plan9fox/sys/lib/python/encodings/uu_codec.py

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2011-05-03 11:25:13 +00:00
""" Python 'uu_codec' Codec - UU content transfer encoding
Unlike most of the other codecs which target Unicode, this codec
will return Python string objects for both encode and decode.
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, binascii
### Codec APIs
def uu_encode(input,errors='strict',filename='<data>',mode=0666):
""" Encodes the object input and returns a tuple (output
object, length consumed).
errors defines the error handling to apply. It defaults to
'strict' handling which is the only currently supported
error handling for this codec.
"""
assert errors == 'strict'
from cStringIO import StringIO
from binascii import b2a_uu
infile = StringIO(input)
outfile = StringIO()
read = infile.read
write = outfile.write
# Encode
write('begin %o %s\n' % (mode & 0777, filename))
chunk = read(45)
while chunk:
write(b2a_uu(chunk))
chunk = read(45)
write(' \nend\n')
return (outfile.getvalue(), len(input))
def uu_decode(input,errors='strict'):
""" Decodes the object input and returns a tuple (output
object, length consumed).
input must be an object which provides the bf_getreadbuf
buffer slot. Python strings, buffer objects and memory
mapped files are examples of objects providing this slot.
errors defines the error handling to apply. It defaults to
'strict' handling which is the only currently supported
error handling for this codec.
Note: filename and file mode information in the input data is
ignored.
"""
assert errors == 'strict'
from cStringIO import StringIO
from binascii import a2b_uu
infile = StringIO(input)
outfile = StringIO()
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] == 'begin':
break
# Decode
while 1:
s = readline()
if not s or \
s == 'end\n':
break
try:
data = a2b_uu(s)
except binascii.Error, v:
# Workaround for broken uuencoders by /Fredrik Lundh
nbytes = (((ord(s[0])-32) & 63) * 4 + 5) / 3
data = 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):
pass
class StreamReader(Codec,codecs.StreamReader):
pass
### encodings module API
def getregentry():
return codecs.CodecInfo(
name='uu',
encode=uu_encode,
decode=uu_decode,
incrementalencoder=IncrementalEncoder,
incrementaldecoder=IncrementalDecoder,
streamreader=StreamReader,
streamwriter=StreamWriter,
)