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/*-------------------------------------------------------------------------
*
* btutils.c
* Utility code for Postgres btree implementation.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/hash/hashutil.c,v 1.15 1999/02/13 23:14:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <postgres.h>
#include <access/hash.h>
#include <fmgr.h>
#include <utils/memutils.h>
#include <access/iqual.h>
#ifndef HAVE_MEMMOVE
#include <regex/utils.h>
#else
#include <string.h>
#endif
ScanKey
_hash_mkscankey(Relation rel, IndexTuple itup, HashMetaPage metap)
{
ScanKey skey;
TupleDesc itupdesc;
int natts;
AttrNumber i;
Datum arg;
RegProcedure proc;
bool null;
natts = rel->rd_rel->relnatts;
itupdesc = RelationGetDescr(rel);
skey = (ScanKey) palloc(natts * sizeof(ScanKeyData));
for (i = 0; i < natts; i++)
{
arg = index_getattr(itup, i + 1, itupdesc, &null);
proc = metap->hashm_procid;
ScanKeyEntryInitialize(&skey[i],
0x0, (AttrNumber) (i + 1), proc, arg);
}
return skey;
}
void
_hash_freeskey(ScanKey skey)
{
pfree(skey);
}
bool
_hash_checkqual(IndexScanDesc scan, IndexTuple itup)
{
if (scan->numberOfKeys > 0)
return (index_keytest(itup,
RelationGetDescr(scan->relation),
scan->numberOfKeys, scan->keyData));
else
return true;
}
HashItem
_hash_formitem(IndexTuple itup)
{
int nbytes_hitem;
HashItem hitem;
Size tuplen;
/* disallow nulls in hash keys */
if (itup->t_info & INDEX_NULL_MASK)
elog(ERROR, "hash indices cannot include null keys");
/* make a copy of the index tuple with room for the sequence number */
tuplen = IndexTupleSize(itup);
nbytes_hitem = tuplen +
(sizeof(HashItemData) - sizeof(IndexTupleData));
hitem = (HashItem) palloc(nbytes_hitem);
memmove((char *) &(hitem->hash_itup), (char *) itup, tuplen);
return hitem;
}
Bucket
_hash_call(Relation rel, HashMetaPage metap, Datum key)
{
uint32 n;
Bucket bucket;
RegProcedure proc;
proc = metap->hashm_procid;
n = (uint32) fmgr(proc, key);
bucket = n & metap->hashm_highmask;
if (bucket > metap->hashm_maxbucket)
bucket = bucket & metap->hashm_lowmask;
return bucket;
}
/*
* _hash_log2 -- returns ceil(lg2(num))
*/
uint32
_hash_log2(uint32 num)
{
uint32 i,
limit;
limit = 1;
for (i = 0; limit < num; limit = limit << 1, i++)
;
return i;
}
/*
* _hash_checkpage -- sanity checks on the format of all hash pages
*/
void
_hash_checkpage(Page page, int flags)
{
HashPageOpaque opaque;
Assert(page);
Assert(((PageHeader) (page))->pd_lower >= (sizeof(PageHeaderData) - sizeof(ItemIdData)));
#if 1
Assert(((PageHeader) (page))->pd_upper <=
(BLCKSZ - DOUBLEALIGN(sizeof(HashPageOpaqueData))));
Assert(((PageHeader) (page))->pd_special ==
(BLCKSZ - DOUBLEALIGN(sizeof(HashPageOpaqueData))));
Assert(((PageHeader) (page))->pd_opaque.od_pagesize == BLCKSZ);
#endif
if (flags)
{
opaque = (HashPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->hasho_flag & flags);
}
}
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