1  """Python 'zlib_codec' Codec - zlib compression encoding.
       2  
       3  This codec de/encodes from bytes to bytes.
       4  
       5  Written by Marc-Andre Lemburg (mal@lemburg.com).
       6  """
       7  
       8  import codecs
       9  import zlib # this codec needs the optional zlib module !
      10  
      11  ### Codec APIs
      12  
      13  def zlib_encode(input, errors='strict'):
      14      assert errors == 'strict'
      15      return (zlib.compress(input), len(input))
      16  
      17  def zlib_decode(input, errors='strict'):
      18      assert errors == 'strict'
      19      return (zlib.decompress(input), len(input))
      20  
      21  class ESC[4;38;5;81mCodec(ESC[4;38;5;149mcodecsESC[4;38;5;149m.ESC[4;38;5;149mCodec):
      22      def encode(self, input, errors='strict'):
      23          return zlib_encode(input, errors)
      24      def decode(self, input, errors='strict'):
      25          return zlib_decode(input, errors)
      26  
      27  class ESC[4;38;5;81mIncrementalEncoder(ESC[4;38;5;149mcodecsESC[4;38;5;149m.ESC[4;38;5;149mIncrementalEncoder):
      28      def __init__(self, errors='strict'):
      29          assert errors == 'strict'
      30          self.errors = errors
      31          self.compressobj = zlib.compressobj()
      32  
      33      def encode(self, input, final=False):
      34          if final:
      35              c = self.compressobj.compress(input)
      36              return c + self.compressobj.flush()
      37          else:
      38              return self.compressobj.compress(input)
      39  
      40      def reset(self):
      41          self.compressobj = zlib.compressobj()
      42  
      43  class ESC[4;38;5;81mIncrementalDecoder(ESC[4;38;5;149mcodecsESC[4;38;5;149m.ESC[4;38;5;149mIncrementalDecoder):
      44      def __init__(self, errors='strict'):
      45          assert errors == 'strict'
      46          self.errors = errors
      47          self.decompressobj = zlib.decompressobj()
      48  
      49      def decode(self, input, final=False):
      50          if final:
      51              c = self.decompressobj.decompress(input)
      52              return c + self.decompressobj.flush()
      53          else:
      54              return self.decompressobj.decompress(input)
      55  
      56      def reset(self):
      57          self.decompressobj = zlib.decompressobj()
      58  
      59  class ESC[4;38;5;81mStreamWriter(ESC[4;38;5;149mCodec, ESC[4;38;5;149mcodecsESC[4;38;5;149m.ESC[4;38;5;149mStreamWriter):
      60      charbuffertype = bytes
      61  
      62  class ESC[4;38;5;81mStreamReader(ESC[4;38;5;149mCodec, ESC[4;38;5;149mcodecsESC[4;38;5;149m.ESC[4;38;5;149mStreamReader):
      63      charbuffertype = bytes
      64  
      65  ### encodings module API
      66  
      67  def getregentry():
      68      return codecs.CodecInfo(
      69          name='zlib',
      70          encode=zlib_encode,
      71          decode=zlib_decode,
      72          incrementalencoder=IncrementalEncoder,
      73          incrementaldecoder=IncrementalDecoder,
      74          streamreader=StreamReader,
      75          streamwriter=StreamWriter,
      76          _is_text_encoding=False,
      77      )