class SlipDecoder:
    buffer = []
    result = []
    state = 1

    def decode_message(self, s):
        #s = bytearray(s, 'ascii')
        for x in s:
            c = ord(x)
            if self.state == 1:
                if c == 0x7e:
                    self.state = 2
            elif self.state == 2:
                if c == 0x7c:
                    if self.buffer != []:
                        self.result += [self.buffer]
                    self.buffer = []
                    self.state = 1
                elif c == 0x7d:
                    self.state = 3
                else:
                    self.buffer += [c]
            elif self.state == 3:
                if c ^ 0x20 not in [0x7d, 0x7c, 0x7e]:
                    self.state = 1
                    self.buffer = []
                else:
                    self.buffer += [c ^ 0x20]
                    self.state = 2

        returned = [''.join(map(chr, e)) for e in self.result]
        self.result = []
        return returned

#decoder = SlipDecoder()
#print(decoder.decode_message('~hell'))
#print(decoder.decode_message('o|'))