"""Python 'uu_codec' Codec - UU content transfer encoding.

This codec de/encodes from bytes to bytes.

Written by Marc-Andre Lemburg (mal@lemburg.com). Some details were

adapted from uu.py which was written by Lance Ellinghouse and

modified by Jack Jansen and Fredrik Lundh.

"""

import codecs

import binascii

from io import BytesIO

### Codec APIs

def uu_encode(input, errors='strict', filename='<data>', mode=0o666):

    assert errors == 'strict'

    infile = BytesIO(input)

    outfile = BytesIO()

    read = infile.read

    write = outfile.write

    # Encode

    write(('begin %o %s\n' % (mode & 0o777, filename)).encode('ascii'))

    chunk = read(45)

    while chunk:

        write(binascii.b2a_uu(chunk))

        chunk = read(45)

    write(b' \nend\n')

    return (outfile.getvalue(), len(input))

def uu_decode(input, errors='strict'):

    assert errors == 'strict'

    infile = BytesIO(input)

    outfile = BytesIO()

    readline = infile.readline

    write = outfile.write

    # Find start of encoded data

    while 1:

        s = readline()

        if not s:

            raise ValueError('Missing "begin" line in input data')

        if s[:5] == b'begin':

            break

    # Decode

    while True:

        s = readline()

        if not s or s == b'end\n':

            break

        try:

            data = binascii.a2b_uu(s)

        except binascii.Error as v:

            # Workaround for broken uuencoders by /Fredrik Lundh

            nbytes = (((s[0]-32) & 63) * 4 + 5) // 3

            data = binascii.a2b_uu(s[:nbytes])

            #sys.stderr.write("Warning: %s\n" % str(v))

        write(data)

    if not s:

        raise ValueError('Truncated input data')

    return (outfile.getvalue(), len(input))

class Codec(codecs.Codec):

    def encode(self, input, errors='strict'):

        return uu_encode(input, errors)

    def decode(self, input, errors='strict'):

        return uu_decode(input, errors)

class IncrementalEncoder(codecs.IncrementalEncoder):

    def encode(self, input, final=False):

        return uu_encode(input, self.errors)[0]

class IncrementalDecoder(codecs.IncrementalDecoder):

    def decode(self, input, final=False):

        return uu_decode(input, self.errors)[0]

class StreamWriter(Codec, codecs.StreamWriter):

    charbuffertype = bytes

class StreamReader(Codec, codecs.StreamReader):

    charbuffertype = bytes

### encodings module API

def getregentry():

    return codecs.CodecInfo(

        name='uu',

        encode=uu_encode,

        decode=uu_decode,

        incrementalencoder=IncrementalEncoder,

        incrementaldecoder=IncrementalDecoder,

        streamreader=StreamReader,

        streamwriter=StreamWriter,

        _is_text_encoding=False,

    )