Issue #27959: Adds oem encoding, alias ansi to mbcs, move aliasmbcs to codec lookup

3 files changed, 52 insertions, 0 deletions

diff --git a/Lib/encodings/__init__.py b/Lib/encodings/__init__.py
index 320011bd0e..9a9b90b004 100644
--- a/Lib/encodings/__init__.py
+++ b/Lib/encodings/__init__.py
@@ -29,6 +29,7 @@ Written by Marc-Andre Lemburg (mal@lemburg.com).
 """#"
 
 import codecs
+import sys
 from . import aliases
 
 _cache = {}
@@ -151,3 +152,12 @@ def search_function(encoding):
 
 # Register the search_function in the Python codec registry
 codecs.register(search_function)
+
+if sys.platform == 'win32':
+    def _alias_mbcs(encoding):
+        import _bootlocale
+        if encoding == _bootlocale.getpreferredencoding(False):
+            import encodings.mbcs
+            return encodings.mbcs.getregentry()
+
+    codecs.register(_alias_mbcs)
diff --git a/Lib/encodings/aliases.py b/Lib/encodings/aliases.py
index 67c828d639..2e63c2f949 100644
--- a/Lib/encodings/aliases.py
+++ b/Lib/encodings/aliases.py
@@ -458,6 +458,7 @@ aliases = {
     'macturkish'         : 'mac_turkish',
 
     # mbcs codec
+    'ansi'               : 'mbcs',
     'dbcs'               : 'mbcs',
 
     # ptcp154 codec
diff --git a/Lib/encodings/oem.py b/Lib/encodings/oem.py
new file mode 100644
index 0000000000..2c3426ba48
--- /dev/null
+++ b/Lib/encodings/oem.py
@@ -0,0 +1,41 @@
+""" Python 'oem' Codec for Windows
+
+"""
+# Import them explicitly to cause an ImportError
+# on non-Windows systems
+from codecs import oem_encode, oem_decode
+# for IncrementalDecoder, IncrementalEncoder, ...
+import codecs
+
+### Codec APIs
+
+encode = oem_encode
+
+def decode(input, errors='strict'):
+    return oem_decode(input, errors, True)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def encode(self, input, final=False):
+        return oem_encode(input, self.errors)[0]
+
+class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
+    _buffer_decode = oem_decode
+
+class StreamWriter(codecs.StreamWriter):
+    encode = oem_encode
+
+class StreamReader(codecs.StreamReader):
+    decode = oem_decode
+
+### encodings module API
+
+def getregentry():
+    return codecs.CodecInfo(
+        name='oem',
+        encode=encode,
+        decode=decode,
+        incrementalencoder=IncrementalEncoder,
+        incrementaldecoder=IncrementalDecoder,
+        streamreader=StreamReader,
+        streamwriter=StreamWriter,
+    )