PageRenderTime 23ms CodeModel.GetById 12ms app.highlight 7ms RepoModel.GetById 1ms app.codeStats 0ms

/Lib/encodings/bz2_codec.py

http://unladen-swallow.googlecode.com/
Python | 102 lines | 102 code | 0 blank | 0 comment | 0 complexity | 4e2719a3cccc5c726f5d46b34fb6850e MD5 | raw file
  1""" Python 'bz2_codec' Codec - bz2 compression 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    Adapted by Raymond Hettinger from zlib_codec.py which was written
  7    by Marc-Andre Lemburg (mal@lemburg.com).
  8
  9"""
 10import codecs
 11import bz2 # this codec needs the optional bz2 module !
 12
 13### Codec APIs
 14
 15def bz2_encode(input,errors='strict'):
 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    output = bz2.compress(input)
 27    return (output, len(input))
 28
 29def bz2_decode(input,errors='strict'):
 30
 31    """ Decodes the object input and returns a tuple (output
 32        object, length consumed).
 33
 34        input must be an object which provides the bf_getreadbuf
 35        buffer slot. Python strings, buffer objects and memory
 36        mapped files are examples of objects providing this slot.
 37
 38        errors defines the error handling to apply. It defaults to
 39        'strict' handling which is the only currently supported
 40        error handling for this codec.
 41
 42    """
 43    assert errors == 'strict'
 44    output = bz2.decompress(input)
 45    return (output, len(input))
 46
 47class Codec(codecs.Codec):
 48
 49    def encode(self, input, errors='strict'):
 50        return bz2_encode(input, errors)
 51    def decode(self, input, errors='strict'):
 52        return bz2_decode(input, errors)
 53
 54class IncrementalEncoder(codecs.IncrementalEncoder):
 55    def __init__(self, errors='strict'):
 56        assert errors == 'strict'
 57        self.errors = errors
 58        self.compressobj = bz2.BZ2Compressor()
 59
 60    def encode(self, input, final=False):
 61        if final:
 62            c = self.compressobj.compress(input)
 63            return c + self.compressobj.flush()
 64        else:
 65            return self.compressobj.compress(input)
 66
 67    def reset(self):
 68        self.compressobj = bz2.BZ2Compressor()
 69
 70class IncrementalDecoder(codecs.IncrementalDecoder):
 71    def __init__(self, errors='strict'):
 72        assert errors == 'strict'
 73        self.errors = errors
 74        self.decompressobj = bz2.BZ2Decompressor()
 75
 76    def decode(self, input, final=False):
 77        try:
 78            return self.decompressobj.decompress(input)
 79        except EOFError:
 80            return ''
 81
 82    def reset(self):
 83        self.decompressobj = bz2.BZ2Decompressor()
 84
 85class StreamWriter(Codec,codecs.StreamWriter):
 86    pass
 87
 88class StreamReader(Codec,codecs.StreamReader):
 89    pass
 90
 91### encodings module API
 92
 93def getregentry():
 94    return codecs.CodecInfo(
 95        name="bz2",
 96        encode=bz2_encode,
 97        decode=bz2_decode,
 98        incrementalencoder=IncrementalEncoder,
 99        incrementaldecoder=IncrementalDecoder,
100        streamwriter=StreamWriter,
101        streamreader=StreamReader,
102    )