/*
* Called when we encounter an overflow or big key/data page during split
* handling. This is special cased since we have to begin checking whether
* the key/data pairs fit on their respective pages and because we may need
* overflow pages for both the old and new pages.
*
* The first page might be a page with regular key/data pairs in which case
* we have a regular overflow condition and just need to go on to the next
* page or it might be a big key/data pair in which case we need to fix the
* big key/data pair.
*
* Returns:
* 0 ==> success
* -1 ==> failure
*/
static int
ugly_split(
HTAB *hashp,
uint32_t obucket, /* Same as __split_page. */
BUFHEAD *old_bufp,
BUFHEAD *new_bufp,
int copyto, /* First byte on page which contains key/data values. */
int moved /* Number of pairs moved to new page. */
)
{
BUFHEAD *bufp; /* Buffer header for ino */
uint16_t *ino; /* Page keys come off of */
uint16_t *np; /* New page */
uint16_t *op; /* Page keys go on to if they aren't moving */
size_t temp;
BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */
DBT key, val;
SPLIT_RETURN ret;
uint16_t n, off, ov_addr, scopyto;
char *cino; /* Character value of ino */
bufp = old_bufp;
ino = (uint16_t *)(void *)old_bufp->page;
np = (uint16_t *)(void *)new_bufp->page;
op = (uint16_t *)(void *)old_bufp->page;
last_bfp = NULL;
scopyto = (uint16_t)copyto; /* ANSI */
n = ino[0] - 1;
while (n < ino[0]) {
if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
if (__big_split(hashp, old_bufp,
new_bufp, bufp, (int)bufp->addr, obucket, &ret))
return (-1);
old_bufp = ret.oldp;
if (!old_bufp)
return (-1);
op = (uint16_t *)(void *)old_bufp->page;
new_bufp = ret.newp;
if (!new_bufp)
return (-1);
np = (uint16_t *)(void *)new_bufp->page;
bufp = ret.nextp;
if (!bufp)
return (0);
cino = (char *)bufp->page;
ino = (uint16_t *)(void *)cino;
last_bfp = ret.nextp;
} else if (ino[n + 1] == OVFLPAGE) {
ov_addr = ino[n];
/*
* Fix up the old page -- the extra 2 are the fields
* which contained the overflow information.
*/
ino[0] -= (moved + 2);
temp = sizeof(uint16_t) * (ino[0] + 3);
_DIAGASSERT(scopyto >= temp);
FREESPACE(ino) = (uint16_t)(scopyto - temp);
OFFSET(ino) = scopyto;
bufp = __get_buf(hashp, (uint32_t)ov_addr, bufp, 0);
if (!bufp)
return (-1);
ino = (uint16_t *)(void *)bufp->page;
n = 1;
scopyto = hashp->BSIZE;
moved = 0;
if (last_bfp)
__free_ovflpage(hashp, last_bfp);
last_bfp = bufp;
}
/* Move regular sized pairs of there are any */
off = hashp->BSIZE;
for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
cino = (char *)(void *)ino;
key.data = (uint8_t *)cino + ino[n];
key.size = off - ino[n];
val.data = (uint8_t *)cino + ino[n + 1];
val.size = ino[n] - ino[n + 1];
off = ino[n + 1];
if (__call_hash(hashp, key.data, (int)key.size) == obucket) {
/* Keep on old page */
if (PAIRFITS(op, (&key), (&val)))
putpair((char *)(void *)op, &key, &val);
else {
old_bufp =
__add_ovflpage(hashp, old_bufp);
if (!old_bufp)
return (-1);
op = (uint16_t *)(void *)old_bufp->page;
putpair((char *)(void *)op, &key, &val);
}
old_bufp->flags |= BUF_MOD;
} else {
/* Move to new page */
if (PAIRFITS(np, (&key), (&val)))
putpair((char *)(void *)np, &key, &val);
else {
new_bufp =
__add_ovflpage(hashp, new_bufp);
if (!new_bufp)
return (-1);
np = (uint16_t *)(void *)new_bufp->page;
putpair((char *)(void *)np, &key, &val);
}
new_bufp->flags |= BUF_MOD;
}
}
}
if (last_bfp)
__free_ovflpage(hashp, last_bfp);
return (0);
}
/*
* Assume that hashp has been set in wrapper routine.
*/
static int
hash_access(HTAB *hashp, ACTION action, DBT *key, DBT *val)
{
BUFHEAD *rbufp;
BUFHEAD *bufp, *save_bufp;
u_int16_t *bp;
int n, ndx, off, size;
char *kp;
u_int16_t pageno;
#ifdef HASH_STATISTICS
hash_accesses++;
#endif
off = hashp->BSIZE;
size = key->size;
kp = (char *)key->data;
rbufp = __get_buf(hashp, __call_hash(hashp, kp, size), NULL, 0);
if (!rbufp)
return (ERROR);
save_bufp = rbufp;
/* Pin the bucket chain */
rbufp->flags |= BUF_PIN;
for (bp = (u_int16_t *)rbufp->page, n = *bp++, ndx = 1; ndx < n;)
if (bp[1] >= REAL_KEY) {
/* Real key/data pair */
if (size == 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) {
rbufp = __get_buf(hashp, *bp, rbufp, 0);
if (!rbufp) {
save_bufp->flags &= ~BUF_PIN;
return (ERROR);
}
/* FOR LOOP INIT */
bp = (u_int16_t *)rbufp->page;
n = *bp++;
ndx = 1;
off = hashp->BSIZE;
} else if (bp[1] < REAL_KEY) {
if ((ndx =
__find_bigpair(hashp, rbufp, ndx, kp, size)) > 0)
goto found;
if (ndx == -2) {
bufp = rbufp;
if (!(pageno =
__find_last_page(hashp, &bufp))) {
ndx = 0;
rbufp = bufp;
break; /* FOR */
}
rbufp = __get_buf(hashp, pageno, bufp, 0);
if (!rbufp) {
save_bufp->flags &= ~BUF_PIN;
return (ERROR);
}
/* FOR LOOP INIT */
bp = (u_int16_t *)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(hashp, 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_int16_t *)rbufp->page;
if (bp[ndx + 1] < REAL_KEY) {
if (__big_return(hashp, rbufp, ndx, val, 0))
return (ERROR);
} else {
val->data = (u_char *)rbufp->page + (int)bp[ndx + 1];
val->size = bp[ndx] - bp[ndx + 1];
}
break;
case HASH_PUT:
if ((__delpair(hashp, rbufp, ndx)) ||
(__addel(hashp, rbufp, key, val))) {
save_bufp->flags &= ~BUF_PIN;
return (ERROR);
}
break;
case HASH_DELETE:
if (__delpair(hashp, rbufp, ndx))
return (ERROR);
break;
default:
abort();
}
save_bufp->flags &= ~BUF_PIN;
return (SUCCESS);
}
/*
* Returns:
* 0 ==> OK
* -1 ==> Error
*/
int
__split_page(HTAB *hashp, uint32_t obucket, uint32_t nbucket)
{
BUFHEAD *new_bufp, *old_bufp;
uint16_t *ino;
char *np;
DBT key, val;
int n, ndx, retval;
uint16_t copyto, diff, off, moved;
char *op;
size_t temp;
copyto = (uint16_t)hashp->BSIZE;
off = (uint16_t)hashp->BSIZE;
old_bufp = __get_buf(hashp, obucket, NULL, 0);
if (old_bufp == NULL)
return (-1);
new_bufp = __get_buf(hashp, nbucket, NULL, 0);
if (new_bufp == NULL)
return (-1);
old_bufp->flags |= (BUF_MOD | BUF_PIN);
new_bufp->flags |= (BUF_MOD | BUF_PIN);
ino = (uint16_t *)(void *)(op = old_bufp->page);
np = new_bufp->page;
moved = 0;
for (n = 1, ndx = 1; n < ino[0]; n += 2) {
if (ino[n + 1] < REAL_KEY) {
retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
(int)copyto, (int)moved);
old_bufp->flags &= ~BUF_PIN;
new_bufp->flags &= ~BUF_PIN;
return (retval);
}
key.data = (uint8_t *)op + ino[n];
key.size = off - ino[n];
if (__call_hash(hashp, key.data, (int)key.size) == obucket) {
/* Don't switch page */
diff = copyto - off;
if (diff) {
copyto = ino[n + 1] + diff;
memmove(op + copyto, op + ino[n + 1],
(size_t)(off - ino[n + 1]));
ino[ndx] = copyto + ino[n] - ino[n + 1];
ino[ndx + 1] = copyto;
} else
copyto = ino[n + 1];
ndx += 2;
} else {
/* Switch page */
val.data = (uint8_t *)op + ino[n + 1];
val.size = ino[n] - ino[n + 1];
putpair(np, &key, &val);
moved += 2;
}
off = ino[n + 1];
}
/* Now clean up the page */
ino[0] -= moved;
temp = sizeof(uint16_t) * (ino[0] + 3);
_DIAGASSERT(copyto >= temp);
FREESPACE(ino) = (uint16_t)(copyto - temp);
OFFSET(ino) = copyto;
#ifdef DEBUG3
(void)fprintf(stderr, "split %d/%d\n",
((uint16_t *)np)[0] / 2,
((uint16_t *)op)[0] / 2);
#endif
/* unpin both pages */
old_bufp->flags &= ~BUF_PIN;
new_bufp->flags &= ~BUF_PIN;
return (0);
}
/*
* Returns:
* 0 => OK
* -1 => error
*/
int
__big_split(
HTAB *hashp,
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 */
BUFHEAD *big_keyp,
int addr, /* Address of big_keyp */
uint32_t obucket,/* Old Bucket */
SPLIT_RETURN *ret
)
{
BUFHEAD *tmpp;
uint16_t *tp;
BUFHEAD *bp;
DBT key, val;
uint32_t change;
uint16_t free_space, n, off;
size_t temp;
bp = big_keyp;
/* Now figure out where the big key/data goes */
if (__big_keydata(hashp, big_keyp, &key, &val, 0))
return (-1);
change = (__call_hash(hashp, key.data, (int)key.size) != obucket);
if ((ret->next_addr = __find_last_page(hashp, &big_keyp)) != 0) {
if (!(ret->nextp =
__get_buf(hashp, (uint32_t)ret->next_addr, big_keyp, 0)))
return (-1);
} else
ret->nextp = NULL;
/* Now make one of np/op point to the big key/data pair */
_DIAGASSERT(np->ovfl == NULL);
if (change)
tmpp = np;
else
tmpp = op;
tmpp->flags |= BUF_MOD;
#ifdef DEBUG1
(void)fprintf(stderr,
"BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp->addr,
(tmpp->ovfl ? tmpp->ovfl->addr : 0), (bp ? bp->addr : 0));
#endif
tmpp->ovfl = bp; /* one of op/np point to big_keyp */
tp = (uint16_t *)(void *)tmpp->page;
_DIAGASSERT(FREESPACE(tp) >= OVFLSIZE);
n = tp[0];
off = OFFSET(tp);
free_space = FREESPACE(tp);
tp[++n] = (uint16_t)addr;
tp[++n] = OVFLPAGE;
tp[0] = n;
OFFSET(tp) = off;
temp = free_space - OVFLSIZE;
_DBFIT(temp, uint16_t);
FREESPACE(tp) = (uint16_t)temp;
/*
* 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
* following page.
*/
ret->newp = np;
ret->oldp = op;
tp = (uint16_t *)(void *)big_keyp->page;
big_keyp->flags |= BUF_MOD;
if (tp[0] > 2) {
/*
* 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.
*/
n = tp[4];
free_space = FREESPACE(tp);
off = OFFSET(tp);
tp[0] -= 2;
temp = free_space + OVFLSIZE;
_DBFIT(temp, uint16_t);
FREESPACE(tp) = (uint16_t)temp;
OFFSET(tp) = off;
tmpp = __add_ovflpage(hashp, big_keyp);
if (!tmpp)
return (-1);
tp[4] = n;
} else
tmpp = big_keyp;
if (change)
ret->newp = tmpp;
else
ret->oldp = tmpp;
return (0);
}
/*
* 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 = __get_buf(hashp, __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 = __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 =
__find_bigpair(hashp, rbufp, ndx, kp, (int)size)) > 0)
goto found;
if (ndx == -2) {
bufp = rbufp;
if (!(pageno =
__find_last_page(hashp, &bufp))) {
ndx = 0;
rbufp = bufp;
break; /* FOR */
}
rbufp = __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 (__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 (__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 ((__delpair(hashp, rbufp, ndx)) ||
(__addel(hashp, rbufp, key, val))) {
save_bufp->flags &= ~BUF_PIN;
return (DBM_ERROR);
}
break;
case HASH_DELETE:
if (__delpair(hashp, rbufp, ndx))
return (DBM_ERROR);
break;
default:
abort();
}
save_bufp->flags &= ~BUF_PIN;
return (SUCCESS);
}
static int
ugly_split(HTAB *hashp, uint32 obucket, BUFHEAD *old_bufp,
BUFHEAD *new_bufp, /* Same as __split_page. */ int copyto, int moved)
/* int copyto; First byte on page which contains key/data values. */
/* int moved; Number of pairs moved to new page. */
{
register BUFHEAD *bufp; /* Buffer header for ino */
register uint16 *ino; /* Page keys come off of */
register uint16 *np; /* New page */
register uint16 *op; /* Page keys go on to if they aren't moving */
uint32 loop_detection = 0;
BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */
DBT key, val;
SPLIT_RETURN ret;
uint16 n, off, ov_addr, scopyto;
char *cino; /* Character value of ino */
int status;
bufp = old_bufp;
ino = (uint16 *)old_bufp->page;
np = (uint16 *)new_bufp->page;
op = (uint16 *)old_bufp->page;
last_bfp = NULL;
scopyto = (uint16)copyto; /* ANSI */
n = ino[0] - 1;
while (n < ino[0]) {
/* this function goes nuts sometimes and never returns.
* I havent found the problem yet but I need a solution
* so if we loop too often we assume a database curruption error
* :LJM
*/
loop_detection++;
if (loop_detection > MAX_UGLY_SPLIT_LOOPS)
return DATABASE_CORRUPTED_ERROR;
if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
if ((status = __big_split(hashp, old_bufp,
new_bufp, bufp, bufp->addr, obucket, &ret)))
return (status);
old_bufp = ret.oldp;
if (!old_bufp)
return (-1);
op = (uint16 *)old_bufp->page;
new_bufp = ret.newp;
if (!new_bufp)
return (-1);
np = (uint16 *)new_bufp->page;
bufp = ret.nextp;
if (!bufp)
return (0);
cino = (char *)bufp->page;
ino = (uint16 *)cino;
last_bfp = ret.nextp;
} else if (ino[n + 1] == OVFLPAGE) {
ov_addr = ino[n];
/*
* Fix up the old page -- the extra 2 are the fields
* which contained the overflow information.
*/
ino[0] -= (moved + 2);
FREESPACE(ino) =
scopyto - sizeof(uint16) * (ino[0] + 3);
OFFSET(ino) = scopyto;
bufp = __get_buf(hashp, ov_addr, bufp, 0);
if (!bufp)
return (-1);
ino = (uint16 *)bufp->page;
n = 1;
scopyto = hashp->BSIZE;
moved = 0;
if (last_bfp)
__free_ovflpage(hashp, last_bfp);
last_bfp = bufp;
}
/* Move regular sized pairs of there are any */
off = hashp->BSIZE;
for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
cino = (char *)ino;
key.data = (uint8 *)cino + ino[n];
key.size = off - ino[n];
val.data = (uint8 *)cino + ino[n + 1];
val.size = ino[n] - ino[n + 1];
off = ino[n + 1];
if (__call_hash(hashp, (char *)key.data, key.size) == obucket) {
/* Keep on old page */
if (PAIRFITS(op, (&key), (&val)))
putpair((char *)op, &key, &val);
else {
old_bufp =
__add_ovflpage(hashp, old_bufp);
if (!old_bufp)
return (-1);
op = (uint16 *)old_bufp->page;
putpair((char *)op, &key, &val);
}
old_bufp->flags |= BUF_MOD;
} else {
/* Move to new page */
if (PAIRFITS(np, (&key), (&val)))
putpair((char *)np, &key, &val);
else {
new_bufp =
__add_ovflpage(hashp, new_bufp);
if (!new_bufp)
return (-1);
np = (uint16 *)new_bufp->page;
putpair((char *)np, &key, &val);
}
new_bufp->flags |= BUF_MOD;
}
}
}
if (last_bfp)
__free_ovflpage(hashp, last_bfp);
return (0);
}
/*
* Returns:
* 0 ==> OK
* -1 ==> Error
*/
extern int
__split_page(HTAB *hashp, uint32 obucket, uint32 nbucket)
{
register BUFHEAD *new_bufp, *old_bufp;
register uint16 *ino;
register uint16 *tmp_uint16_array;
register char *np;
DBT key, val;
uint16 n, ndx;
int retval;
uint16 copyto, diff, moved;
size_t off;
char *op;
copyto = (uint16)hashp->BSIZE;
off = (uint16)hashp->BSIZE;
old_bufp = __get_buf(hashp, obucket, NULL, 0);
if (old_bufp == NULL)
return (-1);
new_bufp = __get_buf(hashp, nbucket, NULL, 0);
if (new_bufp == NULL)
return (-1);
old_bufp->flags |= (BUF_MOD | BUF_PIN);
new_bufp->flags |= (BUF_MOD | BUF_PIN);
ino = (uint16 *)(op = old_bufp->page);
np = new_bufp->page;
moved = 0;
for (n = 1, ndx = 1; n < ino[0]; n += 2) {
if (ino[n + 1] < REAL_KEY) {
retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
(int)copyto, (int)moved);
old_bufp->flags &= ~BUF_PIN;
new_bufp->flags &= ~BUF_PIN;
return (retval);
}
key.data = (uint8 *)op + ino[n];
/* check here for ino[n] being greater than
* off. If it is then the database has
* been corrupted.
*/
if (ino[n] > off)
return (DATABASE_CORRUPTED_ERROR);
key.size = off - ino[n];
#ifdef DEBUG
/* make sure the size is positive */
assert(((int)key.size) > -1);
#endif
if (__call_hash(hashp, (char *)key.data, key.size) == obucket) {
/* Don't switch page */
diff = copyto - off;
if (diff) {
copyto = ino[n + 1] + diff;
memmove(op + copyto, op + ino[n + 1],
off - ino[n + 1]);
ino[ndx] = copyto + ino[n] - ino[n + 1];
ino[ndx + 1] = copyto;
} else
copyto = ino[n + 1];
ndx += 2;
} else {
/* Switch page */
val.data = (uint8 *)op + ino[n + 1];
val.size = ino[n] - ino[n + 1];
/* if the pair doesn't fit something is horribly
* wrong. LJM
*/
tmp_uint16_array = (uint16 *)np;
if (!PAIRFITS(tmp_uint16_array, &key, &val))
return (DATABASE_CORRUPTED_ERROR);
putpair(np, &key, &val);
moved += 2;
}
off = ino[n + 1];
}
/* Now clean up the page */
ino[0] -= moved;
FREESPACE(ino) = copyto - sizeof(uint16) * (ino[0] + 3);
OFFSET(ino) = copyto;
#ifdef DEBUG3
(void)fprintf(stderr, "split %d/%d\n",
((uint16 *)np)[0] / 2,
((uint16 *)op)[0] / 2);
#endif
/* unpin both pages */
old_bufp->flags &= ~BUF_PIN;
new_bufp->flags &= ~BUF_PIN;
return (0);
}