imgtools/imglib/filesystem/source/fat32bootsector.cpp
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     1 /*
       
     2 * Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     3 * All rights reserved.
       
     4 * This component and the accompanying materials are made available
       
     5 * under the terms of the License "Eclipse Public License v1.0"
       
     6 * which accompanies this distribution, and is available
       
     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     8 *
       
     9 * Initial Contributors:
       
    10 * Nokia Corporation - initial contribution.
       
    11 *
       
    12 * Contributors:
       
    13 *
       
    14 * Description: 
       
    15 * This class represents the boot sector of a FAT32 image. 
       
    16 * This class is derived from basebootsector class which is constitutes 
       
    17 * the common boot sector fields for FAT16 and FAT32 class. 
       
    18 * @internalComponent
       
    19 * @released
       
    20 *
       
    21 */
       
    22 
       
    23 #include "fat32bootsector.h"
       
    24 #include <cstring>
       
    25 
       
    26 /**
       
    27 Constructor of the fat16 boot sector class
       
    28 
       
    29 @internalComponent
       
    30 @released
       
    31 */
       
    32 TFAT32BootSector::TFAT32BootSector()
       
    33 {
       
    34 }
       
    35 
       
    36 /**
       
    37 Destructor of the fat16 boot sector class
       
    38 
       
    39 @internalComponent
       
    40 @released
       
    41 */
       
    42 TFAT32BootSector::~TFAT32BootSector()
       
    43 {
       
    44 }
       
    45 /**
       
    46 Set the file system type
       
    47 
       
    48 @internalComponent
       
    49 @released
       
    50 */
       
    51 void TFAT32BootSector::SetFileSysType()
       
    52 {
       
    53 	strcpy(reinterpret_cast<char*>(iFileSysType),"FAT32   ");
       
    54 }
       
    55 
       
    56 
       
    57 //Number of entries allowed in the root directory, specific to Fat12/16, zero for FAT32
       
    58 void TFAT32BootSector::SetRootDirEntries()
       
    59 {
       
    60 	iRootDirEntries = KFat32RootDirEntries;;		
       
    61 }
       
    62 
       
    63 
       
    64 //Sets the number of reserved sectors on the volume
       
    65 void TFAT32BootSector::SetReservedSectors()
       
    66 {
       
    67 	iReservedSectors = KDefaultFat32ReservedSectors;
       
    68 }
       
    69 
       
    70 /**
       
    71 Set the sectors per cluster ratio
       
    72 
       
    73 @internalComponent
       
    74 @released
       
    75 
       
    76 @param aPartitionSize partition size in bytes
       
    77 */
       
    78 void TFAT32BootSector::ComputeSectorsPerCluster(Long64 aPartitionSize)
       
    79 {
       
    80 	if (aPartitionSize > K32GB)
       
    81 	{
       
    82 		iSectorsPerCluster = K64SectorsPerCluster;	
       
    83 	}
       
    84 	else if(aPartitionSize > K16GB)
       
    85 	{
       
    86 		iSectorsPerCluster = K32SectorsPerCluster;
       
    87 	}
       
    88 	else if(aPartitionSize > K8GB)
       
    89 	{
       
    90 		iSectorsPerCluster = K16SectorsPerCluster;
       
    91 	}
       
    92 	else if ( aPartitionSize > K260MB)
       
    93 	{
       
    94 		iSectorsPerCluster = K8SectorsPerCluster;	
       
    95 	}
       
    96 	else 
       
    97 	{
       
    98 		iSectorsPerCluster = K1SectorsPerCluster;
       
    99 	}
       
   100 }
       
   101 	
       
   102 /**
       
   103 Set the sectors per cluster ratio
       
   104 
       
   105 
       
   106 To refer this mathematical computation, Please see:
       
   107 Microsoft Extensible Firmware Initiative FAT32 File System 
       
   108 Specification document
       
   109 
       
   110 @internalComponent
       
   111 @released
       
   112 
       
   113 @param aPartitionSize partition size in bytes
       
   114 */
       
   115 void TFAT32BootSector::ComputeFatSectors(Long64 aPartitionSize)
       
   116 {
       
   117 	int iRootDirSectors = ((iRootDirEntries*32) + (iBytesPerSector - 1)) / iBytesPerSector;
       
   118 	int Log2OfBytesPerSector = Log2(iBytesPerSector);
       
   119 	Long64 TotalSectors64 = aPartitionSize >> Log2OfBytesPerSector;
       
   120 	Long64 tmpval1 = TotalSectors64 - (iReservedSectors + iRootDirSectors);
       
   121 	Long64 tmpval2 =(256 * iSectorsPerCluster) + iNumberOfFats;
       
   122 	tmpval2 = tmpval2 / 2;
       
   123 	Long64 FatSectors = (tmpval1 + (tmpval2 - 1)) / tmpval2;
       
   124 	iFatSectors = 0;
       
   125 	iFatSectors32 = (unsigned int)FatSectors;
       
   126 }
       
   127 /**
       
   128 Sets the Fat flags
       
   129 
       
   130 @internalComponent
       
   131 @released
       
   132 */
       
   133 void TFAT32BootSector::SetExtFlags()
       
   134 {
       
   135 	iExtFlags = KDefaultExtFlags;
       
   136 }
       
   137 
       
   138 /**
       
   139 Returns the Fat flags
       
   140 
       
   141 @internalComponent
       
   142 @released
       
   143 
       
   144 @return fat flags
       
   145 */
       
   146 unsigned short TFAT32BootSector::ExtFlags()
       
   147 {
       
   148 	return iExtFlags;
       
   149 }
       
   150 
       
   151 /**
       
   152 Sets the version number of the file system
       
   153 
       
   154 @internalComponent
       
   155 @released
       
   156 */
       
   157 void TFAT32BootSector::SetFileSystemVersion()
       
   158 {
       
   159 	iFileSystemVersion = KDefaultVersion;
       
   160 }
       
   161 
       
   162 /**
       
   163 Returns the version number of the file system
       
   164 
       
   165 @internalComponent
       
   166 @released
       
   167 
       
   168 @return file system version
       
   169 */
       
   170 unsigned short TFAT32BootSector::FileSystemVersion()
       
   171 {
       
   172 	return iFileSystemVersion;
       
   173 }
       
   174 
       
   175 /**
       
   176 Sets the cluster number of the root directory
       
   177 
       
   178 @internalComponent
       
   179 @released
       
   180 */
       
   181 void TFAT32BootSector::SetRootCluster()
       
   182 {
       
   183 	iRootCluster = KDefaultRootDirClusterNumber;
       
   184 }
       
   185 
       
   186 /**
       
   187 Returns the cluster number of the root directory
       
   188 
       
   189 @internalComponent
       
   190 @released
       
   191 
       
   192 @return cluster number allocated to root directory,usually 2.
       
   193 */
       
   194 unsigned int TFAT32BootSector::RootCluster()
       
   195 {
       
   196 	return iRootCluster;
       
   197 }
       
   198 
       
   199 /**
       
   200 Set the sector number containing the FSIInfo structure
       
   201 
       
   202 @internalComponent
       
   203 @released
       
   204 */
       
   205 void TFAT32BootSector::SetFSInfo()
       
   206 {
       
   207 	iFSInfo = KDefaultFSInfoSector;
       
   208 }
       
   209 
       
   210 /**
       
   211 Returns  the sector number containing the FSIInfo structure
       
   212 
       
   213 @internalComponent
       
   214 @released
       
   215 
       
   216 @return FSInfo structure
       
   217 */
       
   218 unsigned short TFAT32BootSector::FSInfo()
       
   219 {
       
   220 	return iFSInfo;
       
   221 }
       
   222 
       
   223 /**
       
   224 Set the backup boot sector
       
   225 
       
   226 @internalComponent
       
   227 @released
       
   228 */
       
   229 void TFAT32BootSector::SetBackUpBootSector()
       
   230 {
       
   231 	iBackUpBootSector = KDefaultBkUpBootSec;
       
   232 }
       
   233 
       
   234 /**
       
   235 Returns the backup boot sector
       
   236 
       
   237 @internalComponent
       
   238 @released
       
   239 
       
   240 @return backup boot sector
       
   241 */
       
   242 unsigned  short TFAT32BootSector::BackUpBootSector()
       
   243 {
       
   244 	return iBackUpBootSector;
       
   245 }
       
   246 
       
   247 /**
       
   248 Reserved for future expansion. Code that formats FAT32 volumes should always 
       
   249 set all of the bytes of this field to 0.
       
   250 
       
   251 @internalComponent
       
   252 @released
       
   253 */
       
   254 void TFAT32BootSector::SetFutureReserved()
       
   255 {
       
   256 	for(int i = 0;i < KMaxSizeFutureExpansion;i++)
       
   257 	iFutureReserved[i] = 0;
       
   258 }
       
   259 
       
   260 /**
       
   261 Returns field value reserved for future expansion
       
   262 
       
   263 @internalComponent
       
   264 @released
       
   265 
       
   266 @return zero as this field is initialized to null value here
       
   267 */
       
   268 unsigned char* TFAT32BootSector::FutureReserved()
       
   269 {
       
   270 	return iFutureReserved;
       
   271 }
       
   272 
       
   273 
       
   274 /**Returns the file system type
       
   275 
       
   276 @internalComponent
       
   277 @released
       
   278 
       
   279 @return file system type
       
   280 */
       
   281 unsigned char* TFAT32BootSector::FileSysType()
       
   282 {
       
   283 	return iFileSysType;
       
   284 }