hash.c revision 296424
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) 34static 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: stable/10/lib/libc/db/hash/hash.c 296424 2016-03-06 08:40:21Z dwmalone $"); 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 59static int alloc_segs(HTAB *, int); 60static int flush_meta(HTAB *); 61static int hash_access(HTAB *, ACTION, DBT *, DBT *); 62static int hash_close(DB *); 63static int hash_delete(const DB *, const DBT *, u_int32_t); 64static int hash_fd(const DB *); 65static int hash_get(const DB *, const DBT *, DBT *, u_int32_t); 66static int hash_put(const DB *, DBT *, const DBT *, u_int32_t); 67static void *hash_realloc(SEGMENT **, int, int); 68static int hash_seq(const DB *, DBT *, DBT *, u_int32_t); 69static int hash_sync(const DB *, u_int32_t); 70static int hdestroy(HTAB *); 71static HTAB *init_hash(HTAB *, const char *, const HASHINFO *); 72static int init_htab(HTAB *, int); 73#if BYTE_ORDER == LITTLE_ENDIAN 74static void swap_header(HTAB *); 75static 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 89int hash_accesses, hash_collisions, hash_expansions, hash_overflows; 90#endif 91 92/************************** INTERFACE ROUTINES ***************************/ 93/* OPEN/CLOSE */ 94 95/* ARGSUSED */ 96DB * 97__hash_open(const char *file, int flags, int mode, 98 const HASHINFO *info, /* Special directives for create */ 99 int dflags) 100{ 101 HTAB *hashp; 102 struct stat statbuf; 103 DB *dbp; 104 int bpages, hdrsize, new_table, nsegs, save_errno; 105 106 if ((flags & O_ACCMODE) == O_WRONLY) { 107 errno = EINVAL; 108 return (NULL); 109 } 110 111 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 112 return (NULL); 113 hashp->fp = -1; 114 115 /* 116 * Even if user wants write only, we need to be able to read 117 * the actual file, so we need to open it read/write. But, the 118 * field in the hashp structure needs to be accurate so that 119 * we can check accesses. 120 */ 121 hashp->flags = flags; 122 123 if (file) { 124 if ((hashp->fp = _open(file, flags | O_CLOEXEC, mode)) == -1) 125 RETURN_ERROR(errno, error0); 126 new_table = _fstat(hashp->fp, &statbuf) == 0 && 127 statbuf.st_size == 0 && (flags & O_ACCMODE) != O_RDONLY; 128 } else 129 new_table = 1; 130 131 if (new_table) { 132 if (!(hashp = init_hash(hashp, file, info))) 133 RETURN_ERROR(errno, error1); 134 } else { 135 /* Table already exists */ 136 if (info && info->hash) 137 hashp->hash = info->hash; 138 else 139 hashp->hash = __default_hash; 140 141 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 142#if BYTE_ORDER == LITTLE_ENDIAN 143 swap_header(hashp); 144#endif 145 if (hdrsize == -1) 146 RETURN_ERROR(errno, error1); 147 if (hdrsize != sizeof(HASHHDR)) 148 RETURN_ERROR(EFTYPE, error1); 149 /* Verify file type, versions and hash function */ 150 if (hashp->MAGIC != HASHMAGIC) 151 RETURN_ERROR(EFTYPE, error1); 152#define OLDHASHVERSION 1 153 if (hashp->VERSION != HASHVERSION && 154 hashp->VERSION != OLDHASHVERSION) 155 RETURN_ERROR(EFTYPE, error1); 156 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 157 RETURN_ERROR(EFTYPE, error1); 158 /* 159 * Figure out how many segments we need. Max_Bucket is the 160 * maximum bucket number, so the number of buckets is 161 * max_bucket + 1. 162 */ 163 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 164 hashp->SGSIZE; 165 if (alloc_segs(hashp, nsegs)) 166 /* 167 * If alloc_segs fails, table will have been destroyed 168 * and errno will have been set. 169 */ 170 return (NULL); 171 /* Read in bitmaps */ 172 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 173 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 174 (hashp->BSHIFT + BYTE_SHIFT); 175 176 hashp->nmaps = bpages; 177 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 178 } 179 180 /* Initialize Buffer Manager */ 181 if (info && info->cachesize) 182 __buf_init(hashp, info->cachesize); 183 else 184 __buf_init(hashp, DEF_BUFSIZE); 185 186 hashp->new_file = new_table; 187 hashp->save_file = file && (hashp->flags & O_RDWR); 188 hashp->cbucket = -1; 189 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 190 save_errno = errno; 191 hdestroy(hashp); 192 errno = save_errno; 193 return (NULL); 194 } 195 dbp->internal = hashp; 196 dbp->close = hash_close; 197 dbp->del = hash_delete; 198 dbp->fd = hash_fd; 199 dbp->get = hash_get; 200 dbp->put = hash_put; 201 dbp->seq = hash_seq; 202 dbp->sync = hash_sync; 203 dbp->type = DB_HASH; 204 205#ifdef DEBUG 206 (void)fprintf(stderr, 207"%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n", 208 "init_htab:", 209 "TABLE POINTER ", hashp, 210 "BUCKET SIZE ", hashp->BSIZE, 211 "BUCKET SHIFT ", hashp->BSHIFT, 212 "DIRECTORY SIZE ", hashp->DSIZE, 213 "SEGMENT SIZE ", hashp->SGSIZE, 214 "SEGMENT SHIFT ", hashp->SSHIFT, 215 "FILL FACTOR ", hashp->FFACTOR, 216 "MAX BUCKET ", hashp->MAX_BUCKET, 217 "OVFL POINT ", hashp->OVFL_POINT, 218 "LAST FREED ", hashp->LAST_FREED, 219 "HIGH MASK ", hashp->HIGH_MASK, 220 "LOW MASK ", hashp->LOW_MASK, 221 "NSEGS ", hashp->nsegs, 222 "NKEYS ", hashp->NKEYS); 223#endif 224#ifdef HASH_STATISTICS 225 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 226#endif 227 return (dbp); 228 229error1: 230 if (hashp != NULL) 231 (void)_close(hashp->fp); 232 233error0: 234 free(hashp); 235 errno = save_errno; 236 return (NULL); 237} 238 239static int 240hash_close(DB *dbp) 241{ 242 HTAB *hashp; 243 int retval; 244 245 if (!dbp) 246 return (ERROR); 247 248 hashp = (HTAB *)dbp->internal; 249 retval = hdestroy(hashp); 250 free(dbp); 251 return (retval); 252} 253 254static int 255hash_fd(const DB *dbp) 256{ 257 HTAB *hashp; 258 259 if (!dbp) 260 return (ERROR); 261 262 hashp = (HTAB *)dbp->internal; 263 if (hashp->fp == -1) { 264 errno = ENOENT; 265 return (-1); 266 } 267 return (hashp->fp); 268} 269 270/************************** LOCAL CREATION ROUTINES **********************/ 271static HTAB * 272init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 273{ 274 struct stat statbuf; 275 int nelem; 276 277 nelem = 1; 278 hashp->NKEYS = 0; 279 hashp->LORDER = BYTE_ORDER; 280 hashp->BSIZE = DEF_BUCKET_SIZE; 281 hashp->BSHIFT = DEF_BUCKET_SHIFT; 282 hashp->SGSIZE = DEF_SEGSIZE; 283 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 284 hashp->DSIZE = DEF_DIRSIZE; 285 hashp->FFACTOR = DEF_FFACTOR; 286 hashp->hash = __default_hash; 287 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 288 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 289 290 /* Fix bucket size to be optimal for file system */ 291 if (file != NULL) { 292 if (stat(file, &statbuf)) 293 return (NULL); 294 hashp->BSIZE = statbuf.st_blksize; 295 if (hashp->BSIZE > MAX_BSIZE) 296 hashp->BSIZE = MAX_BSIZE; 297 hashp->BSHIFT = __log2(hashp->BSIZE); 298 } 299 300 if (info) { 301 if (info->bsize) { 302 /* Round pagesize up to power of 2 */ 303 hashp->BSHIFT = __log2(info->bsize); 304 hashp->BSIZE = 1 << hashp->BSHIFT; 305 if (hashp->BSIZE > MAX_BSIZE) { 306 errno = EINVAL; 307 return (NULL); 308 } 309 } 310 if (info->ffactor) 311 hashp->FFACTOR = info->ffactor; 312 if (info->hash) 313 hashp->hash = info->hash; 314 if (info->nelem) 315 nelem = info->nelem; 316 if (info->lorder) { 317 if (info->lorder != BIG_ENDIAN && 318 info->lorder != LITTLE_ENDIAN) { 319 errno = EINVAL; 320 return (NULL); 321 } 322 hashp->LORDER = info->lorder; 323 } 324 } 325 /* init_htab should destroy the table and set errno if it fails */ 326 if (init_htab(hashp, nelem)) 327 return (NULL); 328 else 329 return (hashp); 330} 331/* 332 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 333 * the table and set errno, so we just pass the error information along. 334 * 335 * Returns 0 on No Error 336 */ 337static int 338init_htab(HTAB *hashp, int nelem) 339{ 340 int nbuckets, nsegs, l2; 341 342 /* 343 * Divide number of elements by the fill factor and determine a 344 * desired number of buckets. Allocate space for the next greater 345 * power of two number of buckets. 346 */ 347 nelem = (nelem - 1) / hashp->FFACTOR + 1; 348 349 l2 = __log2(MAX(nelem, 2)); 350 nbuckets = 1 << l2; 351 352 hashp->SPARES[l2] = l2 + 1; 353 hashp->SPARES[l2 + 1] = l2 + 1; 354 hashp->OVFL_POINT = l2; 355 hashp->LAST_FREED = 2; 356 357 /* First bitmap page is at: splitpoint l2 page offset 1 */ 358 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 359 return (-1); 360 361 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 362 hashp->HIGH_MASK = (nbuckets << 1) - 1; 363 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 364 hashp->BSHIFT) + 1; 365 366 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 367 nsegs = 1 << __log2(nsegs); 368 369 if (nsegs > hashp->DSIZE) 370 hashp->DSIZE = nsegs; 371 return (alloc_segs(hashp, nsegs)); 372} 373 374/********************** DESTROY/CLOSE ROUTINES ************************/ 375 376/* 377 * Flushes any changes to the file if necessary and destroys the hashp 378 * structure, freeing all allocated space. 379 */ 380static int 381hdestroy(HTAB *hashp) 382{ 383 int i, save_errno; 384 385 save_errno = 0; 386 387#ifdef HASH_STATISTICS 388 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 389 hash_accesses, hash_collisions); 390 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 391 hash_expansions); 392 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 393 hash_overflows); 394 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 395 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 396 397 for (i = 0; i < NCACHED; i++) 398 (void)fprintf(stderr, 399 "spares[%d] = %d\n", i, hashp->SPARES[i]); 400#endif 401 /* 402 * Call on buffer manager to free buffers, and if required, 403 * write them to disk. 404 */ 405 if (__buf_free(hashp, 1, hashp->save_file)) 406 save_errno = errno; 407 if (hashp->dir) { 408 free(*hashp->dir); /* Free initial segments */ 409 /* Free extra segments */ 410 while (hashp->exsegs--) 411 free(hashp->dir[--hashp->nsegs]); 412 free(hashp->dir); 413 } 414 if (flush_meta(hashp) && !save_errno) 415 save_errno = errno; 416 /* Free Bigmaps */ 417 for (i = 0; i < hashp->nmaps; i++) 418 if (hashp->mapp[i]) 419 free(hashp->mapp[i]); 420 if (hashp->tmp_key) 421 free(hashp->tmp_key); 422 if (hashp->tmp_buf) 423 free(hashp->tmp_buf); 424 425 if (hashp->fp != -1) { 426 (void)_fsync(hashp->fp); 427 (void)_close(hashp->fp); 428 } 429 430 free(hashp); 431 432 if (save_errno) { 433 errno = save_errno; 434 return (ERROR); 435 } 436 return (SUCCESS); 437} 438/* 439 * Write modified pages to disk 440 * 441 * Returns: 442 * 0 == OK 443 * -1 ERROR 444 */ 445static int 446hash_sync(const DB *dbp, u_int32_t flags) 447{ 448 HTAB *hashp; 449 450 if (flags != 0) { 451 errno = EINVAL; 452 return (ERROR); 453 } 454 455 if (!dbp) 456 return (ERROR); 457 458 hashp = (HTAB *)dbp->internal; 459 if (!hashp->save_file) 460 return (0); 461 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 462 return (ERROR); 463 if (hashp->fp != -1 && _fsync(hashp->fp) != 0) 464 return (ERROR); 465 hashp->new_file = 0; 466 return (0); 467} 468 469/* 470 * Returns: 471 * 0 == OK 472 * -1 indicates that errno should be set 473 */ 474static int 475flush_meta(HTAB *hashp) 476{ 477 HASHHDR *whdrp; 478#if BYTE_ORDER == LITTLE_ENDIAN 479 HASHHDR whdr; 480#endif 481 int fp, i, wsize; 482 483 if (!hashp->save_file) 484 return (0); 485 hashp->MAGIC = HASHMAGIC; 486 hashp->VERSION = HASHVERSION; 487 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 488 489 fp = hashp->fp; 490 whdrp = &hashp->hdr; 491#if BYTE_ORDER == LITTLE_ENDIAN 492 whdrp = &whdr; 493 swap_header_copy(&hashp->hdr, whdrp); 494#endif 495 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 496 return (-1); 497 else 498 if (wsize != sizeof(HASHHDR)) { 499 errno = EFTYPE; 500 hashp->error = errno; 501 return (-1); 502 } 503 for (i = 0; i < NCACHED; i++) 504 if (hashp->mapp[i]) 505 if (__put_page(hashp, (char *)hashp->mapp[i], 506 hashp->BITMAPS[i], 0, 1)) 507 return (-1); 508 return (0); 509} 510 511/*******************************SEARCH ROUTINES *****************************/ 512/* 513 * All the access routines return 514 * 515 * Returns: 516 * 0 on SUCCESS 517 * 1 to indicate an external ERROR (i.e. key not found, etc) 518 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 519 */ 520static int 521hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 522{ 523 HTAB *hashp; 524 525 hashp = (HTAB *)dbp->internal; 526 if (flag) { 527 hashp->error = errno = EINVAL; 528 return (ERROR); 529 } 530 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 531} 532 533static int 534hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 535{ 536 HTAB *hashp; 537 538 hashp = (HTAB *)dbp->internal; 539 if (flag && flag != R_NOOVERWRITE) { 540 hashp->error = errno = EINVAL; 541 return (ERROR); 542 } 543 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 544 hashp->error = errno = EPERM; 545 return (ERROR); 546 } 547 return (hash_access(hashp, flag == R_NOOVERWRITE ? 548 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 549} 550 551static int 552hash_delete(const DB *dbp, const DBT *key, 553 u_int32_t flag) /* Ignored */ 554{ 555 HTAB *hashp; 556 557 hashp = (HTAB *)dbp->internal; 558 if (flag && flag != R_CURSOR) { 559 hashp->error = errno = EINVAL; 560 return (ERROR); 561 } 562 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 563 hashp->error = errno = EPERM; 564 return (ERROR); 565 } 566 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 567} 568 569/* 570 * Assume that hashp has been set in wrapper routine. 571 */ 572static int 573hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 574{ 575 BUFHEAD *rbufp; 576 BUFHEAD *bufp, *save_bufp; 577 u_int16_t *bp; 578 int n, ndx, off, size; 579 char *kp; 580 u_int16_t pageno; 581 582#ifdef HASH_STATISTICS 583 hash_accesses++; 584#endif 585 586 off = hashp->BSIZE; 587 size = key->size; 588 kp = (char *)key->data; 589 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 590 if (!rbufp) 591 return (ERROR); 592 save_bufp = rbufp; 593 594 /* Pin the bucket chain */ 595 rbufp->flags |= BUF_PIN; 596 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 597 if (bp[1] >= REAL_KEY) { 598 /* Real key/data pair */ 599 if (size == off - *bp && 600 memcmp(kp, rbufp->page + *bp, size) == 0) 601 goto found; 602 off = bp[1]; 603#ifdef HASH_STATISTICS 604 hash_collisions++; 605#endif 606 bp += 2; 607 ndx += 2; 608 } else if (bp[1] == OVFLPAGE) { 609 rbufp = __get_buf(hashp, *bp, rbufp, 0); 610 if (!rbufp) { 611 save_bufp->flags &= ~BUF_PIN; 612 return (ERROR); 613 } 614 /* FOR LOOP INIT */ 615 bp = (u_int16_t *)rbufp->page; 616 n = *bp++; 617 ndx = 1; 618 off = hashp->BSIZE; 619 } else if (bp[1] < REAL_KEY) { 620 if ((ndx = 621 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 622 goto found; 623 if (ndx == -2) { 624 bufp = rbufp; 625 if (!(pageno = 626 __find_last_page(hashp, &bufp))) { 627 ndx = 0; 628 rbufp = bufp; 629 break; /* FOR */ 630 } 631 rbufp = __get_buf(hashp, pageno, bufp, 0); 632 if (!rbufp) { 633 save_bufp->flags &= ~BUF_PIN; 634 return (ERROR); 635 } 636 /* FOR LOOP INIT */ 637 bp = (u_int16_t *)rbufp->page; 638 n = *bp++; 639 ndx = 1; 640 off = hashp->BSIZE; 641 } else { 642 save_bufp->flags &= ~BUF_PIN; 643 return (ERROR); 644 } 645 } 646 647 /* Not found */ 648 switch (action) { 649 case HASH_PUT: 650 case HASH_PUTNEW: 651 if (__addel(hashp, rbufp, key, val)) { 652 save_bufp->flags &= ~BUF_PIN; 653 return (ERROR); 654 } else { 655 save_bufp->flags &= ~BUF_PIN; 656 return (SUCCESS); 657 } 658 case HASH_GET: 659 case HASH_DELETE: 660 default: 661 save_bufp->flags &= ~BUF_PIN; 662 return (ABNORMAL); 663 } 664 665found: 666 switch (action) { 667 case HASH_PUTNEW: 668 save_bufp->flags &= ~BUF_PIN; 669 return (ABNORMAL); 670 case HASH_GET: 671 bp = (u_int16_t *)rbufp->page; 672 if (bp[ndx + 1] < REAL_KEY) { 673 if (__big_return(hashp, rbufp, ndx, val, 0)) 674 return (ERROR); 675 } else { 676 val->data = (u_char *)rbufp->page + (int)bp[ndx + 1]; 677 val->size = bp[ndx] - bp[ndx + 1]; 678 } 679 break; 680 case HASH_PUT: 681 if ((__delpair(hashp, rbufp, ndx)) || 682 (__addel(hashp, rbufp, key, val))) { 683 save_bufp->flags &= ~BUF_PIN; 684 return (ERROR); 685 } 686 break; 687 case HASH_DELETE: 688 if (__delpair(hashp, rbufp, ndx)) 689 return (ERROR); 690 break; 691 default: 692 abort(); 693 } 694 save_bufp->flags &= ~BUF_PIN; 695 return (SUCCESS); 696} 697 698static int 699hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 700{ 701 u_int32_t bucket; 702 BUFHEAD *bufp; 703 HTAB *hashp; 704 u_int16_t *bp, ndx; 705 706 hashp = (HTAB *)dbp->internal; 707 if (flag && flag != R_FIRST && flag != R_NEXT) { 708 hashp->error = errno = EINVAL; 709 return (ERROR); 710 } 711#ifdef HASH_STATISTICS 712 hash_accesses++; 713#endif 714 if ((hashp->cbucket < 0) || (flag == R_FIRST)) { 715 hashp->cbucket = 0; 716 hashp->cndx = 1; 717 hashp->cpage = NULL; 718 } 719next_bucket: 720 for (bp = NULL; !bp || !bp[0]; ) { 721 if (!(bufp = hashp->cpage)) { 722 for (bucket = hashp->cbucket; 723 bucket <= hashp->MAX_BUCKET; 724 bucket++, hashp->cndx = 1) { 725 bufp = __get_buf(hashp, bucket, NULL, 0); 726 if (!bufp) 727 return (ERROR); 728 hashp->cpage = bufp; 729 bp = (u_int16_t *)bufp->page; 730 if (bp[0]) 731 break; 732 } 733 hashp->cbucket = bucket; 734 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 735 hashp->cbucket = -1; 736 return (ABNORMAL); 737 } 738 } else { 739 bp = (u_int16_t *)hashp->cpage->page; 740 if (flag == R_NEXT || flag == 0) { 741 hashp->cndx += 2; 742 if (hashp->cndx > bp[0]) { 743 hashp->cpage = NULL; 744 hashp->cbucket++; 745 hashp->cndx = 1; 746 goto next_bucket; 747 } 748 } 749 } 750 751#ifdef DEBUG 752 assert(bp); 753 assert(bufp); 754#endif 755 while (bp[hashp->cndx + 1] == OVFLPAGE) { 756 bufp = hashp->cpage = 757 __get_buf(hashp, bp[hashp->cndx], bufp, 0); 758 if (!bufp) 759 return (ERROR); 760 bp = (u_int16_t *)(bufp->page); 761 hashp->cndx = 1; 762 } 763 if (!bp[0]) { 764 hashp->cpage = NULL; 765 ++hashp->cbucket; 766 } 767 } 768 ndx = hashp->cndx; 769 if (bp[ndx + 1] < REAL_KEY) { 770 if (__big_keydata(hashp, bufp, key, data, 1)) 771 return (ERROR); 772 } else { 773 if (hashp->cpage == 0) 774 return (ERROR); 775 key->data = (u_char *)hashp->cpage->page + bp[ndx]; 776 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 777 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1]; 778 data->size = bp[ndx] - bp[ndx + 1]; 779 } 780 return (SUCCESS); 781} 782 783/********************************* UTILITIES ************************/ 784 785/* 786 * Returns: 787 * 0 ==> OK 788 * -1 ==> Error 789 */ 790int 791__expand_table(HTAB *hashp) 792{ 793 u_int32_t old_bucket, new_bucket; 794 int dirsize, new_segnum, spare_ndx; 795 796#ifdef HASH_STATISTICS 797 hash_expansions++; 798#endif 799 new_bucket = ++hashp->MAX_BUCKET; 800 old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK); 801 802 new_segnum = new_bucket >> hashp->SSHIFT; 803 804 /* Check if we need a new segment */ 805 if (new_segnum >= hashp->nsegs) { 806 /* Check if we need to expand directory */ 807 if (new_segnum >= hashp->DSIZE) { 808 /* Reallocate directory */ 809 dirsize = hashp->DSIZE * sizeof(SEGMENT *); 810 if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1)) 811 return (-1); 812 hashp->DSIZE = dirsize << 1; 813 } 814 if ((hashp->dir[new_segnum] = 815 (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL) 816 return (-1); 817 hashp->exsegs++; 818 hashp->nsegs++; 819 } 820 /* 821 * If the split point is increasing (MAX_BUCKET's log base 2 822 * * increases), we need to copy the current contents of the spare 823 * split bucket to the next bucket. 824 */ 825 spare_ndx = __log2(hashp->MAX_BUCKET + 1); 826 if (spare_ndx > hashp->OVFL_POINT) { 827 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT]; 828 hashp->OVFL_POINT = spare_ndx; 829 } 830 831 if (new_bucket > hashp->HIGH_MASK) { 832 /* Starting a new doubling */ 833 hashp->LOW_MASK = hashp->HIGH_MASK; 834 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK; 835 } 836 /* Relocate records to the new bucket */ 837 return (__split_page(hashp, old_bucket, new_bucket)); 838} 839 840/* 841 * If realloc guarantees that the pointer is not destroyed if the realloc 842 * fails, then this routine can go away. 843 */ 844static void * 845hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize) 846{ 847 void *p; 848 849 if ( (p = malloc(newsize)) ) { 850 memmove(p, *p_ptr, oldsize); 851 memset((char *)p + oldsize, 0, newsize - oldsize); 852 free(*p_ptr); 853 *p_ptr = p; 854 } 855 return (p); 856} 857 858u_int32_t 859__call_hash(HTAB *hashp, char *k, int len) 860{ 861 unsigned int n, bucket; 862 863 n = hashp->hash(k, len); 864 bucket = n & hashp->HIGH_MASK; 865 if (bucket > hashp->MAX_BUCKET) 866 bucket = bucket & hashp->LOW_MASK; 867 return (bucket); 868} 869 870/* 871 * Allocate segment table. On error, destroy the table and set errno. 872 * 873 * Returns 0 on success 874 */ 875static int 876alloc_segs(HTAB *hashp, int nsegs) 877{ 878 int i; 879 SEGMENT store; 880 881 int save_errno; 882 883 if ((hashp->dir = 884 (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) { 885 save_errno = errno; 886 (void)hdestroy(hashp); 887 errno = save_errno; 888 return (-1); 889 } 890 hashp->nsegs = nsegs; 891 if (nsegs == 0) 892 return (0); 893 /* Allocate segments */ 894 if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT, 895 sizeof(SEGMENT))) == NULL) { 896 save_errno = errno; 897 (void)hdestroy(hashp); 898 errno = save_errno; 899 return (-1); 900 } 901 for (i = 0; i < nsegs; i++) 902 hashp->dir[i] = &store[i << hashp->SSHIFT]; 903 return (0); 904} 905 906#if BYTE_ORDER == LITTLE_ENDIAN 907/* 908 * Hashp->hdr needs to be byteswapped. 909 */ 910static void 911swap_header_copy(HASHHDR *srcp, HASHHDR *destp) 912{ 913 int i; 914 915 P_32_COPY(srcp->magic, destp->magic); 916 P_32_COPY(srcp->version, destp->version); 917 P_32_COPY(srcp->lorder, destp->lorder); 918 P_32_COPY(srcp->bsize, destp->bsize); 919 P_32_COPY(srcp->bshift, destp->bshift); 920 P_32_COPY(srcp->dsize, destp->dsize); 921 P_32_COPY(srcp->ssize, destp->ssize); 922 P_32_COPY(srcp->sshift, destp->sshift); 923 P_32_COPY(srcp->ovfl_point, destp->ovfl_point); 924 P_32_COPY(srcp->last_freed, destp->last_freed); 925 P_32_COPY(srcp->max_bucket, destp->max_bucket); 926 P_32_COPY(srcp->high_mask, destp->high_mask); 927 P_32_COPY(srcp->low_mask, destp->low_mask); 928 P_32_COPY(srcp->ffactor, destp->ffactor); 929 P_32_COPY(srcp->nkeys, destp->nkeys); 930 P_32_COPY(srcp->hdrpages, destp->hdrpages); 931 P_32_COPY(srcp->h_charkey, destp->h_charkey); 932 for (i = 0; i < NCACHED; i++) { 933 P_32_COPY(srcp->spares[i], destp->spares[i]); 934 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); 935 } 936} 937 938static void 939swap_header(HTAB *hashp) 940{ 941 HASHHDR *hdrp; 942 int i; 943 944 hdrp = &hashp->hdr; 945 946 M_32_SWAP(hdrp->magic); 947 M_32_SWAP(hdrp->version); 948 M_32_SWAP(hdrp->lorder); 949 M_32_SWAP(hdrp->bsize); 950 M_32_SWAP(hdrp->bshift); 951 M_32_SWAP(hdrp->dsize); 952 M_32_SWAP(hdrp->ssize); 953 M_32_SWAP(hdrp->sshift); 954 M_32_SWAP(hdrp->ovfl_point); 955 M_32_SWAP(hdrp->last_freed); 956 M_32_SWAP(hdrp->max_bucket); 957 M_32_SWAP(hdrp->high_mask); 958 M_32_SWAP(hdrp->low_mask); 959 M_32_SWAP(hdrp->ffactor); 960 M_32_SWAP(hdrp->nkeys); 961 M_32_SWAP(hdrp->hdrpages); 962 M_32_SWAP(hdrp->h_charkey); 963 for (i = 0; i < NCACHED; i++) { 964 M_32_SWAP(hdrp->spares[i]); 965 M_16_SWAP(hdrp->bitmaps[i]); 966 } 967} 968#endif 969