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|
/*-
* 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. 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[] = "@(#)hash_page.c 8.11 (Berkeley) 11/7/95";
#endif /* LIBC_SCCS and not lint */
/*
* PACKAGE: hashing
*
* DESCRIPTION:
* Page manipulation for hashing package.
*
* ROUTINES:
*
* External
* __get_page
* __add_ovflpage
* Internal
* overflow_page
* open_temp
*/
#include <sys/types.h>
#ifdef DEBUG
#include <assert.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "db-int.h"
#include "hash.h"
#include "page.h"
#include "extern.h"
static int32_t add_bigptr __P((HTAB *, ITEM_INFO *, indx_t));
static u_int32_t *fetch_bitmap __P((HTAB *, int32_t));
static u_int32_t first_free __P((u_int32_t));
static indx_t next_realkey __P((PAGE16 *, indx_t));
static u_int16_t overflow_page __P((HTAB *));
static void page_init __P((HTAB *, PAGE16 *, db_pgno_t, u_int8_t));
static indx_t prev_realkey __P((PAGE16 *, indx_t));
static void putpair __P((PAGE8 *, const DBT *, const DBT *));
static void swap_page_header_in __P((PAGE16 *));
static void swap_page_header_out __P((PAGE16 *));
#ifdef DEBUG_SLOW
static void account_page(HTAB *, db_pgno_t, int);
#endif
u_int32_t
__get_item(hashp, cursorp, key, val, item_info)
HTAB *hashp;
CURSOR *cursorp;
DBT *key, *val;
ITEM_INFO *item_info;
{
db_pgno_t next_pgno;
int32_t i;
/* Check if we need to get a page. */
if (!cursorp->pagep) {
if (cursorp->pgno == INVALID_PGNO) {
cursorp->pagep =
__get_page(hashp, cursorp->bucket, A_BUCKET);
cursorp->pgno = ADDR(cursorp->pagep);
cursorp->ndx = 0;
cursorp->pgndx = 0;
} else
cursorp->pagep =
__get_page(hashp, cursorp->pgno, A_RAW);
if (!cursorp->pagep) {
item_info->status = ITEM_ERROR;
return (-1);
}
}
if (item_info->seek_size &&
FREESPACE(cursorp->pagep) > item_info->seek_size)
item_info->seek_found_page = cursorp->pgno;
if (cursorp->pgndx == NUM_ENT(cursorp->pagep)) {
/* Fetch next page. */
if (NEXT_PGNO(cursorp->pagep) == INVALID_PGNO) {
item_info->status = ITEM_NO_MORE;
return (-1);
}
next_pgno = NEXT_PGNO(cursorp->pagep);
cursorp->pgndx = 0;
__put_page(hashp, cursorp->pagep, A_RAW, 0);
cursorp->pagep = __get_page(hashp, next_pgno, A_RAW);
if (!cursorp->pagep) {
item_info->status = ITEM_ERROR;
return (-1);
}
cursorp->pgno = next_pgno;
}
if (KEY_OFF(cursorp->pagep, cursorp->pgndx) != BIGPAIR) {
if ((i = prev_realkey(cursorp->pagep, cursorp->pgndx)) ==
cursorp->pgndx)
key->size = hashp->hdr.bsize -
KEY_OFF(cursorp->pagep, cursorp->pgndx);
else
key->size = DATA_OFF(cursorp->pagep, i) -
KEY_OFF(cursorp->pagep, cursorp->pgndx);
}
/*
* All of this information will be set incorrectly for big keys, but
* it will be ignored anyway.
*/
val->size = KEY_OFF(cursorp->pagep, cursorp->pgndx) -
DATA_OFF(cursorp->pagep, cursorp->pgndx);
key->data = KEY(cursorp->pagep, cursorp->pgndx);
val->data = DATA(cursorp->pagep, cursorp->pgndx);
item_info->pgno = cursorp->pgno;
item_info->bucket = cursorp->bucket;
item_info->ndx = cursorp->ndx;
item_info->pgndx = cursorp->pgndx;
item_info->key_off = KEY_OFF(cursorp->pagep, cursorp->pgndx);
item_info->data_off = DATA_OFF(cursorp->pagep, cursorp->pgndx);
item_info->status = ITEM_OK;
return (0);
}
u_int32_t
__get_item_reset(hashp, cursorp)
HTAB *hashp;
CURSOR *cursorp;
{
if (cursorp->pagep)
__put_page(hashp, cursorp->pagep, A_RAW, 0);
cursorp->pagep = NULL;
cursorp->bucket = -1;
cursorp->ndx = 0;
cursorp->pgndx = 0;
cursorp->pgno = INVALID_PGNO;
return (0);
}
u_int32_t
__get_item_done(hashp, cursorp)
HTAB *hashp;
CURSOR *cursorp;
{
if (cursorp->pagep)
__put_page(hashp, cursorp->pagep, A_RAW, 0);
cursorp->pagep = NULL;
/*
* We don't throw out the page number since we might want to
* continue getting on this page.
*/
return (0);
}
u_int32_t
__get_item_first(hashp, cursorp, key, val, item_info)
HTAB *hashp;
CURSOR *cursorp;
DBT *key, *val;
ITEM_INFO *item_info;
{
__get_item_reset(hashp, cursorp);
cursorp->bucket = 0;
return (__get_item_next(hashp, cursorp, key, val, item_info));
}
/*
* Returns a pointer to key/data pair on a page. In the case of bigkeys,
* just returns the page number and index of the bigkey pointer pair.
*/
u_int32_t
__get_item_next(hashp, cursorp, key, val, item_info)
HTAB *hashp;
CURSOR *cursorp;
DBT *key, *val;
ITEM_INFO *item_info;
{
int status;
status = __get_item(hashp, cursorp, key, val, item_info);
cursorp->ndx++;
cursorp->pgndx++;
return (status);
}
/*
* Put a non-big pair on a page.
*/
static void
putpair(p, key, val)
PAGE8 *p;
const DBT *key, *val;
{
u_int16_t *pagep, n, off;
pagep = (PAGE16 *)(void *)p;
/* Items on the page are 0-indexed. */
n = NUM_ENT(pagep);
off = OFFSET(pagep) - key->size + 1;
memmove(p + off, key->data, key->size);
KEY_OFF(pagep, n) = off;
off -= val->size;
memmove(p + off, val->data, val->size);
DATA_OFF(pagep, n) = off;
/* Adjust page info. */
NUM_ENT(pagep) = n + 1;
OFFSET(pagep) = off - 1;
}
/*
* Returns the index of the next non-bigkey pair after n on the page.
* Returns -1 if there are no more non-big things on the page.
*/
static indx_t
#ifdef __STDC__
next_realkey(PAGE16 * pagep, indx_t n)
#else
next_realkey(pagep, n)
PAGE16 *pagep;
u_int32_t n;
#endif
{
indx_t i;
for (i = n + 1; i < NUM_ENT(pagep); i++)
if (KEY_OFF(pagep, i) != BIGPAIR)
return (i);
return (-1);
}
/*
* Returns the index of the previous non-bigkey pair after n on the page.
* Returns n if there are no previous non-big things on the page.
*/
static indx_t
#ifdef __STDC__
prev_realkey(PAGE16 * pagep, indx_t n)
#else
prev_realkey(pagep, n)
PAGE16 *pagep;
u_int32_t n;
#endif
{
int32_t i;
/* Need a signed value to do the compare properly. */
for (i = n - 1; i > -1; i--)
if (KEY_OFF(pagep, i) != BIGPAIR)
return (i);
return (n);
}
/*
* Returns:
* 0 OK
* -1 error
*/
extern int32_t
__delpair(hashp, cursorp, item_info)
HTAB *hashp;
CURSOR *cursorp;
ITEM_INFO *item_info;
{
PAGE16 *pagep;
indx_t ndx;
short check_ndx;
int16_t delta, len, next_key;
int32_t n;
u_int8_t *src, *dest;
ndx = cursorp->pgndx;
if (!cursorp->pagep) {
pagep = __get_page(hashp, cursorp->pgno, A_RAW);
if (!pagep)
return (-1);
/*
* KLUGE: pgndx has gone one too far, because cursor points
* to the _next_ item. Use pgndx - 1.
*/
--ndx;
} else
pagep = cursorp->pagep;
#ifdef DEBUG
assert(ADDR(pagep) == cursorp->pgno);
#endif
if (KEY_OFF(pagep, ndx) == BIGPAIR) {
delta = 0;
__big_delete(hashp, pagep, ndx);
} else {
/*
* Compute "delta", the amount we have to shift all of the
* offsets. To find the delta, we need to make sure that
* we aren't looking at the DATA_OFF of a big/keydata pair.
*/
for (check_ndx = (short)(ndx - 1);
check_ndx >= 0 && KEY_OFF(pagep, check_ndx) == BIGPAIR;
check_ndx--);
if (check_ndx < 0)
delta = hashp->hdr.bsize - DATA_OFF(pagep, ndx);
else
delta =
DATA_OFF(pagep, check_ndx) - DATA_OFF(pagep, ndx);
/*
* The hard case: we want to remove something other than
* the last item on the page. We need to shift data and
* offsets down.
*/
if (ndx != NUM_ENT(pagep) - 1) {
/*
* Move the data: src is the address of the last data
* item on the page.
*/
src = (u_int8_t *)pagep + OFFSET(pagep) + 1;
/*
* Length is the distance between where to start
* deleting and end of the data on the page.
*/
len = DATA_OFF(pagep, ndx) - (OFFSET(pagep) + 1);
/*
* Dest is the location of the to-be-deleted item
* occupied - length.
*/
if (check_ndx < 0)
dest =
(u_int8_t *)pagep + hashp->hdr.bsize - len;
else
dest = (u_int8_t *)pagep +
DATA_OFF(pagep, (check_ndx)) - len;
memmove(dest, src, len);
}
}
/* Adjust the offsets. */
for (n = ndx; n < NUM_ENT(pagep) - 1; n++)
if (KEY_OFF(pagep, (n + 1)) != BIGPAIR) {
next_key = next_realkey(pagep, n);
#ifdef DEBUG
assert(next_key != -1);
#endif
KEY_OFF(pagep, n) = KEY_OFF(pagep, (n + 1)) + delta;
DATA_OFF(pagep, n) = DATA_OFF(pagep, (n + 1)) + delta;
} else {
KEY_OFF(pagep, n) = KEY_OFF(pagep, (n + 1));
DATA_OFF(pagep, n) = DATA_OFF(pagep, (n + 1));
}
/* Adjust page metadata. */
OFFSET(pagep) = OFFSET(pagep) + delta;
NUM_ENT(pagep) = NUM_ENT(pagep) - 1;
--hashp->hdr.nkeys;
/* Is this page now an empty overflow page? If so, free it. */
if (TYPE(pagep) == HASH_OVFLPAGE && NUM_ENT(pagep) == 0) {
PAGE16 *empty_page;
db_pgno_t to_find, next_pgno, link_page;
/*
* We need to go back to the first page in the chain and
* look for this page so that we can update the previous
* page's NEXT_PGNO field.
*/
to_find = ADDR(pagep);
empty_page = pagep;
link_page = NEXT_PGNO(empty_page);
pagep = __get_page(hashp, item_info->bucket, A_BUCKET);
if (!pagep)
return (-1);
while (NEXT_PGNO(pagep) != to_find) {
next_pgno = NEXT_PGNO(pagep);
#ifdef DEBUG
assert(next_pgno != INVALID_PGNO);
#endif
__put_page(hashp, pagep, A_RAW, 0);
pagep = __get_page(hashp, next_pgno, A_RAW);
if (!pagep)
return (-1);
}
/*
* At this point, pagep should point to the page before the
* page to be deleted.
*/
NEXT_PGNO(pagep) = link_page;
if (item_info->pgno == to_find) {
item_info->pgno = ADDR(pagep);
item_info->pgndx = NUM_ENT(pagep);
item_info->seek_found_page = ADDR(pagep);
}
__delete_page(hashp, empty_page, A_OVFL);
}
__put_page(hashp, pagep, A_RAW, 1);
return (0);
}
extern int32_t
__split_page(hashp, obucket, nbucket)
HTAB *hashp;
u_int32_t obucket, nbucket;
{
DBT key, val;
ITEM_INFO old_ii, new_ii;
PAGE16 *old_pagep, *temp_pagep;
db_pgno_t next_pgno;
int32_t off;
u_int16_t n;
int8_t base_page;
off = hashp->hdr.bsize;
old_pagep = __get_page(hashp, obucket, A_BUCKET);
base_page = 1;
temp_pagep = hashp->split_buf;
memcpy(temp_pagep, old_pagep, hashp->hdr.bsize);
page_init(hashp, old_pagep, ADDR(old_pagep), HASH_PAGE);
__put_page(hashp, old_pagep, A_RAW, 1);
old_ii.pgno = BUCKET_TO_PAGE(obucket);
new_ii.pgno = BUCKET_TO_PAGE(nbucket);
old_ii.bucket = obucket;
new_ii.bucket = nbucket;
old_ii.seek_found_page = new_ii.seek_found_page = 0;
while (temp_pagep != 0) {
off = hashp->hdr.bsize;
for (n = 0; n < NUM_ENT(temp_pagep); n++) {
if (KEY_OFF(temp_pagep, n) == BIGPAIR) {
__get_bigkey(hashp, temp_pagep, n, &key);
if (__call_hash(hashp,
key.data, key.size) == obucket)
add_bigptr(hashp, &old_ii,
DATA_OFF(temp_pagep, n));
else
add_bigptr(hashp, &new_ii,
DATA_OFF(temp_pagep, n));
} else {
key.size = off - KEY_OFF(temp_pagep, n);
key.data = KEY(temp_pagep, n);
off = KEY_OFF(temp_pagep, n);
val.size = off - DATA_OFF(temp_pagep, n);
val.data = DATA(temp_pagep, n);
if (__call_hash(hashp,
key.data, key.size) == obucket)
__addel(hashp, &old_ii, &key, &val,
NO_EXPAND, 1);
else
__addel(hashp, &new_ii, &key, &val,
NO_EXPAND, 1);
off = DATA_OFF(temp_pagep, n);
}
}
next_pgno = NEXT_PGNO(temp_pagep);
/* Clear temp_page; if it's an overflow page, free it. */
if (!base_page)
__delete_page(hashp, temp_pagep, A_OVFL);
else
base_page = 0;
if (next_pgno != INVALID_PGNO)
temp_pagep = __get_page(hashp, next_pgno, A_RAW);
else
break;
}
return (0);
}
/*
* Add the given pair to the page.
*
*
* Returns:
* 0 ==> OK
* -1 ==> failure
*/
extern int32_t
#ifdef __STDC__
__addel(HTAB *hashp, ITEM_INFO *item_info, const DBT *key, const DBT *val,
u_int32_t num_items, const u_int8_t expanding)
#else
__addel(hashp, item_info, key, val, num_items, expanding)
HTAB *hashp;
ITEM_INFO *item_info;
const DBT *key, *val;
u_int32_t num_items;
const u_int32_t expanding;
#endif
{
PAGE16 *pagep;
int32_t do_expand;
db_pgno_t next_pgno;
do_expand = 0;
pagep = __get_page(hashp,
item_info->seek_found_page != 0 ?
item_info->seek_found_page : item_info->pgno, A_RAW);
if (!pagep)
return (-1);
/* Advance to first page in chain with room for item. */
while (NUM_ENT(pagep) && NEXT_PGNO(pagep) != INVALID_PGNO) {
/*
* This may not be the end of the chain, but the pair may fit
* anyway.
*/
if (ISBIG(PAIRSIZE(key, val), hashp) && BIGPAIRFITS(pagep))
break;
if (PAIRFITS(pagep, key, val))
break;
next_pgno = NEXT_PGNO(pagep);
__put_page(hashp, pagep, A_RAW, 0);
pagep = (PAGE16 *)__get_page(hashp, next_pgno, A_RAW);
if (!pagep)
return (-1);
}
if ((ISBIG(PAIRSIZE(key, val), hashp) &&
!BIGPAIRFITS(pagep)) ||
(!ISBIG(PAIRSIZE(key, val), hashp) &&
!PAIRFITS(pagep, key, val))) {
do_expand = 1;
pagep = __add_ovflpage(hashp, pagep);
if (!pagep)
return (-1);
if ((ISBIG(PAIRSIZE(key, val), hashp) &&
!BIGPAIRFITS(pagep)) ||
(!ISBIG(PAIRSIZE(key, val), hashp) &&
!PAIRFITS(pagep, key, val))) {
__put_page(hashp, pagep, A_RAW, 0);
return (-1);
}
}
/* At this point, we know the page fits, so we just add it */
if (ISBIG(PAIRSIZE(key, val), hashp)) {
if (__big_insert(hashp, pagep, key, val))
return (-1);
} else {
putpair((PAGE8 *)pagep, key, val);
}
/*
* For splits, we are going to update item_info's page number
* field, so that we can easily return to the same page the
* next time we come in here. For other operations, this shouldn't
* matter, since adds are the last thing that happens before we
* return to the user program.
*/
item_info->pgno = ADDR(pagep);
if (!expanding)
hashp->hdr.nkeys++;
/* Kludge: if this is a big page, then it's already been put. */
if (!ISBIG(PAIRSIZE(key, val), hashp))
__put_page(hashp, pagep, A_RAW, 1);
if (expanding)
item_info->caused_expand = 0;
else
switch (num_items) {
case NO_EXPAND:
item_info->caused_expand = 0;
break;
case UNKNOWN:
item_info->caused_expand |=
(hashp->hdr.nkeys / hashp->hdr.max_bucket) >
hashp->hdr.ffactor ||
item_info->pgndx > hashp->hdr.ffactor;
break;
default:
item_info->caused_expand =
num_items > hashp->hdr.ffactor ? 1 : do_expand;
break;
}
return (0);
}
/*
* Special __addel used in big splitting; this one just puts the pointer
* to an already-allocated big page in the appropriate bucket.
*/
static int32_t
#ifdef __STDC__
add_bigptr(HTAB * hashp, ITEM_INFO * item_info, indx_t big_pgno)
#else
add_bigptr(hashp, item_info, big_pgno)
HTAB *hashp;
ITEM_INFO *item_info;
u_int32_t big_pgno;
#endif
{
PAGE16 *pagep;
db_pgno_t next_pgno;
pagep = __get_page(hashp, item_info->bucket, A_BUCKET);
if (!pagep)
return (-1);
/*
* Note: in __addel(), we used item_info->pgno for the beginning of
* our search for space. Now, we use item_info->bucket, since we
* know that the space required by a big pair on the base page is
* quite small, and we may very well find that space early in the
* chain.
*/
/* Find first page in chain that has space for a big pair. */
while (NUM_ENT(pagep) && (NEXT_PGNO(pagep) != INVALID_PGNO)) {
if (BIGPAIRFITS(pagep))
break;
next_pgno = NEXT_PGNO(pagep);
__put_page(hashp, pagep, A_RAW, 0);
pagep = __get_page(hashp, next_pgno, A_RAW);
if (!pagep)
return (-1);
}
if (!BIGPAIRFITS(pagep)) {
pagep = __add_ovflpage(hashp, pagep);
if (!pagep)
return (-1);
#ifdef DEBUG
assert(BIGPAIRFITS(pagep));
#endif
}
KEY_OFF(pagep, NUM_ENT(pagep)) = BIGPAIR;
DATA_OFF(pagep, NUM_ENT(pagep)) = big_pgno;
NUM_ENT(pagep) = NUM_ENT(pagep) + 1;
__put_page(hashp, pagep, A_RAW, 1);
return (0);
}
/*
*
* Returns:
* pointer on success
* NULL on error
*/
extern PAGE16 *
__add_ovflpage(hashp, pagep)
HTAB *hashp;
PAGE16 *pagep;
{
PAGE16 *new_pagep;
u_int16_t ovfl_num;
/* Check if we are dynamically determining the fill factor. */
if (hashp->hdr.ffactor == DEF_FFACTOR) {
hashp->hdr.ffactor = NUM_ENT(pagep) >> 1;
if (hashp->hdr.ffactor < MIN_FFACTOR)
hashp->hdr.ffactor = MIN_FFACTOR;
}
ovfl_num = overflow_page(hashp);
if (!ovfl_num)
return (NULL);
if (__new_page(hashp, (u_int32_t)ovfl_num, A_OVFL) != 0)
return (NULL);
if (!ovfl_num || !(new_pagep = __get_page(hashp, ovfl_num, A_OVFL)))
return (NULL);
NEXT_PGNO(pagep) = (db_pgno_t)OADDR_TO_PAGE(ovfl_num);
TYPE(new_pagep) = HASH_OVFLPAGE;
__put_page(hashp, pagep, A_RAW, 1);
#ifdef HASH_STATISTICS
hash_overflows++;
#endif
return (new_pagep);
}
/*
*
* Returns:
* pointer on success
* NULL on error
*/
extern PAGE16 *
#ifdef __STDC__
__add_bigpage(HTAB * hashp, PAGE16 * pagep, indx_t ndx, const u_int8_t
is_basepage)
#else
__add_bigpage(hashp, pagep, ndx, is_basepage)
HTAB *hashp;
PAGE16 *pagep;
u_int32_t ndx;
const u_int32_t is_basepage;
#endif
{
PAGE16 *new_pagep;
u_int16_t ovfl_num;
ovfl_num = overflow_page(hashp);
if (!ovfl_num)
return (NULL);
if (__new_page(hashp, (u_int32_t)ovfl_num, A_OVFL) != 0)
return (NULL);
if (!ovfl_num || !(new_pagep = __get_page(hashp, ovfl_num, A_OVFL)))
return (NULL);
if (is_basepage) {
KEY_OFF(pagep, ndx) = BIGPAIR;
DATA_OFF(pagep, ndx) = (indx_t)ovfl_num;
} else
NEXT_PGNO(pagep) = ADDR(new_pagep);
__put_page(hashp, pagep, A_RAW, 1);
TYPE(new_pagep) = HASH_BIGPAGE;
#ifdef HASH_STATISTICS
hash_bigpages++;
#endif
return (new_pagep);
}
static void
#ifdef __STDC__
page_init(HTAB * hashp, PAGE16 * pagep, db_pgno_t pgno, u_int8_t type)
#else
page_init(hashp, pagep, pgno, type)
HTAB *hashp;
PAGE16 *pagep;
db_pgno_t pgno;
u_int32_t type;
#endif
{
NUM_ENT(pagep) = 0;
PREV_PGNO(pagep) = NEXT_PGNO(pagep) = INVALID_PGNO;
TYPE(pagep) = type;
OFFSET(pagep) = hashp->hdr.bsize - 1;
/*
* Note: since in the current version ADDR(pagep) == PREV_PGNO(pagep),
* make sure that ADDR(pagep) is set after resetting PREV_PGNO(pagep).
* We reset PREV_PGNO(pagep) just in case the macros are changed.
*/
ADDR(pagep) = pgno;
return;
}
int32_t
__new_page(hashp, addr, addr_type)
HTAB *hashp;
u_int32_t addr;
int32_t addr_type;
{
db_pgno_t paddr;
PAGE16 *pagep;
switch (addr_type) { /* Convert page number. */
case A_BUCKET:
paddr = BUCKET_TO_PAGE(addr);
break;
case A_OVFL:
case A_BITMAP:
paddr = OADDR_TO_PAGE(addr);
break;
default:
paddr = addr;
break;
}
pagep = mpool_new(hashp->mp, &paddr, MPOOL_PAGE_REQUEST);
if (!pagep)
return (-1);
#if DEBUG_SLOW
account_page(hashp, paddr, 1);
#endif
if (addr_type != A_BITMAP)
page_init(hashp, pagep, paddr, HASH_PAGE);
__put_page(hashp, pagep, addr_type, 1);
return (0);
}
int32_t
__delete_page(hashp, pagep, page_type)
HTAB *hashp;
PAGE16 *pagep;
int32_t page_type;
{
if (page_type == A_OVFL)
__free_ovflpage(hashp, pagep);
return (mpool_delete(hashp->mp, pagep));
}
static u_int8_t
is_bitmap_pgno(hashp, pgno)
HTAB *hashp;
db_pgno_t pgno;
{
int32_t i;
for (i = 0; i < hashp->nmaps; i++)
if (OADDR_TO_PAGE(hashp->hdr.bitmaps[i]) == pgno)
return (1);
return (0);
}
void
__pgin_routine(pg_cookie, pgno, page)
void *pg_cookie;
db_pgno_t pgno;
void *page;
{
HTAB *hashp;
PAGE16 *pagep;
int32_t max, i;
pagep = (PAGE16 *)page;
hashp = (HTAB *)pg_cookie;
/*
* There are the following cases for swapping:
* 0) New page that may be unitialized.
* 1) Bucket page or overflow page. Either swap
* the header or initialize the page.
* 2) Bitmap page. Swap the whole page!
* 3) Header pages. Not handled here; these are written directly
* to the file.
*/
if (NUM_ENT(pagep) == 0 && NEXT_PGNO(pagep) == 0 &&
!is_bitmap_pgno(hashp, pgno)) {
/* XXX check for !0 LSN */
page_init(hashp, pagep, pgno, HASH_PAGE);
return;
}
if (hashp->hdr.lorder == DB_BYTE_ORDER)
return;
if (is_bitmap_pgno(hashp, pgno)) {
max = hashp->hdr.bsize >> 2; /* divide by 4 bytes */
for (i = 0; i < max; i++)
M_32_SWAP(((int32_t *)(void *)pagep)[i]);
} else
swap_page_header_in(pagep);
}
void
__pgout_routine(pg_cookie, pgno, page)
void *pg_cookie;
db_pgno_t pgno;
void *page;
{
HTAB *hashp;
PAGE16 *pagep;
int32_t i, max;
pagep = (PAGE16 *)page;
hashp = (HTAB *)pg_cookie;
/*
* There are the following cases for swapping:
* 1) Bucket page or overflow page. Just swap the header.
* 2) Bitmap page. Swap the whole page!
* 3) Header pages. Not handled here; these are written directly
* to the file.
*/
if (hashp->hdr.lorder == DB_BYTE_ORDER)
return;
if (is_bitmap_pgno(hashp, pgno)) {
max = hashp->hdr.bsize >> 2; /* divide by 4 bytes */
for (i = 0; i < max; i++)
M_32_SWAP(((int32_t *)(void *)pagep)[i]);
} else
swap_page_header_out(pagep);
}
/*
*
* Returns:
* 0 ==> OK
* -1 ==>failure
*/
extern int32_t
__put_page(hashp, pagep, addr_type, is_dirty)
HTAB *hashp;
PAGE16 *pagep;
int32_t addr_type, is_dirty;
{
#if DEBUG_SLOW
account_page(hashp,
((BKT *)((char *)pagep - sizeof(BKT)))->pgno, -1);
#endif
return (mpool_put(hashp->mp, pagep, (is_dirty ? MPOOL_DIRTY : 0)));
}
/*
* Returns:
* 0 indicates SUCCESS
* -1 indicates FAILURE
*/
extern PAGE16 *
__get_page(hashp, addr, addr_type)
HTAB *hashp;
u_int32_t addr;
int32_t addr_type;
{
PAGE16 *pagep;
db_pgno_t paddr;
switch (addr_type) { /* Convert page number. */
case A_BUCKET:
paddr = BUCKET_TO_PAGE(addr);
break;
case A_OVFL:
case A_BITMAP:
paddr = OADDR_TO_PAGE(addr);
break;
default:
paddr = addr;
break;
}
pagep = (PAGE16 *)mpool_get(hashp->mp, paddr, 0);
#if DEBUG_SLOW
account_page(hashp, paddr, 1);
#endif
#ifdef DEBUG
assert(ADDR(pagep) == paddr || ADDR(pagep) == 0 ||
addr_type == A_BITMAP || addr_type == A_HEADER);
#endif
return (pagep);
}
static void
swap_page_header_in(pagep)
PAGE16 *pagep;
{
u_int32_t i;
/* can leave type and filler alone, since they're 1-byte quantities */
M_32_SWAP(PREV_PGNO(pagep));
M_32_SWAP(NEXT_PGNO(pagep));
M_16_SWAP(NUM_ENT(pagep));
M_16_SWAP(OFFSET(pagep));
for (i = 0; i < NUM_ENT(pagep); i++) {
M_16_SWAP(KEY_OFF(pagep, i));
M_16_SWAP(DATA_OFF(pagep, i));
}
}
static void
swap_page_header_out(pagep)
PAGE16 *pagep;
{
u_int32_t i;
for (i = 0; i < NUM_ENT(pagep); i++) {
M_16_SWAP(KEY_OFF(pagep, i));
M_16_SWAP(DATA_OFF(pagep, i))
}
/* can leave type and filler alone, since they're 1-byte quantities */
M_32_SWAP(PREV_PGNO(pagep));
M_32_SWAP(NEXT_PGNO(pagep));
M_16_SWAP(NUM_ENT(pagep));
M_16_SWAP(OFFSET(pagep));
}
#define BYTE_MASK ((1 << INT32_T_BYTE_SHIFT) -1)
/*
* Initialize a new bitmap page. Bitmap pages are left in memory
* once they are read in.
*/
extern int32_t
__ibitmap(hashp, pnum, nbits, ndx)
HTAB *hashp;
int32_t pnum, nbits, ndx;
{
u_int32_t *ip;
int32_t clearbytes, clearints;
/* make a new bitmap page */
if (__new_page(hashp, pnum, A_BITMAP) != 0)
return (1);
if (!(ip = (u_int32_t *)(void *)__get_page(hashp, pnum, A_BITMAP)))
return (1);
hashp->nmaps++;
clearints = ((nbits - 1) >> INT32_T_BYTE_SHIFT) + 1;
clearbytes = clearints << INT32_T_TO_BYTE;
(void)memset((int8_t *)ip, 0, clearbytes);
(void)memset((int8_t *)ip + clearbytes,
0xFF, hashp->hdr.bsize - clearbytes);
ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK);
SETBIT(ip, 0);
hashp->hdr.bitmaps[ndx] = (u_int16_t)pnum;
hashp->mapp[ndx] = ip;
return (0);
}
static u_int32_t
first_free(map)
u_int32_t map;
{
u_int32_t i, mask;
for (mask = 0x1, i = 0; i < BITS_PER_MAP; i++) {
if (!(mask & map))
return (i);
mask = mask << 1;
}
return (i);
}
/*
* returns 0 on error
*/
static u_int16_t
overflow_page(hashp)
HTAB *hashp;
{
u_int32_t *freep;
u_int32_t bit, first_page, free_bit, free_page, i, in_use_bits, j;
u_int32_t max_free, offset, splitnum;
u_int16_t addr;
#ifdef DEBUG2
int32_t tmp1, tmp2;
#endif
splitnum = hashp->hdr.ovfl_point;
max_free = hashp->hdr.spares[splitnum];
free_page = (max_free - 1) >> (hashp->hdr.bshift + BYTE_SHIFT);
free_bit = (max_free - 1) & ((hashp->hdr.bsize << BYTE_SHIFT) - 1);
/*
* Look through all the free maps to find the first free block.
* The compiler under -Wall will complain that freep may be used
* before being set, however, this loop will ALWAYS get executed
* at least once, so freep is guaranteed to be set.
*/
freep = NULL;
first_page = hashp->hdr.last_freed >> (hashp->hdr.bshift + BYTE_SHIFT);
for (i = first_page; i <= free_page; i++) {
if (!(freep = fetch_bitmap(hashp, i)))
return (0);
if (i == free_page)
in_use_bits = free_bit;
else
in_use_bits = (hashp->hdr.bsize << BYTE_SHIFT) - 1;
if (i == first_page) {
bit = hashp->hdr.last_freed &
((hashp->hdr.bsize << BYTE_SHIFT) - 1);
j = bit / BITS_PER_MAP;
bit = bit & ~(BITS_PER_MAP - 1);
} else {
bit = 0;
j = 0;
}
for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP)
if (freep[j] != ALL_SET)
goto found;
}
/* No Free Page Found */
hashp->hdr.last_freed = hashp->hdr.spares[splitnum];
hashp->hdr.spares[splitnum]++;
offset = hashp->hdr.spares[splitnum] -
(splitnum ? hashp->hdr.spares[splitnum - 1] : 0);
#define OVMSG "HASH: Out of overflow pages. Increase page size\n"
if (offset > SPLITMASK) {
if (++splitnum >= NCACHED) {
(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
return (0);
}
hashp->hdr.ovfl_point = splitnum;
hashp->hdr.spares[splitnum] = hashp->hdr.spares[splitnum - 1];
hashp->hdr.spares[splitnum - 1]--;
offset = 1;
}
/* Check if we need to allocate a new bitmap page. */
if (free_bit == (hashp->hdr.bsize << BYTE_SHIFT) - 1) {
free_page++;
if (free_page >= NCACHED) {
(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
return (0);
}
/*
* This is tricky. The 1 indicates that you want the new page
* allocated with 1 clear bit. Actually, you are going to
* allocate 2 pages from this map. The first is going to be
* the map page, the second is the overflow page we were
* looking for. The __ibitmap routine automatically, sets
* the first bit of itself to indicate that the bitmap itself
* is in use. We would explicitly set the second bit, but
* don't have to if we tell __ibitmap not to leave it clear
* in the first place.
*/
if (__ibitmap(hashp,
(int32_t)OADDR_OF(splitnum, offset), 1, free_page))
return (0);
hashp->hdr.spares[splitnum]++;
#ifdef DEBUG2
free_bit = 2;
#endif
offset++;
if (offset > SPLITMASK) {
if (++splitnum >= NCACHED) {
(void)write(STDERR_FILENO,
OVMSG, sizeof(OVMSG) - 1);
return (0);
}
hashp->hdr.ovfl_point = splitnum;
hashp->hdr.spares[splitnum] =
hashp->hdr.spares[splitnum - 1];
hashp->hdr.spares[splitnum - 1]--;
offset = 0;
}
} else {
/*
* Free_bit addresses the last used bit. Bump it to address
* the first available bit.
*/
free_bit++;
SETBIT(freep, free_bit);
}
/* Calculate address of the new overflow page */
addr = OADDR_OF(splitnum, offset);
#ifdef DEBUG2
(void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
addr, free_bit, free_page);
#endif
if (OADDR_TO_PAGE(addr) > MAX_PAGES(hashp)) {
(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
return (0);
}
return (addr);
found:
bit = bit + first_free(freep[j]);
SETBIT(freep, bit);
#ifdef DEBUG2
tmp1 = bit;
tmp2 = i;
#endif
/*
* Bits are addressed starting with 0, but overflow pages are addressed
* beginning at 1. Bit is a bit address number, so we need to increment
* it to convert it to a page number.
*/
bit = 1 + bit + (i * (hashp->hdr.bsize << BYTE_SHIFT));
if (bit >= hashp->hdr.last_freed)
hashp->hdr.last_freed = bit - 1;
/* Calculate the split number for this page */
for (i = 0; i < splitnum && (bit > hashp->hdr.spares[i]); i++);
offset = (i ? bit - hashp->hdr.spares[i - 1] : bit);
if (offset >= SPLITMASK)
return (0); /* Out of overflow pages */
addr = OADDR_OF(i, offset);
#ifdef DEBUG2
(void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
addr, tmp1, tmp2);
#endif
if (OADDR_TO_PAGE(addr) > MAX_PAGES(hashp)) {
(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
return (0);
}
/* Allocate and return the overflow page */
return (addr);
}
#ifdef DEBUG
int
bucket_to_page(hashp, n)
HTAB *hashp;
int n;
{
int ret_val;
ret_val = n + hashp->hdr.hdrpages;
if (n != 0)
ret_val += hashp->hdr.spares[__log2(n + 1) - 1];
return (ret_val);
}
int32_t
oaddr_to_page(hashp, n)
HTAB *hashp;
int n;
{
int ret_val, temp;
temp = (1 << SPLITNUM(n)) - 1;
ret_val = bucket_to_page(hashp, temp);
ret_val += (n & SPLITMASK);
return (ret_val);
}
#endif /* DEBUG */
static indx_t
page_to_oaddr(hashp, pgno)
HTAB *hashp;
db_pgno_t pgno;
{
int32_t sp, ret_val;
/*
* To convert page number to overflow address:
*
* 1. Find a starting split point -- use 0 since there are only
* 32 split points.
* 2. Find the split point s.t. 2^sp + hdr.spares[sp] < pgno and
* 2^(sp+1) = hdr.spares[sp+1] > pgno. The overflow address will
* be located at sp.
* 3. return...
*/
pgno -= hashp->hdr.hdrpages;
for (sp = 0; sp < NCACHED - 1; sp++)
if (POW2(sp) + hashp->hdr.spares[sp] < pgno &&
(POW2(sp + 1) + hashp->hdr.spares[sp + 1]) > pgno)
break;
ret_val = OADDR_OF(sp + 1,
pgno - ((POW2(sp + 1) - 1) + hashp->hdr.spares[sp]));
#ifdef DEBUG
assert(OADDR_TO_PAGE(ret_val) == (pgno + hashp->hdr.hdrpages));
#endif
return (ret_val);
}
/*
* Mark this overflow page as free.
*/
extern void
__free_ovflpage(hashp, pagep)
HTAB *hashp;
PAGE16 *pagep;
{
u_int32_t *freep;
u_int32_t bit_address, free_page, free_bit;
u_int16_t addr, ndx;
addr = page_to_oaddr(hashp, ADDR(pagep));
#ifdef DEBUG2
(void)fprintf(stderr, "Freeing %d\n", addr);
#endif
ndx = ((u_int16_t)addr) >> SPLITSHIFT;
bit_address =
(ndx ? hashp->hdr.spares[ndx - 1] : 0) + (addr & SPLITMASK) - 1;
if (bit_address < hashp->hdr.last_freed)
hashp->hdr.last_freed = bit_address;
free_page = (bit_address >> (hashp->hdr.bshift + BYTE_SHIFT));
free_bit = bit_address & ((hashp->hdr.bsize << BYTE_SHIFT) - 1);
freep = fetch_bitmap(hashp, free_page);
#ifdef DEBUG
/*
* This had better never happen. It means we tried to read a bitmap
* that has already had overflow pages allocated off it, and we
* failed to read it from the file.
*/
if (!freep)
assert(0);
#endif
CLRBIT(freep, free_bit);
#ifdef DEBUG2
(void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n",
obufp->addr, free_bit, free_page);
#endif
}
static u_int32_t *
fetch_bitmap(hashp, ndx)
HTAB *hashp;
int32_t ndx;
{
if (ndx >= hashp->nmaps)
return (NULL);
if (!hashp->mapp[ndx])
hashp->mapp[ndx] = (u_int32_t *)(void *)__get_page(hashp,
hashp->hdr.bitmaps[ndx], A_BITMAP);
return (hashp->mapp[ndx]);
}
#ifdef DEBUG_SLOW
static void
account_page(hashp, pgno, inout)
HTAB *hashp;
db_pgno_t pgno;
int inout;
{
static struct {
db_pgno_t pgno;
int times;
} list[100];
static int last;
int i, j;
if (inout == -1) /* XXX: Kluge */
inout = 0;
/* Find page in list. */
for (i = 0; i < last; i++)
if (list[i].pgno == pgno)
break;
/* Not found. */
if (i == last) {
list[last].times = inout;
list[last].pgno = pgno;
last++;
}
list[i].times = inout;
if (list[i].times == 0) {
for (j = i; j < last; j++)
list[j] = list[j + 1];
last--;
}
for (i = 0; i < last; i++, list[i].times++)
if (list[i].times > 20 && !is_bitmap_pgno(hashp, list[i].pgno))
(void)fprintf(stderr,
"Warning: pg %d has been out for %d times\n",
list[i].pgno, list[i].times);
}
#endif /* DEBUG_SLOW */
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