.Net zlib inflate with .Net 4.5

Question

According to MSDN in .Net 4.5 System.IO.Compression is based on zlib.
I am trying now to change my current interop based reading from a zlib deflated stream from a non .

Answer 1

The answer above is correct but isn't exactly clear on the "why". The first two bytes of a raw ZLib stream provide details about the type of compression used. Microsoft's DeflateStream class in System.Io.Compression doesn't understand these. The fix is as follows:

using (MemoryStream ms = new MemoryStream(data))
{
    MemoryStream msInner = new MemoryStream();

    // Read past the first two bytes of the zlib header
    ms.Seek(2, SeekOrigin.Begin);

    using (DeflateStream z = new DeflateStream(ms, CompressionMode.Decompress))
    {
        z.CopyTo(msInner);

In this example, data is a Byte[] with the raw Zlib file. After loading it into a MemoryStream, we simply "seek" past the first two bytes.

The post explains what a Zlib header looks like if you are looking at the raw bytes.

What does a zlib header look like?