optimal for file system */ 312 if (file != NULL) { 313 if (stat(file, &statbuf)) 314 return (NULL); 315 hashp->BSIZE = statbuf.st_blksize; 316 hashp->BSHIFT = __log2(hashp->BSIZE); 317 } 318 319 if (info) { 320 if (info->bsize) { 321 /* Round pagesize up to power of 2 */ 322 hashp->BSHIFT = __log2(info->bsize); 323 hashp->BSIZE = 1 << hashp->BSHIFT; 324 if (hashp->BSIZE > MAX_BSIZE) { 325 errno = EINVAL; 326 return (NULL); 327 } 328 } 329 if (info->ffactor) 330 hashp->FFACTOR = info->ffactor; 331 if (info->hash) 332 hashp->hash = info->hash; 333 if (info->nelem) 334 nelem = info->nelem; 335 if (info->lorder) { 336 if (info->lorder != BIG_ENDIAN && 337 info->lorder != LITTLE_ENDIAN) { 338 errno = EINVAL; 339 return (NULL); 340 } 341 hashp->LORDER = info->lorder; 342 } 343 } 344 /* init_htab should destroy the table and set errno if it fails */ 345 if (init_htab(hashp, nelem)) 346 return (NULL); 347 else 348 return (hashp); 349 } 350 /* 351 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 352 * the table and set errno, so we just pass the error information along. 353 * 354 * Returns 0 on No Error 355 */ 356 static int 357 init_htab(hashp, nelem) 358 HTAB *hashp; 359 int nelem; 360 { 361 int nbuckets, nsegs; 362 int l2; 363 364 /* 365 * Divide number of elements by the fill factor and determine a 366 * desired number of buckets. Allocate space for the next greater 367 * power of two number of buckets. 368 */ 369 nelem = (nelem - 1) / hashp->FFACTOR + 1; 370 371 l2 = __log2(MAX(nelem, 2)); 372 nbuckets = 1 << l2; 373 374 hashp->SPARES[l2] = l2 + 1; 375 hashp->SPARES[l2 + 1] = l2 + 1; 376 hashp->OVFL_POINT = l2; 377 hashp->LAST_FREED = 2; 378 379 /* First bitmap page is at: splitpoint l2 page offset 1 */ 380 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 381 return (-1); 382 383 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 384 hashp->HIGH_MASK = (nbuckets << 1) - 1; 385 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 386 hashp->BSHIFT) + 1; 387 388 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 389 nsegs = 1 << __log2(nsegs); 390 391 if (nsegs > hashp->DSIZE) 392 hashp->DSIZE = nsegs; 393 return (alloc_segs(hashp, nsegs)); 394 } 395 396 /********************** DESTROY/CLOSE ROUTINES ************************/ 397 398 /* 399 * Flushes any changes to the file if necessary and destroys the hashp 400 * structure, freeing all allocated space. 401 */ 402 static int 403 hdestroy(hashp) 404 HTAB *hashp; 405 { 406 int i, save_errno; 407 408 save_errno = 0; 409 410 #ifdef HASH_STATISTICS 411 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 412 hash_accesses, hash_collisions); 413 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 414 hash_expansions); 415 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 416 hash_overflows); 417 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 418 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 419 420 for (i = 0; i < NCACHED; i++) 421 (void)fprintf(stderr, 422 "spares[%d] = %d\n", i, hashp->SPARES[i]); 423 #endif 424 /* 425 * Call on buffer manager to free buffers, and if required, 426 * write them to disk. 427 */ 428 if (__buf_free(hashp, 1, hashp->save_file)) 429 save_errno = errno; 430 if (hashp->dir) { 431 free(*hashp->dir); /* Free initial segments */ 432 /* Free extra segments */ 433 while (hashp->exsegs--) 434 free(hashp->dir[--hashp->nsegs]); 435 free(hashp->dir); 436 } 437 if (flush_meta(hashp) && !save_errno) 438 save_errno = errno; 439 /* Free Bigmaps */ 440 for (i = 0; i < hashp->nmaps; i++) 441 if (hashp->mapp[i]) 442 free(hashp->mapp[i]); 443 444 if (hashp->fp != -1) 445 (void)_close(hashp->fp); 446 447 free(hashp); 448 449 if (save_errno) { 450 errno = save_errno; 451 return (ERROR); 452 } 453 return (SUCCESS); 454 } 455 /* 456 * Write modified pages to disk 457 * 458 * Returns: 459 * 0 == OK 460 * -1 ERROR 461 */ 462 static int 463 hash_sync(dbp, flags) 464 const DB *dbp; 465 u_int32_t flags; 466 { 467 HTAB *hashp; 468 469 if (flags != 0) { 470 errno = EINVAL; 471 return (ERROR); 472 } 473 474 if (!dbp) 475 return (ERROR); 476 477 hashp = (HTAB *)dbp->internal; 478 if (!hashp->save_file) 479 return (0); 480 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 481 return (ERROR); 482 hashp->new_file = 0; 483 return (0); 484 } 485 486 /* 487 * Returns: 488 * 0 == OK 489 * -1 indicates that errno should be set 490 */ 491 static int 492 flush_meta(hashp) 493 HTAB *hashp; 494 { 495 HASHHDR *whdrp; 496 #if BYTE_ORDER == LITTLE_ENDIAN 497 HASHHDR whdr; 498 #endif 499 int fp, i, wsize; 500 501 if (!hashp->save_file) 502 return (0); 503 hashp->MAGIC = HASHMAGIC; 504 hashp->VERSION = HASHVERSION; 505 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 506 507 fp = hashp->fp; 508 whdrp = &hashp->hdr; 509 #if BYTE_ORDER == LITTLE_ENDIAN 510 whdrp = &whdr; 511 swap_header_copy(&hashp->hdr, whdrp); 512 #endif 513 if ((lseek(fp, (off_t)0, SEEK_SET) == -1) || 514 ((wsize = _write(fp, whdrp, sizeof(HASHHDR))) == -1)) 515 return (-1); 516 else 517 if (wsize != sizeof(HASHHDR)) { 518 errno = EFTYPE; 519 hashp->error = errno; 520 return (-1); 521 } 522 for (i = 0; i < NCACHED; i++) 523 if (hashp->mapp[i]) 524 if (__put_page(hashp, (char *)hashp->mapp[i], 525 hashp->BITMAPS[i], 0, 1)) 526 return (-1); 527 return (0); 528 } 529 530 /*******************************SEARCH ROUTINES *****************************/ 531 /* 532 * All the access routines return 533 * 534 * Returns: 535 * 0 on SUCCESS 536 * 1 to indicate an external ERROR (i.e. key not found, etc) 537 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 538 */ 539 static int 540 hash_get(dbp, key, data, flag) 541 const DB *dbp; 542 const DBT *key; 543 DBT *data; 544 u_int32_t flag; 545 { 546 HTAB *hashp; 547 548 hashp = (HTAB *)dbp->internal; 549 if (flag) { 550 hashp->error = errno = EINVAL; 551 return (ERROR); 552 } 553 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 554 } 555 556 static int 557 hash_put(dbp, key, data, flag) 558 const DB *dbp; 559 DBT *key; 560 const DBT *data; 561 u_int32_t flag; 562 { 563 HTAB *hashp; 564 565 hashp = (HTAB *)dbp->internal; 566 if (flag && flag != R_NOOVERWRITE) { 567 hashp->error = EINVAL; 568 errno = EINVAL; 569 return (ERROR); 570 } 571 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 572 hashp->error = errno = EPERM; 573 return (ERROR); 574 } 575 return (hash_access(hashp, flag == R_NOOVERWRITE ? 576 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 577 } 578 579 static int 580 hash_delete(dbp, key, flag) 581 const DB *dbp; 582 const DBT *key; 583 u_int32_t flag; /* Ignored */ 584 { 585 HTAB *hashp; 586 587 hashp = (HTAB *)dbp->internal; 588 if (flag && flag != R_CURSOR) { 589 hashp->error = errno = EINVAL; 590 return (ERROR); 591 } 592 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 593 hashp->error = errno = EPERM; 594 return (ERROR); 595 } 596 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 597 } 598 599 /* 600 * Assume that hashp has been set in wrapper routine. 601 */ 602 static int 603 hash_access(hashp, action, key, val) 604 HTAB *hashp; 605 ACTION action; 606 DBT *key, *val; 607 { 608 BUFHEAD *rbufp; 609 BUFHEAD *bufp, *save_bufp; 610 u_int16_t *bp; 611 int n, ndx, off, size; 612 char *kp; 613 u_int16_t pageno; 614 615 #ifdef HASH_STATISTICS 616 hash_accesses++; 617 #endif 618 619 off = hashp->BSIZE; 620 size = key->size; 621 kp = (char *)key->data; 622 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 623 if (!rbufp) 624 return (ERROR); 625 save_bufp = rbufp; 626 627 /* Pin the bucket chain */ 628 rbufp->flags |= BUF_PIN; 629 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 630 if (bp[1] >= REAL_KEY) { 631 /* Real key/data pair */ 632 if (size == off - *bp && 633 memcmp(kp, rbufp->page + *bp, size) == 0) 634 goto found; 635 off = bp[1]; 636 #ifdef HASH_STATISTICS 637 hash_collisions++; 638 #endif 639 bp += 2; 640 ndx += 2; 641 } else if (bp[1] == OVFLPAGE) { 642 rbufp = __get_buf(hashp, *bp, rbufp, 0); 643 if (!rbufp) { 644 save_bufp->flags &= ~BUF_PIN; 645 return (ERROR); 646 } 647 /* FOR LOOP INIT */ 648 bp = (u_int16_t *)rbufp->page; 649 n = *bp++; 650 ndx = 1; 651 off = hashp->BSIZE; 652 } else if (bp[1] < REAL_KEY) { 653 if ((ndx = 654 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 655 goto found; 656 if (ndx == -2) { 657 bufp = rbufp; 658 if (!(pageno = 659 __find_last_page(hashp, &bufp))) { 660 ndx = 0; 661 rbufp = bufp; 662 break; /* FOR */ 663 } 664 rbufp = __get_buf(hashp, pageno, bufp, 0); 665 if (!rbufp) { 666 save_bufp->flags &= ~BUF_PIN; 667 return (ERROR); 668 } 669 /* FOR LOOP INIT */ 670 bp = (u_int16_t *)rbufp->page; 671 n = *bp++; 672 ndx = 1; 673 off = hashp->BSIZE; 674 } else { 675 save_bufp->flags &= ~BUF_PIN; 676 return (ERROR); 677 } 678 } 679 680 /* Not found */ 681 switch (action) { 682 case HASH_PUT: 683 case HASH_PUTNEW: 684 if (__addel(hashp, rbufp, key, val)) { 685 save_bufp->flags &= ~BUF_PIN; 686 return (ERROR); 687 } else { 688 save_bufp->flags &= ~BUF_PIN; 689 return (SUCCESS); 690 } 691 case HASH_GET: 692 case HASH_DELETE: 693 default: 694 save_bufp->flags &= ~BUF_PIN; 695 return (ABNORMAL); 696 } 697 698 found: 699 switch (action) { 700 case HASH_PUTNEW: 701 save_bufp->flags &= ~BUF_PIN; 702 return (ABNORMAL); 703 case HASH_GET: 704 bp = (u_int16_t *)rbufp->page; 705 if (bp[ndx + 1] < REAL_KEY) { 706 if (__big_return(hashp, rbufp, ndx, val, 0)) 707 return (ERROR); 708 } else { 709 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 710 val->size = bp[ndx] - bp[ndx + 1]; 711 } 712 break; 713 case HASH_PUT: 714 if ((__delpair(hashp, rbufp, ndx)) || 715 (__addel(hashp, rbufp, key, val))) { 716 save_bufp->flags &= ~BUF_PIN; 717 return (ERROR); 718 } 719 break; 720 case HASH_DELETE: 721 if (__delpair(hashp, rbufp, ndx)) 722 return (ERROR); 723 break; 724 default: 725 abort(); 726 } 727 save_bufp->flags &= ~BUF_PIN; 728 return (SUCCESS); 729 } 730 731 static int 732 hash_seq(dbp, key, data, flag) 733 const DB *dbp; 734 DBT *key, *data; 735 u_int32_t flag; 736 { 737 u_int32_t bucket; 738 BUFHEAD *bufp; 739 HTAB *hashp; 740 u_int16_t *bp, ndx; 741 742 hashp = (HTAB *)dbp->internal; 743 if (flag && flag != R_FIRST && flag != R_NEXT) { 744 hashp->error = errno = EINVAL; 745 return (ERROR); 746 } 747 #ifdef HASH_STATISTICS 748 hash_accesses++; 749 #endif 750 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 751 hashp->cbucket = 0; 752 hashp->cndx = 1; 753 hashp->cpage = NULL; 754 } 755 756 for (bp = NULL; !bp || !bp[0]; ) { 757 if (!(bufp = hashp->cpage)) { 758 for (bucket = hashp->cbucket; 759 bucket <= hashp->MAX_BUCKET; 760 bucket++, hashp->cndx = 1) { 761 bufp = __get_buf(hashp, bucket, NULL, 0); 762 if (!bufp) 763 return (ERROR); 764 hashp->cpage = bufp; 765 bp = (u_int16_t *)bufp->page; 766 if (bp[0]) 767 break; 768 } 769 hashp->cbucket = bucket; 770 if (hashp->cbucket > hashp->MAX_BUCKET) { 771 hashp->cbucket = -1; 772 return (ABNORMAL); 773 } 774 } else 775 bp = (u_int16_t *)hashp->cpage->page; 776 777 #ifdef DEBUG 778 assert(bp); 779 assert(bufp); 780 #endif 781 while (bp[hashp->cndx + 1] == OVFLPAGE) { 782 bufp = hashp->cpage = 783 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 784 if (!bufp) 785 return (ERROR); 786 bp = (u_int16_t *)(bufp->page); 787 hashp->cndx = 1; 788 } 789 if (!bp[0]) { 790 hashp->cpage = NULL; 791 ++hashp->cbucket; 792 } 793 } 794 ndx = hashp->cndx; 795 if (bp[ndx + 1] < REAL_KEY) { 796 if (__big_keydata(hashp, bufp, key, data, 1)) 797 return (ERROR); 798 } else { 799 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 800 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 801 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 802 data->size = bp[ndx] - bp[ndx + 1]; 803 ndx += 2; 804 if (ndx > bp[0]) { 805 hashp->cpage = NULL; 806 hashp->cbucket++; 807 hashp->cndx = 1; 808 } else 809 hashp->cndx = ndx; 810 } 811 return (SUCCESS); 812 } 813 814 /********************************* UTILITIES ************************/ 815 816 /* 817 * Returns: 818 * 0 ==> OK 819 * -1 ==> Error 820 */ 821 extern int 822 __expand_table(hashp) 823 HTAB *hashp; 824 { 825 u_int32_t old_bucket, new_bucket; 826 int dirsize, new_segnum, spare_ndx; 827 828 #ifdef HASH_STATISTICS 829 hash_expansions++; 830 #endif 831 new_bucket = ++hashp->MAX_BUCKET; 832 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 833 834 new_segnum = new_bucket >> hashp->SSHIFT; 835 836 /* Check if we need a new segment */ 837 if (new_segnum >= hashp->nsegs) { 838 /* Check if we need to expand directory */ 839 if (new_segnum >= hashp->DSIZE) { 840 /* Reallocate directory */ 841 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 842 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 843 return (-1); 844 hashp->DSIZE = dirsize << 1; 845 } 846 if ((hashp->dir[new_segnum] = 847 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 848 return (-1); 849 hashp->exsegs++; 850 hashp->nsegs++; 851 } 852 /* 853 * If the split point is increasing (MAX_BUCKET's log base 2 854 * * increases), we need to copy the current contents of the spare 855 * split bucket to the next bucket. 856 */ 857 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 858 if (spare_ndx > hashp->OVFL_POINT) { 859 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 860 hashp->OVFL_POINT = spare_ndx; 861 } 862 863 if (new_bucket > hashp->HIGH_MASK) { 864 /* Starting a new doubling */ 865 hashp->LOW_MASK = hashp->HIGH_MASK; 866 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 867 } 868 /* Relocate records to the new bucket */ 869 return (__split_page(hashp, old_bucket, new_bucket)); 870 } 871 872 /* 873 * If realloc guarantees that the pointer is not destroyed if the realloc 874 * fails, then this routine can go away. 875 */ 876 static void * 877 hash_realloc(p_ptr, oldsize, newsize) 878 SEGMENT **p_ptr; 879 int oldsize, newsize; 880 { 881 void *p; 882 883 if ( (p = malloc(newsize)) ) { 884 memmove(p, *p_ptr, oldsize); 885 memset((char *)p + oldsize, 0, newsize - oldsize); 886 free(*p_ptr); 887 *p_ptr = p; 888 } 889 return (p); 890 } 891 892 extern u_int32_t 893 __call_hash(hashp, k, len) 894 HTAB *hashp; 895 char *k; 896 int len; 897 { 898 int n, bucket; 899 900 n = hashp->hash(k, len); 901 bucket = n & hashp->HIGH_MASK; 902 if (bucket > hashp->MAX_BUCKET) 903 bucket = bucket & hashp->LOW_MASK; 904 return (bucket); 905 } 906 907 /* 908 * Allocate segment table. On error, destroy the table and set errno. 909 * 910 * Returns 0 on success 911 */ 912 static int 913 alloc_segs(hashp, nsegs) 914 HTAB *hashp; 915 int nsegs; 916 { 917 int i; 918 SEGMENT store; 919 920 int save_errno; 921 922 if ((hashp->dir = 923 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 924 save_errno = errno; 925 (void)hdestroy(hashp); 926 errno = save_errno; 927 return (-1); 928 } 929 /* Allocate segments */ 930 if ((store = 931 (SEGMENT)calloc(nsegs << hashp->SSHIFT, sizeof(SEGMENT))) == NULL) { 932 save_errno = errno; 933 (void)hdestroy(hashp); 934 errno = save_errno; 935 return (-1); 936 } 937 for (i = 0; i < nsegs; i++, hashp->nsegs++) 938 hashp->dir[i] = &store[i << hashp->SSHIFT]; 939 return (0); 940 } 941 942 #if BYTE_ORDER == LITTLE_ENDIAN 943 /* 944 * Hashp->hdr needs to be byteswapped. 945 */ 946 static void 947 swap_header_copy(srcp, destp) 948 HASHHDR *srcp, *destp; 949 { 950 int i; 951 952 P_32_COPY(srcp->magic, destp->magic); 953 P_32_COPY(srcp->version, destp->version); 954 P_32_COPY(srcp->lorder, destp->lorder); 955 P_32_COPY(srcp->bsize, destp->bsize); 956 P_32_COPY(srcp->bshift, destp->bshift); 957 P_32_COPY(srcp->dsize, destp->dsize); 958 P_32_COPY(srcp->ssize, destp->ssize); 959 P_32_COPY(srcp->sshift, destp->sshift); 960 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 961 P_32_COPY(srcp->last_freed, destp->last_freed); 962 P_32_COPY(srcp->max_bucket, destp->max_bucket); 963 P_32_COPY(srcp->high_mask, destp->high_mask); 964 P_32_COPY(srcp->low_mask, destp->low_mask); 965 P_32_COPY(srcp->ffactor, destp->ffactor); 966 P_32_COPY(srcp->nkeys, destp->nkeys); 967 P_32_COPY(srcp->hdrpages, destp->hdrpages); 968 P_32_COPY(srcp->h_charkey, destp->h_charkey); 969 for (i = 0; i < NCACHED; i++) { 970 P_32_COPY(srcp->spares[i], destp->spares[i]); 971 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 972 } 973 } 974 975 static void 976 swap_header(hashp) 977 HTAB *hashp; 978 { 979 HASHHDR *hdrp; 980 int i; 981 982 hdrp = &hashp->hdr; 983 984 M_32_SWAP(hdrp->magic); 985 M_32_SWAP(hdrp->version); 986 M_32_SWAP(hdrp->lorder); 987 M_32_SWAP(hdrp->bsize); 988 M_32_SWAP(hdrp->bshift); 989 M_32_SWAP(hdrp->dsize); 990 M_32_SWAP(hdrp->ssize); 991 M_32_SWAP(hdrp->sshift); 992 M_32_SWAP(hdrp->ovfl_point); 993 M_32_SWAP(hdrp->last_freed); 994 M_32_SWAP(hdrp->max_bucket); 995 M_32_SWAP(hdrp->high_mask); 996 M_32_SWAP(hdrp->low_mask); 997 M_32_SWAP(hdrp->ffactor); 998 M_32_SWAP(hdrp->nkeys); 999 M_32_SWAP(hdrp->hdrpages); 1000 M_32_SWAP(hdrp->h_charkey); 1001 for (i = 0; i < NCACHED; i++) { 1002 M_32_SWAP(hdrp->spares[i]); 1003 M_16_SWAP(hdrp->bitmaps[i]); 1004 } 1005 } 1006 #endif 1007