First baby steps towards dual Python2+3 compatibility

strutil.py

@@ -0,0 +1,85 @@
+#    (C) Copyright 2015-2019 Sei Lisa. All rights reserved.
+#
+#    This file is part of LSL PyOptimizer.
+#
+#    LSL PyOptimizer is free software: you can redistribute it and/or
+#    modify it under the terms of the GNU General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    LSL PyOptimizer is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with LSL PyOptimizer. If not, see <http://www.gnu.org/licenses/>.
+
+# String <-> Bytes conversion and output utilities
+
+import sys
+if sys.hexversion >= 0x3000000:
+    unicode = str
+    unichr = chr
+    def str2u(s, enc=None):
+        """Convert a native Python3 str to Unicode. This is a NOP."""
+        return s
+
+    def str2b(s, enc=None):
+        """Convert a native Python3 str to bytes, with the given encoding."""
+        return s.encode(enc if type(enc) == str
+                        else getattr(enc, 'encoding', 'utf8'),
+                        'backslashreplace')
+
+    def u2str(s, enc=None):
+        """Convert a Unicode string to native Python 3 str. This is a NOP."""
+        return s
+
+    def b2str(s, enc=None):
+        """Convert a Bytes string to native Python 3 str."""
+        return s.decode(getattr(enc, 'encoding', enc) or 'utf8',
+                        'backslashreplace')
+
+else:
+    def str2u(s, enc=None):
+        """Convert a native Python2 str to Unicode."""
+        return s.decode(getattr(enc, 'encoding', enc) or 'utf8',
+                        'backslashreplace')
+
+    def str2b(s, enc=None):
+        """Convert a native Python2 str to bytes. This is a NOP."""
+        return s
+
+    def u2str(s, enc=None):
+        """Convert a Unicode string to native Python 2 str."""
+        return s.encode(enc if type(enc) == str
+                        else getattr(enc, 'encoding', 'utf8'),
+                        'backslashreplace')
+
+    def b2str(s, enc=None):
+        """Convert a Bytes string to native Python 2 str. This is a NOP."""
+        return s
+
+def b2u(s, enc=None):
+    """Bytes to Unicode"""
+    return str2u(b2str(s, enc), enc)
+
+def u2b(s, enc=None):
+    """Unicode to Bytes"""
+    return u2str(str2b(s, enc), enc)
+
+def any2b(s, enc=None):
+    """Bytes or Unicode to Bytes"""
+    return s if type(s) == bytes else u2b(s, enc)
+
+def any2u(s, enc=None):
+    """Bytes or Unicode to Unicode"""
+    return s if type(s) == unicode else b2u(s, enc)
+
+def werr(s):
+    """Write any string to stderr"""
+    sys.stderr.write(any2u(s, sys.stderr))
+
+def wout(s):
+    """Write any string to stdout"""
+    sys.stdout.write(any2u(s, sys.stdout))