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btree
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bt_put.c
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C/C++ Source or Header
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1994-07-26
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9KB
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321 lines
/*-
* 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
* Mike Olson.
*
* 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[] = "@(#)bt_put.c 8.8 (Berkeley) 7/26/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <db.h>
#include "btree.h"
static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *));
/*
* __BT_PUT -- Add a btree item to the tree.
*
* Parameters:
* dbp: pointer to access method
* key: key
* data: data
* flag: R_NOOVERWRITE
*
* Returns:
* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
* tree and R_NOOVERWRITE specified.
*/
int
__bt_put(dbp, key, data, flags)
const DB *dbp;
DBT *key;
const DBT *data;
u_int flags;
{
BTREE *t;
DBT tkey, tdata;
EPG *e;
PAGE *h;
indx_t index, nxtindex;
pgno_t pg;
u_int32_t nbytes;
int dflags, exact, status;
char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
t = dbp->internal;
/* Toss any page pinned across calls. */
if (t->bt_pinned != NULL) {
mpool_put(t->bt_mp, t->bt_pinned, 0);
t->bt_pinned = NULL;
}
/* Check for change to a read-only tree. */
if (F_ISSET(t, B_RDONLY)) {
errno = EPERM;
return (RET_ERROR);
}
switch (flags) {
case 0:
case R_NOOVERWRITE:
break;
case R_CURSOR:
/*
* If flags is R_CURSOR, put the cursor. Must already
* have started a scan and not have already deleted it.
*/
if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
!F_ISSET(&t->bt_cursor,
CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
break;
/* FALLTHROUGH */
default:
errno = EINVAL;
return (RET_ERROR);
}
/*
* If the key/data pair won't fit on a page, store it on overflow
* pages. Only put the key on the overflow page if the pair are
* still too big after moving the data to an overflow page.
*
* XXX
* If the insert fails later on, the overflow pages aren't recovered.
*/
dflags = 0;
if (key->size + data->size > t->bt_ovflsize) {
if (key->size > t->bt_ovflsize) {
storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
return (RET_ERROR);
tkey.data = kb;
tkey.size = NOVFLSIZE;
memmove(kb, &pg, sizeof(pgno_t));
memmove(kb + sizeof(pgno_t),
&key->size, sizeof(u_int32_t));
dflags |= P_BIGKEY;
key = &tkey;
}
if (key->size + data->size > t->bt_ovflsize) {
if (__ovfl_put(t, data, &pg) == RET_ERROR)
return (RET_ERROR);
tdata.data = db;
tdata.size = NOVFLSIZE;
memmove(db, &pg, sizeof(pgno_t));
memmove(db + sizeof(pgno_t),
&data->size, sizeof(u_int32_t));
dflags |= P_BIGDATA;
data = &tdata;
}
if (key->size + data->size > t->bt_ovflsize)
goto storekey;
}
/* Replace the cursor. */
if (flags == R_CURSOR) {
if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
return (RET_ERROR);
index = t->bt_cursor.pg.index;
goto delete;
}
/*
* Find the key to delete, or, the location at which to insert.
* Bt_fast and __bt_search both pin the returned page.
*/
if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
if ((e = __bt_search(t, key, &exact)) == NULL)
return (RET_ERROR);
h = e->page;
index = e->index;
/*
* Add the key/data pair to the tree. If an identical key is already
* in the tree, and R_NOOVERWRITE is set, an error is returned. If
* R_NOOVERWRITE is not set, the key is either added (if duplicates are
* permitted) or an error is returned.
*/
switch (flags) {
case R_NOOVERWRITE:
if (!exact)
break;
mpool_put(t->bt_mp, h, 0);
return (RET_SPECIAL);
default:
if (!exact || !F_ISSET(t, B_NODUPS))
break;
/*
* !!!
* Note, the delete may empty the page, so we need to put a
* new entry into the page immediately.
*/
delete: if (__bt_dleaf(t, key, h, index) == RET_ERROR) {
mpool_put(t->bt_mp, h, 0);
return (RET_ERROR);
}
break;
}
/*
* If not enough room, or the user has put a ceiling on the number of
* keys permitted in the page, split the page. The split code will
* insert the key and data and unpin the current page. If inserting
* into the offset array, shift the pointers up.
*/
nbytes = NBLEAFDBT(key->size, data->size);
if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
if ((status = __bt_split(t, h, key,
data, dflags, nbytes, index)) != RET_SUCCESS)
return (status);
goto success;
}
if (index < (nxtindex = NEXTINDEX(h)))
memmove(h->linp + index + 1, h->linp + index,
(nxtindex - index) * sizeof(indx_t));
h->lower += sizeof(indx_t);
h->linp[index] = h->upper -= nbytes;
dest = (char *)h + h->upper;
WR_BLEAF(dest, key, data, dflags);
/* If the cursor is on this page, adjust it as necessary. */
if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
!F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= index)
++t->bt_cursor.pg.index;
if (t->bt_order == NOT)
if (h->nextpg == P_INVALID) {
if (index == NEXTINDEX(h) - 1) {
t->bt_order = FORWARD;
t->bt_last.index = index;
t->bt_last.pgno = h->pgno;
}
} else if (h->prevpg == P_INVALID) {
if (index == 0) {
t->bt_order = BACK;
t->bt_last.index = 0;
t->bt_last.pgno = h->pgno;
}
}
mpool_put(t->bt_mp, h, MPOOL_DIRTY);
success:
if (flags == R_SETCURSOR)
__bt_setcur(t, e->page->pgno, e->index);
F_SET(t, B_MODIFIED);
return (RET_SUCCESS);
}
#ifdef STATISTICS
u_long bt_cache_hit, bt_cache_miss;
#endif
/*
* BT_FAST -- Do a quick check for sorted data.
*
* Parameters:
* t: tree
* key: key to insert
*
* Returns:
* EPG for new record or NULL if not found.
*/
static EPG *
bt_fast(t, key, data, exactp)
BTREE *t;
const DBT *key, *data;
int *exactp;
{
PAGE *h;
u_int32_t nbytes;
int cmp;
if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
t->bt_order = NOT;
return (NULL);
}
t->bt_cur.page = h;
t->bt_cur.index = t->bt_last.index;
/*
* If won't fit in this page or have too many keys in this page,
* have to search to get split stack.
*/
nbytes = NBLEAFDBT(key->size, data->size);
if (h->upper - h->lower < nbytes + sizeof(indx_t))
goto miss;
if (t->bt_order == FORWARD) {
if (t->bt_cur.page->nextpg != P_INVALID)
goto miss;
if (t->bt_cur.index != NEXTINDEX(h) - 1)
goto miss;
if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
goto miss;
t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
} else {
if (t->bt_cur.page->prevpg != P_INVALID)
goto miss;
if (t->bt_cur.index != 0)
goto miss;
if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
goto miss;
t->bt_last.index = 0;
}
*exactp = cmp == 0;
#ifdef STATISTICS
++bt_cache_hit;
#endif
return (&t->bt_cur);
miss:
#ifdef STATISTICS
++bt_cache_miss;
#endif
t->bt_order = NOT;
mpool_put(t->bt_mp, h, 0);
return (NULL);
}