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: src/lib/libc/db/hash/hash.c,v 1.21 2009/03/28 07:20:39 delphij Exp $"); 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 "hash_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 flags += O_RDWR - O_WRONLY; /* POSIX */ 108 } 109 110 if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) 111 return (NULL); 112 hashp->fp = -1; 113 114 /* 115 * Even if user wants write only, we need to be able to read 116 * the actual file, so we need to open it read/write. But, the 117 * field in the hashp structure needs to be accurate so that 118 * we can check accesses. 119 */ 120 hashp->flags = flags; 121 122 if (file) { 123 if ((hashp->fp = _open(file, flags, mode)) == -1) 124 RETURN_ERROR(errno, error0); 125 (void)_fcntl(hashp->fp, F_SETFD, 1); 126 new_table = _fstat(hashp->fp, &statbuf) == 0 && 127 statbuf.st_size == 0 && 128 ((flags & O_ACCMODE) != O_RDONLY || (flags & O_CREAT) != 0); 129 } else 130 new_table = 1; 131 132 if (new_table) { 133 if (!(hashp = init_hash(hashp, file, info))) 134 RETURN_ERROR(errno, error1); 135 } else { 136 /* Table already exists */ 137 if (info && info->hash) 138 hashp->hash = info->hash; 139 else 140 hashp->hash = __default_hash; 141 142 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR)); 143#if BYTE_ORDER == LITTLE_ENDIAN 144 swap_header(hashp); 145#endif 146 if (hdrsize == -1) 147 RETURN_ERROR(errno, error1); 148 if (hdrsize != sizeof(HASHHDR)) 149 RETURN_ERROR(EFTYPE, error1); 150 /* Verify file type, versions and hash function */ 151 if (hashp->MAGIC != HASHMAGIC) 152 RETURN_ERROR(EFTYPE, error1); 153#define OLDHASHVERSION 1 154 if (hashp->VERSION != HASHVERSION && 155 hashp->VERSION != OLDHASHVERSION) 156 RETURN_ERROR(EFTYPE, error1); 157 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY) 158 RETURN_ERROR(EFTYPE, error1); 159 /* 160 * Figure out how many segments we need. Max_Bucket is the 161 * maximum bucket number, so the number of buckets is 162 * max_bucket + 1. 163 */ 164 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) / 165 hashp->SGSIZE; 166 if (alloc_segs(hashp, nsegs)) 167 /* 168 * If alloc_segs fails, table will have been destroyed 169 * and errno will have been set. 170 */ 171 return (NULL); 172 /* Read in bitmaps */ 173 bpages = (hashp->SPARES[hashp->OVFL_POINT] + 174 (hashp->BSIZE << BYTE_SHIFT) - 1) >> 175 (hashp->BSHIFT + BYTE_SHIFT); 176 177 hashp->nmaps = bpages; 178 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); 179 } 180 181 /* Initialize Buffer Manager */ 182 if (info && info->cachesize) 183 __buf_init(hashp, info->cachesize); 184 else 185 __buf_init(hashp, DEF_BUFSIZE); 186 187 hashp->new_file = new_table; 188 hashp->save_file = file && (hashp->flags & O_RDWR); 189 hashp->cbucket = -1; 190 if (!(dbp = (DB *)malloc(sizeof(DB)))) { 191 save_errno = errno; 192 hdestroy(hashp); 193 errno = save_errno; 194 return (NULL); 195 } 196 dbp->internal = hashp; 197 dbp->close = hash_close; 198 dbp->del = hash_delete; 199 dbp->fd = hash_fd; 200 dbp->get = hash_get; 201 dbp->put = hash_put; 202 dbp->seq = hash_seq; 203 dbp->sync = hash_sync; 204 dbp->type = DB_HASH; 205 206#ifdef DEBUG 207 (void)fprintf(stderr, 208"%s\n%s%p\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n", 209 "init_htab:", 210 "TABLE POINTER ", hashp, 211 "BUCKET SIZE ", hashp->BSIZE, 212 "BUCKET SHIFT ", hashp->BSHIFT, 213 "DIRECTORY SIZE ", hashp->DSIZE, 214 "SEGMENT SIZE ", hashp->SGSIZE, 215 "SEGMENT SHIFT ", hashp->SSHIFT, 216 "FILL FACTOR ", hashp->FFACTOR, 217 "MAX BUCKET ", hashp->MAX_BUCKET, 218 "OVFL POINT ", hashp->OVFL_POINT, 219 "LAST FREED ", hashp->LAST_FREED, 220 "HIGH MASK ", hashp->HIGH_MASK, 221 "LOW MASK ", hashp->LOW_MASK, 222 "NSEGS ", hashp->nsegs, 223 "NKEYS ", hashp->NKEYS); 224#endif 225#ifdef HASH_STATISTICS 226 hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; 227#endif 228 return (dbp); 229 230error1: 231 if (hashp != NULL) 232 (void)_close(hashp->fp); 233 234error0: 235 free(hashp); 236 errno = save_errno; 237 return (NULL); 238} 239 240static int 241hash_close(DB *dbp) 242{ 243 HTAB *hashp; 244 int retval; 245 246 if (!dbp) 247 return (ERROR); 248 249 hashp = (HTAB *)dbp->internal; 250 retval = hdestroy(hashp); 251 free(dbp); 252 return (retval); 253} 254 255static int 256hash_fd(const DB *dbp) 257{ 258 HTAB *hashp; 259 260 if (!dbp) 261 return (ERROR); 262 263 hashp = (HTAB *)dbp->internal; 264 if (hashp->fp == -1) { 265 errno = ENOENT; 266 return (-1); 267 } 268 return (hashp->fp); 269} 270 271/************************** LOCAL CREATION ROUTINES **********************/ 272static HTAB * 273init_hash(HTAB *hashp, const char *file, const HASHINFO *info) 274{ 275 struct stat statbuf; 276 int nelem; 277 278 nelem = 1; 279 hashp->NKEYS = 0; 280 hashp->LORDER = BYTE_ORDER; 281 hashp->BSIZE = DEF_BUCKET_SIZE; 282 hashp->BSHIFT = DEF_BUCKET_SHIFT; 283 hashp->SGSIZE = DEF_SEGSIZE; 284 hashp->SSHIFT = DEF_SEGSIZE_SHIFT; 285 hashp->DSIZE = DEF_DIRSIZE; 286 hashp->FFACTOR = DEF_FFACTOR; 287 hashp->hash = __default_hash; 288 memset(hashp->SPARES, 0, sizeof(hashp->SPARES)); 289 memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS)); 290 291 /* Fix bucket size to be optimal for file system */ 292 if (file != NULL) { 293 if (stat(file, &statbuf)) 294 return (NULL); 295 hashp->BSIZE = statbuf.st_blksize; 296 hashp->BSHIFT = __log2(hashp->BSIZE); 297 } 298 299 if (info) { 300 if (info->bsize) { 301 /* Round pagesize up to power of 2 */ 302 hashp->BSHIFT = __log2(info->bsize); 303 hashp->BSIZE = 1 << hashp->BSHIFT; 304 if (hashp->BSIZE > MAX_BSIZE) { 305 errno = EINVAL; 306 return (NULL); 307 } 308 } 309 if (info->ffactor) 310 hashp->FFACTOR = info->ffactor; 311 if (info->hash) 312 hashp->hash = info->hash; 313 if (info->nelem) 314 nelem = info->nelem; 315 if (info->lorder) { 316 if (info->lorder != BIG_ENDIAN && 317 info->lorder != LITTLE_ENDIAN) { 318 errno = EINVAL; 319 return (NULL); 320 } 321 hashp->LORDER = info->lorder; 322 } 323 } 324 /* init_htab should destroy the table and set errno if it fails */ 325 if (init_htab(hashp, nelem)) 326 return (NULL); 327 else 328 return (hashp); 329} 330/* 331 * This calls alloc_segs which may run out of memory. Alloc_segs will destroy 332 * the table and set errno, so we just pass the error information along. 333 * 334 * Returns 0 on No Error 335 */ 336static int 337init_htab(HTAB *hashp, int nelem) 338{ 339 int nbuckets, nsegs, l2; 340 341 /* 342 * Divide number of elements by the fill factor and determine a 343 * desired number of buckets. Allocate space for the next greater 344 * power of two number of buckets. 345 */ 346 nelem = (nelem - 1) / hashp->FFACTOR + 1; 347 348 l2 = __log2(MAX(nelem, 2)); 349 nbuckets = 1 << l2; 350 351 hashp->SPARES[l2] = l2 + 1; 352 hashp->SPARES[l2 + 1] = l2 + 1; 353 hashp->OVFL_POINT = l2; 354 hashp->LAST_FREED = 2; 355 356 /* First bitmap page is at: splitpoint l2 page offset 1 */ 357 if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) 358 return (-1); 359 360 hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1; 361 hashp->HIGH_MASK = (nbuckets << 1) - 1; 362 hashp->HDRPAGES = ((MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >> 363 hashp->BSHIFT) + 1; 364 365 nsegs = (nbuckets - 1) / hashp->SGSIZE + 1; 366 nsegs = 1 << __log2(nsegs); 367 368 if (nsegs > hashp->DSIZE) 369 hashp->DSIZE = nsegs; 370 return (alloc_segs(hashp, nsegs)); 371} 372 373/********************** DESTROY/CLOSE ROUTINES ************************/ 374 375/* 376 * Flushes any changes to the file if necessary and destroys the hashp 377 * structure, freeing all allocated space. 378 */ 379static int 380hdestroy(HTAB *hashp) 381{ 382 int i, save_errno; 383 384 save_errno = 0; 385 386#ifdef HASH_STATISTICS 387 (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", 388 hash_accesses, hash_collisions); 389 (void)fprintf(stderr, "hdestroy: expansions %ld\n", 390 hash_expansions); 391 (void)fprintf(stderr, "hdestroy: overflows %ld\n", 392 hash_overflows); 393 (void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n", 394 hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs); 395 396 for (i = 0; i < NCACHED; i++) 397 (void)fprintf(stderr, 398 "spares[%d] = %d\n", i, hashp->SPARES[i]); 399#endif 400 /* 401 * Call on buffer manager to free buffers, and if required, 402 * write them to disk. 403 */ 404 if (__buf_free(hashp, 1, hashp->save_file)) 405 save_errno = errno; 406 if (hashp->dir) { 407 free(*hashp->dir); /* Free initial segments */ 408 /* Free extra segments */ 409 while (hashp->exsegs--) 410 free(hashp->dir[--hashp->nsegs]); 411 free(hashp->dir); 412 } 413 if (flush_meta(hashp) && !save_errno) 414 save_errno = errno; 415 /* Free Bigmaps */ 416 for (i = 0; i < hashp->nmaps; i++) 417 if (hashp->mapp[i]) 418 free(hashp->mapp[i]); 419 if (hashp->tmp_key) 420 free(hashp->tmp_key); 421 if (hashp->tmp_buf) 422 free(hashp->tmp_buf); 423 424 if (hashp->fp != -1) 425 (void)_close(hashp->fp); 426 427 free(hashp); 428 429 if (save_errno) { 430 errno = save_errno; 431 return (ERROR); 432 } 433 return (SUCCESS); 434} 435/* 436 * Write modified pages to disk 437 * 438 * Returns: 439 * 0 == OK 440 * -1 ERROR 441 */ 442static int 443hash_sync(const DB *dbp, u_int32_t flags) 444{ 445 HTAB *hashp; 446 447 if (flags != 0) { 448 errno = EINVAL; 449 return (ERROR); 450 } 451 452 if (!dbp) 453 return (ERROR); 454 455 hashp = (HTAB *)dbp->internal; 456 if (!hashp->save_file) 457 return (0); 458 if (__buf_free(hashp, 0, 1) || flush_meta(hashp)) 459 return (ERROR); 460 hashp->new_file = 0; 461 return (0); 462} 463 464/* 465 * Returns: 466 * 0 == OK 467 * -1 indicates that errno should be set 468 */ 469static int 470flush_meta(HTAB *hashp) 471{ 472 HASHHDR *whdrp; 473#if BYTE_ORDER == LITTLE_ENDIAN 474 HASHHDR whdr; 475#endif 476 int fp, i, wsize; 477 478 if (!hashp->save_file) 479 return (0); 480 hashp->MAGIC = HASHMAGIC; 481 hashp->VERSION = HASHVERSION; 482 hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY)); 483 484 fp = hashp->fp; 485 whdrp = &hashp->hdr; 486#if BYTE_ORDER == LITTLE_ENDIAN 487 whdrp = &whdr; 488 swap_header_copy(&hashp->hdr, whdrp); 489#endif 490 if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1) 491 return (-1); 492 else 493 if (wsize != sizeof(HASHHDR)) { 494 errno = EFTYPE; 495 hashp->error = errno; 496 return (-1); 497 } 498 for (i = 0; i < NCACHED; i++) 499 if (hashp->mapp[i]) 500 if (__put_page(hashp, (char *)hashp->mapp[i], 501 hashp->BITMAPS[i], 0, 1)) 502 return (-1); 503 return (0); 504} 505 506/*******************************SEARCH ROUTINES *****************************/ 507/* 508 * All the access routines return 509 * 510 * Returns: 511 * 0 on SUCCESS 512 * 1 to indicate an external ERROR (i.e. key not found, etc) 513 * -1 to indicate an internal ERROR (i.e. out of memory, etc) 514 */ 515static int 516hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag) 517{ 518 HTAB *hashp; 519 520 hashp = (HTAB *)dbp->internal; 521 if (flag) { 522 hashp->error = errno = EINVAL; 523 return (ERROR); 524 } 525 return (hash_access(hashp, HASH_GET, (DBT *)key, data)); 526} 527 528static int 529hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag) 530{ 531 HTAB *hashp; 532 533 hashp = (HTAB *)dbp->internal; 534 if (flag && flag != R_NOOVERWRITE) { 535 hashp->error = errno = EINVAL; 536 return (ERROR); 537 } 538 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 539 hashp->error = errno = EPERM; 540 return (ERROR); 541 } 542 return (hash_access(hashp, flag == R_NOOVERWRITE ? 543 HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data)); 544} 545 546static int 547hash_delete(const DB *dbp, const DBT *key, 548 u_int32_t flag) /* Ignored */ 549{ 550 HTAB *hashp; 551 552 hashp = (HTAB *)dbp->internal; 553 if (flag && flag != R_CURSOR) { 554 hashp->error = errno = EINVAL; 555 return (ERROR); 556 } 557 if ((hashp->flags & O_ACCMODE) == O_RDONLY) { 558 hashp->error = errno = EPERM; 559 return (ERROR); 560 } 561 return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL)); 562} 563 564/* 565 * Assume that hashp has been set in wrapper routine. 566 */ 567static int 568hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val) 569{ 570 BUFHEAD *rbufp; 571 BUFHEAD *bufp, *save_bufp; 572 u_int16_t *bp; 573 int n, ndx, off, size; 574 char *kp; 575 u_int16_t pageno; 576 577#ifdef HASH_STATISTICS 578 hash_accesses++; 579#endif 580 581 off = hashp->BSIZE; 582 size = key->size; 583 kp = (char *)key->data; 584 rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0); 585 if (!rbufp) 586 return (ERROR); 587 save_bufp = rbufp; 588 589 /* Pin the bucket chain */ 590 rbufp->flags |= BUF_PIN; 591 for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) 592 if (bp[1] >= REAL_KEY) { 593 /* Real key/data pair */ 594 if (size == off - *bp && 595 memcmp(kp, rbufp->page + *bp, size) == 0) 596 goto found; 597 off = bp[1]; 598#ifdef HASH_STATISTICS 599 hash_collisions++; 600#endif 601 bp += 2; 602 ndx += 2; 603 } else if (bp[1] == OVFLPAGE) { 604 rbufp = __get_buf(hashp, *bp, rbufp, 0); 605 if (!rbufp) { 606 save_bufp->flags &= ~BUF_PIN; 607 return (ERROR); 608 } 609 /* FOR LOOP INIT */ 610 bp = (u_int16_t *)rbufp->page; 611 n = *bp++; 612 ndx = 1; 613 off = hashp->BSIZE; 614 } else if (bp[1] < REAL_KEY) { 615 if ((ndx = 616 __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0) 617 goto found; 618 if (ndx == -2) { 619 bufp = rbufp; 620 if (!(pageno = 621 __find_last_page(hashp, &bufp))) { 622 ndx = 0; 623 rbufp = bufp; 624 break; /* FOR */ 625 } 626 rbufp = __get_buf(hashp, pageno, bufp, 0); 627 if (!rbufp) { 628 save_bufp->flags &= ~BUF_PIN; 629 return (ERROR); 630 } 631 /* FOR LOOP INIT */ 632 bp = (u_int16_t *)rbufp->page; 633 n = *bp++; 634 ndx = 1; 635 off = hashp->BSIZE; 636 } else { 637 save_bufp->flags &= ~BUF_PIN; 638 return (ERROR); 639 } 640 } 641 642 /* Not found */ 643 switch (action) { 644 case HASH_PUT: 645 case HASH_PUTNEW: 646 if (__addel(hashp, rbufp, key, val)) { 647 save_bufp->flags &= ~BUF_PIN; 648 return (ERROR); 649 } else { 650 save_bufp->flags &= ~BUF_PIN; 651 return (SUCCESS); 652 } 653 case HASH_GET: 654 case HASH_DELETE: 655 default: 656 save_bufp->flags &= ~BUF_PIN; 657 return (ABNORMAL); 658 } 659 660found: 661 switch (action) { 662 case HASH_PUTNEW: 663 save_bufp->flags &= ~BUF_PIN; 664 return (ABNORMAL); 665 case HASH_GET: 666 bp = (u_int16_t *)rbufp->page; 667 if (bp[ndx + 1] < REAL_KEY) { 668 if (__big_return(hashp, rbufp, ndx, val, 0)) 669 return (ERROR); 670 } else { 671 val->data = (u_char *)rbufp->page + (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 LIBC_ABORT("illegal action (%d)", action); 688 } 689 save_bufp->flags &= ~BUF_PIN; 690 return (SUCCESS); 691} 692 693static int 694hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag) 695{ 696 u_int32_t bucket; 697 BUFHEAD *bufp; 698 HTAB *hashp; 699 u_int16_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 = (u_int16_t *)bufp->page; 725 if (bp[0]) 726 break; 727 } 728 hashp->cbucket = bucket; 729 if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) { 730 hashp->cbucket = -1; 731 return (ABNORMAL); 732 } 733 } else { 734 bp = (u_int16_t *)hashp->cpage->page; 735 if (flag == R_NEXT) { 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 = (u_int16_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 = (u_char *)hashp->cpage->page + bp[ndx]; 771 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx]; 772 data->data = (u_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 */ 785int 786__expand_table(HTAB *hashp) 787{ 788 u_int32_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 */ 839static void * 840hash_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 853u_int32_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 */ 870static int 871alloc_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 (void)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 (void)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 */ 905static void 906swap_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 933static void 934swap_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