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BSD 4_3_Net_2 release
[unix-history] / usr / src / lib / libc / db / hash / dynahash.c
/*-
* Copyright (c) 1990 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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[] = "@(#)dynahash.c 5.14 (Berkeley) 4/2/91";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <assert.h>
#include <db.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "hash.h"
/* 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 ERROR -1
#define ABNORMAL 1
/* page.c */
extern int __get_page();
extern int __split_page();
extern int __addel();
extern int __delpair();
extern u_long *__init_bitmap();
/* big.c */
extern int __big_return();
extern int __big_keydata();
extern u_short __find_last_page();
/* buf.c */
extern BUFHEAD *__get_buf();
extern void __buf_init();
extern int __buf_free();
/* hash function */
extern int (*default_hash)();
/* My externals */
extern int __expand_table();
extern u_int __call_hash();
/* Internal routines */
static HTAB *init_hash();
static int hash_access();
static int flush_meta();
static int alloc_segs();
static int init_htab();
static char *hash_realloc();
static int hdestroy();
static int hash_put();
static int hash_delete();
static int hash_get();
static int hash_sync();
static int hash_close();
static int hash_seq();
static void swap_header_copy();
static void swap_header();
/* Local data */
HTAB *hashp = NULL;
#ifdef HASH_STATISTICS
long hash_accesses, hash_collisions, hash_expansions, hash_overflows;
#endif
/************************** INTERFACE ROUTINES **********************/
/* OPEN/CLOSE */
extern DB *
hash_open ( file, flags, mode, info )
const char *file;
int flags;
int mode;
const HASHINFO *info; /* Special directives for create */
{
int buckets;
int bpages;
int hdrsize;
int i;
int new_table = 0;
int nkey;
int nsegs;
int save_errno;
struct stat statbuf;
DB *dbp;
if ( !(hashp = (HTAB *) calloc( 1, sizeof(HTAB) ))) {
/* calloc should set errno */
return(0);
}
hashp->fp = -1;
/*
Select flags relevant to us.
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.
*/
flags = flags & (O_CREAT | O_EXCL | O_RDONLY | O_RDWR | O_TRUNC | O_WRONLY);
hashp->flags = flags;
if ( flags & O_WRONLY ) flags = (flags & ~O_WRONLY) | O_RDWR;
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;
}
if ( file ) {
if ((hashp->fp = open ( file, flags, mode )) == -1) {
RETURN_ERROR (errno, error0);
}
(void)fcntl(hashp->fp, F_SETFD, 1);
}
if ( new_table ) {
if ( !(hashp = init_hash( info )) ) {
RETURN_ERROR(errno,error1);
}
} else {
/* Table already exists */
if ( info && info->hash ) hashp->hash = info->hash;
else hashp->hash = default_hash;
hdrsize = read ( hashp->fp, &hashp->hdr, sizeof(HASHHDR) );
#if BYTE_ORDER == LITTLE_ENDIAN
swap_header ( );
#endif
if ( hdrsize == -1 ) {
RETURN_ERROR(errno, error1);
}
if ( hdrsize != sizeof(HASHHDR) ) {
RETURN_ERROR(EFTYPE, error1);
}
/* Verify file type, versions and hash function */
if ( hashp->MAGIC != HASHMAGIC )
RETURN_ERROR ( EFTYPE, error1 );
if ( hashp->VERSION != VERSION_NO )
RETURN_ERROR ( EFTYPE, error1 );
if (hashp->hash ( CHARKEY, sizeof(CHARKEY) ) != hashp->H_CHARKEY ) {
RETURN_ERROR ( EFTYPE, error1 );
}
/*
Figure out how many segments we need.
*/
nsegs = (hashp->MAX_BUCKET + hashp->SGSIZE -1)/ hashp->SGSIZE;
hashp->nsegs = 0;
if (alloc_segs( nsegs )) {
/*
If alloc_segs fails, table will have been destroyed
and errno will have been set.
*/
return( (DB *) NULL );
}
/* Read in bitmaps */
bpages = (hashp->SPARES[__log2(hashp->MAX_BUCKET)] +
(hashp->BSIZE << BYTE_SHIFT) - 1) >>
(hashp->BSHIFT + BYTE_SHIFT);
hashp->nmaps = bpages;
memset ( &hashp->mapp[0], 0, bpages * sizeof ( u_long *) );
}
/* Initialize Buffer Manager */
if ( info && info->cachesize ) {
__buf_init (info->cachesize);
} else {
__buf_init (DEF_BUFSIZE);
}
hashp->new_file = new_table;
hashp->save_file = file && (hashp->flags & (O_WRONLY|O_RDWR));
hashp->cbucket = -1;
if ( !(dbp = (DB *)malloc ( sizeof (DB) )) ) {
save_errno = errno;
hdestroy();
errno = save_errno;
return ( NULL );
}
dbp->internal = (char *)hashp;
dbp->close = hash_close;
dbp->del = hash_delete;
dbp->get = hash_get;
dbp->put = hash_put;
dbp->seq = hash_seq;
dbp->sync = hash_sync;
dbp->type = DB_HASH;
#ifdef DEBUG
(void)fprintf(stderr, "%s\n%s%x\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",
"init_htab:",
"TABLE POINTER ", hashp,
"BUCKET SIZE ", hashp->BSIZE,
"BUCKET SHIFT ", hashp->BSHIFT,
"DIRECTORY SIZE ", hashp->DSIZE,
"SEGMENT SIZE ", hashp->SGSIZE,
"SEGMENT SHIFT ", hashp->SSHIFT,
"FILL FACTOR ", hashp->FFACTOR,
"MAX BUCKET ", hashp->MAX_BUCKET,
"HIGH MASK ", hashp->HIGH_MASK,
"LOW MASK ", hashp->LOW_MASK,
"NSEGS ", hashp->nsegs,
"NKEYS ", hashp->NKEYS );
#endif
#ifdef HASH_STATISTICS
hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0;
#endif
return (dbp);
error2:
(void)hdestroy();
errno = save_errno;
return ( (DB *)NULL );
error1:
(void) close ( hashp->fp );
error0:
free ( hashp );
errno = save_errno;
return ( (DB *) NULL );
}
static int
hash_close (dbp)
DB *dbp;
{
int retval;
if ( !dbp ) {
return(ERROR);
}
hashp = (HTAB *)dbp->internal;
retval = hdestroy();
(void)free ( dbp );
return ( retval );
}
/************************** LOCAL CREATION ROUTINES **********************/
static HTAB *
init_hash( info )
HASHINFO *info;
{
int nelem;
nelem = 1;
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 = default_hash;
bzero (hashp->SPARES, sizeof (hashp->SPARES));
if ( info ) {
if ( info->bsize ) {
/* Round pagesize up to power of 2 */
hashp->BSHIFT = __log2(info->bsize);
hashp->BSIZE = 1 << hashp->BSHIFT;
if ( hashp->BSIZE > MAX_BSIZE ) {
errno = EINVAL;
return(0);
}
}
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(0);
}
hashp->LORDER = info->lorder;
}
}
/* init_htab should destroy the table and set errno if it fails */
if ( init_htab ( nelem ) ) {
return(0);
} else {
return(hashp);
}
}
/*
This calls alloc_segs which may run out of memory.
Alloc_segs will destroy the table and set errno,
so we just pass the error information along.
Returns 0 on No Error
*/
static int
init_htab ( nelem )
int nelem;
{
register SEGMENT *segp;
register int nbuckets;
register int 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 = __log2(nelem);
nbuckets = 1 << l2;
nbuckets = MAX ( nbuckets, 2 );
hashp->SPARES[l2] = l2 + 1;
hashp->SPARES[l2+1] = l2 + 1;
/*
First bitmap page is at:
splitpoint l2
page offset 1
*/
__init_bitmap ( OADDR_OF(l2,1), l2+1, 0 );
hashp->MAX_BUCKET = hashp->LOW_MASK = nbuckets - 1;
hashp->HIGH_MASK = (nbuckets << 1) - 1;
hashp->HDRPAGES = ((MAX(sizeof(HASHHDR),MINHDRSIZE) - 1) >>
hashp->BSHIFT) + 1;
nsegs = (nbuckets - 1) / hashp->SGSIZE + 1;
nsegs = 1 << __log2(nsegs);
if ( nsegs > hashp->DSIZE ) {
hashp->DSIZE = nsegs;
}
return (alloc_segs ( nsegs ) );
}
/********************** DESTROY/CLOSE ROUTINES ************************/
/*
Flushes any changes to the file if necessary and
destroys the hashp structure, freeing all allocated
space.
*/
static int
hdestroy()
{
int save_errno;
int i;
save_errno = 0;
if (hashp != NULL) {
#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 (__buf_free(1, hashp->save_file)) {
save_errno = errno;
}
if ( hashp->dir ) {
(void)free(*hashp->dir); /* Free initial segments */
/* Free extra segments */
while ( hashp->exsegs-- ) {
(void)free ( hashp->dir[--hashp->nsegs] );
}
(void)free(hashp->dir);
}
if (flush_meta() && !save_errno) {
save_errno = errno;
}
/* Free Bigmaps */
for ( i = 0; i < hashp->nmaps; i++ ) {
if ( hashp->mapp[i] ) {
(void) free ( hashp->mapp[i] );
}
}
if ( hashp->fp != -1 ) {
(void)close (hashp->fp);
}
(void)free(hashp);
hashp = NULL;
}
if ( save_errno ) {
errno = save_errno;
return(ERROR);
} else {
return(SUCCESS);
}
}
/*
Write modified pages to disk
0 == OK
-1 ERROR
*/
static int
hash_sync(dbp)
DB *dbp;
{
if ( !dbp ) {
return (ERROR);
}
hashp = (HTAB *)dbp->internal;
if (!hashp->save_file) return(0);
if ( __buf_free ( 0, 1 ) || flush_meta()) {
return(ERROR);
}
hashp->new_file = 0;
return(0);
}
/*
0 == OK
-1 indicates that errno should be set
*/
static int
flush_meta()
{
int fp;
int hdrsize;
int i;
int wsize;
HASHHDR *whdrp;
HASHHDR whdr;
if (!hashp->save_file) return(0);
hashp->MAGIC = HASHMAGIC;
hashp->VERSION = VERSION_NO;
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, 0, SEEK_SET) == -1 ) ||
((wsize = write ( fp, whdrp, sizeof(HASHHDR))) == -1)) {
return(-1);
} else if ( wsize != sizeof(HASHHDR) ) {
errno = EFTYPE;
hashp->errno = errno;
return(-1);
}
for ( i = 0; i < NCACHED; i++ ) {
if ( hashp->mapp[i] ) {
if (!__put_page((char *)hashp->mapp[i],
hashp->BITMAPS[i], 0, 1)){
return(-1);
}
}
}
return(0);
}
/*******************************SEARCH ROUTINES *****************************/
/*
All the access routines return
0 on SUCCESS
1 to indicate an external ERROR (i.e. key not found, etc)
-1 to indicate an internal ERROR (i.e. out of memory, etc)
*/
static int
hash_get ( dbp, key, data, flag )
DB *dbp;
DBT *key, *data;
u_int flag;
{
#ifdef lint
flag = flag;
#endif
if ( !dbp ) {
return (ERROR);
}
hashp = (HTAB *)dbp->internal;
if ( hashp->flags & O_WRONLY ) {
errno = EBADF;
hashp->errno = errno;
return ( ERROR );
}
return ( hash_access ( HASH_GET, key, data ) );
}
static int
hash_put ( dbp, key, data, flag )
DB *dbp;
DBT *key, *data;
u_int flag;
{
if ( !dbp ) {
return (ERROR);
}
hashp = (HTAB *)dbp->internal;
if ( (hashp->flags & O_ACCMODE) == O_RDONLY ) {
errno = EBADF;
hashp->errno = errno;
return ( ERROR );
}
if ( flag == R_NOOVERWRITE ) {
return ( hash_access ( HASH_PUTNEW, key, data ) );
} else {
return ( hash_access ( HASH_PUT, key, data ) );
}
}
static int
hash_delete ( dbp, key, flag )
DB *dbp;
DBT *key;
u_int flag; /* Ignored */
{
#ifdef lint
flag = flag;
#endif
if ( !dbp ) {
return (ERROR);
}
hashp = (HTAB *)dbp->internal;
if ( (hashp->flags & O_ACCMODE) == O_RDONLY ) {
errno = EBADF;
hashp->errno = errno;
return ( ERROR );
}
return ( hash_access ( HASH_DELETE, key, NULL ) );
}
/*
Assume that hashp has been set in wrapper routine
*/
static int
hash_access(action, key, val)
ACTION action;
DBT *key, *val;
{
register BUFHEAD *rbufp;
register u_short *bp;
register int ndx;
register int n;
register int off = hashp->BSIZE;
register int size;
register char *kp;
BUFHEAD *bufp;
BUFHEAD *save_bufp;
u_short pageno;
#ifdef HASH_STATISTICS
hash_accesses++;
#endif
size = key->size;
kp = (char *)key->data;
rbufp = __get_buf ( __call_hash(kp, size), NULL, 0 );
if ( !rbufp ) return(ERROR);
save_bufp = rbufp;
/* Pin the bucket chain */
rbufp->flags |= BUF_PIN;
for ( bp = (u_short *)rbufp->page, n = *bp++, ndx = 1; ndx < n; ) {
if ( bp[1] >= REAL_KEY ) {
/* Real key/data pair */
if (size == off - *bp &&
bcmp(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 ) {
rbufp = __get_buf ( *bp, rbufp, 0 );
if ( !rbufp ) {
save_bufp->flags &= ~BUF_PIN;
return (ERROR);
}
/* FOR LOOP INIT */
bp = (u_short *)rbufp->page;
n = *bp++;
ndx = 1;
off = hashp->BSIZE;
} else if ( bp[1] < REAL_KEY ) {
if ( (ndx = __find_bigpair(rbufp, ndx, kp, size )) > 0 ) {
goto found;
} else if ( ndx == -2 ) {
bufp = rbufp;
if ( !(pageno = __find_last_page ( &bufp )) ) {
ndx = 0;
rbufp = bufp;
break; /* FOR */
}
rbufp = __get_buf ( pageno, bufp, 0 );
if ( !rbufp ) {
save_bufp->flags &= ~BUF_PIN;
return (ERROR);
}
/* FOR LOOP INIT */
bp = (u_short *)rbufp->page;
n = *bp++;
ndx = 1;
off = hashp->BSIZE;
} else {
save_bufp->flags &= ~BUF_PIN;
return(ERROR);
}
}
}
/* Not found */
switch ( action ) {
case HASH_PUT:
case HASH_PUTNEW:
if (__addel(rbufp, key, val)) {
save_bufp->flags &= ~BUF_PIN;
return(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 = (u_short *)rbufp->page;
if (bp[ndx+1] < REAL_KEY) __big_return(rbufp, ndx, val, 0);
else {
val->data = (u_char *)rbufp->page + (int) bp[ndx + 1];
val->size = bp[ndx] - bp[ndx + 1];
}
break;
case HASH_PUT:
if ((__delpair (rbufp, ndx)) || (__addel (rbufp, key, val)) ) {
save_bufp->flags &= ~BUF_PIN;
return(ERROR);
}
break;
case HASH_DELETE:
if (__delpair (rbufp, ndx))return(ERROR);
break;
}
save_bufp->flags &= ~BUF_PIN;
return (SUCCESS);
}
static int
hash_seq(dbp, key, data, flag)
DB *dbp;
DBT *key, *data;
u_int flag;
{
register u_int bucket;
register BUFHEAD *bufp;
BUFHEAD *save_bufp;
u_short *bp;
u_short ndx;
u_short pageno;
if ( !dbp ) {
return (ERROR);
}
hashp = (HTAB *)dbp->internal;
if ( hashp->flags & O_WRONLY ) {
errno = EBADF;
hashp->errno = errno;
return ( ERROR );
}
#ifdef HASH_STATISTICS
hash_accesses++;
#endif
if ( (hashp->cbucket < 0) || (flag == R_FIRST) ) {
hashp->cbucket = 0;
hashp->cndx = 1;
hashp->cpage = NULL;
}
if ( !(bufp = hashp->cpage) ) {
for (bucket = hashp->cbucket;
bucket <= hashp->MAX_BUCKET;
bucket++, hashp->cndx = 1 ) {
bufp = __get_buf ( bucket, NULL, 0 );
if (!bufp) return(ERROR);
hashp->cpage = bufp;
bp = (u_short *)bufp->page;
if (bp[0]) break;
}
hashp->cbucket = bucket;
if ( hashp->cbucket > hashp->MAX_BUCKET ) {
hashp->cbucket = -1;
return ( ABNORMAL );
}
} else {
bp = (u_short *)hashp->cpage->page;
}
#ifdef DEBUG
assert (bp);
assert (bufp);
#endif
while ( bp[hashp->cndx+1] == OVFLPAGE ) {
bufp = hashp->cpage = __get_buf ( bp[hashp->cndx], bufp, 0 );
if (!bufp) return(ERROR);
bp = (u_short *)(bufp->page);
hashp->cndx = 1;
}
ndx = hashp->cndx;
if (bp[ndx+1] < REAL_KEY) {
if (__big_keydata(bufp, ndx, key, data, 1)) {
return(ERROR);
}
} else {
key->data = (u_char *)hashp->cpage->page + bp[ndx];
key->size = (ndx > 1 ? bp[ndx-1] : hashp->BSIZE) - bp[ndx];
data->data = (u_char *)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 ************************/
/*
0 ==> OK
-1 ==> Error
*/
extern int
__expand_table()
{
u_int old_bucket, new_bucket;
int new_segnum;
int dirsize;
int spare_ndx;
register char **old, **new;
#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 ( hashp->SGSIZE, sizeof(SEGMENT)))) {
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 = __log2(hashp->MAX_BUCKET);
if ( spare_ndx != (__log2(hashp->MAX_BUCKET - 1))) {
hashp->SPARES[spare_ndx] = hashp->SPARES[spare_ndx-1];
}
if ( new_bucket > 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(__split_page ( old_bucket, new_bucket ));
}
/*
If realloc guarantees that the pointer is not destroyed
if the realloc fails, then this routine can go away
*/
static char *
hash_realloc ( p_ptr, oldsize, newsize )
char **p_ptr;
int oldsize;
int newsize;
{
register char *p;
if (p = (char *)malloc ( newsize ) ) {
bcopy ( *p_ptr, p, oldsize );
bzero ( *p_ptr + oldsize, newsize-oldsize );
free(*p_ptr);
*p_ptr = p;
}
return (p);
}
extern u_int
__call_hash ( k, len )
char *k;
int len;
{
int n, bucket;
n = hashp->hash(k, len);
bucket = n & hashp->HIGH_MASK;
if ( bucket > hashp->MAX_BUCKET ) {
bucket = bucket & hashp->LOW_MASK;
}
return(bucket);
}
/*
Allocate segment table. On error, destroy the table
and set errno.
Returns 0 on success
*/
static int
alloc_segs ( nsegs )
int nsegs;
{
register int i;
register SEGMENT store;
int save_errno;
if (!(hashp->dir = (SEGMENT *)calloc(hashp->DSIZE, sizeof(SEGMENT *)))) {
save_errno = errno;
(void)hdestroy();
errno = save_errno;
return(-1);
}
/* Allocate segments */
store = (SEGMENT)calloc ( nsegs << hashp->SSHIFT, sizeof (SEGMENT) );
if ( !store ) {
save_errno = errno;
(void)hdestroy();
errno = save_errno;
return(-1);
}
for ( i=0; i < nsegs; i++, hashp->nsegs++ ) {
hashp->dir[i] = &store[i<<hashp->SSHIFT];
}
return(0);
}
/*
Hashp->hdr needs to be byteswapped.
*/
static void
swap_header_copy ( srcp, destp )
HASHHDR *srcp;
HASHHDR *destp;
{
int i;
BLSWAP_COPY(srcp->magic, destp->magic);
BLSWAP_COPY(srcp->version, destp->version);
BLSWAP_COPY(srcp->lorder, destp->lorder);
BLSWAP_COPY(srcp->bsize, destp->bsize);
BLSWAP_COPY(srcp->bshift, destp->bshift);
BLSWAP_COPY(srcp->dsize, destp->dsize);
BLSWAP_COPY(srcp->ssize, destp->ssize);
BLSWAP_COPY(srcp->sshift, destp->sshift);
BLSWAP_COPY(srcp->max_bucket, destp->max_bucket);
BLSWAP_COPY(srcp->high_mask, destp->high_mask);
BLSWAP_COPY(srcp->low_mask, destp->low_mask);
BLSWAP_COPY(srcp->ffactor, destp->ffactor);
BLSWAP_COPY(srcp->nkeys, destp->nkeys);
BLSWAP_COPY(srcp->hdrpages, destp->hdrpages);
BLSWAP_COPY(srcp->h_charkey, destp->h_charkey);
for ( i=0; i < NCACHED; i++ ) {
BLSWAP_COPY ( srcp->spares[i] , destp->spares[i]);
BSSWAP_COPY ( srcp->bitmaps[i] , destp->bitmaps[i]);
}
return;
}
static void
swap_header ( )
{
HASHHDR *hdrp;
int i;
hdrp = &hashp->hdr;
BLSWAP(hdrp->magic);
BLSWAP(hdrp->version);
BLSWAP(hdrp->lorder);
BLSWAP(hdrp->bsize);
BLSWAP(hdrp->bshift);
BLSWAP(hdrp->dsize);
BLSWAP(hdrp->ssize);
BLSWAP(hdrp->sshift);
BLSWAP(hdrp->max_bucket);
BLSWAP(hdrp->high_mask);
BLSWAP(hdrp->low_mask);
BLSWAP(hdrp->ffactor);
BLSWAP(hdrp->nkeys);
BLSWAP(hdrp->hdrpages);
BLSWAP(hdrp->h_charkey);
for ( i=0; i < NCACHED; i++ ) {
BLSWAP ( hdrp->spares[i] );
BSSWAP ( hdrp->bitmaps[i] );
}
return;
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.