/// <summary>
/// Initializes a new FAT file stream for the specified file.
/// </summary>
/// <param name="aFile">The file to create a stream to.</param>
/// <param name="ignoreFileSize">Whether to ignore the file size or not. True for directories.</param>
public FATFileStream(FATFile aFile, bool ignoreFileSize)
: base(aFile)
{
IgnoreFileSize = ignoreFileSize;
if (TheFATFile == null)
{
ExceptionMethods.Throw(new Exception("Could not create FATFileStream. Specified file object was null!"));
}
GetClusterNums();
}
/// <summary>
/// Writes the specified number of the bytes from the buffer starting at offset in the buffer.
/// </summary>
/// <param name="buffer">The data to write.</param>
/// <param name="offset">The offset within the buffer to start writing from.</param>
/// <param name="count">The number of bytes to write.</param>
public override void Write(byte[] buffer, int offset, int count)
{
if (count < 0)
{
ExceptionMethods.Throw(new Exceptions.ArgumentException("FATFileStream.Write: aCount must be > 0"));
}
else if (offset < 0)
{
ExceptionMethods.Throw(new Exceptions.ArgumentException("FATFileStream.Write: anOffset must be > 0"));
}
else if (buffer == null)
{
ExceptionMethods.Throw(new Exceptions.ArgumentException("FATFileStream.Write: aBuffer must not be null!"));
}
else if (buffer.Length - offset < count)
{
ExceptionMethods.Throw(new Exceptions.ArgumentException("FATFileStream.Write: Invalid offset / length values!"));
}
//BasicConsole.WriteLine("Checks passed.");
FATFileSystem mFS = (FATFileSystem)TheFile.TheFileSystem;
FATFile mFile = TheFATFile;
if (ClusterNums == null)
{
//BasicConsole.WriteLine("Getting cluster nums...");
GetClusterNums();
if (ClusterNums == null)
{
//BasicConsole.WriteLine("Failed to get cluster nums.");
return;
}
//BasicConsole.WriteLine("Got cluster nums.");
}
//BasicConsole.WriteLine("Creating write buffer...");
UInt32 xClusterSize = mFS.BytesPerCluster;
byte[] writeBuffer = mFS.NewClusterArray();
//BasicConsole.WriteLine("Writing data...");
while (count > 0)
{
UInt32 clusterIdx = (UInt32)position / xClusterSize;
UInt32 posInCluster = (UInt32)position % xClusterSize;
bool newCluster = false;
while (clusterIdx >= ClusterNums.Count)
{
//BasicConsole.WriteLine("Expanding clusters...");
UInt32 lastClusterNum = ClusterNums[ClusterNums.Count - 1];
UInt32 nextClusterNum = mFS.GetNextFreeCluster(lastClusterNum);
//Clear cluster
mFS.WriteCluster(nextClusterNum, null);
//Set last FAT entry to point to next cluster
mFS.SetFATEntryAndSave(lastClusterNum, nextClusterNum);
//Set next cluster as EOF
mFS.SetFATEntryAndSave(nextClusterNum, FATFileSystem.GetFATEntryEOFValue(mFS.FATType));
//Add next cluster num to our list
ClusterNums.Add(nextClusterNum);
newCluster = true;
}
if ((posInCluster != 0 || count < xClusterSize) && !newCluster)
{
//BasicConsole.WriteLine("Reading existing data...");
mFS.ReadClusters(ClusterNums[(int)clusterIdx], 1, writeBuffer);
//BasicConsole.WriteLine("Read existing data.");
}
//BasicConsole.WriteLine("Calculating write size...");
int writeSize = count < (xClusterSize - posInCluster) ? count :
(int)(xClusterSize - posInCluster);
//BasicConsole.WriteLine("Calculated write size. Copying data to write...");
Array.Copy(buffer, offset, writeBuffer, (int)posInCluster, writeSize);
//BasicConsole.WriteLine("Data copied. Writing data to disk...");
mFS.WriteCluster(ClusterNums[(int)clusterIdx], writeBuffer);
//BasicConsole.WriteLine("Written data.");
count -= writeSize;
offset += writeSize;
position += (uint)writeSize;
}
mFS.CleanDiskCaches();
//BasicConsole.WriteLine("Write completed.");
if (!IgnoreFileSize)
{
if (position > mFile.Size)
{
//Update file info
mFile.Size = position;
//Update directory entry
mFile.Parent.WriteListings();
}
}
}
