#7475: add (un)transform method to bytes/bytearray and str, add back codecs that can be used with them from Python 2.
diff --git a/Lib/encodings/hex_codec.py b/Lib/encodings/hex_codec.py
new file mode 100644
index 0000000..e003fc3
--- /dev/null
+++ b/Lib/encodings/hex_codec.py
@@ -0,0 +1,55 @@
+"""Python 'hex_codec' Codec - 2-digit hex content transfer 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 binascii
+
+### Codec APIs
+
+def hex_encode(input, errors='strict'):
+ assert errors == 'strict'
+ return (binascii.b2a_hex(input), len(input))
+
+def hex_decode(input, errors='strict'):
+ assert errors == 'strict'
+ return (binascii.a2b_hex(input), len(input))
+
+class Codec(codecs.Codec):
+ def encode(self, input, errors='strict'):
+ return hex_encode(input, errors)
+ def decode(self, input, errors='strict'):
+ return hex_decode(input, errors)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+ def encode(self, input, final=False):
+ assert self.errors == 'strict'
+ return binascii.b2a_hex(input)
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+ def decode(self, input, final=False):
+ assert self.errors == 'strict'
+ return binascii.a2b_hex(input)
+
+class StreamWriter(Codec, codecs.StreamWriter):
+ charbuffertype = bytes
+
+class StreamReader(Codec, codecs.StreamReader):
+ charbuffertype = bytes
+
+### encodings module API
+
+def getregentry():
+ return codecs.CodecInfo(
+ name='hex',
+ encode=hex_encode,
+ decode=hex_decode,
+ incrementalencoder=IncrementalEncoder,
+ incrementaldecoder=IncrementalDecoder,
+ streamwriter=StreamWriter,
+ streamreader=StreamReader,
+ )