/// <summary>
/// Finds the entry.
/// </summary>
/// <param name="compare">The compare.</param>
/// <param name="startCluster">The start cluster.</param>
/// <returns></returns>
public FatFileLocation FindEntry(FatFileSystem.ICompare compare, uint startCluster)
{
uint activeSector = startCluster * sectorsPerCluster;
if (startCluster == 0)
activeSector = (fatType == FatType.FAT32) ? GetSectorByCluster(rootCluster32) : firstRootDirectorySector;
uint increment = 0;
for (;;)
{
BinaryFormat directory = new BinaryFormat(partition.ReadBlock(activeSector, 1));
for (uint index = 0; index < entriesPerSector; index++)
{
if (compare.Compare(directory.Data, index * 32, fatType))
{
FatFileAttributes attribute = (FatFileAttributes)directory.GetByte((index * Entry.EntrySize) + Entry.FileAttributes);
return new FatFileLocation(GetClusterEntry(directory.Data, index, fatType), activeSector, index, (attribute & FatFileAttributes.SubDirectory) != 0);
}
if (directory.GetByte(Entry.DOSName + (index * Entry.EntrySize)) == FileNameAttribute.LastEntry)
return new FatFileLocation();
}
++increment;
if ((startCluster == 0) && (fatType != FatType.FAT32))
{
// FAT12/16 Root directory
if (increment >= rootDirSectors)
return new FatFileLocation();
activeSector = startCluster + increment;
continue;
}
else
{
// subdirectory
if (increment < sectorsPerCluster)
{
// still within cluster
activeSector = startCluster + increment;
continue;
}
// exiting cluster
// goto next cluster (if any)
uint cluster = GetClusterBySector(startCluster);
if (cluster == 0)
return new FatFileLocation();
uint nextCluster = GetClusterEntryValue(cluster);
if ((IsClusterLast(nextCluster)) || (IsClusterBad(nextCluster)) || (IsClusterFree(nextCluster)) || (IsClusterReserved(nextCluster)))
return new FatFileLocation();
activeSector = (uint)(dataAreaStart + (nextCluster - 1 * sectorsPerCluster));
continue;
}
}
}
