def fill(self, byte):
"""
fill: byte -> None
Adds the given byte to this LinkFrame. If this byte is an escape
byte, the next byte in a call to fill() will be unescaped.
"""
if self._unescape_next_byte:
byte = intToByte(byteToInt(byte) ^ 0x20)
self._unescape_next_byte = False
elif byte == LinkFrame.ESCAPE_BYTE:
self._unescape_next_byte = True
return
self.raw_data += intToByte(byteToInt(byte))
def escape(data):
"""
escape: byte string -> byte string
When the 'special' byte is found in the data string,
it must be preceded by an escape byte and XOR'd with 0x20
"""
escaped_data = b""
for byte in data:
if intToByte(byteToInt(byte)) in LinkFrame.ESCAPE_BYTES:
escaped_data += LinkFrame.ESCAPE_BYTE
escaped_data += intToByte(0x20 ^ byteToInt(byte))
else:
escaped_data += intToByte(byteToInt(byte))
return escaped_data