AppPkg/Applications/Python/Python-2.7.10/Lib/encodings/uu_codec.py

   1 """ Python 'uu_codec' Codec - UU content transfer encoding
   2
   3     Unlike most of the other codecs which target Unicode, this codec
   4     will return Python string objects for both encode and decode.
   5
   6     Written by Marc-Andre Lemburg (mal@lemburg.com). Some details were
   7     adapted from uu.py which was written by Lance Ellinghouse and
   8     modified by Jack Jansen and Fredrik Lundh.
   9
  10 """
  11 import codecs, binascii
  12
  13 ### Codec APIs
  14
  15 def uu_encode(input,errors='strict',filename='<data>',mode=0666):
  16
  17     """ Encodes the object input and returns a tuple (output
  18         object, length consumed).
  19
  20         errors defines the error handling to apply. It defaults to
  21         'strict' handling which is the only currently supported
  22         error handling for this codec.
  23
  24     """
  25     assert errors == 'strict'
  26     from cStringIO import StringIO
  27     from binascii import b2a_uu
  28     # using str() because of cStringIO's Unicode undesired Unicode behavior.
  29     infile = StringIO(str(input))
  30     outfile = StringIO()
  31     read = infile.read
  32     write = outfile.write
  33
  34     # Encode
  35     write('begin %o %s\n' % (mode & 0777, filename))
  36     chunk = read(45)
  37     while chunk:
  38         write(b2a_uu(chunk))
  39         chunk = read(45)
  40     write(' \nend\n')
  41
  42     return (outfile.getvalue(), len(input))
  43
  44 def uu_decode(input,errors='strict'):
  45
  46     """ Decodes the object input and returns a tuple (output
  47         object, length consumed).
  48
  49         input must be an object which provides the bf_getreadbuf
  50         buffer slot. Python strings, buffer objects and memory
  51         mapped files are examples of objects providing this slot.
  52
  53         errors defines the error handling to apply. It defaults to
  54         'strict' handling which is the only currently supported
  55         error handling for this codec.
  56
  57         Note: filename and file mode information in the input data is
  58         ignored.
  59
  60     """
  61     assert errors == 'strict'
  62     from cStringIO import StringIO
  63     from binascii import a2b_uu
  64     infile = StringIO(str(input))
  65     outfile = StringIO()
  66     readline = infile.readline
  67     write = outfile.write
  68
  69     # Find start of encoded data
  70     while 1:
  71         s = readline()
  72         if not s:
  73             raise ValueError, 'Missing "begin" line in input data'
  74         if s[:5] == 'begin':
  75             break
  76
  77     # Decode
  78     while 1:
  79         s = readline()
  80         if not s or \
  81            s == 'end\n':
  82             break
  83         try:
  84             data = a2b_uu(s)
  85         except binascii.Error, v:
  86             # Workaround for broken uuencoders by /Fredrik Lundh
  87             nbytes = (((ord(s[0])-32) & 63) * 4 + 5) // 3
  88             data = a2b_uu(s[:nbytes])
  89             #sys.stderr.write("Warning: %s\n" % str(v))
  90         write(data)
  91     if not s:
  92         raise ValueError, 'Truncated input data'
  93
  94     return (outfile.getvalue(), len(input))
  95
  96 class Codec(codecs.Codec):
  97
  98     def encode(self,input,errors='strict'):
  99         return uu_encode(input,errors)
 100
 101     def decode(self,input,errors='strict'):
 102         return uu_decode(input,errors)
 103
 104 class IncrementalEncoder(codecs.IncrementalEncoder):
 105     def encode(self, input, final=False):
 106         return uu_encode(input, self.errors)[0]
 107
 108 class IncrementalDecoder(codecs.IncrementalDecoder):
 109     def decode(self, input, final=False):
 110         return uu_decode(input, self.errors)[0]
 111
 112 class StreamWriter(Codec,codecs.StreamWriter):
 113     pass
 114
 115 class StreamReader(Codec,codecs.StreamReader):
 116     pass
 117
 118 ### encodings module API
 119
 120 def getregentry():
 121     return codecs.CodecInfo(
 122         name='uu',
 123         encode=uu_encode,
 124         decode=uu_decode,
 125         incrementalencoder=IncrementalEncoder,
 126         incrementaldecoder=IncrementalDecoder,
 127         streamreader=StreamReader,
 128         streamwriter=StreamWriter,
 129     )