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

1 files changed, 77 insertions, 0 deletions

diff --git a/Lib/encodings/zlib_codec.py b/Lib/encodings/zlib_codec.py
new file mode 100644
index 0000000..e0b9cda
--- /dev/null
+++ b/Lib/encodings/zlib_codec.py
@@ -0,0 +1,77 @@
+"""Python 'zlib_codec' Codec - zlib compression encoding.
+
+This codec de/encodes from bytes to bytes and is therefore usable with
+bytes.transform() and bytes.untransform().
+
+Written by Marc-Andre Lemburg (mal@lemburg.com).
+"""
+
+import codecs
+import zlib # this codec needs the optional zlib module !
+
+### Codec APIs
+
+def zlib_encode(input, errors='strict'):
+    assert errors == 'strict'
+    return (zlib.compress(input), len(input))
+
+def zlib_decode(input, errors='strict'):
+    assert errors == 'strict'
+    return (zlib.decompress(input), len(input))
+
+class Codec(codecs.Codec):
+    def encode(self, input, errors='strict'):
+        return zlib_encode(input, errors)
+    def decode(self, input, errors='strict'):
+        return zlib_decode(input, errors)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def __init__(self, errors='strict'):
+        assert errors == 'strict'
+        self.errors = errors
+        self.compressobj = zlib.compressobj()
+
+    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 = zlib.compressobj()
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    def __init__(self, errors='strict'):
+        assert errors == 'strict'
+        self.errors = errors
+        self.decompressobj = zlib.decompressobj()
+
+    def decode(self, input, final=False):
+        if final:
+            c = self.decompressobj.decompress(input)
+            return c + self.decompressobj.flush()
+        else:
+            return self.decompressobj.decompress(input)
+
+    def reset(self):
+        self.decompressobj = zlib.decompressobj()
+
+class StreamWriter(Codec, codecs.StreamWriter):
+    charbuffertype = bytes
+
+class StreamReader(Codec, codecs.StreamReader):
+    charbuffertype = bytes
+
+### encodings module API
+
+def getregentry():
+    return codecs.CodecInfo(
+        name='zlib',
+        encode=zlib_encode,
+        decode=zlib_decode,
+        incrementalencoder=IncrementalEncoder,
+        incrementaldecoder=IncrementalDecoder,
+        streamreader=StreamReader,
+        streamwriter=StreamWriter,
+    )