191 lines
5.8 KiB
C
191 lines
5.8 KiB
C
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/*****************************************************************************
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* *
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* BTKTSZ.C *
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* *
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* Copyright (C) Microsoft Corporation 1990, 1990. *
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* All Rights reserved. *
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* *
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******************************************************************************
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* *
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* Module Intent *
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* *
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* Functions for SZ (0-terminated string) keys. *
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* *
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******************************************************************************
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* *
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* Testing Notes *
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* *
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******************************************************************************
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* *
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* Current Owner: JohnSc *
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* *
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******************************************************************************
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* *
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* Released by Development: long, long ago *
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* *
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*****************************************************************************/
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/*****************************************************************************
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*
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* Revision History: Created 00/00/89 by JohnSc
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*
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* 08/21/90 JohnSc autodocified
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*
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*****************************************************************************/
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#include <windows.h>
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#include <orkin.h>
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#include <string.h>
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#include "_mvfs.h"
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#include "imvfs.h"
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#include "btpriv.h"
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// _subsystem( btree );
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/***************************************************************************\
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*
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- Function: BkScanSzInternal( bk, key, wLevel, qbthr )
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-
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* Purpose: Scan an internal node for a key and return child BK.
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*
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* ASSUMES
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* args IN: bk - BK of internal node to scan
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* key - key to search for
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* wLevel - level of btree bk lives on
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* qbthr - btree header containing cache, and btree specs
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* qiKey - address of an int or NULL to not get it
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*
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* PROMISES
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* returns: bk of subtree that might contain key; bkNil on error
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* args OUT: qbthr->qCache - bk's block will be cached
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* qiKey - index into rgbBlock of first key >= key
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*
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* Side Effects: bk's block will be cached
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*
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\***************************************************************************/
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_private BK FAR PASCAL
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BkScanSzInternal(
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BK bk,
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KEY key,
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INT wLevel,
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QBTHR qbthr,
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QI qiKey)
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{
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QCB qcb;
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QB q;
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INT cKeys;
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if ( ( qcb = QFromBk( bk, wLevel, qbthr ) ) == NULL )
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{
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return bkNil;
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}
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q = qcb->db.rgbBlock;
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cKeys = qcb->db.cKeys;
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bk = *(UNALIGNED BK FAR *)q;
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q += sizeof( BK );
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while ( cKeys-- > 0 )
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{
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if ( strcmp( (SZ)key, (SZ)q ) >= 0 )
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{
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q += lstrlen( (SZ)q ) + 1;
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bk = *(UNALIGNED BK FAR *)q;
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q += sizeof( BK );
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}
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else
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break;
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}
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if ( qiKey != NULL )
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{
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*qiKey = q - (QB)qcb->db.rgbBlock;
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}
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return bk;
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}
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/***************************************************************************\
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*
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- Function: RcScanSzLeaf( bk, key, wLevel, qbthr, qRec, qbtpos )
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-
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* Purpose: Scan a leaf node for a key and copy the associated data.
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*
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* ASSUMES
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* args IN: bk - the leaf block
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* key - the key we're looking for
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* wLevel - the level of leaves (unnecessary)
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* qbthr - the btree header
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*
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* PROMISES
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* returns: rcSuccess if found; rcNoExists if not found
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* args OUT: qRec - if found, record gets copied into this buffer
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* qbtpos - pos of first key >= key goes here
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*
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* Notes: If we are scanning for a key greater than any key in this
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* block, the pos returned will be invalid and will point just
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* past the last valid key in this block.
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*
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\***************************************************************************/
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_private RC FAR PASCAL
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RcScanSzLeaf(
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BK bk,
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KEY key,
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INT wLevel,
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QBTHR qbthr,
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QV qRec,
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QBTPOS qbtpos)
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{
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QCB qcb;
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SZ sz;
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INT w, cKey;
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QB qb;
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if ( ( qcb = QFromBk( bk, wLevel, qbthr ) ) == NULL )
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{
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return RcGetBtreeError();
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}
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SetBtreeErrorRc(rcNoExists);
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sz = qcb->db.rgbBlock + 2 * sizeof( BK );
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for ( cKey = 0; cKey < qcb->db.cKeys; cKey++ )
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{
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w = strcmp( (SZ)key, sz );
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if ( w > 0 ) /* still looking for key */
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{
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sz += lstrlen( sz ) + 1;
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sz += CbSizeRec( sz, qbthr );
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}
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else if ( w < 0 ) /* key not found */
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{
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break;
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}
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else /* matched the key */
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{
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if ( qRec != NULL )
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{
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qb = (QB)sz + lstrlen( sz ) + 1;
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QvCopy( qRec, qb, (LONG)CbSizeRec( qb, qbthr ) );
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}
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SetBtreeErrorRc(rcSuccess);
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break;
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}
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}
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if ( qbtpos != NULL )
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{
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qbtpos->bk = bk;
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qbtpos->cKey = cKey;
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qbtpos->iKey = (QB)sz - (QB)qcb->db.rgbBlock;
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}
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return RcGetBtreeError();;
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}
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/* EOF */
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