lib/3rdparty/fullfat/ff_blk.c

   1 /*****************************************************************************
   2  *  FullFAT - High Performance, Thread-Safe Embedded FAT File-System         *
   3  *  Copyright (C) 2009  James Walmsley (james@worm.me.uk)                    *
   4  *                                                                           *
   5  *  This program is free software: you can redistribute it and/or modify     *
   6  *  it under the terms of the GNU General Public License as published by     *
   7  *  the Free Software Foundation, either version 3 of the License, or        *
   8  *  (at your option) any later version.                                      *
   9  *                                                                           *
  10  *  This program is distributed in the hope that it will be useful,          *
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of           *
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            *
  13  *  GNU General Public License for more details.                             *
  14  *                                                                           *
  15  *  You should have received a copy of the GNU General Public License        *
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.    *
  17  *                                                                           *
  18  *  IMPORTANT NOTICE:                                                        *
  19  *  =================                                                        *
  20  *  Alternative Licensing is available directly from the Copyright holder,   *
  21  *  (James Walmsley). For more information consult LICENSING.TXT to obtain   *
  22  *  a Commercial license.                                                    *
  23  *                                                                           *
  24  *  See RESTRICTIONS.TXT for extra restrictions on the use of FullFAT.       *
  25  *                                                                           *
  26  *  Removing the above notice is illegal and will invalidate this license.   *
  27  *****************************************************************************
  28  *  See http://worm.me.uk/fullfat for more information.                      *
  29  *  Or  http://fullfat.googlecode.com/ for latest releases and the wiki.     *
  30  *****************************************************************************/
  31
  32 /**
  33  *      @file           ff_blk.c
  34  *      @author         James Walmsley
  35  *      @ingroup        BLK
  36  *
  37  *      @defgroup       BLK Block Calculater
  38  *      @brief          Handle Block Number conversions
  39  *
  40  *      Helps calculate block numbers.
  41  **/
  42
  43 #include "ff_blk.h"
  44 /**
  45  *      @private
  46  **/
  47 FF_T_UINT32 FF_getClusterChainNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
  48         FF_PARTITION *pPart                             = pIoman->pPartition;
  49         FF_T_UINT32 clusterChainNumber  = nEntry / (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
  50         return clusterChainNumber;
  51 }
  52
  53 FF_T_UINT32 FF_getClusterPosition(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
  54         return nEntry % ((pIoman->BlkSize * (pIoman->pPartition->SectorsPerCluster * pIoman->pPartition->BlkFactor)) / nEntrySize);
  55 }
  56 /**
  57  *      @private
  58  **/
  59 FF_T_UINT32 FF_getMajorBlockNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
  60         FF_PARTITION *pPart = pIoman->pPartition;
  61         FF_T_UINT32 relClusterEntry             = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
  62         FF_T_UINT32 majorBlockNumber    = relClusterEntry / (pPart->BlkSize / nEntrySize);
  63         return majorBlockNumber;
  64 }
  65 /**
  66  *      @private
  67  **/
  68 FF_T_UINT8 FF_getMinorBlockNumber(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
  69         FF_PARTITION *pPart                             = pIoman->pPartition;
  70         FF_T_UINT32 relClusterEntry             = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
  71         FF_T_UINT16 relmajorBlockEntry  = (FF_T_UINT16)(relClusterEntry % (pPart->BlkSize / nEntrySize));
  72         FF_T_UINT8 minorBlockNumber             = (FF_T_UINT8) (relmajorBlockEntry / (pIoman->BlkSize / nEntrySize));
  73         return minorBlockNumber;
  74 }
  75 /**
  76  *      @private
  77  **/
  78 FF_T_UINT32 FF_getMinorBlockEntry(FF_IOMAN *pIoman, FF_T_UINT32 nEntry, FF_T_UINT16 nEntrySize) {
  79         FF_PARTITION *pPart                             = pIoman->pPartition;
  80         FF_T_UINT32 relClusterEntry             = nEntry % (pIoman->BlkSize * (pPart->SectorsPerCluster * pPart->BlkFactor) / nEntrySize);
  81         FF_T_UINT32 relmajorBlockEntry  = (FF_T_UINT32)(relClusterEntry % (pPart->BlkSize / nEntrySize));
  82         FF_T_UINT32 minorBlockEntry             = (FF_T_UINT32)(relmajorBlockEntry % (pIoman->BlkSize / nEntrySize));
  83         return minorBlockEntry;
  84 }
  85