Lib/encodings/hex_codec.py

   1 """ Python 'hex_codec' Codec - 2-digit hex 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).
   7
   8 """
   9 import codecs, binascii
  10
  11 ### Codec APIs
  12
  13 def hex_encode(input,errors='strict'):
  14
  15     """ Encodes the object input and returns a tuple (output
  16         object, length consumed).
  17
  18         errors defines the error handling to apply. It defaults to
  19         'strict' handling which is the only currently supported
  20         error handling for this codec.
  21
  22     """
  23     assert errors == 'strict'
  24     output = binascii.b2a_hex(input)
  25     return (output, len(input))
  26
  27 def hex_decode(input,errors='strict'):
  28
  29     """ Decodes the object input and returns a tuple (output
  30         object, length consumed).
  31
  32         input must be an object which provides the bf_getreadbuf
  33         buffer slot. Python strings, buffer objects and memory
  34         mapped files are examples of objects providing this slot.
  35
  36         errors defines the error handling to apply. It defaults to
  37         'strict' handling which is the only currently supported
  38         error handling for this codec.
  39
  40     """
  41     assert errors == 'strict'
  42     output = binascii.a2b_hex(input)
  43     return (output, len(input))
  44
  45 class Codec(codecs.Codec):
  46
  47     def encode(self, input,errors='strict'):
  48         return hex_encode(input,errors)
  49     def decode(self, input,errors='strict'):
  50         return hex_decode(input,errors)
  51
  52 class IncrementalEncoder(codecs.IncrementalEncoder):
  53     def encode(self, input, final=False):
  54         assert self.errors == 'strict'
  55         return binascii.b2a_hex(input)
  56
  57 class IncrementalDecoder(codecs.IncrementalDecoder):
  58     def decode(self, input, final=False):
  59         assert self.errors == 'strict'
  60         return binascii.a2b_hex(input)
  61
  62 class StreamWriter(Codec,codecs.StreamWriter):
  63     pass
  64
  65 class StreamReader(Codec,codecs.StreamReader):
  66     pass
  67
  68 ### encodings module API
  69
  70 def getregentry():
  71     return codecs.CodecInfo(
  72         name='hex',
  73         encode=hex_encode,
  74         decode=hex_decode,
  75         incrementalencoder=IncrementalEncoder,
  76         incrementaldecoder=IncrementalDecoder,
  77         streamwriter=StreamWriter,
  78         streamreader=StreamReader,
  79     )