/**
* Skips the integrity pad and pad length fields.
*
* @param rawMessage - Byte array holding whole message data.
* @param offset - Offset to integrity pad.
* @return Offset to Auth Code
* @throws IndexOutOfBoundsException when message is corrupted and pad length does not appear
* after integrity pad or length is incorrect.
*/
private int skipIntegrityPAD(byte[] rawMessage, int offset) throws IndexOutOfBoundsException {
int skip = 0;
while (TypeConverter.byteToInt(rawMessage[offset + skip]) == 0xff) {
++skip;
}
int length = TypeConverter.byteToInt(rawMessage[offset + skip]);
if (length != skip) {
throw new IndexOutOfBoundsException("Message is corrupted.");
}
offset += skip + 2; // skip pad length and next header fields
if (offset >= rawMessage.length) {
throw new IndexOutOfBoundsException("Message is corrupted.");
}
return offset;
}
/**
* Decodes OEM IANA.
*
* @param rawMessage - Byte array holding whole message data.
* @return OEM IANA number.
*/
private int decodeOEMIANA(byte[] rawMessage) {
byte[] oemIANA = new byte[4];
System.arraycopy(rawMessage, 3, oemIANA, 0, 3);
oemIANA[3] = 0;
return TypeConverter.littleEndianByteArrayToInt(oemIANA);
}
@Override
protected int decodePayloadLength(byte[] rawData, int offset) {
byte[] payloadLength = new byte[4];
System.arraycopy(rawData, offset, payloadLength, 0, 2);
payloadLength[2] = 0;
payloadLength[3] = 0;
return TypeConverter.littleEndianByteArrayToInt(payloadLength);
}
public static PayloadType decodePayloadType(byte payloadType) throws IllegalArgumentException {
return PayloadType.parseInt(
TypeConverter.intToByte(payloadType & TypeConverter.intToByte(0x3f)));
}
/**
* Decodes second bit of Payload Type.
*
* @param payloadType
* @return True if payload is authenticated, false otherwise.
*/
public boolean decodeAuthentication(byte payloadType) {
return !((payloadType & TypeConverter.intToByte(0x40)) == 0);
}
/**
* Decodes first bit of Payload Type.
*
* @param payloadType
* @return True if payload is encrypted, false otherwise.
*/
private boolean decodeEncryption(byte payloadType) {
return !((payloadType & TypeConverter.intToByte(0x80)) == 0);
}