from easybits import Bits

import codecs

def register_codec(encode, decode, name):
    def encode_wrapper(text):
        return encode(text), len(text)

    def decode_wrapper(data):
        return decode(data), len(data)

    def search_for_codec(query):
        if query == name:
            return codecs.CodecInfo(encode_wrapper, decode_wrapper, name=name)

    codecs.register(search_for_codec)

characters=['A','B','C','D','E','F','G','H','I','J','K','L','M', 'N', 'O','P','Q','R','S','T','U','V','W','X','Y','Z',' ','.',',','?','!']


def encode(text):
    """This encoder consists of the 26 uppercase letters and select punctuation. 
    Characters that are not defined are removed, which makes the encoding less accurate than ascii7. 
    There are 5 bits for each byte, so the function ascii5 compresses text into 5/8 of its original size."""
    result= Bits()
    text = text.upper()
    for character in text:
        if character in characters:
            index = characters.index(character)
            b=Bits(bin(index)[2:].zfill(5))
            result = result.concat(b)
    return result.bytes

def decode(data):
    """This function reads 5 bits and returns the text to match."""
    bits=Bits(bytes(data))
    text = ''
    for i in range(0,len(bits),5):
        s=bits[i:i+5]
        index=int(s.bin,2)
        text+= characters[index]
    return text


register_codec(encode, decode, "ascii5")