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

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,
+    )