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      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 (at] 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     )
     80