db/hash/hash-fbsd.c.orig

   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)
  34 static 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 "extern.h"
  58
  59 static int   alloc_segs(HTAB *, int);
  60 static int   flush_meta(HTAB *);
  61 static int   hash_access(HTAB *, ACTION, DBT *, DBT *);
  62 static int   hash_close(DB *);
  63 static int   hash_delete(const DB *, const DBT *, u_int32_t);
  64 static int   hash_fd(const DB *);
  65 static int   hash_get(const DB *, const DBT *, DBT *, u_int32_t);
  66 static int   hash_put(const DB *, DBT *, const DBT *, u_int32_t);
  67 static void *hash_realloc(SEGMENT **, int, int);
  68 static int   hash_seq(const DB *, DBT *, DBT *, u_int32_t);
  69 static int   hash_sync(const DB *, u_int32_t);
  70 static int   hdestroy(HTAB *);
  71 static HTAB *init_hash(HTAB *, const char *, const HASHINFO *);
  72 static int   init_htab(HTAB *, int);
  73 #if BYTE_ORDER == LITTLE_ENDIAN
  74 static void  swap_header(HTAB *);
  75 static 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
  89 int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
  90 #endif
  91
  92 /************************** INTERFACE ROUTINES ***************************/
  93 /* OPEN/CLOSE */
  94
  95 /* ARGSUSED */
  96 DB *
  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, mode)) == -1)
 125                         RETURN_ERROR(errno, error0);
 126                 (void)_fcntl(hashp->fp, F_SETFD, 1);
 127                 new_table = _fstat(hashp->fp, &statbuf) == 0 &&
 128                     statbuf.st_size == 0 &&
 129                     ((flags & O_ACCMODE) != O_RDONLY || (flags & O_CREAT) != 0);
 130         } else
 131                 new_table = 1;
 132
 133         if (new_table) {
 134                 if (!(hashp = init_hash(hashp, file, info)))
 135                         RETURN_ERROR(errno, error1);
 136         } else {
 137                 /* Table already exists */
 138                 if (info && info->hash)
 139                         hashp->hash = info->hash;
 140                 else
 141                         hashp->hash = __default_hash;
 142
 143                 hdrsize = _read(hashp->fp, &hashp->hdr, sizeof(HASHHDR));
 144 #if BYTE_ORDER == LITTLE_ENDIAN
 145                 swap_header(hashp);
 146 #endif
 147                 if (hdrsize == -1)
 148                         RETURN_ERROR(errno, error1);
 149                 if (hdrsize != sizeof(HASHHDR))
 150                         RETURN_ERROR(EFTYPE, error1);
 151                 /* Verify file type, versions and hash function */
 152                 if (hashp->MAGIC != HASHMAGIC)
 153                         RETURN_ERROR(EFTYPE, error1);
 154 #define OLDHASHVERSION  1
 155                 if (hashp->VERSION != HASHVERSION &&
 156                     hashp->VERSION != OLDHASHVERSION)
 157                         RETURN_ERROR(EFTYPE, error1);
 158                 if ((int32_t)hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
 159                         RETURN_ERROR(EFTYPE, error1);
 160                 /*
 161                  * Figure out how many segments we need.  Max_Bucket is the
 162                  * maximum bucket number, so the number of buckets is
 163                  * max_bucket + 1.
 164                  */
 165                 nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
 166                          hashp->SGSIZE;
 167                 if (alloc_segs(hashp, nsegs))
 168                         /*
 169                          * If alloc_segs fails, table will have been destroyed
 170                          * and errno will have been set.
 171                          */
 172                         return (NULL);
 173                 /* Read in bitmaps */
 174                 bpages = (hashp->SPARES[hashp->OVFL_POINT] +
 175                     (hashp->BSIZE << BYTE_SHIFT) - 1) >>
 176                     (hashp->BSHIFT + BYTE_SHIFT);
 177
 178                 hashp->nmaps = bpages;
 179                 (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *));
 180         }
 181
 182         /* Initialize Buffer Manager */
 183         if (info && info->cachesize)
 184                 __buf_init(hashp, info->cachesize);
 185         else
 186                 __buf_init(hashp, DEF_BUFSIZE);
 187
 188         hashp->new_file = new_table;
 189         hashp->save_file = file && (hashp->flags & O_RDWR);
 190         hashp->cbucket = -1;
 191         if (!(dbp = (DB *)malloc(sizeof(DB)))) {
 192                 save_errno = errno;
 193                 hdestroy(hashp);
 194                 errno = save_errno;
 195                 return (NULL);
 196         }
 197         dbp->internal = hashp;
 198         dbp->close = hash_close;
 199         dbp->del = hash_delete;
 200         dbp->fd = hash_fd;
 201         dbp->get = hash_get;
 202         dbp->put = hash_put;
 203         dbp->seq = hash_seq;
 204         dbp->sync = hash_sync;
 205         dbp->type = DB_HASH;
 206
 207 #ifdef DEBUG
 208         (void)fprintf(stderr,
 209 "%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",
 210             "init_htab:",
 211             "TABLE POINTER   ", hashp,
 212             "BUCKET SIZE     ", hashp->BSIZE,
 213             "BUCKET SHIFT    ", hashp->BSHIFT,
 214             "DIRECTORY SIZE  ", hashp->DSIZE,
 215             "SEGMENT SIZE    ", hashp->SGSIZE,
 216             "SEGMENT SHIFT   ", hashp->SSHIFT,
 217             "FILL FACTOR     ", hashp->FFACTOR,
 218             "MAX BUCKET      ", hashp->MAX_BUCKET,
 219             "OVFL POINT      ", hashp->OVFL_POINT,
 220             "LAST FREED      ", hashp->LAST_FREED,
 221             "HIGH MASK       ", hashp->HIGH_MASK,
 222             "LOW  MASK       ", hashp->LOW_MASK,
 223             "NSEGS           ", hashp->nsegs,
 224             "NKEYS           ", hashp->NKEYS);
 225 #endif
 226 #ifdef HASH_STATISTICS
 227         hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
 228 #endif
 229         return (dbp);
 230
 231 error1:
 232         if (hashp != NULL)
 233                 (void)_close(hashp->fp);
 234
 235 error0:
 236         free(hashp);
 237         errno = save_errno;
 238         return (NULL);
 239 }
 240
 241 static int
 242 hash_close(DB *dbp)
 243 {
 244         HTAB *hashp;
 245         int retval;
 246
 247         if (!dbp)
 248                 return (ERROR);
 249
 250         hashp = (HTAB *)dbp->internal;
 251         retval = hdestroy(hashp);
 252         free(dbp);
 253         return (retval);
 254 }
 255
 256 static int
 257 hash_fd(const DB *dbp)
 258 {
 259         HTAB *hashp;
 260
 261         if (!dbp)
 262                 return (ERROR);
 263
 264         hashp = (HTAB *)dbp->internal;
 265         if (hashp->fp == -1) {
 266                 errno = ENOENT;
 267                 return (-1);
 268         }
 269         return (hashp->fp);
 270 }
 271
 272 /************************** LOCAL CREATION ROUTINES **********************/
 273 static HTAB *
 274 init_hash(HTAB *hashp, const char *file, const HASHINFO *info)
 275 {
 276         struct stat statbuf;
 277         int nelem;
 278
 279         nelem = 1;
 280         hashp->NKEYS = 0;
 281         hashp->LORDER = BYTE_ORDER;
 282         hashp->BSIZE = DEF_BUCKET_SIZE;
 283         hashp->BSHIFT = DEF_BUCKET_SHIFT;
 284         hashp->SGSIZE = DEF_SEGSIZE;
 285         hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
 286         hashp->DSIZE = DEF_DIRSIZE;
 287         hashp->FFACTOR = DEF_FFACTOR;
 288         hashp->hash = __default_hash;
 289         memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
 290         memset(hashp->BITMAPS, 0, sizeof (hashp->BITMAPS));
 291
 292         /* Fix bucket size to be optimal for file system */
 293         if (file != NULL) {
 294                 if (stat(file, &statbuf))
 295                         return (NULL);
 296                 hashp->BSIZE = statbuf.st_blksize;
 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  */
 337 static int
 338 init_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  */
 380 static int
 381 hdestroy(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)_close(hashp->fp);
 427
 428         free(hashp);
 429
 430         if (save_errno) {
 431                 errno = save_errno;
 432                 return (ERROR);
 433         }
 434         return (SUCCESS);
 435 }
 436 /*
 437  * Write modified pages to disk
 438  *
 439  * Returns:
 440  *       0 == OK
 441  *      -1 ERROR
 442  */
 443 static int
 444 hash_sync(const DB *dbp, u_int32_t flags)
 445 {
 446         HTAB *hashp;
 447
 448         if (flags != 0) {
 449                 errno = EINVAL;
 450                 return (ERROR);
 451         }
 452
 453         if (!dbp)
 454                 return (ERROR);
 455
 456         hashp = (HTAB *)dbp->internal;
 457         if (!hashp->save_file)
 458                 return (0);
 459         if (__buf_free(hashp, 0, 1) || flush_meta(hashp))
 460                 return (ERROR);
 461         hashp->new_file = 0;
 462         return (0);
 463 }
 464
 465 /*
 466  * Returns:
 467  *       0 == OK
 468  *      -1 indicates that errno should be set
 469  */
 470 static int
 471 flush_meta(HTAB *hashp)
 472 {
 473         HASHHDR *whdrp;
 474 #if BYTE_ORDER == LITTLE_ENDIAN
 475         HASHHDR whdr;
 476 #endif
 477         int fp, i, wsize;
 478
 479         if (!hashp->save_file)
 480                 return (0);
 481         hashp->MAGIC = HASHMAGIC;
 482         hashp->VERSION = HASHVERSION;
 483         hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
 484
 485         fp = hashp->fp;
 486         whdrp = &hashp->hdr;
 487 #if BYTE_ORDER == LITTLE_ENDIAN
 488         whdrp = &whdr;
 489         swap_header_copy(&hashp->hdr, whdrp);
 490 #endif
 491         if ((wsize = pwrite(fp, whdrp, sizeof(HASHHDR), (off_t)0)) == -1)
 492                 return (-1);
 493         else
 494                 if (wsize != sizeof(HASHHDR)) {
 495                         errno = EFTYPE;
 496                         hashp->error = errno;
 497                         return (-1);
 498                 }
 499         for (i = 0; i < NCACHED; i++)
 500                 if (hashp->mapp[i])
 501                         if (__put_page(hashp, (char *)hashp->mapp[i],
 502                                 hashp->BITMAPS[i], 0, 1))
 503                                 return (-1);
 504         return (0);
 505 }
 506
 507 /*******************************SEARCH ROUTINES *****************************/
 508 /*
 509  * All the access routines return
 510  *
 511  * Returns:
 512  *       0 on SUCCESS
 513  *       1 to indicate an external ERROR (i.e. key not found, etc)
 514  *      -1 to indicate an internal ERROR (i.e. out of memory, etc)
 515  */
 516 static int
 517 hash_get(const DB *dbp, const DBT *key, DBT *data, u_int32_t flag)
 518 {
 519         HTAB *hashp;
 520
 521         hashp = (HTAB *)dbp->internal;
 522         if (flag) {
 523                 hashp->error = errno = EINVAL;
 524                 return (ERROR);
 525         }
 526         return (hash_access(hashp, HASH_GET, (DBT *)key, data));
 527 }
 528
 529 static int
 530 hash_put(const DB *dbp, DBT *key, const DBT *data, u_int32_t flag)
 531 {
 532         HTAB *hashp;
 533
 534         hashp = (HTAB *)dbp->internal;
 535         if (flag && flag != R_NOOVERWRITE) {
 536                 hashp->error = errno = EINVAL;
 537                 return (ERROR);
 538         }
 539         if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
 540                 hashp->error = errno = EPERM;
 541                 return (ERROR);
 542         }
 543         return (hash_access(hashp, flag == R_NOOVERWRITE ?
 544             HASH_PUTNEW : HASH_PUT, (DBT *)key, (DBT *)data));
 545 }
 546
 547 static int
 548 hash_delete(const DB *dbp, const DBT *key,
 549     u_int32_t flag)             /* Ignored */
 550 {
 551         HTAB *hashp;
 552
 553         hashp = (HTAB *)dbp->internal;
 554         if (flag && flag != R_CURSOR) {
 555                 hashp->error = errno = EINVAL;
 556                 return (ERROR);
 557         }
 558         if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
 559                 hashp->error = errno = EPERM;
 560                 return (ERROR);
 561         }
 562         return (hash_access(hashp, HASH_DELETE, (DBT *)key, NULL));
 563 }
 564
 565 /*
 566  * Assume that hashp has been set in wrapper routine.
 567  */
 568 static int
 569 hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
 570 {
 571         BUFHEAD *rbufp;
 572         BUFHEAD *bufp, *save_bufp;
 573         u_int16_t *bp;
 574         int n, ndx, off, size;
 575         char *kp;
 576         u_int16_t pageno;
 577
 578 #ifdef HASH_STATISTICS
 579         hash_accesses++;
 580 #endif
 581
 582         off = hashp->BSIZE;
 583         size = key->size;
 584         kp = (char *)key->data;
 585         rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
 586         if (!rbufp)
 587                 return (ERROR);
 588         save_bufp = rbufp;
 589
 590         /* Pin the bucket chain */
 591         rbufp->flags |= BUF_PIN;
 592         for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
 593                 if (bp[1] >= REAL_KEY) {
 594                         /* Real key/data pair */
 595                         if (size == off - *bp &&
 596                             memcmp(kp, rbufp->page + *bp, size) == 0)
 597                                 goto found;
 598                         off = bp[1];
 599 #ifdef HASH_STATISTICS
 600                         hash_collisions++;
 601 #endif
 602                         bp += 2;
 603                         ndx += 2;
 604                 } else if (bp[1] == OVFLPAGE) {
 605                         rbufp = __get_buf(hashp, *bp, rbufp, 0);
 606                         if (!rbufp) {
 607                                 save_bufp->flags &= ~BUF_PIN;
 608                                 return (ERROR);
 609                         }
 610                         /* FOR LOOP INIT */
 611                         bp = (u_int16_t *)rbufp->page;
 612                         n = *bp++;
 613                         ndx = 1;
 614                         off = hashp->BSIZE;
 615                 } else if (bp[1] < REAL_KEY) {
 616                         if ((ndx =
 617                             __find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
 618                                 goto found;
 619                         if (ndx == -2) {
 620                                 bufp = rbufp;
 621                                 if (!(pageno =
 622                                     __find_last_page(hashp, &bufp))) {
 623                                         ndx = 0;
 624                                         rbufp = bufp;
 625                                         break;  /* FOR */
 626                                 }
 627                                 rbufp = __get_buf(hashp, pageno, bufp, 0);
 628                                 if (!rbufp) {
 629                                         save_bufp->flags &= ~BUF_PIN;
 630                                         return (ERROR);
 631                                 }
 632                                 /* FOR LOOP INIT */
 633                                 bp = (u_int16_t *)rbufp->page;
 634                                 n = *bp++;
 635                                 ndx = 1;
 636                                 off = hashp->BSIZE;
 637                         } else {
 638                                 save_bufp->flags &= ~BUF_PIN;
 639                                 return (ERROR);
 640                         }
 641                 }
 642
 643         /* Not found */
 644         switch (action) {
 645         case HASH_PUT:
 646         case HASH_PUTNEW:
 647                 if (__addel(hashp, rbufp, key, val)) {
 648                         save_bufp->flags &= ~BUF_PIN;
 649                         return (ERROR);
 650                 } else {
 651                         save_bufp->flags &= ~BUF_PIN;
 652                         return (SUCCESS);
 653                 }
 654         case HASH_GET:
 655         case HASH_DELETE:
 656         default:
 657                 save_bufp->flags &= ~BUF_PIN;
 658                 return (ABNORMAL);
 659         }
 660
 661 found:
 662         switch (action) {
 663         case HASH_PUTNEW:
 664                 save_bufp->flags &= ~BUF_PIN;
 665                 return (ABNORMAL);
 666         case HASH_GET:
 667                 bp = (u_int16_t *)rbufp->page;
 668                 if (bp[ndx + 1] < REAL_KEY) {
 669                         if (__big_return(hashp, rbufp, ndx, val, 0))
 670                                 return (ERROR);
 671                 } else {
 672                         val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
 673                         val->size = bp[ndx] - bp[ndx + 1];
 674                 }
 675                 break;
 676         case HASH_PUT:
 677                 if ((__delpair(hashp, rbufp, ndx)) ||
 678                     (__addel(hashp, rbufp, key, val))) {
 679                         save_bufp->flags &= ~BUF_PIN;
 680                         return (ERROR);
 681                 }
 682                 break;
 683         case HASH_DELETE:
 684                 if (__delpair(hashp, rbufp, ndx))
 685                         return (ERROR);
 686                 break;
 687         default:
 688                 abort();
 689         }
 690         save_bufp->flags &= ~BUF_PIN;
 691         return (SUCCESS);
 692 }
 693
 694 static int
 695 hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag)
 696 {
 697         u_int32_t bucket;
 698         BUFHEAD *bufp;
 699         HTAB *hashp;
 700         u_int16_t *bp, ndx;
 701
 702         hashp = (HTAB *)dbp->internal;
 703         if (flag && flag != R_FIRST && flag != R_NEXT) {
 704                 hashp->error = errno = EINVAL;
 705                 return (ERROR);
 706         }
 707 #ifdef HASH_STATISTICS
 708         hash_accesses++;
 709 #endif
 710         if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
 711                 hashp->cbucket = 0;
 712                 hashp->cndx = 1;
 713                 hashp->cpage = NULL;
 714         }
 715  next_bucket:
 716         for (bp = NULL; !bp || !bp[0]; ) {
 717                 if (!(bufp = hashp->cpage)) {
 718                         for (bucket = hashp->cbucket;
 719                             bucket <= hashp->MAX_BUCKET;
 720                             bucket++, hashp->cndx = 1) {
 721                                 bufp = __get_buf(hashp, bucket, NULL, 0);
 722                                 if (!bufp)
 723                                         return (ERROR);
 724                                 hashp->cpage = bufp;
 725                                 bp = (u_int16_t *)bufp->page;
 726                                 if (bp[0])
 727                                         break;
 728                         }
 729                         hashp->cbucket = bucket;
 730                         if ((u_int32_t)hashp->cbucket > hashp->MAX_BUCKET) {
 731                                 hashp->cbucket = -1;
 732                                 return (ABNORMAL);
 733                         }
 734                 } else {
 735                         bp = (u_int16_t *)hashp->cpage->page;
 736                         if (flag == R_NEXT) {
 737                                 hashp->cndx += 2;
 738                                 if (hashp->cndx > bp[0]) {
 739                                         hashp->cpage = NULL;
 740                                         hashp->cbucket++;
 741                                         hashp->cndx = 1;
 742                                         goto next_bucket;
 743                                 }
 744                         }
 745                 }
 746
 747 #ifdef DEBUG
 748                 assert(bp);
 749                 assert(bufp);
 750 #endif
 751                 while (bp[hashp->cndx + 1] == OVFLPAGE) {
 752                         bufp = hashp->cpage =
 753                             __get_buf(hashp, bp[hashp->cndx], bufp, 0);
 754                         if (!bufp)
 755                                 return (ERROR);
 756                         bp = (u_int16_t *)(bufp->page);
 757                         hashp->cndx = 1;
 758                 }
 759                 if (!bp[0]) {
 760                         hashp->cpage = NULL;
 761                         ++hashp->cbucket;
 762                 }
 763         }
 764         ndx = hashp->cndx;
 765         if (bp[ndx + 1] < REAL_KEY) {
 766                 if (__big_keydata(hashp, bufp, key, data, 1))
 767                         return (ERROR);
 768         } else {
 769                 if (hashp->cpage == 0)
 770                         return (ERROR);
 771                 key->data = (u_char *)hashp->cpage->page + bp[ndx];
 772                 key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
 773                 data->data = (u_char *)hashp->cpage->page + bp[ndx + 1];
 774                 data->size = bp[ndx] - bp[ndx + 1];
 775         }
 776         return (SUCCESS);
 777 }
 778
 779 /********************************* UTILITIES ************************/
 780
 781 /*
 782  * Returns:
 783  *       0 ==> OK
 784  *      -1 ==> Error
 785  */
 786 int
 787 __expand_table(HTAB *hashp)
 788 {
 789         u_int32_t old_bucket, new_bucket;
 790         int dirsize, new_segnum, spare_ndx;
 791
 792 #ifdef HASH_STATISTICS
 793         hash_expansions++;
 794 #endif
 795         new_bucket = ++hashp->MAX_BUCKET;
 796         old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
 797
 798         new_segnum = new_bucket >> hashp->SSHIFT;
 799
 800         /* Check if we need a new segment */
 801         if (new_segnum >= hashp->nsegs) {
 802                 /* Check if we need to expand directory */
 803                 if (new_segnum >= hashp->DSIZE) {
 804                         /* Reallocate directory */
 805                         dirsize = hashp->DSIZE * sizeof(SEGMENT *);
 806                         if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
 807                                 return (-1);
 808                         hashp->DSIZE = dirsize << 1;
 809                 }
 810                 if ((hashp->dir[new_segnum] =
 811                     (SEGMENT)calloc(hashp->SGSIZE, sizeof(SEGMENT))) == NULL)
 812                         return (-1);
 813                 hashp->exsegs++;
 814                 hashp->nsegs++;
 815         }
 816         /*
 817          * If the split point is increasing (MAX_BUCKET's log base 2
 818          * * increases), we need to copy the current contents of the spare
 819          * split bucket to the next bucket.
 820          */
 821         spare_ndx = __log2(hashp->MAX_BUCKET + 1);
 822         if (spare_ndx > hashp->OVFL_POINT) {
 823                 hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
 824                 hashp->OVFL_POINT = spare_ndx;
 825         }
 826
 827         if (new_bucket > hashp->HIGH_MASK) {
 828                 /* Starting a new doubling */
 829                 hashp->LOW_MASK = hashp->HIGH_MASK;
 830                 hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
 831         }
 832         /* Relocate records to the new bucket */
 833         return (__split_page(hashp, old_bucket, new_bucket));
 834 }
 835
 836 /*
 837  * If realloc guarantees that the pointer is not destroyed if the realloc
 838  * fails, then this routine can go away.
 839  */
 840 static void *
 841 hash_realloc(SEGMENT **p_ptr, int oldsize, int newsize)
 842 {
 843         void *p;
 844
 845         if ( (p = malloc(newsize)) ) {
 846                 memmove(p, *p_ptr, oldsize);
 847                 memset((char *)p + oldsize, 0, newsize - oldsize);
 848                 free(*p_ptr);
 849                 *p_ptr = p;
 850         }
 851         return (p);
 852 }
 853
 854 u_int32_t
 855 __call_hash(HTAB *hashp, char *k, int len)
 856 {
 857         unsigned int n, bucket;
 858
 859         n = hashp->hash(k, len);
 860         bucket = n & hashp->HIGH_MASK;
 861         if (bucket > hashp->MAX_BUCKET)
 862                 bucket = bucket & hashp->LOW_MASK;
 863         return (bucket);
 864 }
 865
 866 /*
 867  * Allocate segment table.  On error, destroy the table and set errno.
 868  *
 869  * Returns 0 on success
 870  */
 871 static int
 872 alloc_segs(HTAB *hashp, int nsegs)
 873 {
 874         int i;
 875         SEGMENT store;
 876
 877         int save_errno;
 878
 879         if ((hashp->dir =
 880             (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *))) == NULL) {
 881                 save_errno = errno;
 882                 (void)hdestroy(hashp);
 883                 errno = save_errno;
 884                 return (-1);
 885         }
 886         hashp->nsegs = nsegs;
 887         if (nsegs == 0)
 888                 return (0);
 889         /* Allocate segments */
 890         if ((store = (SEGMENT)calloc(nsegs << hashp->SSHIFT,
 891             sizeof(SEGMENT))) == NULL) {
 892                 save_errno = errno;
 893                 (void)hdestroy(hashp);
 894                 errno = save_errno;
 895                 return (-1);
 896         }
 897         for (i = 0; i < nsegs; i++)
 898                 hashp->dir[i] = &store[i << hashp->SSHIFT];
 899         return (0);
 900 }
 901
 902 #if BYTE_ORDER == LITTLE_ENDIAN
 903 /*
 904  * Hashp->hdr needs to be byteswapped.
 905  */
 906 static void
 907 swap_header_copy(HASHHDR *srcp, HASHHDR *destp)
 908 {
 909         int i;
 910
 911         P_32_COPY(srcp->magic, destp->magic);
 912         P_32_COPY(srcp->version, destp->version);
 913         P_32_COPY(srcp->lorder, destp->lorder);
 914         P_32_COPY(srcp->bsize, destp->bsize);
 915         P_32_COPY(srcp->bshift, destp->bshift);
 916         P_32_COPY(srcp->dsize, destp->dsize);
 917         P_32_COPY(srcp->ssize, destp->ssize);
 918         P_32_COPY(srcp->sshift, destp->sshift);
 919         P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
 920         P_32_COPY(srcp->last_freed, destp->last_freed);
 921         P_32_COPY(srcp->max_bucket, destp->max_bucket);
 922         P_32_COPY(srcp->high_mask, destp->high_mask);
 923         P_32_COPY(srcp->low_mask, destp->low_mask);
 924         P_32_COPY(srcp->ffactor, destp->ffactor);
 925         P_32_COPY(srcp->nkeys, destp->nkeys);
 926         P_32_COPY(srcp->hdrpages, destp->hdrpages);
 927         P_32_COPY(srcp->h_charkey, destp->h_charkey);
 928         for (i = 0; i < NCACHED; i++) {
 929                 P_32_COPY(srcp->spares[i], destp->spares[i]);
 930                 P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
 931         }
 932 }
 933
 934 static void
 935 swap_header(HTAB *hashp)
 936 {
 937         HASHHDR *hdrp;
 938         int i;
 939
 940         hdrp = &hashp->hdr;
 941
 942         M_32_SWAP(hdrp->magic);
 943         M_32_SWAP(hdrp->version);
 944         M_32_SWAP(hdrp->lorder);
 945         M_32_SWAP(hdrp->bsize);
 946         M_32_SWAP(hdrp->bshift);
 947         M_32_SWAP(hdrp->dsize);
 948         M_32_SWAP(hdrp->ssize);
 949         M_32_SWAP(hdrp->sshift);
 950         M_32_SWAP(hdrp->ovfl_point);
 951         M_32_SWAP(hdrp->last_freed);
 952         M_32_SWAP(hdrp->max_bucket);
 953         M_32_SWAP(hdrp->high_mask);
 954         M_32_SWAP(hdrp->low_mask);
 955         M_32_SWAP(hdrp->ffactor);
 956         M_32_SWAP(hdrp->nkeys);
 957         M_32_SWAP(hdrp->hdrpages);
 958         M_32_SWAP(hdrp->h_charkey);
 959         for (i = 0; i < NCACHED; i++) {
 960                 M_32_SWAP(hdrp->spares[i]);
 961                 M_16_SWAP(hdrp->bitmaps[i]);
 962         }
 963 }
 964 #endif