public void DecodePayload(byte[] buffer, int offset, ActorFrameHeader frameHeader, out byte[] payload, out int payloadOffset, out int payloadCount)
{
payload = buffer;
payloadOffset = offset + frameHeader.Length;
payloadCount = frameHeader.PayloadLength;
if (frameHeader.IsMasked)
{
payload = new byte[payloadCount];
for (var i = 0; i < payloadCount; i++)
{
payload[i] = (byte)(buffer[payloadOffset + i] ^ buffer[offset + frameHeader.MaskingKeyOffset + i % MaskingKeyLength]);
}
payloadOffset = 0;
payloadCount = payload.Length;
}
}
private ActorFrameHeader DecodeFrameHeader(byte[] buffer, int offset, int count)
{
if (count < 2)
{
return(null);
}
// parse fixed header
var header = new ActorFrameHeader()
{
IsRSV0 = ((buffer[offset + 0] & 0x80) == 0x80),
IsRSV1 = ((buffer[offset + 0] & 0x40) == 0x40),
IsRSV2 = ((buffer[offset + 0] & 0x20) == 0x20),
IsRSV3 = ((buffer[offset + 0] & 0x10) == 0x10),
OpCode = (OpCode)(buffer[offset + 0] & 0x0f),
IsMasked = ((buffer[offset + 1] & 0x80) == 0x80),
PayloadLength = (buffer[offset + 1] & 0x7f),
Length = 2,
};
// parse extended payload length
if (header.PayloadLength >= 126)
{
if (header.PayloadLength == 126)
{
header.Length += 2;
}
else
{
header.Length += 8;
}
if (count < header.Length)
{
return(null);
}
if (header.PayloadLength == 126)
{
header.PayloadLength = buffer[offset + 2] * 256 + buffer[offset + 3];
}
else
{
int totalLength = 0;
int level = 1;
for (int i = 7; i >= 0; i--)
{
totalLength += buffer[offset + i + 2] * level;
level *= 256;
}
header.PayloadLength = totalLength;
}
}
// parse masking key
if (header.IsMasked)
{
if (count < header.Length + MaskingKeyLength)
{
return(null);
}
header.MaskingKeyOffset = header.Length;
header.Length += MaskingKeyLength;
}
return(header);
}
public bool TryDecodeFrameHeader(byte[] buffer, int offset, int count, out ActorFrameHeader frameHeader)
{
frameHeader = DecodeFrameHeader(buffer, offset, count);
return(frameHeader != null);
}
