public static Boolean TryParse(Byte[] frameStart, Int32 offset, Int32 headerLength, ArraySegment<Byte> keySegment, out WebSocketFrameHeader header) { header = null; if (frameStart == null || frameStart.Length < 6 || frameStart.Length < (offset + headerLength)) return false; Int32 value = frameStart[offset+1]; UInt64 contentLength = (UInt64)(value>=128?value - 128:value); if (contentLength <= 125) { // small frame } else if (contentLength == 126) { if (frameStart.Length < headerLength) return false; if(BitConverter.IsLittleEndian) frameStart.ReversePortion(offset + 2, 2); contentLength = BitConverter.ToUInt16(frameStart, 2); } else if (contentLength == 127) { if (frameStart.Length < headerLength) return false; if (BitConverter.IsLittleEndian) frameStart.ReversePortion(offset + 2, 8); contentLength = (UInt64)BitConverter.ToUInt64(frameStart, 2); } else return false; WebSocketFrameHeaderFlags flags; if (WebSocketFrameHeaderFlags.TryParse(frameStart, offset, out flags)) { header = new WebSocketFrameHeader(keySegment) { ContentLength = contentLength, HeaderLength = headerLength, Flags = flags, RemainingBytes = contentLength }; if (flags.MASK) { headerLength -= 4; for (int i = 0; i < 4; i++) header._key.Array[header._key.Offset + i] = frameStart[offset + i + headerLength]; } return true; } return false; }
public static Boolean TryParse(Byte[] frameStart, Int32 offset, Int32 headerLength, ArraySegment<Byte> keySegment, out WebSocketFrameHeader header) { header = null; if (frameStart == null || frameStart.Length < 6 || frameStart.Length < (offset + headerLength)) return false; Int32 value = frameStart[offset+1]; Int64 contentLength = (Int64)(value>=128?value - 128:value); if (contentLength <= 125) { // small frame } else if (contentLength == 126) { if (frameStart.Length < headerLength) return false; if(BitConverter.IsLittleEndian) frameStart.ReversePortion(offset + 2, 2); contentLength = BitConverter.ToUInt16(frameStart, 2); } else if (contentLength == 127) { if (frameStart.Length < headerLength) return false; if (BitConverter.IsLittleEndian) frameStart.ReversePortion(offset + 2, 8); UInt64 length = BitConverter.ToUInt64(frameStart, 2); if(length > Int64.MaxValue) { throw new WebSocketException("The maximum supported frame length is 9223372036854775807, current frame is " + length.ToString()); } contentLength = (Int64)length; } else return false; WebSocketFrameHeaderFlags flags; if (WebSocketFrameHeaderFlags.TryParse(frameStart, offset, out flags)) { header = new WebSocketFrameHeader(keySegment) { ContentLength = contentLength, HeaderLength = headerLength, Flags = flags, RemainingBytes = contentLength }; if (flags.MASK) { headerLength -= 4; for (int i = 0; i < 4; i++) header._key.Array[header._key.Offset + i] = frameStart[offset + i + headerLength]; } return true; } return false; }