/// <summary>
/// Parse the header from the input stream.
///
/// This will read bytes up to the start of the data block.
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
public static FrameHeader Parse(Stream input)
{
byte[] buffer = new byte[MaxHeaderSize];
// Read the header
if (!WebSocket.ReadBytes(input, buffer, 0, 2))
{
return(null);
}
// Decode it
FrameHeader header = new FrameHeader();
header.Finished = ((buffer[0] & 0x80) == 0x80);
header.OpCode = (byte)(buffer[0] & 0x0f);
header.Masked = ((buffer[1] & 0x80) == 0x80);
// Get the length
long length = (long)(buffer[1] & 0x7f);
// Check for extended length
if (length == 126)
{
// 16 bit payload length
if (!WebSocket.ReadBytes(input, buffer, 0, 2))
{
return(null);
}
length = ConvertBytes(buffer, 2);
}
else if (length == 127)
{
// 64 bit payload length
if (!ReadBytes(input, buffer, 0, 8))
{
return(null);
}
length = ConvertBytes(buffer, 8);
}
header.Length = length;
// If the frame is masked we need the key
if (header.Masked)
{
header.Key = new byte[KeySize];
if (!WebSocket.ReadBytes(input, header.Key, 0, KeySize))
{
return(null);
}
}
return(header);
}
