protected override unsafe void Encode(IChannelHandlerContext ctx, WebSocketFrame msg, List <object> output)
{
IByteBuffer data = msg.Content;
var mask = stackalloc byte[4];
byte opcode = 0;
switch (msg.Opcode)
{
case Opcode.Text:
opcode = OpcodeText;
break;
case Opcode.Ping:
opcode = OpcodePing;
break;
case Opcode.Pong:
opcode = OpcodePong;
break;
case Opcode.Close:
opcode = OpcodeClose;
break;
case Opcode.Binary:
opcode = OpcodeBinary;
break;
case Opcode.Cont:
opcode = OpcodeCont;
break;
default:
ThrowNotSupportedException(msg);
break;
}
int length = data.ReadableBytes;
if (Logger.TraceEnabled)
{
Logger.EncodingWebSocketFrameOpCode(opcode, length);
}
int b0 = 0;
if (msg.IsFinalFragment)
{
b0 |= 1 << 7;
}
b0 |= msg.Rsv % 8 << 4;
b0 |= opcode % 128;
if (opcode == OpcodePing && length > 125)
{
ThrowTooLongFrameException(length);
}
bool release = true;
IByteBuffer buf = null;
try
{
int maskLength = this.maskPayload ? 4 : 0;
if (length <= 125)
{
int size = 2 + maskLength;
if (this.maskPayload || length <= GatheringWriteThreshold)
{
size += length;
}
buf = ctx.Allocator.Buffer(size);
_ = buf.WriteByte(b0);
byte b = (byte)(this.maskPayload ? 0x80 | (byte)length : (byte)length);
_ = buf.WriteByte(b);
}
else if (length <= 0xFFFF)
{
int size = 4 + maskLength;
if (this.maskPayload || length <= GatheringWriteThreshold)
{
size += length;
}
buf = ctx.Allocator.Buffer(size);
_ = buf.WriteByte(b0);
_ = buf.WriteByte(this.maskPayload ? 0xFE : 126);
_ = buf.WriteByte(length.RightUShift(8) & 0xFF);
_ = buf.WriteByte(length & 0xFF);
}
else
{
int size = 10 + maskLength;
if (this.maskPayload || length <= GatheringWriteThreshold)
{
size += length;
}
buf = ctx.Allocator.Buffer(size);
_ = buf.WriteByte(b0);
_ = buf.WriteByte(this.maskPayload ? 0xFF : 127);
_ = buf.WriteLong(length);
}
// Write payload
if (this.maskPayload)
{
int intMask = (this.random.Next() * int.MaxValue);
// Mask bytes in BE
uint unsignedValue = (uint)intMask;
* mask = (byte)(unsignedValue >> 24);
*(mask + 1) = (byte)(unsignedValue >> 16);
*(mask + 2) = (byte)(unsignedValue >> 8);
*(mask + 3) = (byte)unsignedValue;
// Mask in BE
_ = buf.WriteInt(intMask);
int counter = 0;
int i = data.ReaderIndex;
int end = data.WriterIndex;
for (; i + 3 < end; i += 4)
{
int intData = data.GetInt(i);
_ = buf.WriteInt(intData ^ intMask);
}
for (; i < end; i++)
{
byte byteData = data.GetByte(i);
_ = buf.WriteByte(byteData ^ mask[counter++ % 4]);
}
output.Add(buf);
}
else
{
if (buf.WritableBytes >= data.ReadableBytes)
{
// merge buffers as this is cheaper then a gathering write if the payload is small enough
_ = buf.WriteBytes(data);
output.Add(buf);
}
else
{
output.Add(buf);
output.Add(data.Retain());
}
}
release = false;
}
finally
{
if (release)
{
_ = (buf?.Release());
}
}
}