| # $Id: _compat.py 5908 2009-04-21 13:43:23Z goodger $ |
| # Author: Georg Brandl <georg@python.org> |
| # Copyright: This module has been placed in the public domain. |
| |
| """ |
| Python 2/3 compatibility definitions. |
| |
| This module currently provides the following helper symbols: |
| |
| * bytes (name of byte string type; str in 2.x, bytes in 3.x) |
| * b (function converting a string literal to an ASCII byte string; |
| can be also used to convert a Unicode string into a byte string) |
| * u_prefix (unicode repr prefix, 'u' in 2.x, nothing in 3.x) |
| * BytesIO (a StringIO class that works with bytestrings) |
| """ |
| |
| import sys |
| |
| if sys.version_info < (3,0): |
| b = bytes = str |
| u_prefix = 'u' |
| from StringIO import StringIO as BytesIO |
| else: |
| import builtins |
| bytes = builtins.bytes |
| u_prefix = '' |
| def b(s): |
| if isinstance(s, str): |
| return s.encode('latin1') |
| elif isinstance(s, bytes): |
| return s |
| else: |
| raise TypeError("Invalid argument %r for b()" % (s,)) |
| # using this hack since 2to3 "fixes" the relative import |
| # when using ``from io import BytesIO`` |
| BytesIO = __import__('io').BytesIO |
