db/hash/hash-fbsd.c

   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 "hash_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                 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
 230 error1:
 231         if (hashp != NULL)
 232                 (void)_close(hashp->fp);
 233
 234 error0:
 235         free(hashp);
 236         errno = save_errno;
 237         return (NULL);
 238 }
 239
 240 static int
 241 hash_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
 255 static int
 256 hash_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 **********************/
 272 static HTAB *
 273 init_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  */
 336 static int
 337 init_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  */
 379 static int
 380 hdestroy(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  */
 442 static int
 443 hash_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  */
 469 static int
 470 flush_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  */
 515 static int
 516 hash_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
 528 static int
 529 hash_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
 546 static int
 547 hash_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  */
 567 static int
 568 hash_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
 660 found:
 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
 693 static int
 694 hash_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  */
 785 int
 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  */
 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 u_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  */
 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                 (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  */
 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