BplusDotNet.LinkedFile.readHeader C# (CSharp) Method

        void readHeader()
        {
            byte[] header = new byte[this.headersize];
            this.fromfile.Seek(this.seekStart, System.IO.SeekOrigin.Begin);
            this.fromfile.Read(header, 0, this.headersize);
            int index = 0;
            // check prefix
            foreach (byte b in HEADERPREFIX)
            {
                if (header[index]!=b)
                {
                    throw new LinkedFileException("invalid header prefix");
                }
                index++;
            }
            // skip version (for now)
            index++;
            // read buffersize
            this.buffersize = BufferFile.Retrieve(header, index);
            index += BufferFile.INTSTORAGE;
            this.FreeListHead = BufferFile.RetrieveLong(header, index);
            this.sanityCheck();
            this.headerDirty = false;
        }

 public static LinkedFile SetupFromExistingStream(System.IO.Stream fromfile, long StartSeek)
 {
     LinkedFile result = new LinkedFile(100, StartSeek); // dummy buffer size for now
     result.fromfile = fromfile;
     result.readHeader();
     result.buffers = BufferFile.SetupFromExistingStream(fromfile, StartSeek+result.headersize);
     return result;
 }