jpayne@68: """Python 'zlib_codec' Codec - zlib compression encoding.
jpayne@68: 
jpayne@68: This codec de/encodes from bytes to bytes.
jpayne@68: 
jpayne@68: Written by Marc-Andre Lemburg (mal@lemburg.com).
jpayne@68: """
jpayne@68: 
jpayne@68: import codecs
jpayne@68: import zlib # this codec needs the optional zlib module !
jpayne@68: 
jpayne@68: ### Codec APIs
jpayne@68: 
jpayne@68: def zlib_encode(input, errors='strict'):
jpayne@68:     assert errors == 'strict'
jpayne@68:     return (zlib.compress(input), len(input))
jpayne@68: 
jpayne@68: def zlib_decode(input, errors='strict'):
jpayne@68:     assert errors == 'strict'
jpayne@68:     return (zlib.decompress(input), len(input))
jpayne@68: 
jpayne@68: class Codec(codecs.Codec):
jpayne@68:     def encode(self, input, errors='strict'):
jpayne@68:         return zlib_encode(input, errors)
jpayne@68:     def decode(self, input, errors='strict'):
jpayne@68:         return zlib_decode(input, errors)
jpayne@68: 
jpayne@68: class IncrementalEncoder(codecs.IncrementalEncoder):
jpayne@68:     def __init__(self, errors='strict'):
jpayne@68:         assert errors == 'strict'
jpayne@68:         self.errors = errors
jpayne@68:         self.compressobj = zlib.compressobj()
jpayne@68: 
jpayne@68:     def encode(self, input, final=False):
jpayne@68:         if final:
jpayne@68:             c = self.compressobj.compress(input)
jpayne@68:             return c + self.compressobj.flush()
jpayne@68:         else:
jpayne@68:             return self.compressobj.compress(input)
jpayne@68: 
jpayne@68:     def reset(self):
jpayne@68:         self.compressobj = zlib.compressobj()
jpayne@68: 
jpayne@68: class IncrementalDecoder(codecs.IncrementalDecoder):
jpayne@68:     def __init__(self, errors='strict'):
jpayne@68:         assert errors == 'strict'
jpayne@68:         self.errors = errors
jpayne@68:         self.decompressobj = zlib.decompressobj()
jpayne@68: 
jpayne@68:     def decode(self, input, final=False):
jpayne@68:         if final:
jpayne@68:             c = self.decompressobj.decompress(input)
jpayne@68:             return c + self.decompressobj.flush()
jpayne@68:         else:
jpayne@68:             return self.decompressobj.decompress(input)
jpayne@68: 
jpayne@68:     def reset(self):
jpayne@68:         self.decompressobj = zlib.decompressobj()
jpayne@68: 
jpayne@68: class StreamWriter(Codec, codecs.StreamWriter):
jpayne@68:     charbuffertype = bytes
jpayne@68: 
jpayne@68: class StreamReader(Codec, codecs.StreamReader):
jpayne@68:     charbuffertype = bytes
jpayne@68: 
jpayne@68: ### encodings module API
jpayne@68: 
jpayne@68: def getregentry():
jpayne@68:     return codecs.CodecInfo(
jpayne@68:         name='zlib',
jpayne@68:         encode=zlib_encode,
jpayne@68:         decode=zlib_decode,
jpayne@68:         incrementalencoder=IncrementalEncoder,
jpayne@68:         incrementaldecoder=IncrementalDecoder,
jpayne@68:         streamreader=StreamReader,
jpayne@68:         streamwriter=StreamWriter,
jpayne@68:         _is_text_encoding=False,
jpayne@68:     )