Postgres95 1.01 Distribution - Virgin Sources

src/backend/access/hash/hashutil.c

@@ -0,0 +1,147 @@
+/*-------------------------------------------------------------------------
+ *
+ * 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 1.1.1.1 1996/07/09 06:21:10 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "storage/bufmgr.h"
+#include "storage/bufpage.h"
+
+#include "fmgr.h"
+#include "utils/elog.h"
+#include "utils/palloc.h"
+#include "utils/rel.h"
+#include "utils/excid.h"
+
+#include "access/heapam.h"
+#include "access/genam.h"
+#include "access/iqual.h"
+#include "access/hash.h"
+
+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 = RelationGetTupleDescriptor(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, 
+			      RelationGetTupleDescriptor(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(WARN, "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)
+{
+    PageHeader ph = (PageHeader) page;
+    HashPageOpaque opaque;
+
+    Assert(page);
+    Assert(ph->pd_lower >= (sizeof(PageHeaderData) - sizeof(ItemIdData)));
+#if 1
+    Assert(ph->pd_upper <=
+	   (BLCKSZ - DOUBLEALIGN(sizeof(HashPageOpaqueData))));
+    Assert(ph->pd_special ==
+	   (BLCKSZ - DOUBLEALIGN(sizeof(HashPageOpaqueData))));
+    Assert(ph->pd_opaque.od_pagesize == BLCKSZ);
+#endif
+    if (flags) {
+	opaque = (HashPageOpaque) PageGetSpecialPointer(page);
+	Assert(opaque->hasho_flag & flags);
+    }
+}