* Copyright (c) 1990 The Regents of the University of California.
* This code is derived from software contributed to Berkeley by
* %sccs.include.redist.c%
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)hash.c 5.15 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
static int alloc_segs
__P((int));
static int flush_meta
__P((void));
static int hash_access
__P((ACTION
, DBT
*, DBT
*));
static int hash_close
__P((DB
*));
static int hash_delete
__P((const DB
*, const DBT
*, u_int
));
static int hash_get
__P((const DB
*, DBT
*, DBT
*, u_int
));
static int hash_put
__P((const DB
*, const DBT
*, const DBT
*, u_int
));
static void *hash_realloc
__P((SEGMENT
**, int, int));
static int hash_seq
__P((const DB
*, DBT
*, DBT
*, u_int
));
static int hash_sync
__P((const DB
*));
static int hdestroy
__P((void));
static HTAB
*init_hash
__P((HASHINFO
*));
static int init_htab
__P((int));
#if BYTE_ORDER == LITTLE_ENDIAN
static void swap_header
__P((void));
static void swap_header_copy
__P((HASHHDR
*, HASHHDR
*));
/* Fast arithmetic, relying on powers of 2, */
#define MOD(x, y) ((x) & ((y) - 1))
#define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; }
long hash_accesses
, hash_collisions
, hash_expansions
, hash_overflows
;
/************************** INTERFACE ROUTINES ***************************/
hash_open(file
, flags
, mode
, info
)
const HASHINFO
*info
; /* Special directives for create */
int bpages
, hdrsize
, new_table
, nsegs
, save_errno
;
if (!(hashp
= calloc(1, sizeof(HTAB
))))
* 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
flags
& (O_CREAT
| O_EXCL
| O_RDONLY
| O_RDWR
| O_TRUNC
| O_WRONLY
);
flags
= (flags
& ~O_WRONLY
) | O_RDWR
;
if (!file
|| (flags
& O_TRUNC
) ||
(stat(file
, &statbuf
) && (errno
== ENOENT
))) {
errno
= 0; /* Just in case someone looks at errno */
if ((hashp
->fp
= open(file
, flags
, mode
)) == -1)
RETURN_ERROR(errno
, error0
);
(void)fcntl(hashp
->fp
, F_SETFD
, 1);
if (!(hashp
= init_hash((HASHINFO
*)info
)))
RETURN_ERROR(errno
, error1
);
/* Table already exists */
hashp
->hash
= info
->hash
;
hashp
->hash
= default_hash
;
hdrsize
= read(hashp
->fp
, &hashp
->hdr
, sizeof(HASHHDR
));
#if BYTE_ORDER == LITTLE_ENDIAN
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.
Max_Bucket it the maximum bucket number, so the
number of buckets is max_bucket+1.
nsegs
= (hashp
->MAX_BUCKET
+ 1 + hashp
->SGSIZE
- 1) /
* If alloc_segs fails, table will have been destroyed
* and errno will have been set.
bpages
= (hashp
->SPARES
[__log2(hashp
->MAX_BUCKET
)] +
(hashp
->BSIZE
<< BYTE_SHIFT
) - 1) >>
(hashp
->BSHIFT
+ BYTE_SHIFT
);
memset(&hashp
->mapp
[0], 0, bpages
* sizeof(u_long
*));
/* Initialize Buffer Manager */
if (info
&& info
->cachesize
)
__buf_init(info
->cachesize
);
hashp
->new_file
= new_table
;
hashp
->save_file
= file
&& (hashp
->flags
& (O_WRONLY
| O_RDWR
));
if (!(dbp
= malloc(sizeof(DB
)))) {
dbp
->internal
= (char *)hashp
;
"%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",
"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
,
hash_overflows
= hash_accesses
= hash_collisions
= hash_expansions
= 0;
hashp
= (HTAB
*)dbp
->internal
;
/************************** LOCAL CREATION ROUTINES **********************/
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
));
/* Round pagesize up to power of 2 */
hashp
->BSHIFT
= __log2(info
->bsize
);
hashp
->BSIZE
= 1 << hashp
->BSHIFT
;
if (hashp
->BSIZE
> MAX_BSIZE
) {
hashp
->FFACTOR
= info
->ffactor
;
hashp
->hash
= info
->hash
;
if (info
->lorder
!= BIG_ENDIAN
&&
info
->lorder
!= LITTLE_ENDIAN
) {
hashp
->LORDER
= info
->lorder
;
/* init_htab should destroy the table and set errno if it fails */
* 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.
register int nbuckets
, nsegs
;
* 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;
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) >>
nsegs
= (nbuckets
- 1) / hashp
->SGSIZE
+ 1;
nsegs
= 1 << __log2(nsegs
);
if (nsegs
> hashp
->DSIZE
)
return (alloc_segs(nsegs
));
/********************** DESTROY/CLOSE ROUTINES ************************/
* Flushes any changes to the file if necessary and destroys the hashp
* structure, freeing all allocated space.
(void)fprintf(stderr
, "hdestroy: accesses %ld collisions %ld\n",
hash_accesses
, hash_collisions
);
(void)fprintf(stderr
, "hdestroy: expansions %ld\n",
(void)fprintf(stderr
, "hdestroy: overflows %ld\n",
(void)fprintf(stderr
, "keys %ld maxp %d segmentcount %d\n",
hashp
->NKEYS
, hashp
->MAX_BUCKET
, hashp
->nsegs
);
for (i
= 0; i
< NCACHED
; i
++)
"spares[%d] = %d\n", i
, hashp
->SPARES
[i
]);
* Call on buffer manager to free buffers, and if required,
if (__buf_free(1, hashp
->save_file
))
free(*hashp
->dir
); /* Free initial segments */
/* Free extra segments */
free(hashp
->dir
[--hashp
->nsegs
]);
if (flush_meta() && !save_errno
)
for (i
= 0; i
< hashp
->nmaps
; i
++)
* Write modified pages to disk
hashp
= (HTAB
*)dbp
->internal
;
if (__buf_free(0, 1) || flush_meta())
* -1 indicates that errno should be set
hashp
->MAGIC
= HASHMAGIC
;
hashp
->VERSION
= VERSION_NO
;
hashp
->H_CHARKEY
= hashp
->hash(CHARKEY
, sizeof(CHARKEY
));
#if BYTE_ORDER == LITTLE_ENDIAN
swap_header_copy(&hashp
->hdr
, whdrp
);
if ((lseek(fp
, 0, SEEK_SET
) == -1) ||
((wsize
= write(fp
, whdrp
, sizeof(HASHHDR
))) == -1))
if (wsize
!= sizeof(HASHHDR
)) {
for (i
= 0; i
< NCACHED
; i
++)
if (!__put_page((char *)hashp
->mapp
[i
],
hashp
->BITMAPS
[i
], 0, 1))
/*******************************SEARCH ROUTINES *****************************/
* All the access routines return
* 1 to indicate an external ERROR (i.e. key not found, etc)
* -1 to indicate an internal ERROR (i.e. out of memory, etc)
hash_get(dbp
, key
, data
, flag
)
hashp
->errno
= errno
= EINVAL
;
hashp
= (HTAB
*)dbp
->internal
;
if (hashp
->flags
& O_WRONLY
) {
hashp
->errno
= errno
= EPERM
;
return (hash_access(HASH_GET
, key
, data
));
hash_put(dbp
, key
, data
, flag
)
if (flag
&& flag
!= R_NOOVERWRITE
) {
hashp
->errno
= errno
= EINVAL
;
hashp
= (HTAB
*)dbp
->internal
;
if ((hashp
->flags
& O_ACCMODE
) == O_RDONLY
) {
hashp
->errno
= errno
= EPERM
;
return (hash_access(flag
== R_NOOVERWRITE
?
HASH_PUTNEW
: HASH_PUT
, (DBT
*)key
, (DBT
*)data
));
hash_delete(dbp
, key
, flag
)
u_int flag
; /* Ignored */
if (flag
&& flag
!= R_CURSOR
) {
hashp
->errno
= errno
= EINVAL
;
hashp
= (HTAB
*)dbp
->internal
;
if ((hashp
->flags
& O_ACCMODE
) == O_RDONLY
) {
hashp
->errno
= errno
= EPERM
;
return (hash_access(HASH_DELETE
, (DBT
*)key
, NULL
));
* Assume that hashp has been set in wrapper routine.
hash_access(action
, key
, val
)
BUFHEAD
*bufp
, *save_bufp
;
register int n
, ndx
, off
, size
;
rbufp
= __get_buf(__call_hash(kp
, size
), NULL
, 0);
/* Pin the bucket chain */
for (bp
= (u_short
*)rbufp
->page
, n
= *bp
++, ndx
= 1; ndx
< n
;)
bcmp(kp
, rbufp
->page
+ *bp
, size
) == 0)
} else if (bp
[1] == OVFLPAGE
) {
rbufp
= __get_buf(*bp
, rbufp
, 0);
save_bufp
->flags
&= ~BUF_PIN
;
bp
= (u_short
*)rbufp
->page
;
} else if (bp
[1] < REAL_KEY
) {
if ((ndx
= __find_bigpair(rbufp
, ndx
, kp
, size
)) > 0)
if (!(pageno
= __find_last_page(&bufp
))) {
rbufp
= __get_buf(pageno
, bufp
, 0);
save_bufp
->flags
&= ~BUF_PIN
;
bp
= (u_short
*)rbufp
->page
;
save_bufp
->flags
&= ~BUF_PIN
;
if (__addel(rbufp
, key
, val
)) {
save_bufp
->flags
&= ~BUF_PIN
;
save_bufp
->flags
&= ~BUF_PIN
;
save_bufp
->flags
&= ~BUF_PIN
;
save_bufp
->flags
&= ~BUF_PIN
;
bp
= (u_short
*)rbufp
->page
;
if (bp
[ndx
+ 1] < REAL_KEY
)
__big_return(rbufp
, ndx
, val
, 0);
val
->data
= (u_char
*)rbufp
->page
+ (int)bp
[ndx
+ 1];
val
->size
= bp
[ndx
] - bp
[ndx
+ 1];
if ((__delpair(rbufp
, ndx
)) || (__addel(rbufp
, key
, val
))) {
save_bufp
->flags
&= ~BUF_PIN
;
if (__delpair(rbufp
, ndx
))
save_bufp
->flags
&= ~BUF_PIN
;
hash_seq(dbp
, key
, data
, flag
)
if (flag
&& flag
!= R_FIRST
&& flag
!= R_NEXT
) {
hashp
->errno
= errno
= EINVAL
;
hashp
= (HTAB
*)dbp
->internal
;
if (hashp
->flags
& O_WRONLY
) {
hashp
->errno
= errno
= EPERM
;
if ((hashp
->cbucket
< 0) || (flag
== R_FIRST
)) {
if (!(bufp
= hashp
->cpage
)) {
for (bucket
= hashp
->cbucket
; bucket
<= hashp
->MAX_BUCKET
;
bucket
++, hashp
->cndx
= 1) {
bufp
= __get_buf(bucket
, NULL
, 0);
bp
= (u_short
*)bufp
->page
;
if (hashp
->cbucket
> hashp
->MAX_BUCKET
) {
bp
= (u_short
*)hashp
->cpage
->page
;
while (bp
[hashp
->cndx
+ 1] == OVFLPAGE
) {
bufp
= hashp
->cpage
= __get_buf(bp
[hashp
->cndx
], bufp
, 0);
bp
= (u_short
*)(bufp
->page
);
if (bp
[ndx
+ 1] < REAL_KEY
) {
if (__big_keydata(bufp
, ndx
, key
, data
, 1))
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];
/********************************* UTILITIES ************************/
u_int old_bucket
, new_bucket
;
int dirsize
, new_segnum
, spare_ndx
;
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))
hashp
->DSIZE
= dirsize
<< 1;
if (!(hashp
->dir
[new_segnum
] =
calloc(hashp
->SGSIZE
, sizeof(SEGMENT
))))
* 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.
hash_realloc(p_ptr
, oldsize
, newsize
)
if (p
= malloc(newsize
)) {
bcopy(*p_ptr
, p
, oldsize
);
bzero(*p_ptr
+ oldsize
, newsize
- oldsize
);
bucket
= n
& hashp
->HIGH_MASK
;
if (bucket
> hashp
->MAX_BUCKET
)
bucket
= bucket
& hashp
->LOW_MASK
;
* Allocate segment table. On error, destroy the table and set errno.
if (!(hashp
->dir
= calloc(hashp
->DSIZE
, sizeof(SEGMENT
*)))) {
store
= calloc(nsegs
<< hashp
->SSHIFT
, sizeof(SEGMENT
));
for (i
= 0; i
< nsegs
; i
++, hashp
->nsegs
++)
hashp
->dir
[i
] = &store
[i
<< hashp
->SSHIFT
];
#if BYTE_ORDER == LITTLE_ENDIAN
* Hashp->hdr needs to be byteswapped.
swap_header_copy(srcp
, destp
)
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
]);
BLSWAP(hdrp
->max_bucket
);
for (i
= 0; i
< NCACHED
; i
++) {
BSSWAP(hdrp
->bitmaps
[i
]);