* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* This code is derived from software contributed to Berkeley by
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 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
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)hash_bigkey.c 8.2 (Berkeley) 2/21/94";
#endif /* LIBC_SCCS and not lint */
* Big key/data handling for the hashing package.
static int collect_key
__P((HTAB
*, BUFHEAD
*, int, DBT
*, int));
static int collect_data
__P((HTAB
*, BUFHEAD
*, int, int));
* You need to do an insert and the key/data pair is too big
__big_insert(hashp
, bufp
, key
, val
)
int key_size
, n
, val_size
;
u_short space
, move_bytes
, off
;
char *cp
, *key_data
, *val_data
;
cp
= bufp
->page
; /* Character pointer of p. */
key_data
= (char *)key
->data
;
val_data
= (char *)val
->data
;
for (space
= FREESPACE(p
) - BIGOVERHEAD
; key_size
;
space
= FREESPACE(p
) - BIGOVERHEAD
) {
move_bytes
= MIN(space
, key_size
);
off
= OFFSET(p
) - move_bytes
;
memmove(cp
+ off
, key_data
, move_bytes
);
FREESPACE(p
) = off
- PAGE_META(n
);
bufp
= __add_ovflpage(hashp
, bufp
);
move_bytes
= MIN(FREESPACE(p
), val_size
);
off
= OFFSET(p
) - move_bytes
;
memmove(cp
+ off
, val_data
, move_bytes
);
p
[n
- 2] = FULL_KEY_DATA
;
FREESPACE(p
) = FREESPACE(p
) - move_bytes
;
p
= (u_short
*)bufp
->page
;
for (space
= FREESPACE(p
) - BIGOVERHEAD
; val_size
;
space
= FREESPACE(p
) - BIGOVERHEAD
) {
move_bytes
= MIN(space
, val_size
);
* Here's the hack to make sure that if the data ends on the
* same page as the key ends, FREESPACE is at least one.
if (space
== val_size
&& val_size
== val
->size
)
off
= OFFSET(p
) - move_bytes
;
memmove(cp
+ off
, val_data
, move_bytes
);
FREESPACE(p
) = off
- PAGE_META(n
);
bufp
= __add_ovflpage(hashp
, bufp
);
* Called when bufp's page contains a partial key (index should be 1)
* All pages in the big key/data pair except bufp are freed. We cannot
* free bufp because the page pointing to it is lost and we can't get rid
__big_delete(hashp
, bufp
)
register BUFHEAD
*last_bfp
, *rbufp
;
bp
= (u_short
*)bufp
->page
;
while (!key_done
|| (bp
[2] != FULL_KEY_DATA
)) {
if (bp
[2] == FULL_KEY
|| bp
[2] == FULL_KEY_DATA
)
* If there is freespace left on a FULL_KEY_DATA page, then
* the data is short and fits entirely on this page, and this
if (bp
[2] == FULL_KEY_DATA
&& FREESPACE(bp
))
rbufp
= __get_buf(hashp
, pageno
, rbufp
, 0);
__free_ovflpage(hashp
, last_bfp
);
return (-1); /* Error. */
bp
= (u_short
*)rbufp
->page
;
* If we get here then rbufp points to the last page of the big
* key/data pair. Bufp points to the first one -- it should now be
* empty pointing to the next page after this pair. Can't free it
* because we don't have the page pointing to it.
/* This is information from the last page of the pair. */
/* Now, bp is the first page of the pair. */
bp
= (u_short
*)bufp
->page
;
/* There is an overflow page. */
bufp
->ovfl
= rbufp
->ovfl
;
/* This is the last page. */
FREESPACE(bp
) = hashp
->BSIZE
- PAGE_META(n
);
OFFSET(bp
) = hashp
->BSIZE
- 1;
__free_ovflpage(hashp
, rbufp
);
__free_ovflpage(hashp
, last_bfp
);
* -1 = get next overflow page
* -2 means key not found and this is big key/data
__find_bigpair(hashp
, bufp
, ndx
, key
, size
)
bp
= (u_short
*)bufp
->page
;
for (bytes
= hashp
->BSIZE
- bp
[ndx
];
bytes
<= size
&& bp
[ndx
+ 1] == PARTIAL_KEY
;
bytes
= hashp
->BSIZE
- bp
[ndx
]) {
if (memcmp(p
+ bp
[ndx
], kkey
, bytes
))
bufp
= __get_buf(hashp
, bp
[ndx
+ 2], bufp
, 0);
if (bytes
!= ksize
|| memcmp(p
+ bp
[ndx
], kkey
, bytes
)) {
* Given the buffer pointer of the first overflow page of a big pair,
* find the end of the big pair
* This will set bpp to the buffer header of the last page of the big pair.
* It will return the pageno of the overflow page following the last page
* of the pair; 0 if there isn't any (i.e. big pair is the last key in the
__find_last_page(hashp
, bpp
)
bp
= (u_short
*)bufp
->page
;
* This is the last page if: the tag is FULL_KEY_DATA and
* either only 2 entries OVFLPAGE marker is explicit there
* is freespace on the page.
if (bp
[2] == FULL_KEY_DATA
&&
((n
== 2) || (bp
[n
] == OVFLPAGE
) || (FREESPACE(bp
))))
bufp
= __get_buf(hashp
, pageno
, bufp
, 0);
return (0); /* Need to indicate an error! */
bp
= (u_short
*)bufp
->page
;
* Return the data for the key/data pair that begins on this page at this
* index (index should always be 1).
__big_return(hashp
, bufp
, ndx
, val
, set_current
)
u_short
*bp
, len
, off
, save_addr
;
bp
= (u_short
*)bufp
->page
;
while (bp
[ndx
+ 1] == PARTIAL_KEY
) {
bufp
= __get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
bp
= (u_short
*)bufp
->page
;
if (bp
[ndx
+ 1] == FULL_KEY
) {
bufp
= __get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
bp
= (u_short
*)bufp
->page
;
save_addr
= save_p
->addr
;
* This is a hack. We can't distinguish between
* FULL_KEY_DATA that contains complete data or
* incomplete data, so we require that if the data
* is complete, there is at least 1 byte of free
bufp
= __get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
bp
= (u_short
*)bufp
->page
;
/* The data is all on one page. */
val
->data
= (u_char
*)tp
+ off
;
if (bp
[0] == 2) { /* No more buckets in
hashp
->cpage
= __get_buf(hashp
,
hashp
->cpage
->page
)[0]) {
val
->size
= collect_data(hashp
, bufp
, (int)len
, set_current
);
if (save_p
->addr
!= save_addr
) {
/* We are pretty short on buffers. */
errno
= EINVAL
; /* OUT OF BUFFERS */
memmove(hashp
->tmp_buf
, (save_p
->page
) + off
, len
);
val
->data
= (u_char
*)hashp
->tmp_buf
;
* Count how big the total datasize is by recursing through the pages. Then
* allocate a buffer and copy the data as you recurse up.
collect_data(hashp
, bufp
, len
, set
)
mylen
= hashp
->BSIZE
- bp
[1];
if (bp
[2] == FULL_KEY_DATA
) { /* End of Data */
if ((hashp
->tmp_buf
= (char *)malloc(totlen
)) == NULL
)
if (bp
[0] == 2) { /* No more buckets in chain */
__get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
else if (!((u_short
*)hashp
->cpage
->page
)[0]) {
xbp
= __get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
collect_data(hashp
, xbp
, len
+ mylen
, set
)) < 1))
if (bufp
->addr
!= save_addr
) {
errno
= EINVAL
; /* Out of buffers. */
memmove(&hashp
->tmp_buf
[len
], (bufp
->page
) + bp
[1], mylen
);
* Fill in the key and data for this big pair.
__big_keydata(hashp
, bufp
, key
, val
, set
)
key
->size
= collect_key(hashp
, bufp
, 0, val
, set
);
key
->data
= (u_char
*)hashp
->tmp_key
;
* Count how big the total key size is by recursing through the pages. Then
* collect the data, allocate a buffer and copy the key as you recurse up.
collect_key(hashp
, bufp
, len
, val
, set
)
mylen
= hashp
->BSIZE
- bp
[1];
if (bp
[2] == FULL_KEY
|| bp
[2] == FULL_KEY_DATA
) { /* End of Key. */
if (hashp
->tmp_key
!= NULL
)
if ((hashp
->tmp_key
= (char *)malloc(totlen
)) == NULL
)
if (__big_return(hashp
, bufp
, 1, val
, set
))
xbp
= __get_buf(hashp
, bp
[bp
[0] - 1], bufp
, 0);
collect_key(hashp
, xbp
, totlen
, val
, set
)) < 1))
if (bufp
->addr
!= save_addr
) {
errno
= EINVAL
; /* MIS -- OUT OF BUFFERS */
memmove(&hashp
->tmp_key
[len
], (bufp
->page
) + bp
[1], mylen
);
__big_split(hashp
, op
, np
, big_keyp
, addr
, obucket
, ret
)
BUFHEAD
*op
; /* Pointer to where to put keys that go in old bucket */
BUFHEAD
*np
; /* Pointer to new bucket page */
/* Pointer to first page containing the big key/data */
int addr
; /* Address of big_keyp */
u_int obucket
;/* Old Bucket */
u_short free_space
, n
, off
;
/* Now figure out where the big key/data goes */
if (__big_keydata(hashp
, big_keyp
, &key
, &val
, 0))
change
= (__call_hash(hashp
, key
.data
, key
.size
) != obucket
);
if (ret
->next_addr
= __find_last_page(hashp
, &big_keyp
)) {
__get_buf(hashp
, ret
->next_addr
, big_keyp
, 0)))
/* Now make one of np/op point to the big key/data pair */
assert(np
->ovfl
== NULL
);
"BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp
->addr
,
(tmpp
->ovfl
? tmpp
->ovfl
->addr
: 0), (bp
? bp
->addr
: 0));
tmpp
->ovfl
= bp
; /* one of op/np point to big_keyp */
tp
= (u_short
*)tmpp
->page
;
assert(FREESPACE(tp
) >= OVFLSIZE
);
free_space
= FREESPACE(tp
);
FREESPACE(tp
) = free_space
- OVFLSIZE
;
* Finally, set the new and old return values. BIG_KEYP contains a
* pointer to the last page of the big key_data pair. Make sure that
* big_keyp has no following page (2 elements) or create an empty
tp
= (u_short
*)big_keyp
->page
;
big_keyp
->flags
|= BUF_MOD
;
* There may be either one or two offsets on this page. If
* there is one, then the overflow page is linked on normally
* and tp[4] is OVFLPAGE. If there are two, tp[4] contains
* the second offset and needs to get stuffed in after the
* next overflow page is added.
free_space
= FREESPACE(tp
);
FREESPACE(tp
) = free_space
+ OVFLSIZE
;
tmpp
= __add_ovflpage(hashp
, big_keyp
);