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https://github.com/reactos/reactos.git
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86 lines
4.4 KiB
C
86 lines
4.4 KiB
C
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/*****************************************************************************
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* FullFAT - High Performance, Thread-Safe Embedded FAT File-System *
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* Copyright (C) 2009 James Walmsley (james@worm.me.uk) *
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* *
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* This program is free software: you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation, either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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* *
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* IMPORTANT NOTICE: *
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* ================= *
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* Alternative Licensing is available directly from the Copyright holder, *
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* (James Walmsley). For more information consult LICENSING.TXT to obtain *
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* a Commercial license. *
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* *
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* See RESTRICTIONS.TXT for extra restrictions on the use of FullFAT. *
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* *
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* Removing the above notice is illegal and will invalidate this license. *
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*****************************************************************************
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* See http://worm.me.uk/fullfat for more information. *
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* Or http://fullfat.googlecode.com/ for latest releases and the wiki. *
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*****************************************************************************/
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/**
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* @file ff_blk.c
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* @author James Walmsley
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* @ingroup BLK
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*
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* @defgroup BLK Block Calculater
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* @brief Handle Block Number conversions
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*
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* Helps calculate block numbers.
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**/
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#include "ff_blk.h"
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/**
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* @private
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**/
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FF_T_UINT32 FF_getClusterChainNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
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FF_PARTITION *pPart = pIoman->pPartition;
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FF_T_UINT32 clusterChainNumber = nEntry / (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
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return clusterChainNumber;
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}
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FF_T_UINT32 FF_getClusterPosition(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
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return nEntry % ((pIoman->BlkSize * (pIoman->pPartition->SectorsPerCluster * pIoman->pPartition->BlkFactor)) / nEntrySize);
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}
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/**
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* @private
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**/
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FF_T_UINT32 FF_getMajorBlockNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
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FF_PARTITION *pPart = pIoman->pPartition;
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FF_T_UINT32 relClusterEntry = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
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FF_T_UINT32 majorBlockNumber = relClusterEntry / (pPart->BlkSize / nEntrySize);
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return majorBlockNumber;
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}
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/**
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* @private
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**/
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FF_T_UINT8 FF_getMinorBlockNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
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FF_PARTITION *pPart = pIoman->pPartition;
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FF_T_UINT32 relClusterEntry = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
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FF_T_UINT16 relmajorBlockEntry = (FF_T_UINT16)(relClusterEntry % (pPart->BlkSize / nEntrySize));
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FF_T_UINT8 minorBlockNumber = (FF_T_UINT8) (relmajorBlockEntry / (pIoman->BlkSize / nEntrySize));
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return minorBlockNumber;
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}
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/**
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* @private
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**/
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FF_T_UINT32 FF_getMinorBlockEntry(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
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FF_PARTITION *pPart = pIoman->pPartition;
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FF_T_UINT32 relClusterEntry = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
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FF_T_UINT32 relmajorBlockEntry = (FF_T_UINT32)(relClusterEntry % (pPart->BlkSize / nEntrySize));
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FF_T_UINT32 minorBlockEntry = (FF_T_UINT32)(relmajorBlockEntry % (pIoman->BlkSize / nEntrySize));
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return minorBlockEntry;
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}
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