public void TestAlignedBytes()
{
Byte[] bytesIn = System.Text.Encoding.UTF8.GetBytes("Some aligned bytes");
DatagramWriter writer = new DatagramWriter();
writer.WriteBytes(bytesIn);
DatagramReader reader = new DatagramReader(writer.ToByteArray());
Byte[] bytesOut = reader.ReadBytesLeft();
Assert.IsSequenceEqualTo(bytesIn, bytesOut);
}
public void TestBytesLeftUnaligned()
{
Int32 bitCount = 7;
Int32 bitsIn = 0x55;
Byte[] bytesIn = System.Text.Encoding.UTF8.GetBytes("Some aligned bytes");
DatagramWriter writer = new DatagramWriter();
writer.Write(bitsIn, bitCount);
writer.WriteBytes(bytesIn);
DatagramReader reader = new DatagramReader(writer.ToByteArray());
Int32 bitsOut = reader.Read(bitCount);
Byte[] bytesOut = reader.ReadBytesLeft();
Assert.IsEqualTo(bitsIn, bitsOut);
Assert.IsSequenceEqualTo(bytesIn, bytesOut);
}
public Message Decode(Byte[] bytes)
#endif
{
DatagramReader datagram = new DatagramReader(bytes);
// read headers
Int32 version = datagram.Read(VersionBits);
if (version != SupportedVersion)
{
return(null);
}
MessageType type = (MessageType)datagram.Read(TypeBits);
Int32 tokenLength = datagram.Read(TokenLengthBits);
Int32 code = datagram.Read(CodeBits);
// create new message with subtype according to code number
Message msg = Message.Create(code);
msg.Type = type;
msg.ID = datagram.Read(IDBits);
// read token
if (tokenLength > 0)
{
msg.Token = datagram.ReadBytes(tokenLength);
}
else
{
msg.RequiresToken = false;
}
// read options
Int32 currentOption = 0;
while (datagram.BytesAvailable)
{
Byte nextByte = datagram.ReadNextByte();
if (nextByte == PayloadMarker)
{
if (!datagram.BytesAvailable)
{
// the presence of a marker followed by a zero-length payload
// must be processed as a message format error
return(null);
}
msg.Payload = datagram.ReadBytesLeft();
}
else
{
// the first 4 bits of the byte represent the option delta
Int32 optionDeltaNibble = (0xF0 & nextByte) >> 4;
currentOption += GetValueFromOptionNibble(optionDeltaNibble, datagram);
// the second 4 bits represent the option length
Int32 optionLengthNibble = (0x0F & nextByte);
Int32 optionLength = GetValueFromOptionNibble(optionLengthNibble, datagram);
// read option
OptionType currentOptionType = GetOptionType(currentOption);
Option opt = Option.Create(currentOptionType);
opt.RawValue = datagram.ReadBytes(optionLength);
msg.AddOption(opt);
}
}
return(msg);
}
public Message Decode(Byte[] bytes)
#endif
{
DatagramReader datagram = new DatagramReader(bytes);
// read headers
Int32 version = datagram.Read(VersionBits);
if (version != SupportedVersion)
{
return(null);
}
MessageType type = (MessageType)datagram.Read(TypeBits);
Int32 optionCount = datagram.Read(OptionCountBits);
Int32 code = datagram.Read(CodeBits);
// create new message with subtype according to code number
Message msg = Message.Create(code);
msg.Type = type;
msg.ID = datagram.Read(IDBits);
// read options
Int32 currentOption = 0;
for (Int32 i = 0; i < optionCount; i++)
{
// read option delta bits
Int32 optionDelta = datagram.Read(OptionDeltaBits);
currentOption += optionDelta;
OptionType currentOptionType = GetOptionType(currentOption);
if (IsFencepost(currentOptionType))
{
// read number of options
datagram.Read(OptionLengthBaseBits);
}
else
{
// read option length
Int32 length = datagram.Read(OptionLengthBaseBits);
if (length > MaxOptionLengthBase)
{
// read extended option length
length += datagram.Read(OptionLengthExtendedBits);
}
// read option
Option opt = Option.Create(currentOptionType);
opt.RawValue = datagram.ReadBytes(length);
msg.AddOption(opt);
}
}
msg.Payload = datagram.ReadBytesLeft();
// incoming message already have a token,
// including implicit empty token
msg.RequiresToken = false;
return(msg);
}
public Message Decode(Byte[] bytes)
#endif
{
DatagramReader datagram = new DatagramReader(bytes);
// read headers
Int32 version = datagram.Read(VersionBits);
if (version != SupportedVersion)
{
return(null);
}
MessageType type = (MessageType)datagram.Read(TypeBits);
Int32 optionCount = datagram.Read(OptionCountBits);
Int32 code = datagram.Read(CodeBits);
// create new message with subtype according to code number
Message msg = Message.Create(code);
msg.Type = type;
msg.ID = datagram.Read(IDBits);
// read options
Int32 currentOption = 0;
Boolean hasMoreOptions = optionCount == 15;
for (Int32 i = 0; (i < optionCount || hasMoreOptions) && datagram.BytesAvailable; i++)
{
// first 4 option bits: either option jump or option delta
Int32 optionDelta = datagram.Read(OptionDeltaBits);
if (optionDelta == 15)
{
// option jump or end-of-options marker
Int32 bits = datagram.Read(4);
switch (bits)
{
case 0:
// end-of-options marker read (0xF0), payload follows
hasMoreOptions = false;
continue;
case 1:
// 0xF1 (Delta = 15)
optionDelta = 15 + datagram.Read(OptionDeltaBits);
break;
case 2:
// Delta = ((Option Jump Value) + 2) * 8
optionDelta = (datagram.Read(8) + 2) * 8 + datagram.Read(OptionDeltaBits);
break;
case 3:
// Delta = ((Option Jump Value) + 258) * 8
optionDelta = (datagram.Read(16) + 258) * 8 + datagram.Read(OptionDeltaBits);
break;
default:
break;
}
}
currentOption += optionDelta;
OptionType currentOptionType = GetOptionType(currentOption);
Int32 length = datagram.Read(OptionLengthBaseBits);
if (length == 15)
{
/*
* When the Length field is set to 15, another byte is added as
* an 8-bit unsigned integer whose value is added to the 15,
* allowing option value lengths of 15-270 bytes. For option
* lengths beyond 270 bytes, we reserve the value 255 of an
* extension byte to mean
* "add 255, read another extension byte".
*/
Int32 additionalLength = 0;
do
{
additionalLength = datagram.Read(8);
length += additionalLength;
} while (additionalLength >= 255);
}
// read option
Option opt = Option.Create(currentOptionType);
opt.RawValue = datagram.ReadBytes(length);
msg.AddOption(opt);
}
msg.Payload = datagram.ReadBytesLeft();
// incoming message already have a token, including implicit empty token
msg.RequiresToken = false;
return(msg);
}
