Index: Lib/io.py
===================================================================
--- Lib/io.py	(révision 67670)
+++ Lib/io.py	(copie de travail)
@@ -1280,17 +1280,32 @@
     translate=False, it ensures that the newline sequence is returned in
     one piece.
     """
-    def __init__(self, decoder, translate, errors='strict'):
+    BOMS = (
+        codecs.BOM_UTF32_LE, codecs.BOM_UTF16_LE,
+        codecs.BOM_UTF32_BE, codecs.BOM_UTF16_BE,
+    )
+    def __init__(self, decoder, encoding, translate, errors='strict'):
         codecs.IncrementalDecoder.__init__(self, errors=errors)
         self.buffer = b''
         self.translate = translate
         self.decoder = decoder
         self.seennl = 0
+        self.crbytes = '\r'.encode(encoding)
+        for bom in self.BOMS:
+            if not self.crbytes.startswith(bom):
+                continue
+            self.crbytes = self.crbytes[len(bom):]
+            break
 
     def decode(self, input, final=False):
         # decode input (with the eventual \r from a previous pass)
         if self.buffer:
-            input = self.buffer + input
+            buf, flag = self.decoder.getstate()
+            if buf:
+                buf = self.buffer + buf
+                self.decoder.setstate((buf, flag))
+            else:
+                input = self.buffer + input
 
         output = self.decoder.decode(input, final=final)
 
@@ -1298,7 +1313,7 @@
         # then readline() is sure to get \r\n in one pass
         if output.endswith("\r") and not final:
             output = output[:-1]
-            self.buffer = b'\r'
+            self.buffer = self.crbytes
         else:
             self.buffer = b''
 
@@ -1319,13 +1334,14 @@
 
     def getstate(self):
         buf, flag = self.decoder.getstate()
-        return buf + self.buffer, flag
+        return self.buffer + buf, flag
 
     def setstate(self, state):
         buf, flag = state
-        if buf.endswith(b'\r'):
-            self.buffer = b'\r'
-            buf = buf[:-1]
+        if buf.startswith(self.crbytes):
+            pos = len(self.crbytes)
+            self.buffer = buf[:pos]
+            buf = buf[pos:]
         else:
             self.buffer = b''
         self.decoder.setstate((buf, flag))
@@ -1506,7 +1522,7 @@
         make_decoder = codecs.getincrementaldecoder(self._encoding)
         decoder = make_decoder(self._errors)
         if self._readuniversal:
-            decoder = IncrementalNewlineDecoder(decoder, self._readtranslate)
+            decoder = IncrementalNewlineDecoder(decoder, self.encoding, self._readtranslate)
         self._decoder = decoder
         return decoder
 
Index: Lib/test/test_io.py
===================================================================
--- Lib/test/test_io.py	(révision 67670)
+++ Lib/test/test_io.py	(copie de travail)
@@ -679,8 +679,9 @@
     @classmethod
     def lookupTestDecoder(cls, name):
         if cls.codecEnabled and name == 'test_decoder':
+            latin1 = codecs.lookup('latin-1')
             return codecs.CodecInfo(
-                name='test_decoder', encode=None, decode=None,
+                name='test_decoder', encode=latin1.encode, decode=None,
                 incrementalencoder=None,
                 streamreader=None, streamwriter=None,
                 incrementaldecoder=cls)
@@ -840,9 +841,12 @@
             [ '\r\n', [ "unix\nwindows\r\n", "os9\rlast\nnonl" ] ],
             [ '\r', [ "unix\nwindows\r", "\nos9\r", "last\nnonl" ] ],
         ]
+        encodings = (
+            'utf-8', 'latin-1',
+            'utf-16', 'utf-16-le', 'utf-16-be',
+            'utf-32', 'utf-32-le', 'utf-32-be',
+        )
 
-        encodings = ('utf-8', 'latin-1')
-
         # Try a range of buffer sizes to test the case where \r is the last
         # character in TextIOWrapper._pending_line.
         for encoding in encodings:
@@ -1198,7 +1202,7 @@
     def test_newline_decoder(self):
         import codecs
         decoder = codecs.getincrementaldecoder("utf-8")()
-        decoder = io.IncrementalNewlineDecoder(decoder, translate=True)
+        decoder = io.IncrementalNewlineDecoder(decoder, "utf-8", translate=True)
 
         self.assertEquals(decoder.decode(b'\xe8\xa2\x88'), "\u8888")
 
@@ -1230,7 +1234,7 @@
         self.assertEquals(decoder.decode(b'\n'), "\n")
 
         decoder = codecs.getincrementaldecoder("utf-8")()
-        decoder = io.IncrementalNewlineDecoder(decoder, translate=True)
+        decoder = io.IncrementalNewlineDecoder(decoder, "utf-8", translate=True)
         self.assertEquals(decoder.newlines, None)
         decoder.decode(b"abc\n\r")
         self.assertEquals(decoder.newlines, '\n')