#7475: add (un)transform method to bytes/bytearray and str, add back codecs that can be used with them from Python 2.

Lib/encodings/bz2_codec.py

@@ -0,0 +1,77 @@
+"""Python 'bz2_codec' Codec - bz2 compression encoding.
+
+This codec de/encodes from bytes to bytes and is therefore usable with
+bytes.transform() and bytes.untransform().
+
+Adapted by Raymond Hettinger from zlib_codec.py which was written
+by Marc-Andre Lemburg (mal@lemburg.com).
+"""
+
+import codecs
+import bz2 # this codec needs the optional bz2 module !
+
+### Codec APIs
+
+def bz2_encode(input, errors='strict'):
+    assert errors == 'strict'
+    return (bz2.compress(input), len(input))
+
+def bz2_decode(input, errors='strict'):
+    assert errors == 'strict'
+    return (bz2.decompress(input), len(input))
+
+class Codec(codecs.Codec):
+    def encode(self, input, errors='strict'):
+        return bz2_encode(input, errors)
+    def decode(self, input, errors='strict'):
+        return bz2_decode(input, errors)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def __init__(self, errors='strict'):
+        assert errors == 'strict'
+        self.errors = errors
+        self.compressobj = bz2.BZ2Compressor()
+
+    def encode(self, input, final=False):
+        if final:
+            c = self.compressobj.compress(input)
+            return c + self.compressobj.flush()
+        else:
+            return self.compressobj.compress(input)
+
+    def reset(self):
+        self.compressobj = bz2.BZ2Compressor()
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    def __init__(self, errors='strict'):
+        assert errors == 'strict'
+        self.errors = errors
+        self.decompressobj = bz2.BZ2Decompressor()
+
+    def decode(self, input, final=False):
+        try:
+            return self.decompressobj.decompress(input)
+        except EOFError:
+            return ''
+
+    def reset(self):
+        self.decompressobj = bz2.BZ2Decompressor()
+
+class StreamWriter(Codec, codecs.StreamWriter):
+    charbuffertype = bytes
+
+class StreamReader(Codec, codecs.StreamReader):
+    charbuffertype = bytes
+
+### encodings module API
+
+def getregentry():
+    return codecs.CodecInfo(
+        name="bz2",
+        encode=bz2_encode,
+        decode=bz2_decode,
+        incrementalencoder=IncrementalEncoder,
+        incrementaldecoder=IncrementalDecoder,
+        streamwriter=StreamWriter,
+        streamreader=StreamReader,
+    )