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     )