"""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,
)