1 /* $OpenBSD: hash.c,v 1.22 2008/05/11 22:21:25 millert Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Margo Seltzer. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/param.h> 36 #include <sys/stat.h> 37 38 #include <errno.h> 39 #include <fcntl.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <unistd.h> 44 #ifdef DEBUG 45 #include <assert.h> 46 #endif 47 48 #include <db.h> 49 #include "hash.h" 50 #include "page.h" 51 #include "extern.h" 52 53 static int alloc_segs(HTAB *, int); 54 static int flush_meta(HTAB *); 55 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 56 static int hash_close(DB *); 57 static int hash_delete(const DB *, const DBT *, u_int32_t); 58 static int hash_fd(const DB *); 59 static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 60 static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 61 static void *hash_realloc(SEGMENT **, int, int); 62 static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 63 static int hash_sync(const DB *, u_int32_t); 64 static int hdestroy(HTAB *); 65 static HTAB *init_hash(HTAB *, const char *, HASHINFO *); 66 static int init_htab(HTAB *, int); 67 #if BYTE_ORDER == LITTLE_ENDIAN 68 static void swap_header(HTAB *); 69 static void swap_header_copy(HASHHDR *, HASHHDR *); 70 #endif 71 72 /* Fast arithmetic, relying on powers of 2, */ 73 #define MOD(x, y) ((x) & ((y) - 1)) 74 75 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 76 77 /* Return values */ 78 #define SUCCESS (0) 79 #define ERROR (-1) 80 #define ABNORMAL (1) 81 82 #ifdef HASH_STATISTICS 83 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 84 #endif 85 86 /************************** INTERFACE ROUTINES ***************************/ 87 /* OPEN/CLOSE */ 88 89 /* ARGSUSED */ 90 DB * 91 __hash_open(const char *file, int flags, int mode, 92 const HASHINFO *info, /* Special directives for create */ 93 int dflags) 94 { 95 HTAB *hashp; 96 struct stat statbuf; 97 DB *dbp; 98 int bpages, hdrsize, new_table, nsegs, save_errno; 99 100 if ((flags & O_ACCMODE) == O_WRONLY) { 101 errno = EINVAL; 102 return (NULL); 103 } 104 105 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 106 return (NULL); 107 hashp->fp = -1; 108 109 /* 110 * Even if user wants write only, we need to be able to read 111 * the actual file, so we need to open it read/write. But, the 112 * field in the hashp structure needs to be accurate so that 113 * we can check accesses. 114 */ 115 hashp->flags = flags; 116 117 if (file) { 118 if ((hashp->fp = open(file, flags, mode)) == -1) 119 RETURN_ERROR(errno, error0); 120 (void)fcntl(hashp->fp, F_SETFD, 1); 121 new_table = fstat(hashp->fp, &statbuf) == 0 && 122 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 123 } else 124 new_table = 1; 125 126 if (new_table) { 127 if (!(hashp = init_hash(hashp, file, (HASHINFO *)info))) 128 RETURN_ERROR(errno, error1); 129 } else { 130 /* Table already exists */ 131 if (info && info->hash) 132 hashp->hash = info->hash; 133 else 134 hashp->hash = __default_hash; 135 136 hdrsize = read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 137 #if BYTE_ORDER == LITTLE_ENDIAN 138 swap_header(hashp); 139 #endif 140 if (hdrsize == -1) 141 RETURN_ERROR(errno, error1); 142 if (hdrsize != sizeof(HASHHDR)) 143 RETURN_ERROR(EFTYPE, error1); 144 /* Verify file type, versions and hash function */ 145 if (hashp->MAGIC != HASHMAGIC) 146 RETURN_ERROR(EFTYPE, error1); 147 #define OLDHASHVERSION 1 148 if (hashp->VERSION != HASHVERSION && 149 hashp->VERSION != OLDHASHVERSION) 150 RETURN_ERROR(EFTYPE, error1); 151 if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 152 RETURN_ERROR(EFTYPE, error1); 153 /* 154 * Figure out how many segments we need. Max_Bucket is the 155 * maximum bucket number, so the number of buckets is 156 * max_bucket + 1. 157 */ 158 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 159 hashp->SGSIZE; 160 if (alloc_segs(hashp, nsegs)) 161 /* 162 * If alloc_segs fails, table will have been destroyed 163 * and errno will have been set. 164 */ 165 return (NULL); 166 /* Read in bitmaps */ 167 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 168 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 169 (hashp->BSHIFT + BYTE_SHIFT); 170 171 hashp->nmaps = bpages; 172 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 173 } 174 175 /* Initialize Buffer Manager */ 176 if (info && info->cachesize) 177 __buf_init(hashp, info->cachesize); 178 else 179 __buf_init(hashp, DEF_BUFSIZE); 180 181 hashp->new_file = new_table; 182 hashp->save_file = file && (hashp->flags & O_RDWR); 183 hashp->cbucket = -1; 184 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 185 save_errno = errno; 186 hdestroy(hashp); 187 errno = save_errno; 188 return (NULL); 189 } 190 dbp->internal = hashp; 191 dbp->close = hash_close; 192 dbp->del = hash_delete; 193 dbp->fd = hash_fd; 194 dbp->get = hash_get; 195 dbp->put = hash_put; 196 dbp->seq = hash_seq; 197 dbp->sync = hash_sync; 198 dbp->type = DB_HASH; 199 200 #ifdef DEBUG 201 (void)fprintf(stderr, 202 "%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", 203 "init_htab:", 204 "TABLE POINTER ", hashp, 205 "BUCKET SIZE ", hashp->BSIZE, 206 "BUCKET SHIFT ", hashp->BSHIFT, 207 "DIRECTORY SIZE ", hashp->DSIZE, 208 "SEGMENT SIZE ", hashp->SGSIZE, 209 "SEGMENT SHIFT ", hashp->SSHIFT, 210 "FILL FACTOR ", hashp->FFACTOR, 211 "MAX BUCKET ", hashp->MAX_BUCKET, 212 "OVFL POINT ", hashp->OVFL_POINT, 213 "LAST FREED ", hashp->LAST_FREED, 214 "HIGH MASK ", hashp->HIGH_MASK, 215 "LOW MASK ", hashp->LOW_MASK, 216 "NSEGS ", hashp->nsegs, 217 "NKEYS ", hashp->NKEYS); 218 #endif 219 #ifdef HASH_STATISTICS 220 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 221 #endif 222 return (dbp); 223 224 error1: 225 if (hashp != NULL) 226 (void)close(hashp->fp); 227 228 error0: 229 free(hashp); 230 errno = save_errno; 231 return (NULL); 232 } 233 234 static int 235 hash_close(DB *dbp) 236 { 237 HTAB *hashp; 238 int retval; 239 240 if (!dbp) 241 return (ERROR); 242 243 hashp = (HTAB *)dbp->internal; 244 retval = hdestroy(hashp); 245 free(dbp); 246 return (retval); 247 } 248 249 static int 250 hash_fd(const DB *dbp) 251 { 252 HTAB *hashp; 253 254 if (!dbp) 255 return (ERROR); 256 257 hashp = (HTAB *)dbp->internal; 258 if (hashp->fp == -1) { 259 errno = ENOENT; 260 return (-1); 261 } 262 return (hashp->fp); 263 } 264 265 /************************** LOCAL CREATION ROUTINES **********************/ 266 static HTAB * 267 init_hash(HTAB *hashp, const char *file, HASHINFO *info) 268 { 269 struct stat statbuf; 270 int nelem; 271 272 nelem = 1; 273 hashp->NKEYS = 0; 274 hashp->LORDER = BYTE_ORDER; 275 hashp->BSIZE = DEF_BUCKET_SIZE; 276 hashp->BSHIFT = DEF_BUCKET_SHIFT; 277 hashp->SGSIZE = DEF_SEGSIZE; 278 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 279 hashp->DSIZE = DEF_DIRSIZE; 280 hashp->FFACTOR = DEF_FFACTOR; 281 hashp->hash = __default_hash; 282 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 283 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 284 285 /* Fix bucket size to be optimal for file system */ 286 if (file != NULL) { 287 if (stat(file, &statbuf)) 288 return (NULL); 289 hashp->BSIZE = statbuf.st_blksize; 290 hashp->BSHIFT = __log2(hashp->BSIZE); 291 } 292 293 if (info) { 294 if (info->bsize) { 295 /* Round pagesize up to power of 2 */ 296 hashp->BSHIFT = __log2(info->bsize); 297 hashp->BSIZE = 1 << hashp->BSHIFT; 298 if (hashp->BSIZE > MAX_BSIZE) { 299 errno = EINVAL; 300 return (NULL); 301 } 302 } 303 if (info->ffactor) 304 hashp->FFACTOR = info->ffactor; 305 if (info->hash) 306 hashp->hash = info->hash; 307 if (info->nelem) 308 nelem = info->nelem; 309 if (info->lorder) { 310 if (info->lorder != BIG_ENDIAN && 311 info->lorder != LITTLE_ENDIAN) { 312 errno = EINVAL; 313 return (NULL); 314 } 315 hashp->LORDER = info->lorder; 316 } 317 } 318 /* init_htab should destroy the table and set errno if it fails */ 319 if (init_htab(hashp, nelem)) 320 return (NULL); 321 else 322 return (hashp); 323 } 324 /* 325 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 326 * the table and set errno, so we just pass the error information along. 327 * 328 * Returns 0 on No Error 329 */ 330 static int 331 init_htab(HTAB *hashp, int nelem) 332 { 333 int nbuckets, nsegs, l2; 334 335 /* 336 * Divide number of elements by the fill factor and determine a 337 * desired number of buckets. Allocate space for the next greater 338 * power of two number of buckets. 339 */ 340 nelem = (nelem - 1) / hashp->FFACTOR + 1; 341 342 l2 = __log2(MAX(nelem, 2)); 343 nbuckets = 1 << l2; 344 345 hashp->SPARES[l2] = l2 + 1; 346 hashp->SPARES[l2 + 1] = l2 + 1; 347 hashp->OVFL_POINT = l2; 348 hashp->LAST_FREED = 2; 349 350 /* First bitmap page is at: splitpoint l2 page offset 1 */ 351 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 352 return (-1); 353 354 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 355 hashp->HIGH_MASK = (nbuckets << 1) - 1; 356 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 357 hashp->BSHIFT) + 1; 358 359 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 360 nsegs = 1 << __log2(nsegs); 361 362 if (nsegs > hashp->DSIZE) 363 hashp->DSIZE = nsegs; 364 return (alloc_segs(hashp, nsegs)); 365 } 366 367 /********************** DESTROY/CLOSE ROUTINES ************************/ 368 369 /* 370 * Flushes any changes to the file if necessary and destroys the hashp 371 * structure, freeing all allocated space. 372 */ 373 static int 374 hdestroy(HTAB *hashp) 375 { 376 int i, save_errno; 377 378 save_errno = 0; 379 380 #ifdef HASH_STATISTICS 381 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 382 hash_accesses, hash_collisions); 383 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 384 hash_expansions); 385 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 386 hash_overflows); 387 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 388 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 389 390 for (i = 0; i < NCACHED; i++) 391 (void)fprintf(stderr, 392 "spares[%d] = %d\n", i, hashp->SPARES[i]); 393 #endif 394 /* 395 * Call on buffer manager to free buffers, and if required, 396 * write them to disk. 397 */ 398 if (__buf_free(hashp, 1, hashp->save_file)) 399 save_errno = errno; 400 if (hashp->dir) { 401 free(*hashp->dir); /* Free initial segments */ 402 /* Free extra segments */ 403 while (hashp->exsegs--) 404 free(hashp->dir[--hashp->nsegs]); 405 free(hashp->dir); 406 } 407 if (flush_meta(hashp) && !save_errno) 408 save_errno = errno; 409 /* Free Bigmaps */ 410 for (i = 0; i < hashp->nmaps; i++) 411 if (hashp->mapp[i]) 412 free(hashp->mapp[i]); 413 if (hashp->tmp_key) 414 free(hashp->tmp_key); 415 if (hashp->tmp_buf) 416 free(hashp->tmp_buf); 417 418 if (hashp->fp != -1) 419 (void)close(hashp->fp); 420 421 free(hashp); 422 423 if (save_errno) { 424 errno = save_errno; 425 return (ERROR); 426 } 427 return (SUCCESS); 428 } 429 /* 430 * Write modified pages to disk 431 * 432 * Returns: 433 * 0 == OK 434 * -1 ERROR 435 */ 436 static int 437 hash_sync(const DB *dbp, u_int32_t flags) 438 { 439 HTAB *hashp; 440 441 if (flags != 0) { 442 errno = EINVAL; 443 return (ERROR); 444 } 445 446 if (!dbp) 447 return (ERROR); 448 449 hashp = (HTAB *)dbp->internal; 450 if (!hashp->save_file) 451 return (0); 452 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 453 return (ERROR); 454 hashp->new_file = 0; 455 return (0); 456 } 457 458 /* 459 * Returns: 460 * 0 == OK 461 * -1 indicates that errno should be set 462 */ 463 static int 464 flush_meta(HTAB *hashp) 465 { 466 HASHHDR *whdrp; 467 #if BYTE_ORDER == LITTLE_ENDIAN 468 HASHHDR whdr; 469 #endif 470 int fp, i, wsize; 471 472 if (!hashp->save_file) 473 return (0); 474 hashp->MAGIC = HASHMAGIC; 475 hashp->VERSION = HASHVERSION; 476 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 477 478 fp = hashp->fp; 479 whdrp = &hashp->hdr; 480 #if BYTE_ORDER == LITTLE_ENDIAN 481 whdrp = &whdr; 482 swap_header_copy(&hashp->hdr, whdrp); 483 #endif 484 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 485 return (-1); 486 else 487 if (wsize != sizeof(HASHHDR)) { 488 errno = EFTYPE; 489 hashp->err = errno; 490 return (-1); 491 } 492 for (i = 0; i < NCACHED; i++) 493 if (hashp->mapp[i]) 494 if (__put_page(hashp, (char *)hashp->mapp[i], 495 hashp->BITMAPS[i], 0, 1)) 496 return (-1); 497 return (0); 498 } 499 500 /*******************************SEARCH ROUTINES *****************************/ 501 /* 502 * All the access routines return 503 * 504 * Returns: 505 * 0 on SUCCESS 506 * 1 to indicate an external ERROR (i.e. key not found, etc) 507 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 508 */ 509 static int 510 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 511 { 512 HTAB *hashp; 513 514 hashp = (HTAB *)dbp->internal; 515 if (flag) { 516 hashp->err = errno = EINVAL; 517 return (ERROR); 518 } 519 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 520 } 521 522 static int 523 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 524 { 525 HTAB *hashp; 526 527 hashp = (HTAB *)dbp->internal; 528 if (flag && flag != R_NOOVERWRITE) { 529 hashp->err = errno = EINVAL; 530 return (ERROR); 531 } 532 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 533 hashp->err = errno = EPERM; 534 return (ERROR); 535 } 536 return (hash_access(hashp, flag == R_NOOVERWRITE ? 537 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 538 } 539 540 static int 541 hash_delete(const DB *dbp, const DBT *key, 542 u_int32_t flag) /* Ignored */ 543 { 544 HTAB *hashp; 545 546 hashp = (HTAB *)dbp->internal; 547 if (flag && flag != R_CURSOR) { 548 hashp->err = errno = EINVAL; 549 return (ERROR); 550 } 551 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 552 hashp->err = errno = EPERM; 553 return (ERROR); 554 } 555 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 556 } 557 558 /* 559 * Assume that hashp has been set in wrapper routine. 560 */ 561 static int 562 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 563 { 564 BUFHEAD *rbufp; 565 BUFHEAD *bufp, *save_bufp; 566 u_int16_t *bp; 567 int n, ndx, off, size; 568 char *kp; 569 u_int16_t pageno; 570 571 #ifdef HASH_STATISTICS 572 hash_accesses++; 573 #endif 574 575 off = hashp->BSIZE; 576 size = key->size; 577 kp = (char *)key->data; 578 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 579 if (!rbufp) 580 return (ERROR); 581 save_bufp = rbufp; 582 583 /* Pin the bucket chain */ 584 rbufp->flags |= BUF_PIN; 585 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 586 if (bp[1] >= REAL_KEY) { 587 /* Real key/data pair */ 588 if (size == off - *bp && 589 memcmp(kp, rbufp->page + *bp, size) == 0) 590 goto found; 591 off = bp[1]; 592 #ifdef HASH_STATISTICS 593 hash_collisions++; 594 #endif 595 bp += 2; 596 ndx += 2; 597 } else if (bp[1] == OVFLPAGE) { 598 rbufp = __get_buf(hashp, *bp, rbufp, 0); 599 if (!rbufp) { 600 save_bufp->flags &= ~BUF_PIN; 601 return (ERROR); 602 } 603 /* FOR LOOP INIT */ 604 bp = (u_int16_t *)rbufp->page; 605 n = *bp++; 606 ndx = 1; 607 off = hashp->BSIZE; 608 } else if (bp[1] < REAL_KEY) { 609 if ((ndx = 610 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 611 goto found; 612 if (ndx == -2) { 613 bufp = rbufp; 614 if (!(pageno = 615 __find_last_page(hashp, &bufp))) { 616 ndx = 0; 617 rbufp = bufp; 618 break; /* FOR */ 619 } 620 rbufp = __get_buf(hashp, pageno, bufp, 0); 621 if (!rbufp) { 622 save_bufp->flags &= ~BUF_PIN; 623 return (ERROR); 624 } 625 /* FOR LOOP INIT */ 626 bp = (u_int16_t *)rbufp->page; 627 n = *bp++; 628 ndx = 1; 629 off = hashp->BSIZE; 630 } else { 631 save_bufp->flags &= ~BUF_PIN; 632 return (ERROR); 633 } 634 } 635 636 /* Not found */ 637 switch (action) { 638 case HASH_PUT: 639 case HASH_PUTNEW: 640 if (__addel(hashp, rbufp, key, val)) { 641 save_bufp->flags &= ~BUF_PIN; 642 return (ERROR); 643 } else { 644 save_bufp->flags &= ~BUF_PIN; 645 return (SUCCESS); 646 } 647 case HASH_GET: 648 case HASH_DELETE: 649 default: 650 save_bufp->flags &= ~BUF_PIN; 651 return (ABNORMAL); 652 } 653 654 found: 655 switch (action) { 656 case HASH_PUTNEW: 657 save_bufp->flags &= ~BUF_PIN; 658 return (ABNORMAL); 659 case HASH_GET: 660 bp = (u_int16_t *)rbufp->page; 661 if (bp[ndx + 1] < REAL_KEY) { 662 if (__big_return(hashp, rbufp, ndx, val, 0)) 663 return (ERROR); 664 } else { 665 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 666 val->size = bp[ndx] - bp[ndx + 1]; 667 } 668 break; 669 case HASH_PUT: 670 if ((__delpair(hashp, rbufp, ndx)) || 671 (__addel(hashp, rbufp, key, val))) { 672 save_bufp->flags &= ~BUF_PIN; 673 return (ERROR); 674 } 675 break; 676 case HASH_DELETE: 677 if (__delpair(hashp, rbufp, ndx)) 678 return (ERROR); 679 break; 680 default: 681 abort(); 682 } 683 save_bufp->flags &= ~BUF_PIN; 684 return (SUCCESS); 685 } 686 687 static int 688 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 689 { 690 u_int32_t bucket; 691 BUFHEAD *bufp; 692 HTAB *hashp; 693 u_int16_t *bp, ndx; 694 695 hashp = (HTAB *)dbp->internal; 696 if (flag && flag != R_FIRST && flag != R_NEXT) { 697 hashp->err = errno = EINVAL; 698 return (ERROR); 699 } 700 #ifdef HASH_STATISTICS 701 hash_accesses++; 702 #endif 703 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 704 hashp->cbucket = 0; 705 hashp->cndx = 1; 706 hashp->cpage = NULL; 707 } 708 next_bucket: 709 for (bp = NULL; !bp || !bp[0]; ) { 710 if (!(bufp = hashp->cpage)) { 711 for (bucket = hashp->cbucket; 712 bucket <= hashp->MAX_BUCKET; 713 bucket++, hashp->cndx = 1) { 714 bufp = __get_buf(hashp, bucket, NULL, 0); 715 if (!bufp) 716 return (ERROR); 717 hashp->cpage = bufp; 718 bp = (u_int16_t *)bufp->page; 719 if (bp[0]) 720 break; 721 } 722 hashp->cbucket = bucket; 723 if (hashp->cbucket > hashp->MAX_BUCKET) { 724 hashp->cbucket = -1; 725 return (ABNORMAL); 726 } 727 } else { 728 bp = (u_int16_t *)hashp->cpage->page; 729 if (flag == R_NEXT) { 730 hashp->cndx += 2; 731 if (hashp->cndx > bp[0]) { 732 hashp->cpage = NULL; 733 hashp->cbucket++; 734 hashp->cndx = 1; 735 goto next_bucket; 736 } 737 } 738 } 739 740 #ifdef DEBUG 741 assert(bp); 742 assert(bufp); 743 #endif 744 while (bp[hashp->cndx + 1] == OVFLPAGE) { 745 bufp = hashp->cpage = 746 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 747 if (!bufp) 748 return (ERROR); 749 bp = (u_int16_t *)(bufp->page); 750 hashp->cndx = 1; 751 } 752 if (!bp[0]) { 753 hashp->cpage = NULL; 754 ++hashp->cbucket; 755 } 756 } 757 ndx = hashp->cndx; 758 if (bp[ndx + 1] < REAL_KEY) { 759 if (__big_keydata(hashp, bufp, key, data, 1)) 760 return (ERROR); 761 } else { 762 if (hashp->cpage == 0) 763 return (ERROR); 764 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 765 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 766 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 767 data->size = bp[ndx] - bp[ndx + 1]; 768 } 769 return (SUCCESS); 770 } 771 772 /********************************* UTILITIES ************************/ 773 774 /* 775 * Returns: 776 * 0 ==> OK 777 * -1 ==> Error 778 */ 779 int 780 __expand_table(HTAB *hashp) 781 { 782 u_int32_t old_bucket, new_bucket; 783 int dirsize, new_segnum, spare_ndx; 784 785 #ifdef HASH_STATISTICS 786 hash_expansions++; 787 #endif 788 new_bucket = ++hashp->MAX_BUCKET; 789 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 790 791 new_segnum = new_bucket >> hashp->SSHIFT; 792 793 /* Check if we need a new segment */ 794 if (new_segnum >= hashp->nsegs) { 795 /* Check if we need to expand directory */ 796 if (new_segnum >= hashp->DSIZE) { 797 /* Reallocate directory */ 798 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 799 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 800 return (-1); 801 hashp->DSIZE = dirsize << 1; 802 } 803 if ((hashp->dir[new_segnum] = 804 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 805 return (-1); 806 hashp->exsegs++; 807 hashp->nsegs++; 808 } 809 /* 810 * If the split point is increasing (MAX_BUCKET's log base 2 811 * * increases), we need to copy the current contents of the spare 812 * split bucket to the next bucket. 813 */ 814 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 815 if (spare_ndx > hashp->OVFL_POINT) { 816 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 817 hashp->OVFL_POINT = spare_ndx; 818 } 819 820 if (new_bucket > hashp->HIGH_MASK) { 821 /* Starting a new doubling */ 822 hashp->LOW_MASK = hashp->HIGH_MASK; 823 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 824 } 825 /* Relocate records to the new bucket */ 826 return (__split_page(hashp, old_bucket, new_bucket)); 827 } 828 829 /* 830 * If realloc guarantees that the pointer is not destroyed if the realloc 831 * fails, then this routine can go away. 832 */ 833 static void * 834 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 835 { 836 void *p; 837 838 if ((p = malloc(newsize))) { 839 memmove(p, *p_ptr, oldsize); 840 memset((char *)p + oldsize, 0, newsize - oldsize); 841 free(*p_ptr); 842 *p_ptr = p; 843 } 844 return (p); 845 } 846 847 u_int32_t 848 __call_hash(HTAB *hashp, char *k, int len) 849 { 850 int n, bucket; 851 852 n = hashp->hash(k, len); 853 bucket = n & hashp->HIGH_MASK; 854 if (bucket > hashp->MAX_BUCKET) 855 bucket = bucket & hashp->LOW_MASK; 856 return (bucket); 857 } 858 859 /* 860 * Allocate segment table. On error, destroy the table and set errno. 861 * 862 * Returns 0 on success 863 */ 864 static int 865 alloc_segs(HTAB *hashp, int nsegs) 866 { 867 int i; 868 SEGMENT store; 869 870 int save_errno; 871 872 if ((hashp->dir = 873 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 874 save_errno = errno; 875 (void)hdestroy(hashp); 876 errno = save_errno; 877 return (-1); 878 } 879 hashp->nsegs = nsegs; 880 if (nsegs == 0) 881 return (0); 882 /* Allocate segments */ 883 if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT, 884 sizeof(SEGMENT))) == NULL) { 885 save_errno = errno; 886 (void)hdestroy(hashp); 887 errno = save_errno; 888 return (-1); 889 } 890 for (i = 0; i < nsegs; i++) 891 hashp->dir[i] = &store[i << hashp->SSHIFT]; 892 return (0); 893 } 894 895 #if BYTE_ORDER == LITTLE_ENDIAN 896 /* 897 * Hashp->hdr needs to be byteswapped. 898 */ 899 static void 900 swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 901 { 902 int i; 903 904 P_32_COPY(srcp->magic, destp->magic); 905 P_32_COPY(srcp->version, destp->version); 906 P_32_COPY(srcp->lorder, destp->lorder); 907 P_32_COPY(srcp->bsize, destp->bsize); 908 P_32_COPY(srcp->bshift, destp->bshift); 909 P_32_COPY(srcp->dsize, destp->dsize); 910 P_32_COPY(srcp->ssize, destp->ssize); 911 P_32_COPY(srcp->sshift, destp->sshift); 912 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 913 P_32_COPY(srcp->last_freed, destp->last_freed); 914 P_32_COPY(srcp->max_bucket, destp->max_bucket); 915 P_32_COPY(srcp->high_mask, destp->high_mask); 916 P_32_COPY(srcp->low_mask, destp->low_mask); 917 P_32_COPY(srcp->ffactor, destp->ffactor); 918 P_32_COPY(srcp->nkeys, destp->nkeys); 919 P_32_COPY(srcp->hdrpages, destp->hdrpages); 920 P_32_COPY(srcp->h_charkey, destp->h_charkey); 921 for (i = 0; i < NCACHED; i++) { 922 P_32_COPY(srcp->spares[i], destp->spares[i]); 923 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 924 } 925 } 926 927 static void 928 swap_header(HTAB *hashp) 929 { 930 HASHHDR *hdrp; 931 int i; 932 933 hdrp = &hashp->hdr; 934 935 M_32_SWAP(hdrp->magic); 936 M_32_SWAP(hdrp->version); 937 M_32_SWAP(hdrp->lorder); 938 M_32_SWAP(hdrp->bsize); 939 M_32_SWAP(hdrp->bshift); 940 M_32_SWAP(hdrp->dsize); 941 M_32_SWAP(hdrp->ssize); 942 M_32_SWAP(hdrp->sshift); 943 M_32_SWAP(hdrp->ovfl_point); 944 M_32_SWAP(hdrp->last_freed); 945 M_32_SWAP(hdrp->max_bucket); 946 M_32_SWAP(hdrp->high_mask); 947 M_32_SWAP(hdrp->low_mask); 948 M_32_SWAP(hdrp->ffactor); 949 M_32_SWAP(hdrp->nkeys); 950 M_32_SWAP(hdrp->hdrpages); 951 M_32_SWAP(hdrp->h_charkey); 952 for (i = 0; i < NCACHED; i++) { 953 M_32_SWAP(hdrp->spares[i]); 954 M_16_SWAP(hdrp->bitmaps[i]); 955 } 956 } 957 #endif 958