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. 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 * @(#)hash.c 8.9 (Berkeley) 6/16/94 33 * $FreeBSD: head/lib/libc/db/hash/hash.c 206178 2010-04-05 10:12:21Z avg $ 34 */ 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/stat.h> 39 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 #ifdef DEBUG 47 #include <assert.h> 48 #endif 49 #include "un-namespace.h" 50 51 #include <db.h> 52 #include "hash.h" 53 #include "page.h" 54 #include "extern.h" 55 56 static int alloc_segs(HTAB *, int); 57 static int flush_meta(HTAB *); 58 static int hash_access(HTAB *, ACTION, DBT *, DBT *); 59 static int hash_close(DB *); 60 static int hash_delete(const DB *, const DBT *, uint32_t); 61 static int hash_fd(const DB *); 62 static int hash_get(const DB *, const DBT *, DBT *, uint32_t); 63 static int hash_put(const DB *, DBT *, const DBT *, uint32_t); 64 static void *hash_realloc(SEGMENT **, int, int); 65 static int hash_seq(const DB *, DBT *, DBT *, uint32_t); 66 static int hash_sync(const DB *, uint32_t); 67 static int hdestroy(HTAB *); 68 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 69 static int init_htab(HTAB *, int); 70 #if BYTE_ORDER == LITTLE_ENDIAN 71 static void swap_header(HTAB *); 72 static void swap_header_copy(HASHHDR *, HASHHDR *); 73 #endif 74 75 /* Fast arithmetic, relying on powers of 2, */ 76 #define MOD(x, y) ((x) & ((y) - 1)) 77 78 #define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } 79 80 /* Return values */ 81 #define SUCCESS (0) 82 #define ERROR (-1) 83 #define ABNORMAL (1) 84 85 #ifdef HASH_STATISTICS 86 int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 87 #endif 88 89 /************************** INTERFACE ROUTINES ***************************/ 90 /* OPEN/CLOSE */ 91 92 /* ARGSUSED */ 93 DB * 94 __hash_open(const char *file, int flags, mode_t mode, 95 const HASHINFO *info, /* Special directives for create */ 96 __unused int dflags) 97 { 98 HTAB *hashp; 99 struct stat statbuf; 100 DB *dbp; 101 int bpages, hdrsize, new_table, nsegs, save_errno; 102 103 if ((flags & O_ACCMODE) == O_WRONLY) { 104 errno = EINVAL; 105 return (NULL); 106 } 107 108 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 109 return (NULL); 110 hashp->fp = -1; 111 112 /* 113 * Even if user wants write only, we need to be able to read 114 * the actual file, so we need to open it read/write. But, the 115 * field in the hashp structure needs to be accurate so that 116 * we can check accesses. 117 */ 118 hashp->flags = flags; 119 120 if (file) { 121 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1) 122 RETURN_ERROR(errno, error0); 123 _fcntl(hashp->fp, F_SETFD, 1); 124 new_table = _fstat(hashp->fp, &statbuf) == 0 && 125 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 126 } else 127 new_table = 1; 128 129 if (new_table) { 130 if (!(hashp = init_hash(hashp, file, info))) 131 RETURN_ERROR(errno, error1); 132 } else { 133 /* Table already exists */ 134 if (info && info->hash) 135 hashp->hash = info->hash; 136 else 137 hashp->hash = __default_hash; 138 139 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 140 #if BYTE_ORDER == LITTLE_ENDIAN 141 swap_header(hashp); 142 #endif 143 if (hdrsize == -1) 144 RETURN_ERROR(errno, error1); 145 if (hdrsize != sizeof(HASHHDR)) 146 RETURN_ERROR(EFTYPE, error1); 147 /* Verify file type, versions and hash function */ 148 if (hashp->MAGIC != HASHMAGIC) 149 RETURN_ERROR(EFTYPE, error1); 150 #define OLDHASHVERSION 1 151 if (hashp->VERSION != HASHVERSION && 152 hashp->VERSION != OLDHASHVERSION) 153 RETURN_ERROR(EFTYPE, error1); 154 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 155 RETURN_ERROR(EFTYPE, error1); 156 /* 157 * Figure out how many segments we need. Max_Bucket is the 158 * maximum bucket number, so the number of buckets is 159 * max_bucket + 1. 160 */ 161 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 162 hashp->SGSIZE; 163 if (alloc_segs(hashp, nsegs)) 164 /* 165 * If alloc_segs fails, table will have been destroyed 166 * and errno will have been set. 167 */ 168 return (NULL); 169 /* Read in bitmaps */ 170 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 171 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 172 (hashp->BSHIFT + BYTE_SHIFT); 173 174 hashp->nmaps = bpages; 175 memset(&hashp->mapp[0], 0, bpages * sizeof(uint32_t *)); 176 } 177 178 /* Initialize Buffer Manager */ 179 if (info && info->cachesize) 180 __buf_init(hashp, info->cachesize); 181 else 182 __buf_init(hashp, DEF_BUFSIZE); 183 184 hashp->new_file = new_table; 185 hashp->save_file = file && (hashp->flags & O_RDWR); 186 hashp->cbucket = -1; 187 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 188 save_errno = errno; 189 hdestroy(hashp); 190 errno = save_errno; 191 return (NULL); 192 } 193 dbp->internal = hashp; 194 dbp->close = hash_close; 195 dbp->del = hash_delete; 196 dbp->fd = hash_fd; 197 dbp->get = hash_get; 198 dbp->put = hash_put; 199 dbp->seq = hash_seq; 200 dbp->sync = hash_sync; 201 dbp->type = DB_HASH; 202 203 #ifdef DEBUG 204 fprintf(stderr, 205 "%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", 206 "init_htab:", 207 "TABLE POINTER ", hashp, 208 "BUCKET SIZE ", hashp->BSIZE, 209 "BUCKET SHIFT ", hashp->BSHIFT, 210 "DIRECTORY SIZE ", hashp->DSIZE, 211 "SEGMENT SIZE ", hashp->SGSIZE, 212 "SEGMENT SHIFT ", hashp->SSHIFT, 213 "FILL FACTOR ", hashp->FFACTOR, 214 "MAX BUCKET ", hashp->MAX_BUCKET, 215 "OVFL POINT ", hashp->OVFL_POINT, 216 "LAST FREED ", hashp->LAST_FREED, 217 "HIGH MASK ", hashp->HIGH_MASK, 218 "LOW MASK ", hashp->LOW_MASK, 219 "NSEGS ", hashp->nsegs, 220 "NKEYS ", hashp->NKEYS); 221 #endif 222 #ifdef HASH_STATISTICS 223 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 224 #endif 225 return (dbp); 226 227 error1: 228 if (hashp != NULL) 229 _close(hashp->fp); 230 231 error0: 232 free(hashp); 233 errno = save_errno; 234 return (NULL); 235 } 236 237 static int 238 hash_close(DB *dbp) 239 { 240 HTAB *hashp; 241 int retval; 242 243 if (!dbp) 244 return (ERROR); 245 246 hashp = (HTAB *)dbp->internal; 247 retval = hdestroy(hashp); 248 free(dbp); 249 return (retval); 250 } 251 252 static int 253 hash_fd(const DB *dbp) 254 { 255 HTAB *hashp; 256 257 if (!dbp) 258 return (ERROR); 259 260 hashp = (HTAB *)dbp->internal; 261 if (hashp->fp == -1) { 262 errno = ENOENT; 263 return (-1); 264 } 265 return (hashp->fp); 266 } 267 268 /************************** LOCAL CREATION ROUTINES **********************/ 269 static HTAB * 270 init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 271 { 272 struct stat statbuf; 273 int nelem; 274 275 nelem = 1; 276 hashp->NKEYS = 0; 277 hashp->LORDER = BYTE_ORDER; 278 hashp->BSIZE = DEF_BUCKET_SIZE; 279 hashp->BSHIFT = DEF_BUCKET_SHIFT; 280 hashp->SGSIZE = DEF_SEGSIZE; 281 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 282 hashp->DSIZE = DEF_DIRSIZE; 283 hashp->FFACTOR = DEF_FFACTOR; 284 hashp->hash = __default_hash; 285 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 286 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 287 288 /* Fix bucket size to be optimal for file system */ 289 if (file != NULL) { 290 if (stat(file, &statbuf)) 291 return (NULL); 292 hashp->BSIZE = NOM_BSIZE; 293 if (hashp->BSIZE > MAX_BSIZE) 294 hashp->BSIZE = MAX_BSIZE; 295 hashp->BSHIFT = __log2(hashp->BSIZE); 296 } 297 298 if (info) { 299 if (info->bsize) { 300 /* Round pagesize up to power of 2 */ 301 hashp->BSHIFT = __log2(info->bsize); 302 hashp->BSIZE = 1 << hashp->BSHIFT; 303 if (hashp->BSIZE > MAX_BSIZE) { 304 errno = EINVAL; 305 return (NULL); 306 } 307 } 308 if (info->ffactor) 309 hashp->FFACTOR = info->ffactor; 310 if (info->hash) 311 hashp->hash = info->hash; 312 if (info->nelem) 313 nelem = info->nelem; 314 if (info->lorder) { 315 if (info->lorder != BIG_ENDIAN && 316 info->lorder != LITTLE_ENDIAN) { 317 errno = EINVAL; 318 return (NULL); 319 } 320 hashp->LORDER = info->lorder; 321 } 322 } 323 /* init_htab should destroy the table and set errno if it fails */ 324 if (init_htab(hashp, nelem)) 325 return (NULL); 326 else 327 return (hashp); 328 } 329 /* 330 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 331 * the table and set errno, so we just pass the error information along. 332 * 333 * Returns 0 on No Error 334 */ 335 static int 336 init_htab(HTAB *hashp, int nelem) 337 { 338 int nbuckets, nsegs, l2; 339 340 /* 341 * Divide number of elements by the fill factor and determine a 342 * desired number of buckets. Allocate space for the next greater 343 * power of two number of buckets. 344 */ 345 nelem = (nelem - 1) / hashp->FFACTOR + 1; 346 347 l2 = __log2(MAX(nelem, 2)); 348 nbuckets = 1 << l2; 349 350 hashp->SPARES[l2] = l2 + 1; 351 hashp->SPARES[l2 + 1] = l2 + 1; 352 hashp->OVFL_POINT = l2; 353 hashp->LAST_FREED = 2; 354 355 /* First bitmap page is at: splitpoint l2 page offset 1 */ 356 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 357 return (-1); 358 359 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 360 hashp->HIGH_MASK = (nbuckets << 1) - 1; 361 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 362 hashp->BSHIFT) + 1; 363 364 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 365 nsegs = 1 << __log2(nsegs); 366 367 if (nsegs > hashp->DSIZE) 368 hashp->DSIZE = nsegs; 369 return (alloc_segs(hashp, nsegs)); 370 } 371 372 /********************** DESTROY/CLOSE ROUTINES ************************/ 373 374 /* 375 * Flushes any changes to the file if necessary and destroys the hashp 376 * structure, freeing all allocated space. 377 */ 378 static int 379 hdestroy(HTAB *hashp) 380 { 381 int i, save_errno; 382 383 save_errno = 0; 384 385 #ifdef HASH_STATISTICS 386 fprintf(stderr, "hdestroy: accesses %d collisions %d\n", 387 hash_accesses, hash_collisions); 388 fprintf(stderr, "hdestroy: expansions %d\n", 389 hash_expansions); 390 fprintf(stderr, "hdestroy: overflows %d\n", 391 hash_overflows); 392 fprintf(stderr, "keys %d maxp %d segmentcount %d\n", 393 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 394 395 for (i = 0; i < NCACHED; i++) 396 fprintf(stderr, 397 "spares[%d] = %d\n", i, hashp->SPARES[i]); 398 #endif 399 /* 400 * Call on buffer manager to free buffers, and if required, 401 * write them to disk. 402 */ 403 if (__buf_free(hashp, 1, hashp->save_file)) 404 save_errno = errno; 405 if (hashp->dir) { 406 free(*hashp->dir); /* Free initial segments */ 407 /* Free extra segments */ 408 while (hashp->exsegs--) 409 free(hashp->dir[--hashp->nsegs]); 410 free(hashp->dir); 411 } 412 if (flush_meta(hashp) && !save_errno) 413 save_errno = errno; 414 /* Free Bigmaps */ 415 for (i = 0; i < hashp->nmaps; i++) 416 if (hashp->mapp[i]) 417 free(hashp->mapp[i]); 418 if (hashp->tmp_key) 419 free(hashp->tmp_key); 420 if (hashp->tmp_buf) 421 free(hashp->tmp_buf); 422 423 if (hashp->fp != -1) 424 _close(hashp->fp); 425 426 free(hashp); 427 428 if (save_errno) { 429 errno = save_errno; 430 return (ERROR); 431 } 432 return (SUCCESS); 433 } 434 /* 435 * Write modified pages to disk 436 * 437 * Returns: 438 * 0 == OK 439 * -1 ERROR 440 */ 441 static int 442 hash_sync(const DB *dbp, uint32_t flags) 443 { 444 HTAB *hashp; 445 446 if (flags != 0) { 447 errno = EINVAL; 448 return (ERROR); 449 } 450 451 if (!dbp) 452 return (ERROR); 453 454 hashp = (HTAB *)dbp->internal; 455 if (!hashp->save_file) 456 return (0); 457 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 458 return (ERROR); 459 hashp->new_file = 0; 460 return (0); 461 } 462 463 /* 464 * Returns: 465 * 0 == OK 466 * -1 indicates that errno should be set 467 */ 468 static int 469 flush_meta(HTAB *hashp) 470 { 471 HASHHDR *whdrp; 472 #if BYTE_ORDER == LITTLE_ENDIAN 473 HASHHDR whdr; 474 #endif 475 int fp, i, wsize; 476 477 if (!hashp->save_file) 478 return (0); 479 hashp->MAGIC = HASHMAGIC; 480 hashp->VERSION = HASHVERSION; 481 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 482 483 fp = hashp->fp; 484 whdrp = &hashp->hdr; 485 #if BYTE_ORDER == LITTLE_ENDIAN 486 whdrp = &whdr; 487 swap_header_copy(&hashp->hdr, whdrp); 488 #endif 489 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 490 return (-1); 491 else 492 if (wsize != sizeof(HASHHDR)) { 493 errno = EFTYPE; 494 hashp->error = errno; 495 return (-1); 496 } 497 for (i = 0; i < NCACHED; i++) 498 if (hashp->mapp[i]) 499 if (__put_page(hashp, (char *)hashp->mapp[i], 500 hashp->BITMAPS[i], 0, 1)) 501 return (-1); 502 return (0); 503 } 504 505 /*******************************SEARCH ROUTINES *****************************/ 506 /* 507 * All the access routines return 508 * 509 * Returns: 510 * 0 on SUCCESS 511 * 1 to indicate an external ERROR (i.e. key not found, etc) 512 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 513 */ 514 static int 515 hash_get(const DB *dbp, const DBT *key, DBT *data, uint32_t flag) 516 { 517 HTAB *hashp; 518 519 hashp = (HTAB *)dbp->internal; 520 if (flag) { 521 hashp->error = errno = EINVAL; 522 return (ERROR); 523 } 524 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 525 } 526 527 static int 528 hash_put(const DB *dbp, DBT *key, const DBT *data, uint32_t flag) 529 { 530 HTAB *hashp; 531 532 hashp = (HTAB *)dbp->internal; 533 if (flag && flag != R_NOOVERWRITE) { 534 hashp->error = errno = EINVAL; 535 return (ERROR); 536 } 537 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 538 hashp->error = errno = EPERM; 539 return (ERROR); 540 } 541 return (hash_access(hashp, flag == R_NOOVERWRITE ? 542 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 543 } 544 545 static int 546 hash_delete(const DB *dbp, const DBT *key, 547 uint32_t flag) /* Ignored */ 548 { 549 HTAB *hashp; 550 551 hashp = (HTAB *)dbp->internal; 552 if (flag && flag != R_CURSOR) { 553 hashp->error = errno = EINVAL; 554 return (ERROR); 555 } 556 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 557 hashp->error = errno = EPERM; 558 return (ERROR); 559 } 560 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 561 } 562 563 /* 564 * Assume that hashp has been set in wrapper routine. 565 */ 566 static int 567 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 568 { 569 BUFHEAD *rbufp; 570 BUFHEAD *bufp, *save_bufp; 571 uint16_t *bp; 572 int n, ndx, off, size; 573 char *kp; 574 uint16_t pageno; 575 576 #ifdef HASH_STATISTICS 577 hash_accesses++; 578 #endif 579 580 off = hashp->BSIZE; 581 size = key->size; 582 kp = (char *)key->data; 583 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 584 if (!rbufp) 585 return (ERROR); 586 save_bufp = rbufp; 587 588 /* Pin the bucket chain */ 589 rbufp->flags |= BUF_PIN; 590 for (bp = (uint16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 591 if (bp[1] >= REAL_KEY) { 592 /* Real key/data pair */ 593 if (size == off - *bp && 594 memcmp(kp, rbufp->page + *bp, size) == 0) 595 goto found; 596 off = bp[1]; 597 #ifdef HASH_STATISTICS 598 hash_collisions++; 599 #endif 600 bp += 2; 601 ndx += 2; 602 } else if (bp[1] == OVFLPAGE) { 603 rbufp = __get_buf(hashp, *bp, rbufp, 0); 604 if (!rbufp) { 605 save_bufp->flags &= ~BUF_PIN; 606 return (ERROR); 607 } 608 /* FOR LOOP INIT */ 609 bp = (uint16_t *)rbufp->page; 610 n = *bp++; 611 ndx = 1; 612 off = hashp->BSIZE; 613 } else if (bp[1] < REAL_KEY) { 614 if ((ndx = 615 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 616 goto found; 617 if (ndx == -2) { 618 bufp = rbufp; 619 if (!(pageno = 620 __find_last_page(hashp, &bufp))) { 621 ndx = 0; 622 rbufp = bufp; 623 break; /* FOR */ 624 } 625 rbufp = __get_buf(hashp, pageno, bufp, 0); 626 if (!rbufp) { 627 save_bufp->flags &= ~BUF_PIN; 628 return (ERROR); 629 } 630 /* FOR LOOP INIT */ 631 bp = (uint16_t *)rbufp->page; 632 n = *bp++; 633 ndx = 1; 634 off = hashp->BSIZE; 635 } else { 636 save_bufp->flags &= ~BUF_PIN; 637 return (ERROR); 638 } 639 } 640 641 /* Not found */ 642 switch (action) { 643 case HASH_PUT: 644 case HASH_PUTNEW: 645 if (__addel(hashp, rbufp, key, val)) { 646 save_bufp->flags &= ~BUF_PIN; 647 return (ERROR); 648 } else { 649 save_bufp->flags &= ~BUF_PIN; 650 return (SUCCESS); 651 } 652 case HASH_GET: 653 case HASH_DELETE: 654 default: 655 save_bufp->flags &= ~BUF_PIN; 656 return (ABNORMAL); 657 } 658 659 found: 660 switch (action) { 661 case HASH_PUTNEW: 662 save_bufp->flags &= ~BUF_PIN; 663 return (ABNORMAL); 664 case HASH_GET: 665 bp = (uint16_t *)rbufp->page; 666 if (bp[ndx + 1] < REAL_KEY) { 667 if (__big_return(hashp, rbufp, ndx, val, 0)) 668 return (ERROR); 669 } else { 670 val->data = (unsigned char *)rbufp->page + 671 (int)bp[ndx + 1]; 672 val->size = bp[ndx] - bp[ndx + 1]; 673 } 674 break; 675 case HASH_PUT: 676 if ((__delpair(hashp, rbufp, ndx)) || 677 (__addel(hashp, rbufp, key, val))) { 678 save_bufp->flags &= ~BUF_PIN; 679 return (ERROR); 680 } 681 break; 682 case HASH_DELETE: 683 if (__delpair(hashp, rbufp, ndx)) 684 return (ERROR); 685 break; 686 default: 687 abort(); 688 } 689 save_bufp->flags &= ~BUF_PIN; 690 return (SUCCESS); 691 } 692 693 static int 694 hash_seq(const DB *dbp, DBT *key, DBT *data, uint32_t flag) 695 { 696 uint32_t bucket; 697 BUFHEAD *bufp; 698 HTAB *hashp; 699 uint16_t *bp, ndx; 700 701 hashp = (HTAB *)dbp->internal; 702 if (flag && flag != R_FIRST && flag != R_NEXT) { 703 hashp->error = errno = EINVAL; 704 return (ERROR); 705 } 706 #ifdef HASH_STATISTICS 707 hash_accesses++; 708 #endif 709 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 710 hashp->cbucket = 0; 711 hashp->cndx = 1; 712 hashp->cpage = NULL; 713 } 714 next_bucket: 715 for (bp = NULL; !bp || !bp[0]; ) { 716 if (!(bufp = hashp->cpage)) { 717 for (bucket = hashp->cbucket; 718 bucket <= hashp->MAX_BUCKET; 719 bucket++, hashp->cndx = 1) { 720 bufp = __get_buf(hashp, bucket, NULL, 0); 721 if (!bufp) 722 return (ERROR); 723 hashp->cpage = bufp; 724 bp = (uint16_t *)bufp->page; 725 if (bp[0]) 726 break; 727 } 728 hashp->cbucket = bucket; 729 if ((uint32_t)hashp->cbucket > hashp->MAX_BUCKET) { 730 hashp->cbucket = -1; 731 return (ABNORMAL); 732 } 733 } else { 734 bp = (uint16_t *)hashp->cpage->page; 735 if (flag == R_NEXT || flag == 0) { 736 hashp->cndx += 2; 737 if (hashp->cndx > bp[0]) { 738 hashp->cpage = NULL; 739 hashp->cbucket++; 740 hashp->cndx = 1; 741 goto next_bucket; 742 } 743 } 744 } 745 746 #ifdef DEBUG 747 assert(bp); 748 assert(bufp); 749 #endif 750 while (bp[hashp->cndx + 1] == OVFLPAGE) { 751 bufp = hashp->cpage = 752 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 753 if (!bufp) 754 return (ERROR); 755 bp = (uint16_t *)(bufp->page); 756 hashp->cndx = 1; 757 } 758 if (!bp[0]) { 759 hashp->cpage = NULL; 760 ++hashp->cbucket; 761 } 762 } 763 ndx = hashp->cndx; 764 if (bp[ndx + 1] < REAL_KEY) { 765 if (__big_keydata(hashp, bufp, key, data, 1)) 766 return (ERROR); 767 } else { 768 if (hashp->cpage == 0) 769 return (ERROR); 770 key->data = (unsigned char *)hashp->cpage->page + bp[ndx]; 771 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 772 data->data = (unsigned char *)hashp->cpage->page + bp[ndx + 1]; 773 data->size = bp[ndx] - bp[ndx + 1]; 774 } 775 return (SUCCESS); 776 } 777 778 /********************************* UTILITIES ************************/ 779 780 /* 781 * Returns: 782 * 0 ==> OK 783 * -1 ==> Error 784 */ 785 int 786 __expand_table(HTAB *hashp) 787 { 788 uint32_t old_bucket, new_bucket; 789 int dirsize, new_segnum, spare_ndx; 790 791 #ifdef HASH_STATISTICS 792 hash_expansions++; 793 #endif 794 new_bucket = ++hashp->MAX_BUCKET; 795 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 796 797 new_segnum = new_bucket >> hashp->SSHIFT; 798 799 /* Check if we need a new segment */ 800 if (new_segnum >= hashp->nsegs) { 801 /* Check if we need to expand directory */ 802 if (new_segnum >= hashp->DSIZE) { 803 /* Reallocate directory */ 804 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 805 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 806 return (-1); 807 hashp->DSIZE = dirsize << 1; 808 } 809 if ((hashp->dir[new_segnum] = 810 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 811 return (-1); 812 hashp->exsegs++; 813 hashp->nsegs++; 814 } 815 /* 816 * If the split point is increasing (MAX_BUCKET's log base 2 817 * * increases), we need to copy the current contents of the spare 818 * split bucket to the next bucket. 819 */ 820 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 821 if (spare_ndx > hashp->OVFL_POINT) { 822 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 823 hashp->OVFL_POINT = spare_ndx; 824 } 825 826 if (new_bucket > hashp->HIGH_MASK) { 827 /* Starting a new doubling */ 828 hashp->LOW_MASK = hashp->HIGH_MASK; 829 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 830 } 831 /* Relocate records to the new bucket */ 832 return (__split_page(hashp, old_bucket, new_bucket)); 833 } 834 835 /* 836 * If realloc guarantees that the pointer is not destroyed if the realloc 837 * fails, then this routine can go away. 838 */ 839 static void * 840 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 841 { 842 void *p; 843 844 if ( (p = malloc(newsize)) ) { 845 memmove(p, *p_ptr, oldsize); 846 memset((char *)p + oldsize, 0, newsize - oldsize); 847 free(*p_ptr); 848 *p_ptr = p; 849 } 850 return (p); 851 } 852 853 uint32_t 854 __call_hash(HTAB *hashp, char *k, int len) 855 { 856 unsigned int n, bucket; 857 858 n = hashp->hash(k, len); 859 bucket = n & hashp->HIGH_MASK; 860 if (bucket > hashp->MAX_BUCKET) 861 bucket = bucket & hashp->LOW_MASK; 862 return (bucket); 863 } 864 865 /* 866 * Allocate segment table. On error, destroy the table and set errno. 867 * 868 * Returns 0 on success 869 */ 870 static int 871 alloc_segs(HTAB *hashp, int nsegs) 872 { 873 int i; 874 SEGMENT store; 875 876 int save_errno; 877 878 if ((hashp->dir = 879 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 880 save_errno = errno; 881 hdestroy(hashp); 882 errno = save_errno; 883 return (-1); 884 } 885 hashp->nsegs = nsegs; 886 if (nsegs == 0) 887 return (0); 888 /* Allocate segments */ 889 if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT, 890 sizeof(SEGMENT))) == NULL) { 891 save_errno = errno; 892 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