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