windows-nt/Source/XPSP1/NT/enduser/stuff/itircl/common/btree/btktvsti.c

/*****************************************************************************
 *                                                                            *
 *  BTKTVSTI.C                                                                 *
 *                                                                            *
 *  Copyright (C) Microsoft Corporation 1989 - 1994.                          *
 *  All Rights reserved.                                                      *
 *                                                                            *
 ******************************************************************************
 *                                                                            *
 *  Module Intent                                                             *
 *                                                                            *
 *  Functions for VSTI (Variable length previxed pascal strings               *
 *                                                                            *
 ******************************************************************************
 *                                                                            *
 *  Current Owner:  davej                                                     *
 *                                                                            *
 ******************************************************************************

 Format for a key & record is:
 
 KEY:

 Key Length		[Variable 1 or 2]
 Key String		[<Length> chars]

 RECORD:

 File Offset	[Variable 3, 4, 5, or 6]
 File Length	[Variable 1, 2, 3, 4, or 5]
 File Flags		1

static char s_aszModule[] = __FILE__;	/* For error report */

#include <mvopsys.h>
#include <orkin.h>
#include <misc.h>
#include <iterror.h>
#include <wrapstor.h>
#include <mvsearch.h>
#include <_mvutil.h>
#include "common.h"


/***************************************************************************
 *
 *	@doc	INTERNAL
 *
 *	@func	BK FAR PASCAL | BkScanVstiInternal |
 *		Scan an internal node for a key and return child BK.
 *
 *	@parm	BK | bk |
 *		BK of internal node to scan
 *
 *	@parm	KEY | key |
 *		key to search for
 *
 *	@parm	SHORT | wLevel |
 *		level of btree bk lives on
 *
 *	@parm	QBTHR | qbthr |
 *		btree header containing cache, and btree specs
 *
 *	@parm	QW | qiKey |
 *		address of an int or NULL to not get it
 *
 *	@parm	QBTHR | qbthr |
 *		qbthr->qCache - bk's block will be cached
 *
 *	@parm	QW | qiKey |
 *		index into rgbBlock of first key >= key
 *
 *	@rdesc	bk of subtree that might contain key; bkNil on error
 *		Side Effects:   bk's block will be cached
 *
 ***************************************************************************/

PUBLIC BK FAR PASCAL BkScanVstiInternal(BK bk, KEY key, SHORT wLevel,
	QBTHR qbthr, QW qiKey, PHRESULT phr)
{
	QCB qcb;
	QB  q;
	SHORT cKeys;
    LPB   lpLigatureTable;
	WORD 	wStringLen;
	WORD	wStringLenComp;
	WORD	wLongLen;
	FILEOFFSET fo;
	
	fo=FoFromSz((LPBYTE)key);
	wStringLen=(WORD)fo.dwOffset;

	ADVANCE_FO((LPBYTE)key);
	
	if ((qcb = QFromBk(bk, wLevel, qbthr, phr)) == NULL)
	{
		return bkNil;
	}
	q     = qcb->db.rgbBlock;
	cKeys = qcb->db.cKeys;
	
	
	bk = (BK)GETLONG(q);
	q += sizeof(BK);

	lpLigatureTable =  (!qbthr->lrglpCharTab)?NULL:(LPB)(((LPCHARTAB)*qbthr->lrglpCharTab)->lpLigature);

	while (cKeys-- > 0)
	{
		fo=FoFromSz((LPBYTE)q);
		wStringLenComp=(WORD)fo.dwOffset;
		wLongLen=LenSzFo((LPBYTE)q);			// Length of variable length 'long'
	
    	if (WCmpiSnn((SZ)key, (SZ)(q+wLongLen), lpLigatureTable,wStringLen, wStringLenComp) >= 0)
		{
			q += wStringLenComp + wLongLen;
			bk = (BK)GETLONG(q);
			q += sizeof(BK);
		}
		else
			break;
	}

	if (qiKey != NULL)
	{
		*qiKey = (WORD)(q - (QB)qcb->db.rgbBlock);
	}

	return bk;
}

/***************************************************************************
 *
 *	@doc	INTERNAL
 *
 *	@func	HRESULT FAR PASCAL | RcScanVstiLeaf |
 *		Scan a leaf node for a key and copy the associated data.
 *
 *	@parm	BK | bk |
 *		the leaf block
 *
 *	@parm	KEY | key |
 *		the key we're looking for
 *
 *	@parm	SHORT | wLevel |
 *		the level of leaves (unnecessary)
 *
 *	@parm	QBTHR | qbthr |
 *		the btree header
 *
 *	@parm	QV | qRec |
 *		if found, record gets copied into this buffer
 *
 *	@parm	QTPOS | qbtpos |
 *		pos of first key >= key goes here
 *
 *	@rdesc	ERR_SUCCESS if found; ERR_NOTEXIST if not found
 *		If we are scanning for a key greater than any key in this
 *		block, the pos returned will be invalid and will point just
 *		past the last valid key in this block.
 *
 ***************************************************************************/

PUBLIC HRESULT FAR PASCAL RcScanVstiLeaf( BK bk, KEY key, SHORT wLevel,
	QBTHR qbthr, QV qRec, QBTPOS qbtpos)
{
	QCB   qcb;
	SZ    sz;
	SHORT   w, cKey;
	QB    qb;
	HRESULT    rc;
    HRESULT  errb;
    LPB   lpLigatureTable;
	WORD 	wStringLen;
	WORD	wStringLenComp;
	WORD	wLongLen;
	
	if ((qcb = QFromBk(bk, wLevel, qbthr, &errb)) == NULL) {
		return errb;
	}
	
	wStringLen=(WORD)FoFromSz((LPBYTE)key).dwOffset;
	ADVANCE_FO((LPBYTE)key);
	
	rc = E_NOTEXIST;

	sz = qcb->db.rgbBlock + 2 * sizeof(BK);
    lpLigatureTable =  (!qbthr->lrglpCharTab)?NULL:(LPB)(((LPCHARTAB)*qbthr->lrglpCharTab)->lpLigature);


	for (cKey = 0; cKey < qcb->db.cKeys; cKey++)
	{
		wStringLenComp=(WORD)FoFromSz((LPBYTE)sz).dwOffset;
		wLongLen=LenSzFo((LPBYTE)sz);			// Length of variable length 'long'

		w = WCmpiSnn((SZ)key, sz+wLongLen, lpLigatureTable, wStringLen, wStringLenComp);

		if (w > 0) /* still looking for key */
		{
			sz += wLongLen+wStringLenComp;
			sz += CbSizeRec(sz, qbthr);
		}
		else if (w < 0) /* key not found */
		{
			break;
		}
		else /* matched the key */
		{
			if (qRec != NULL)
			{
			  qb = (QB)sz + wLongLen + wStringLenComp;
			  QVCOPY(qRec, qb, (LONG)CbSizeRec(qb, qbthr));
			}

			rc = S_OK;
			break;
		}
	}

	if (qbtpos != NULL)
	{
		qbtpos->bk   = bk;
		qbtpos->cKey = cKey;
		qbtpos->iKey = (int)((QB)sz - (QB)qcb->db.rgbBlock);
	}

	return rc;
}

/* EOF */