HttpPostedFile::SaveAs in .net 1, 2 and 4

asp-net-file-uploads-advanced.cs

// HttpPostedFile::SaveAs

// from .net 1.0
public void SaveAs(string filename)
{
	FileStream fileStream = new FileStream(filename, 2);
	try
	{
		if (this._stream.DataLength > 0)
		{
			fileStream.Write(this._stream.Data, this._stream.DataOffset, this._stream.DataLength);
		}
		fileStream.Flush();
	}
	finally
	{
		fileStream.Close();
	}
}

// from .net 2.0 (same in 4.0)
public void SaveAs(string filename)
{
	if (!Path.IsPathRooted(filename))
	{
		HttpRuntimeSection httpRuntime = RuntimeConfig.GetConfig().HttpRuntime;
		if (httpRuntime.RequireRootedSaveAsPath)
		{
			throw new HttpException(SR.GetString("SaveAs_requires_rooted_path", new object[]
			{
				filename
			}));
		}
	}
	FileStream fileStream = new FileStream(filename, FileMode.Create);
	try
	{
		this._stream.WriteTo(fileStream);
		fileStream.Flush();
	}
	finally
	{
		fileStream.Close();
	}
}

// relevant extraction

FileStream fileStream = new FileStream(filename, FileMode.Create);
try
{
	this._stream.WriteTo(fileStream);
	fileStream.Flush();
}
finally
{
	fileStream.Close();
}

// .net 1 does FileStream::Write
// .net 2+ does HttpInputStream::WriteTo (which does HttpRawUploadContent::WriteBytes)

// System.Web.HttpRawUploadedContent
internal void WriteBytes(int offset, int length, Stream stream)
{
	if (!this._completed)
	{
		throw new InvalidOperationException();
	}
	if (this._file != null)
	{
		int num = offset;
		int i = length;
		byte[] buffer = new byte[(i > this._fileThreshold) ? this._fileThreshold : i];
		while (i > 0)
		{
			int length2 = (i > this._fileThreshold) ? this._fileThreshold : i;
			int bytes = this._file.GetBytes(num, length2, buffer, 0);
			if (bytes == 0)
			{
				return;
			}
			stream.Write(buffer, 0, bytes);
			num += bytes;
			i -= bytes;
		}
		return;
	}
	stream.Write(this._data, offset, length);
}

// regular streams

// System.Web.HttpRawUploadedContent.TempFile
internal int GetBytes(int offset, int length, byte[] buffer, int bufferOffset)
{
	if (this._filestream == null)
	{
		throw new InvalidOperationException();
	}
	this._filestream.Seek((long)offset, SeekOrigin.Begin);
	return this._filestream.Read(buffer, bufferOffset, length);
}

// System.Web.HttpRequest
private HttpRawUploadedContent GetEntireRawContent()