private IEnumerable <DriveBlock> readAvailableContentBlocks()
{
lock (_entriesTableLock)
{
var operation = _synchronizer.EnqueueOperation(drive =>
{
if (drive.Length < ByteHelper.GetLength <int>())
{
return(new byte[0]);
}
var buffer = new byte[ByteHelper.GetLength <int>()];
drive.Position = drive.Length - ByteHelper.GetLength <int>() * 2;// read last 4 but 4 bytes
drive.Read(buffer, 0, buffer.Length);
var infoLength = BitConverter.ToInt32(buffer, 0);
if (infoLength <= 0)
{
buffer = new byte[0];
}
else
{
buffer = new byte[infoLength];
drive.Position = drive.Length - ByteHelper.GetLength <int>() * 2 - infoLength;
drive.Read(buffer, 0, infoLength);
}
drive.SetLength(drive.Length - infoLength - ByteHelper.GetLength <int>() * 2); //get rid of available blocks info
return(buffer);
}, OperationType.FileTable);
_synchronizer.EnqueueOperation(operation);
var readBytes = operation.Task.Result;
var processedBytes = 0;
while (processedBytes < readBytes.Length)
{
var retv = AvailableDriveBlock.Read(readBytes.Skip(processedBytes).Take(AvailableDriveBlock.BytesBlockLength)
.ToArray());
processedBytes += AvailableDriveBlock.BytesBlockLength;
yield return(retv);
}
}
}
public static AvailableDriveBlock Read(byte[] block)
{
if (block.Length != BytesBlockLength)
{
throw new InvalidOperationException("Unable to read block");
}
var position = 0;
var blockPosition = BitConverter.ToInt64(block, position);
position += ByteHelper.GetLength <long>();
var blockLength = BitConverter.ToInt32(block, position);
var retv = new AvailableDriveBlock(blockPosition, blockLength);
return(retv);
}
