AppPkg/Applications/Python/Python-2.7.10/Lib/encodings/utf_16.py

   1 """ Python 'utf-16' Codec
   2
   3
   4 Written by Marc-Andre Lemburg (mal@lemburg.com).
   5
   6 (c) Copyright CNRI, All Rights Reserved. NO WARRANTY.
   7
   8 """
   9 import codecs, sys
  10
  11 ### Codec APIs
  12
  13 encode = codecs.utf_16_encode
  14
  15 def decode(input, errors='strict'):
  16     return codecs.utf_16_decode(input, errors, True)
  17
  18 class IncrementalEncoder(codecs.IncrementalEncoder):
  19     def __init__(self, errors='strict'):
  20         codecs.IncrementalEncoder.__init__(self, errors)
  21         self.encoder = None
  22
  23     def encode(self, input, final=False):
  24         if self.encoder is None:
  25             result = codecs.utf_16_encode(input, self.errors)[0]
  26             if sys.byteorder == 'little':
  27                 self.encoder = codecs.utf_16_le_encode
  28             else:
  29                 self.encoder = codecs.utf_16_be_encode
  30             return result
  31         return self.encoder(input, self.errors)[0]
  32
  33     def reset(self):
  34         codecs.IncrementalEncoder.reset(self)
  35         self.encoder = None
  36
  37     def getstate(self):
  38         # state info we return to the caller:
  39         # 0: stream is in natural order for this platform
  40         # 2: endianness hasn't been determined yet
  41         # (we're never writing in unnatural order)
  42         return (2 if self.encoder is None else 0)
  43
  44     def setstate(self, state):
  45         if state:
  46             self.encoder = None
  47         else:
  48             if sys.byteorder == 'little':
  49                 self.encoder = codecs.utf_16_le_encode
  50             else:
  51                 self.encoder = codecs.utf_16_be_encode
  52
  53 class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
  54     def __init__(self, errors='strict'):
  55         codecs.BufferedIncrementalDecoder.__init__(self, errors)
  56         self.decoder = None
  57
  58     def _buffer_decode(self, input, errors, final):
  59         if self.decoder is None:
  60             (output, consumed, byteorder) = \
  61                 codecs.utf_16_ex_decode(input, errors, 0, final)
  62             if byteorder == -1:
  63                 self.decoder = codecs.utf_16_le_decode
  64             elif byteorder == 1:
  65                 self.decoder = codecs.utf_16_be_decode
  66             elif consumed >= 2:
  67                 raise UnicodeError("UTF-16 stream does not start with BOM")
  68             return (output, consumed)
  69         return self.decoder(input, self.errors, final)
  70
  71     def reset(self):
  72         codecs.BufferedIncrementalDecoder.reset(self)
  73         self.decoder = None
  74
  75 class StreamWriter(codecs.StreamWriter):
  76     def __init__(self, stream, errors='strict'):
  77         codecs.StreamWriter.__init__(self, stream, errors)
  78         self.encoder = None
  79
  80     def reset(self):
  81         codecs.StreamWriter.reset(self)
  82         self.encoder = None
  83
  84     def encode(self, input, errors='strict'):
  85         if self.encoder is None:
  86             result = codecs.utf_16_encode(input, errors)
  87             if sys.byteorder == 'little':
  88                 self.encoder = codecs.utf_16_le_encode
  89             else:
  90                 self.encoder = codecs.utf_16_be_encode
  91             return result
  92         else:
  93             return self.encoder(input, errors)
  94
  95 class StreamReader(codecs.StreamReader):
  96
  97     def reset(self):
  98         codecs.StreamReader.reset(self)
  99         try:
 100             del self.decode
 101         except AttributeError:
 102             pass
 103
 104     def decode(self, input, errors='strict'):
 105         (object, consumed, byteorder) = \
 106             codecs.utf_16_ex_decode(input, errors, 0, False)
 107         if byteorder == -1:
 108             self.decode = codecs.utf_16_le_decode
 109         elif byteorder == 1:
 110             self.decode = codecs.utf_16_be_decode
 111         elif consumed>=2:
 112             raise UnicodeError,"UTF-16 stream does not start with BOM"
 113         return (object, consumed)
 114
 115 ### encodings module API
 116
 117 def getregentry():
 118     return codecs.CodecInfo(
 119         name='utf-16',
 120         encode=encode,
 121         decode=decode,
 122         incrementalencoder=IncrementalEncoder,
 123         incrementaldecoder=IncrementalDecoder,
 124         streamreader=StreamReader,
 125         streamwriter=StreamWriter,
 126     )