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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995
* 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.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)bt_compare.c 10.14 (Sleepycat) 10/9/98";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <string.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "btree.h"
/*
* __bam_cmp --
* Compare a key to a given record.
*
* PUBLIC: int __bam_cmp __P((DB *, const DBT *,
* PUBLIC: PAGE *, u_int32_t, int (*)(const DBT *, const DBT *)));
*/
int
__bam_cmp(dbp, dbt, h, indx, func)
DB *dbp;
const DBT *dbt;
PAGE *h;
u_int32_t indx;
int (*func)__P((const DBT *, const DBT *));
{
BINTERNAL *bi;
BKEYDATA *bk;
BOVERFLOW *bo;
DBT pg_dbt;
int ret;
/*
* Returns:
* < 0 if dbt is < page record
* = 0 if dbt is = page record
* > 0 if dbt is > page record
*
* !!!
* We do not clear the pg_dbt DBT even though it's likely to contain
* random bits. That should be okay, because the app's comparison
* routine had better not be looking at fields other than data/size.
* We don't clear it because we go through this path a lot and it's
* expensive.
*/
if (TYPE(h) == P_LBTREE || TYPE(h) == P_DUPLICATE) {
bk = GET_BKEYDATA(h, indx);
if (B_TYPE(bk->type) == B_OVERFLOW)
bo = (BOVERFLOW *)bk;
else {
pg_dbt.data = bk->data;
pg_dbt.size = bk->len;
return (func(dbt, &pg_dbt));
}
} else {
/*
* The following code guarantees that the left-most key on an
* internal page at any level of the btree is less than any
* user specified key. This saves us from having to update the
* leftmost key on an internal page when the user inserts a new
* key in the tree smaller than anything we've seen before.
*/
if (indx == 0 && h->prev_pgno == PGNO_INVALID)
return (1);
bi = GET_BINTERNAL(h, indx);
if (B_TYPE(bi->type) == B_OVERFLOW)
bo = (BOVERFLOW *)(bi->data);
else {
pg_dbt.data = bi->data;
pg_dbt.size = bi->len;
return (func(dbt, &pg_dbt));
}
}
/*
* Overflow.
*
* XXX
* We ignore __db_moff() errors, because we have no way of returning
* them.
*/
(void) __db_moff(dbp,
dbt, bo->pgno, bo->tlen, func == __bam_defcmp ? NULL : func, &ret);
return (ret);
}
/*
* __bam_defcmp --
* Default comparison routine.
*
* PUBLIC: int __bam_defcmp __P((const DBT *, const DBT *));
*/
int
__bam_defcmp(a, b)
const DBT *a, *b;
{
size_t len;
u_int8_t *p1, *p2;
/*
* Returns:
* < 0 if a is < b
* = 0 if a is = b
* > 0 if a is > b
*
* XXX
* If a size_t doesn't fit into a long, or if the difference between
* any two characters doesn't fit into an int, this routine can lose.
* What we need is a signed integral type that's guaranteed to be at
* least as large as a size_t, and there is no such thing.
*/
len = a->size > b->size ? b->size : a->size;
for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
if (*p1 != *p2)
return ((long)*p1 - (long)*p2);
return ((long)a->size - (long)b->size);
}
/*
* __bam_defpfx --
* Default prefix routine.
*
* PUBLIC: size_t __bam_defpfx __P((const DBT *, const DBT *));
*/
size_t
__bam_defpfx(a, b)
const DBT *a, *b;
{
size_t cnt, len;
u_int8_t *p1, *p2;
cnt = 1;
len = a->size > b->size ? b->size : a->size;
for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
if (*p1 != *p2)
return (cnt);
/*
* We know that a->size must be <= b->size, or they wouldn't be
* in this order.
*/
return (a->size < b->size ? a->size + 1 : a->size);
}
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