Real pickling for bytes.

Restore complex pickling.
Use cPickle in io.py.

Lib/copy_reg.py

@@ -23,12 +23,18 @@ def constructor(object):
     if not callable(object):
         raise TypeError("constructors must be callable")
 
-# Example: provide pickling support for bytes objects.
+# Example: provide pickling support for complex numbers.
 
-def _pickle_bytes(b):
-    return bytes, (str(b),)
+try:
+    complex
+except NameError:
+    pass
+else:
 
-pickle(bytes, _pickle_bytes)
+    def pickle_complex(c):
+        return complex, (c.real, c.imag)
+
+    pickle(complex, pickle_complex, complex)
 
 # Support for pickling new-style objects
 

Lib/io.py

@@ -30,10 +30,14 @@ __all__ = ["BlockingIOError", "open", "IOBase", "RawIOBase", "FileIO",
 import os
 import sys
 import codecs
-import pickle
 import _fileio
 import warnings
 
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
 # XXX Shouldn't we use st_blksize whenever we can?
 DEFAULT_BUFFER_SIZE = 8 * 1024  # bytes