Source code
Revision control
Copy as Markdown
Other Tools
/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Margo Seltzer.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. ***REMOVED*** - see
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)hash.c 8.9 (Berkeley) 6/16/94";
#endif /* LIBC_SCCS and not lint */
#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
#include <sys/param.h>
#endif
#if !defined(macintosh)
#include <sys/stat.h>
#endif
#if defined(macintosh)
#include <unix.h>
#include <unistd.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
#include <unistd.h>
#endif
#if defined(_WIN32) || defined(_WINDOWS)
#include <windows.h>
#endif
#include <assert.h>
#include "mcom_db.h"
#include "hash.h"
#include "page.h"
/*
#include "extern.h"
*/
static int alloc_segs(HTAB *, int);
static int flush_meta(HTAB *);
static int hash_access(HTAB *, ACTION, DBT *, DBT *);
static int hash_close(DB *);
static int hash_delete(const DB *, const DBT *, uint);
static int hash_fd(const DB *);
static int hash_get(const DB *, const DBT *, DBT *, uint);
static int hash_put(const DB *, DBT *, const DBT *, uint);
static void *hash_realloc(SEGMENT **, size_t, size_t);
static int hash_seq(const DB *, DBT *, DBT *, uint);
static int hash_sync(const DB *, uint);
static int hdestroy(HTAB *);
static HTAB *init_hash(HTAB *, const char *, HASHINFO *);
static int init_htab(HTAB *, int);
#if BYTE_ORDER == LITTLE_ENDIAN
static void swap_header(HTAB *);
static void swap_header_copy(HASHHDR *, HASHHDR *);
#endif
/* Fast arithmetic, relying on powers of 2, */
#define MOD(x, y) ((x) & ((y)-1))
#define RETURN_ERROR(ERR, LOC) \
{ \
save_errno = ERR; \
goto LOC; \
}
/* Return values */
#define SUCCESS (0)
#define DBM_ERROR (-1)
#define ABNORMAL (1)
#ifdef HASH_STATISTICS
int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
#endif
/* A new Lou (montulli@mozilla.com) routine.
*
* The database is screwed.
*
* This closes the file, flushing buffers as appropriate.
*/
static void
dbm_remove_database(DB *dbp)
{
HTAB *hashp = (HTAB *)dbp->internal;
assert(0);
if (!hashp)
return;
hdestroy(hashp);
dbp->internal = NULL;
}
/************************** INTERFACE ROUTINES ***************************/
/* OPEN/CLOSE */
extern DB *
dbm_hash_open(const char *file, int flags, int mode, const HASHINFO *info, int dflags)
{
HTAB *hashp = NULL;
struct stat statbuf;
DB *dbp;
int bpages, hdrsize, new_table, nsegs, save_errno;
if ((flags & O_ACCMODE) == O_WRONLY) {
errno = EINVAL;
return NULL;
}
/* zero the statbuffer so that
* we can check it for a non-zero
* date to see if stat succeeded
*/
memset(&statbuf, 0, sizeof(struct stat));
if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) {
errno = ENOMEM;
return NULL;
}
hashp->fp = NO_FILE;
if (file)
hashp->filename = strdup(file);
/*
* Even if user wants write only, we need to be able to read
* the actual file, so we need to open it read/write. But, the
* field in the hashp structure needs to be accurate so that
* we can check accesses.
*/
hashp->flags = flags;
new_table = 0;
if (!file || (flags & O_TRUNC) || (stat(file, &statbuf) && (errno == ENOENT))) {
if (errno == ENOENT)
errno = 0; /* Just in case someone looks at errno */
new_table = 1;
} else if (statbuf.st_mtime && statbuf.st_size == 0) {
/* check for a zero length file and delete it
* if it exists
*/
new_table = 1;
}
hashp->file_size = statbuf.st_size;
if (file) {
#if defined(_WIN32) || defined(_WINDOWS) || defined(macintosh)
if ((hashp->fp = DBFILE_OPEN(file, flags | O_BINARY, mode)) == -1)
RETURN_ERROR(errno, error1);
#else
if ((hashp->fp = open(file, flags, mode)) == -1)
RETURN_ERROR(errno, error1);
(void)fcntl(hashp->fp, F_SETFD, 1);
#endif
}
if (new_table) {
if (!init_hash(hashp, file, (HASHINFO *)info))
RETURN_ERROR(errno, error1);
} else {
/* Table already exists */
if (info && info->hash)
hashp->hash = info->hash;
else
hashp->hash = dbm_default_hash;
hdrsize = read(hashp->fp, (char *)&hashp->hdr, sizeof(HASHHDR));
if (hdrsize == -1)
RETURN_ERROR(errno, error1);
if (hdrsize != sizeof(HASHHDR))
RETURN_ERROR(EFTYPE, error1);
#if BYTE_ORDER == LITTLE_ENDIAN
swap_header(hashp);
#endif
/* Verify file type, versions and hash function */
if (hashp->MAGIC != HASHMAGIC)
RETURN_ERROR(EFTYPE, error1);
#define OLDHASHVERSION 1
if (hashp->VERSION != HASHVERSION &&
hashp->VERSION != OLDHASHVERSION)
RETURN_ERROR(EFTYPE, error1);
if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
RETURN_ERROR(EFTYPE, error1);
if (hashp->NKEYS < 0) /* Old bad database. */
RETURN_ERROR(EFTYPE, error1);
/*
* Figure out how many segments we need. Max_Bucket is the
* maximum bucket number, so the number of buckets is
* max_bucket + 1.
*/
nsegs = (hashp->MAX_BUCKET + 1 + hashp->SGSIZE - 1) /
hashp->SGSIZE;
hashp->nsegs = 0;
if (alloc_segs(hashp, nsegs))
/* If alloc_segs fails, errno will have been set. */
RETURN_ERROR(errno, error1);
/* Read in bitmaps */
bpages = (hashp->SPARES[hashp->OVFL_POINT] +
(hashp->BSIZE << BYTE_SHIFT) - 1) >>
(hashp->BSHIFT + BYTE_SHIFT);
hashp->nmaps = bpages;
(void)memset(&hashp->mapp[0], 0, bpages * sizeof(uint32 *));
}
/* Initialize Buffer Manager */
if (info && info->cachesize)
dbm_buf_init(hashp, (int32)info->cachesize);
else
dbm_buf_init(hashp, DEF_BUFSIZE);
hashp->new_file = new_table;
#ifdef macintosh
hashp->save_file = file && !(hashp->flags & O_RDONLY);
#else
hashp->save_file = file && (hashp->flags & O_RDWR);
#endif
hashp->cbucket = -1;
if (!(dbp = (DB *)malloc(sizeof(DB)))) {
RETURN_ERROR(ENOMEM, error1);
}
dbp->internal = hashp;
dbp->close = hash_close;
dbp->del = hash_delete;
dbp->fd = hash_fd;
dbp->get = hash_get;
dbp->put = hash_put;
dbp->seq = hash_seq;
dbp->sync = hash_sync;
dbp->type = DB_HASH;
#ifdef HASH_STATISTICS
hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
#endif
return (dbp);
error1:
hdestroy(hashp);
errno = save_errno;
return (NULL);
}
static int
hash_close(DB *dbp)
{
HTAB *hashp;
int retval;
if (!dbp)
return (DBM_ERROR);
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
retval = hdestroy(hashp);
free(dbp);
return (retval);
}
static int
hash_fd(const DB *dbp)
{
HTAB *hashp;
if (!dbp)
return (DBM_ERROR);
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (hashp->fp == -1) {
errno = ENOENT;
return (-1);
}
return (hashp->fp);
}
/************************** LOCAL CREATION ROUTINES **********************/
static HTAB *
init_hash(HTAB *hashp, const char *file, HASHINFO *info)
{
struct stat statbuf;
int nelem;
nelem = 1;
hashp->NKEYS = 0;
hashp->LORDER = BYTE_ORDER;
hashp->BSIZE = DEF_BUCKET_SIZE;
hashp->BSHIFT = DEF_BUCKET_SHIFT;
hashp->SGSIZE = DEF_SEGSIZE;
hashp->SSHIFT = DEF_SEGSIZE_SHIFT;
hashp->DSIZE = DEF_DIRSIZE;
hashp->FFACTOR = DEF_FFACTOR;
hashp->hash = dbm_default_hash;
memset(hashp->SPARES, 0, sizeof(hashp->SPARES));
memset(hashp->BITMAPS, 0, sizeof(hashp->BITMAPS));
/* Fix bucket size to be optimal for file system */
if (file != NULL) {
if (stat(file, &statbuf))
return (NULL);
#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
#if defined(__QNX__) && !defined(__QNXNTO__)
hashp->BSIZE = 512; /* preferred blk size on qnx4 */
#else
hashp->BSIZE = statbuf.st_blksize;
#endif
/* new code added by Lou to reduce block
* size down below MAX_BSIZE
*/
if (hashp->BSIZE > MAX_BSIZE)
hashp->BSIZE = MAX_BSIZE;
#endif
hashp->BSHIFT = dbm_log2((uint32)hashp->BSIZE);
}
if (info) {
if (info->bsize) {
/* Round pagesize up to power of 2 */
hashp->BSHIFT = dbm_log2(info->bsize);
hashp->BSIZE = 1 << hashp->BSHIFT;
if (hashp->BSIZE > MAX_BSIZE) {
errno = EINVAL;
return (NULL);
}
}
if (info->ffactor)
hashp->FFACTOR = info->ffactor;
if (info->hash)
hashp->hash = info->hash;
if (info->nelem)
nelem = info->nelem;
if (info->lorder) {
if (info->lorder != BIG_ENDIAN &&
info->lorder != LITTLE_ENDIAN) {
errno = EINVAL;
return (NULL);
}
hashp->LORDER = info->lorder;
}
}
/* init_htab sets errno if it fails */
if (init_htab(hashp, nelem))
return (NULL);
else
return (hashp);
}
/*
* This calls alloc_segs which may run out of memory. Alloc_segs will
* set errno, so we just pass the error information along.
*
* Returns 0 on No Error
*/
static int
init_htab(HTAB *hashp, int nelem)
{
register int nbuckets, nsegs;
int l2;
/*
* Divide number of elements by the fill factor and determine a
* desired number of buckets. Allocate space for the next greater
* power of two number of buckets.
*/
nelem = (nelem - 1) / hashp->FFACTOR + 1;
l2 = dbm_log2((uint32)PR_MAX(nelem, 2));
nbuckets = 1 << l2;
hashp->SPARES[l2] = l2 + 1;
hashp->SPARES[l2 + 1] = l2 + 1;
hashp->OVFL_POINT = l2;
hashp->LAST_FREED = 2;
/* First bitmap page is at: splitpoint l2 page offset 1 */
if (dbm_ibitmap(hashp, (int)OADDR_OF(l2, 1), l2 + 1, 0))
return (-1);
hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
hashp->HIGH_MASK = (nbuckets << 1) - 1;
hashp->HDRPAGES = ((PR_MAX(sizeof(HASHHDR), MINHDRSIZE) - 1) >>
hashp->BSHIFT) +
1;
nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
nsegs = 1 << dbm_log2((uint32)nsegs);
if (nsegs > hashp->DSIZE)
hashp->DSIZE = nsegs;
return (alloc_segs(hashp, nsegs));
}
/********************** DESTROY/CLOSE ROUTINES ************************/
/*
* Flushes any changes to the file if necessary and destroys the hashp
* structure, freeing all allocated space.
*/
static int
hdestroy(HTAB *hashp)
{
int i, save_errno;
save_errno = 0;
#ifdef HASH_STATISTICS
(void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n",
hash_accesses, hash_collisions);
(void)fprintf(stderr, "hdestroy: expansions %ld\n",
hash_expansions);
(void)fprintf(stderr, "hdestroy: overflows %ld\n",
hash_overflows);
(void)fprintf(stderr, "keys %ld maxp %d segmentcount %d\n",
hashp->NKEYS, hashp->MAX_BUCKET, hashp->nsegs);
for (i = 0; i < NCACHED; i++)
(void)fprintf(stderr,
"spares[%d] = %d\n", i, hashp->SPARES[i]);
#endif
/*
* Call on buffer manager to free buffers, and if required,
* write them to disk.
*/
if (dbm_buf_free(hashp, 1, hashp->save_file))
save_errno = errno;
if (hashp->dir) {
free(*hashp->dir); /* Free initial segments */
/* Free extra segments */
while (hashp->exsegs--)
free(hashp->dir[--hashp->nsegs]);
free(hashp->dir);
}
if (flush_meta(hashp) && !save_errno)
save_errno = errno;
/* Free Bigmaps */
for (i = 0; i < hashp->nmaps; i++)
if (hashp->mapp[i])
free(hashp->mapp[i]);
if (hashp->fp != -1)
(void)close(hashp->fp);
if (hashp->filename) {
#if defined(_WIN32) || defined(_WINDOWS)
if (hashp->is_temp)
(void)unlink(hashp->filename);
#endif
free(hashp->filename);
}
if (hashp->tmp_buf)
free(hashp->tmp_buf);
if (hashp->tmp_key)
free(hashp->tmp_key);
free(hashp);
if (save_errno) {
errno = save_errno;
return (DBM_ERROR);
}
return (SUCCESS);
}
#if defined(_WIN32) || defined(_WINDOWS)
/*
* Close and reopen file to force file length update on windows.
*
* Returns:
* 0 == OK
* -1 DBM_ERROR
*/
static int
update_EOF(HTAB *hashp)
{
#if defined(DBM_REOPEN_ON_FLUSH)
char *file = hashp->filename;
off_t file_size;
int flags;
int mode = -1;
struct stat statbuf;
memset(&statbuf, 0, sizeof statbuf);
/* make sure we won't lose the file by closing it. */
if (!file || (stat(file, &statbuf) && (errno == ENOENT))) {
/* pretend we did it. */
return 0;
}
(void)close(hashp->fp);
flags = hashp->flags & ~(O_TRUNC | O_CREAT | O_EXCL);
if ((hashp->fp = DBFILE_OPEN(file, flags | O_BINARY, mode)) == -1)
return -1;
file_size = lseek(hashp->fp, (off_t)0, SEEK_END);
if (file_size == -1)
return -1;
hashp->file_size = file_size;
return 0;
#else
int fd = hashp->fp;
off_t file_size = lseek(fd, (off_t)0, SEEK_END);
HANDLE handle = (HANDLE)_get_osfhandle(fd);
BOOL cool = FlushFileBuffers(handle);
#ifdef DEBUG3
if (!cool) {
DWORD err = GetLastError();
(void)fprintf(stderr,
"FlushFileBuffers failed, last error = %d, 0x%08x\n",
err, err);
}
#endif
if (file_size == -1)
return -1;
hashp->file_size = file_size;
return cool ? 0 : -1;
#endif
}
#endif
/*
* Write modified pages to disk
*
* Returns:
* 0 == OK
* -1 DBM_ERROR
*/
static int
hash_sync(const DB *dbp, uint flags)
{
HTAB *hashp;
if (flags != 0) {
errno = EINVAL;
return (DBM_ERROR);
}
if (!dbp)
return (DBM_ERROR);
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (!hashp->save_file)
return (0);
if (dbm_buf_free(hashp, 0, 1) || flush_meta(hashp))
return (DBM_ERROR);
#if defined(_WIN32) || defined(_WINDOWS)
if (hashp->updateEOF && hashp->filename && !hashp->is_temp) {
int status = update_EOF(hashp);
hashp->updateEOF = 0;
if (status)
return status;
}
#endif
hashp->new_file = 0;
return (0);
}
/*
* Returns:
* 0 == OK
* -1 indicates that errno should be set
*/
static int
flush_meta(HTAB *hashp)
{
HASHHDR *whdrp;
#if BYTE_ORDER == LITTLE_ENDIAN
HASHHDR whdr;
#endif
int fp, i, wsize;
if (!hashp->save_file)
return (0);
hashp->MAGIC = HASHMAGIC;
hashp->VERSION = HASHVERSION;
hashp->H_CHARKEY = hashp->hash(CHARKEY, sizeof(CHARKEY));
fp = hashp->fp;
whdrp = &hashp->hdr;
#if BYTE_ORDER == LITTLE_ENDIAN
whdrp = &whdr;
swap_header_copy(&hashp->hdr, whdrp);
#endif
if ((lseek(fp, (off_t)0, SEEK_SET) == -1) ||
((wsize = write(fp, (char *)whdrp, sizeof(HASHHDR))) == -1))
return (-1);
else if (wsize != sizeof(HASHHDR)) {
errno = EFTYPE;
hashp->dbmerrno = errno;
return (-1);
}
for (i = 0; i < NCACHED; i++)
if (hashp->mapp[i])
if (dbm_put_page(hashp, (char *)hashp->mapp[i],
hashp->BITMAPS[i], 0, 1))
return (-1);
return (0);
}
/*******************************SEARCH ROUTINES *****************************/
/*
* All the access routines return
*
* Returns:
* 0 on SUCCESS
* 1 to indicate an external DBM_ERROR (i.e. key not found, etc)
* -1 to indicate an internal DBM_ERROR (i.e. out of memory, etc)
*/
static int
hash_get(
const DB *dbp,
const DBT *key,
DBT *data,
uint flag)
{
HTAB *hashp;
int rv;
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (flag) {
hashp->dbmerrno = errno = EINVAL;
return (DBM_ERROR);
}
rv = hash_access(hashp, HASH_GET, (DBT *)key, data);
if (rv == DATABASE_CORRUPTED_ERROR) {
#if defined(unix) && defined(DEBUG)
printf("\n\nDBM Database has been corrupted, tell Lou...\n\n");
#endif
dbm_remove_database((DB *)dbp);
}
return (rv);
}
static int
hash_put(
const DB *dbp,
DBT *key,
const DBT *data,
uint flag)
{
HTAB *hashp;
int rv;
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (flag && flag != R_NOOVERWRITE) {
hashp->dbmerrno = errno = EINVAL;
return (DBM_ERROR);
}
if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
hashp->dbmerrno = errno = EPERM;
return (DBM_ERROR);
}
rv = hash_access(hashp, flag == R_NOOVERWRITE ? HASH_PUTNEW : HASH_PUT,
(DBT *)key, (DBT *)data);
if (rv == DATABASE_CORRUPTED_ERROR) {
#if defined(unix) && defined(DEBUG)
printf("\n\nDBM Database has been corrupted, tell Lou...\n\n");
#endif
dbm_remove_database((DB *)dbp);
}
return (rv);
}
static int
hash_delete(
const DB *dbp,
const DBT *key,
uint flag) /* Ignored */
{
HTAB *hashp;
int rv;
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (flag && flag != R_CURSOR) {
hashp->dbmerrno = errno = EINVAL;
return (DBM_ERROR);
}
if ((hashp->flags & O_ACCMODE) == O_RDONLY) {
hashp->dbmerrno = errno = EPERM;
return (DBM_ERROR);
}
rv = hash_access(hashp, HASH_DELETE, (DBT *)key, NULL);
if (rv == DATABASE_CORRUPTED_ERROR) {
#if defined(unix) && defined(DEBUG)
printf("\n\nDBM Database has been corrupted, tell Lou...\n\n");
#endif
dbm_remove_database((DB *)dbp);
}
return (rv);
}
#define MAX_OVERFLOW_HASH_ACCESS_LOOPS 2000
/*
* Assume that hashp has been set in wrapper routine.
*/
static int
hash_access(
HTAB *hashp,
ACTION action,
DBT *key, DBT *val)
{
register BUFHEAD *rbufp;
BUFHEAD *bufp, *save_bufp;
register uint16 *bp;
register long n, ndx, off;
register size_t size;
register char *kp;
uint16 pageno;
uint32 ovfl_loop_count = 0;
int32 last_overflow_page_no = -1;
#ifdef HASH_STATISTICS
hash_accesses++;
#endif
off = hashp->BSIZE;
size = key->size;
kp = (char *)key->data;
rbufp = dbm_get_buf(hashp, dbm_call_hash(hashp, kp, size), NULL, 0);
if (!rbufp)
return (DATABASE_CORRUPTED_ERROR);
save_bufp = rbufp;
/* Pin the bucket chain */
rbufp->flags |= BUF_PIN;
for (bp = (uint16 *)rbufp->page, n = *bp++, ndx = 1; ndx < n;) {
if (bp[1] >= REAL_KEY) {
/* Real key/data pair */
if (size == (unsigned long)(off - *bp) &&
memcmp(kp, rbufp->page + *bp, size) == 0)
goto found;
off = bp[1];
#ifdef HASH_STATISTICS
hash_collisions++;
#endif
bp += 2;
ndx += 2;
} else if (bp[1] == OVFLPAGE) {
/* database corruption: overflow loop detection */
if (last_overflow_page_no == (int32)*bp)
return (DATABASE_CORRUPTED_ERROR);
last_overflow_page_no = *bp;
rbufp = dbm_get_buf(hashp, *bp, rbufp, 0);
if (!rbufp) {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
}
ovfl_loop_count++;
if (ovfl_loop_count > MAX_OVERFLOW_HASH_ACCESS_LOOPS)
return (DATABASE_CORRUPTED_ERROR);
/* FOR LOOP INIT */
bp = (uint16 *)rbufp->page;
n = *bp++;
ndx = 1;
off = hashp->BSIZE;
} else if (bp[1] < REAL_KEY) {
if ((ndx =
dbm_find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0)
goto found;
if (ndx == -2) {
bufp = rbufp;
if (!(pageno =
dbm_find_last_page(hashp, &bufp))) {
ndx = 0;
rbufp = bufp;
break; /* FOR */
}
rbufp = dbm_get_buf(hashp, pageno, bufp, 0);
if (!rbufp) {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
}
/* FOR LOOP INIT */
bp = (uint16 *)rbufp->page;
n = *bp++;
ndx = 1;
off = hashp->BSIZE;
} else {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
}
}
}
/* Not found */
switch (action) {
case HASH_PUT:
case HASH_PUTNEW:
if (dbm_addel(hashp, rbufp, key, val)) {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
} else {
save_bufp->flags &= ~BUF_PIN;
return (SUCCESS);
}
case HASH_GET:
case HASH_DELETE:
default:
save_bufp->flags &= ~BUF_PIN;
return (ABNORMAL);
}
found:
switch (action) {
case HASH_PUTNEW:
save_bufp->flags &= ~BUF_PIN;
return (ABNORMAL);
case HASH_GET:
bp = (uint16 *)rbufp->page;
if (bp[ndx + 1] < REAL_KEY) {
if (dbm_big_return(hashp, rbufp, ndx, val, 0))
return (DBM_ERROR);
} else {
val->data = (uint8 *)rbufp->page + (int)bp[ndx + 1];
val->size = bp[ndx] - bp[ndx + 1];
}
break;
case HASH_PUT:
if ((dbm_delpair(hashp, rbufp, ndx)) ||
(dbm_addel(hashp, rbufp, key, val))) {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
}
break;
case HASH_DELETE:
if (dbm_delpair(hashp, rbufp, ndx))
return (DBM_ERROR);
break;
default:
abort();
}
save_bufp->flags &= ~BUF_PIN;
return (SUCCESS);
}
static int
hash_seq(
const DB *dbp,
DBT *key, DBT *data,
uint flag)
{
register uint32 bucket;
register BUFHEAD *bufp = NULL;
HTAB *hashp;
uint16 *bp, ndx;
hashp = (HTAB *)dbp->internal;
if (!hashp)
return (DBM_ERROR);
if (flag && flag != R_FIRST && flag != R_NEXT) {
hashp->dbmerrno = errno = EINVAL;
return (DBM_ERROR);
}
#ifdef HASH_STATISTICS
hash_accesses++;
#endif
if ((hashp->cbucket < 0) || (flag == R_FIRST)) {
hashp->cbucket = 0;
hashp->cndx = 1;
hashp->cpage = NULL;
}
for (bp = NULL; !bp || !bp[0];) {
if (!(bufp = hashp->cpage)) {
for (bucket = hashp->cbucket;
bucket <= (uint32)hashp->MAX_BUCKET;
bucket++, hashp->cndx = 1) {
bufp = dbm_get_buf(hashp, bucket, NULL, 0);
if (!bufp)
return (DBM_ERROR);
hashp->cpage = bufp;
bp = (uint16 *)bufp->page;
if (bp[0])
break;
}
hashp->cbucket = bucket;
if (hashp->cbucket > hashp->MAX_BUCKET) {
hashp->cbucket = -1;
return (ABNORMAL);
}
} else
bp = (uint16 *)hashp->cpage->page;
#ifdef DEBUG
assert(bp);
assert(bufp);
#endif
while (bp[hashp->cndx + 1] == OVFLPAGE) {
bufp = hashp->cpage =
dbm_get_buf(hashp, bp[hashp->cndx], bufp, 0);
if (!bufp)
return (DBM_ERROR);
bp = (uint16 *)(bufp->page);
hashp->cndx = 1;
}
if (!bp[0]) {
hashp->cpage = NULL;
++hashp->cbucket;
}
}
ndx = hashp->cndx;
if (bp[ndx + 1] < REAL_KEY) {
if (dbm_big_keydata(hashp, bufp, key, data, 1))
return (DBM_ERROR);
} else {
key->data = (uint8 *)hashp->cpage->page + bp[ndx];
key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];
data->data = (uint8 *)hashp->cpage->page + bp[ndx + 1];
data->size = bp[ndx] - bp[ndx + 1];
ndx += 2;
if (ndx > bp[0]) {
hashp->cpage = NULL;
hashp->cbucket++;
hashp->cndx = 1;
} else
hashp->cndx = ndx;
}
return (SUCCESS);
}
/********************************* UTILITIES ************************/
/*
* Returns:
* 0 ==> OK
* -1 ==> Error
*/
extern int
dbm_expand_table(HTAB *hashp)
{
uint32 old_bucket, new_bucket;
int new_segnum, spare_ndx;
size_t dirsize;
#ifdef HASH_STATISTICS
hash_expansions++;
#endif
new_bucket = ++hashp->MAX_BUCKET;
old_bucket = (hashp->MAX_BUCKET & hashp->LOW_MASK);
new_segnum = new_bucket >> hashp->SSHIFT;
/* Check if we need a new segment */
if (new_segnum >= hashp->nsegs) {
/* Check if we need to expand directory */
if (new_segnum >= hashp->DSIZE) {
/* Reallocate directory */
dirsize = hashp->DSIZE * sizeof(SEGMENT *);
if (!hash_realloc(&hashp->dir, dirsize, dirsize << 1))
return (-1);
hashp->DSIZE = dirsize << 1;
}
if ((hashp->dir[new_segnum] =
(SEGMENT)calloc((size_t)hashp->SGSIZE, sizeof(BUFHEAD *))) == NULL)
return (-1);
hashp->exsegs++;
hashp->nsegs++;
}
/*
* If the split point is increasing (MAX_BUCKET's log base 2
* * increases), we need to copy the current contents of the spare
* split bucket to the next bucket.
*/
spare_ndx = dbm_log2((uint32)(hashp->MAX_BUCKET + 1));
if (spare_ndx > hashp->OVFL_POINT) {
hashp->SPARES[spare_ndx] = hashp->SPARES[hashp->OVFL_POINT];
hashp->OVFL_POINT = spare_ndx;
}
if (new_bucket > (uint32)hashp->HIGH_MASK) {
/* Starting a new doubling */
hashp->LOW_MASK = hashp->HIGH_MASK;
hashp->HIGH_MASK = new_bucket | hashp->LOW_MASK;
}
/* Relocate records to the new bucket */
return (dbm_split_page(hashp, old_bucket, new_bucket));
}
/*
* If realloc guarantees that the pointer is not destroyed if the realloc
* fails, then this routine can go away.
*/
static void *
hash_realloc(
SEGMENT **p_ptr,
size_t oldsize, size_t newsize)
{
register void *p;
if ((p = malloc(newsize))) {
memmove(p, *p_ptr, oldsize);
memset((char *)p + oldsize, 0, newsize - oldsize);
free(*p_ptr);
*p_ptr = (SEGMENT *)p;
}
return (p);
}
extern uint32
dbm_call_hash(HTAB *hashp, char *k, size_t len)
{
uint32 n, bucket;
n = hashp->hash(k, len);
bucket = n & hashp->HIGH_MASK;
if (bucket > (uint32)hashp->MAX_BUCKET)
bucket = bucket & hashp->LOW_MASK;
return (bucket);
}
/*
* Allocate segment table. On error, set errno.
*
* Returns 0 on success
*/
static int
alloc_segs(
HTAB *hashp,
int nsegs)
{
register int i;
register SEGMENT store;
if ((hashp->dir =
(SEGMENT *)calloc((size_t)hashp->DSIZE, sizeof(SEGMENT))) == NULL) {
errno = ENOMEM;
return (-1);
}
/* Allocate segments */
if ((store =
(SEGMENT)calloc((size_t)nsegs << hashp->SSHIFT, sizeof(BUFHEAD *))) == NULL) {
errno = ENOMEM;
return (-1);
}
for (i = 0; i < nsegs; i++, hashp->nsegs++)
hashp->dir[i] = &store[i << hashp->SSHIFT];
return (0);
}
#if BYTE_ORDER == LITTLE_ENDIAN
/*
* Hashp->hdr needs to be byteswapped.
*/
static void
swap_header_copy(
HASHHDR *srcp, HASHHDR *destp)
{
int i;
P_32_COPY(srcp->magic, destp->magic);
P_32_COPY(srcp->version, destp->version);
P_32_COPY(srcp->lorder, destp->lorder);
P_32_COPY(srcp->bsize, destp->bsize);
P_32_COPY(srcp->bshift, destp->bshift);
P_32_COPY(srcp->dsize, destp->dsize);
P_32_COPY(srcp->ssize, destp->ssize);
P_32_COPY(srcp->sshift, destp->sshift);
P_32_COPY(srcp->ovfl_point, destp->ovfl_point);
P_32_COPY(srcp->last_freed, destp->last_freed);
P_32_COPY(srcp->max_bucket, destp->max_bucket);
P_32_COPY(srcp->high_mask, destp->high_mask);
P_32_COPY(srcp->low_mask, destp->low_mask);
P_32_COPY(srcp->ffactor, destp->ffactor);
P_32_COPY(srcp->nkeys, destp->nkeys);
P_32_COPY(srcp->hdrpages, destp->hdrpages);
P_32_COPY(srcp->h_charkey, destp->h_charkey);
for (i = 0; i < NCACHED; i++) {
P_32_COPY(srcp->spares[i], destp->spares[i]);
P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]);
}
}
static void
swap_header(HTAB *hashp)
{
HASHHDR *hdrp;
int i;
hdrp = &hashp->hdr;
M_32_SWAP(hdrp->magic);
M_32_SWAP(hdrp->version);
M_32_SWAP(hdrp->lorder);
M_32_SWAP(hdrp->bsize);
M_32_SWAP(hdrp->bshift);
M_32_SWAP(hdrp->dsize);
M_32_SWAP(hdrp->ssize);
M_32_SWAP(hdrp->sshift);
M_32_SWAP(hdrp->ovfl_point);
M_32_SWAP(hdrp->last_freed);
M_32_SWAP(hdrp->max_bucket);
M_32_SWAP(hdrp->high_mask);
M_32_SWAP(hdrp->low_mask);
M_32_SWAP(hdrp->ffactor);
M_32_SWAP(hdrp->nkeys);
M_32_SWAP(hdrp->hdrpages);
M_32_SWAP(hdrp->h_charkey);
for (i = 0; i < NCACHED; i++) {
M_32_SWAP(hdrp->spares[i]);
M_16_SWAP(hdrp->bitmaps[i]);
}
}
#endif