public PartitionedFileStreamFactory(string fileName)
{
_fileStream = new FileStream(fileName, FileMode.OpenOrCreate);
if (_fileStream.Length == 0)
{
_header = new PartitionedFileHeader(0);
_dataStart = _newStreamOffset = PartitionedFileHeader.DataOffset;
_header.Write(_fileStream);
}
}
public PartitionedFileStream GetNewStream()
{
var bufferOverrun = (_newStreamOffset + sizeof (long)) - (_dataStart + _header.LengthOfCurrentBuffer);
if (bufferOverrun > 0)
{
_header.OffsetOfNextHeader = _fileStream.Length;
_fileStream.Seek(_currentHeaderOffset, SeekOrigin.Begin);
_header.Write(_fileStream);
_currentHeaderOffset = _header.OffsetOfHeader;
_header = AddNewHeaderSection();
_header.OffsetOfPrevHeader = _currentHeaderOffset;
_fileStream.Seek(_header.OffsetOfHeader, SeekOrigin.Begin);
_header.Write(_fileStream);
}
_fileStream.Seek(_newStreamOffset, SeekOrigin.Begin);
var newHeader = AddNewHeaderSection();
Serializer.Serialize(_fileStream, _fileStream.Length);
_newStreamOffset += sizeof (long);
return new PartitionedFileStream(_fileStream, newHeader, AddNewHeaderSection);
}
public PartitionedFileHeader AddNewHeaderSection()
{
var header = new PartitionedFileHeader(_fileStream.Length) { LengthOfCurrentBuffer = _bufferSize };
_fileStream.Seek(0, SeekOrigin.End);
header.Write(_fileStream);
var buffer = new byte[_bufferSize];
_fileStream.Write(buffer, 0, buffer.Length);
_fileStream.Seek(PartitionedFileHeader.DataOffset, SeekOrigin.Begin);
return header;
}
private PartitionedFileHeader AddNewHeaderSection()
{
const int bufferSize = 4096;
var header = new PartitionedFileHeader(_fileStream.Length) {LengthOfCurrentBuffer = bufferSize};
_fileStream.Seek(0, SeekOrigin.End);
header.Write(_fileStream);
var buffer = new byte[bufferSize];
_fileStream.Write(buffer, 0, buffer.Length);
return header;
}
