/// <summary>
/// 解析请求的数据
/// 返回请求数据包
/// </summary>
/// <param name="streamReader">数据读取器</param>
/// <param name="requiredMask">是否要求必须Mask</param>
/// <exception cref="NotSupportedException"></exception>
/// <returns></returns>
public static FrameRequest Parse(IByteStream streamReader, bool requiredMask = true)
{
if (streamReader.Length < 2)
{
return(null);
}
ByteBits byte0 = streamReader.ReadByte();
bool fin = byte0[0];
ByteBits rsv = byte0.Take(1, 3);
FrameCodes frameCode = (FrameCodes)(byte)byte0.Take(4, 4);
ByteBits byte1 = streamReader.ReadByte();
bool mask = byte1[0];
if (requiredMask && mask == false)
{
throw new NotSupportedException("mask is required");
}
if (Enum.IsDefined(typeof(FrameCodes), frameCode) == false || rsv != 0)
{
throw new NotSupportedException();
}
int contentSize = 0;
int contentLength = byte1.Take(1, 7);
if (contentLength == 127)
{
contentSize = 8;
contentLength = (int)streamReader.ReadLong();
}
else if (contentLength == 126)
{
contentSize = 2;
contentLength = (ushort)streamReader.ReadShort();
}
int maskSize = mask ? 4 : 0;
int packetLength = 2 + maskSize + contentSize + contentLength;
if (streamReader.Length < packetLength)
{
return(null);
}
byte[] maskingKey = mask ? streamReader.ReadBytes(4) : null;
byte[] content = streamReader.ReadBytes(contentLength);
if (mask && contentLength > 0)
{
for (int i = 0; i < contentLength; i++)
{
content[i] = (byte)(content[i] ^ maskingKey[i % 4]);
}
}
return(new FrameRequest
{
Fin = fin,
Rsv = rsv,
Mask = mask,
Frame = frameCode,
ContentLength = contentLength,
MaskingKey = maskingKey,
Content = content
});
}
public byte ReadByte()
{
return(_stream.ReadByte());
}