Apply SF patch #1775604: This adds three new codecs (utf-32, utf-32-le and

ut-32-be). On narrow builds the codecs combine surrogate pairs in the unicode
object into one codepoint on encoding and create surrogate pairs for
codepoints outside the BMP on decoding. Lone surrogates are passed through
unchanged in all cases.

Backport to the trunk will follow.

Lib/encodings/utf_32.py

@@ -0,0 +1,144 @@
+"""
+Python 'utf-32' Codec
+"""
+import codecs, sys
+
+### Codec APIs
+
+encode = codecs.utf_32_encode
+
+def decode(input, errors='strict'):
+    return codecs.utf_32_decode(input, errors, True)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def __init__(self, errors='strict'):
+        codecs.IncrementalEncoder.__init__(self, errors)
+        self.encoder = None
+
+    def encode(self, input, final=False):
+        if self.encoder is None:
+            result = codecs.utf_32_encode(input, self.errors)[0]
+            if sys.byteorder == 'little':
+                self.encoder = codecs.utf_32_le_encode
+            else:
+                self.encoder = codecs.utf_32_be_encode
+            return result
+        return self.encoder(input, self.errors)[0]
+
+    def reset(self):
+        codecs.IncrementalEncoder.reset(self)
+        self.encoder = None
+
+    def getstate(self):
+        # state info we return to the caller:
+        # 0: stream is in natural order for this platform
+        # 2: endianness hasn't been determined yet
+        # (we're never writing in unnatural order)
+        return (2 if self.encoder is None else 0)
+
+    def setstate(self, state):
+        if state:
+            self.encoder = None
+        else:
+            if sys.byteorder == 'little':
+                self.encoder = codecs.utf_32_le_encode
+            else:
+                self.encoder = codecs.utf_32_be_encode
+
+class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
+    def __init__(self, errors='strict'):
+        codecs.BufferedIncrementalDecoder.__init__(self, errors)
+        self.decoder = None
+
+    def _buffer_decode(self, input, errors, final):
+        if self.decoder is None:
+            (output, consumed, byteorder) = \
+                codecs.utf_32_ex_decode(input, errors, 0, final)
+            if byteorder == -1:
+                self.decoder = codecs.utf_32_le_decode
+            elif byteorder == 1:
+                self.decoder = codecs.utf_32_be_decode
+            elif consumed >= 4:
+                raise UnicodeError("UTF-32 stream does not start with BOM")
+            return (output, consumed)
+        return self.decoder(input, self.errors, final)
+
+    def reset(self):
+        codecs.BufferedIncrementalDecoder.reset(self)
+        self.decoder = None
+
+    def getstate(self):
+        # additonal state info from the base class must be None here,
+        # as it isn't passed along to the caller
+        state = codecs.BufferedIncrementalDecoder.getstate(self)[0]
+        # additional state info we pass to the caller:
+        # 0: stream is in natural order for this platform
+        # 1: stream is in unnatural order
+        # 2: endianness hasn't been determined yet
+        if self.decoder is None:
+            return (state, 2)
+        addstate = int((sys.byteorder == "big") !=
+                       (self.decoder is codecs.utf_32_be_decode))
+        return (state, addstate)
+
+    def setstate(self, state):
+        # state[1] will be ignored by BufferedIncrementalDecoder.setstate()
+        codecs.BufferedIncrementalDecoder.setstate(self, state)
+        state = state[1]
+        if state == 0:
+            self.decoder = (codecs.utf_32_be_decode
+                            if sys.byteorder == "big"
+                            else codecs.utf_32_le_decode)
+        elif state == 1:
+            self.decoder = (codecs.utf_32_le_decode
+                            if sys.byteorder == "big"
+                            else codecs.utf_32_be_decode)
+        else:
+            self.decoder = None
+
+class StreamWriter(codecs.StreamWriter):
+    def __init__(self, stream, errors='strict'):
+        self.bom_written = False
+        codecs.StreamWriter.__init__(self, stream, errors)
+
+    def encode(self, input, errors='strict'):
+        self.bom_written = True
+        result = codecs.utf_32_encode(input, errors)
+        if sys.byteorder == 'little':
+            self.encode = codecs.utf_32_le_encode
+        else:
+            self.encode = codecs.utf_32_be_encode
+        return result
+
+class StreamReader(codecs.StreamReader):
+
+    def reset(self):
+        codecs.StreamReader.reset(self)
+        try:
+            del self.decode
+        except AttributeError:
+            pass
+
+    def decode(self, input, errors='strict'):
+        (object, consumed, byteorder) = \
+            codecs.utf_32_ex_decode(input, errors, 0, False)
+        if byteorder == -1:
+            self.decode = codecs.utf_32_le_decode
+        elif byteorder == 1:
+            self.decode = codecs.utf_32_le_decode
+        elif consumed>=4:
+            raise UnicodeError,"UTF-32 stream does not start with BOM"
+        return (object, consumed)
+
+### encodings module API
+
+def getregentry():
+    return codecs.CodecInfo(
+        name='utf-32',
+        encode=encode,
+        decode=decode,
+        incrementalencoder=IncrementalEncoder,
+        incrementaldecoder=IncrementalDecoder,
+        streamreader=StreamReader,
+        streamwriter=StreamWriter,
+    )