add hg and python

sys/lib/python/encodings/utf_8_sig.py

@@ -0,0 +1,100 @@
+""" Python 'utf-8-sig' Codec
+This work similar to UTF-8 with the following changes:
+
+* On encoding/writing a UTF-8 encoded BOM will be prepended/written as the
+  first three bytes.
+
+* On decoding/reading if the first three bytes are a UTF-8 encoded BOM, these
+  bytes will be skipped.
+"""
+import codecs
+
+### Codec APIs
+
+def encode(input, errors='strict'):
+    return (codecs.BOM_UTF8 + codecs.utf_8_encode(input, errors)[0], len(input))
+
+def decode(input, errors='strict'):
+    prefix = 0
+    if input[:3] == codecs.BOM_UTF8:
+        input = input[3:]
+        prefix = 3
+    (output, consumed) = codecs.utf_8_decode(input, errors, True)
+    return (output, consumed+prefix)
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def __init__(self, errors='strict'):
+        codecs.IncrementalEncoder.__init__(self, errors)
+        self.first = True
+
+    def encode(self, input, final=False):
+        if self.first:
+            self.first = False
+            return codecs.BOM_UTF8 + codecs.utf_8_encode(input, self.errors)[0]
+        else:
+            return codecs.utf_8_encode(input, self.errors)[0]
+
+    def reset(self):
+        codecs.IncrementalEncoder.reset(self)
+        self.first = True
+
+class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
+    def __init__(self, errors='strict'):
+        codecs.BufferedIncrementalDecoder.__init__(self, errors)
+        self.first = True
+
+    def _buffer_decode(self, input, errors, final):
+        if self.first and codecs.BOM_UTF8.startswith(input): # might be a BOM
+            if len(input) < 3:
+                # not enough data to decide if this really is a BOM
+                # => try again on the next call
+                return (u"", 0)
+            (output, consumed) = codecs.utf_8_decode(input[3:], errors, final)
+            self.first = False
+            return (output, consumed+3)
+        return codecs.utf_8_decode(input, errors, final)
+
+    def reset(self):
+        codecs.BufferedIncrementalDecoder.reset(self)
+        self.first = True
+
+class StreamWriter(codecs.StreamWriter):
+    def reset(self):
+        codecs.StreamWriter.reset(self)
+        try:
+            del self.encode
+        except AttributeError:
+            pass
+
+    def encode(self, input, errors='strict'):
+        self.encode = codecs.utf_8_encode
+        return encode(input, errors)
+
+class StreamReader(codecs.StreamReader):
+    def reset(self):
+        codecs.StreamReader.reset(self)
+        try:
+            del self.decode
+        except AttributeError:
+            pass
+
+    def decode(self, input, errors='strict'):
+        if len(input) < 3 and codecs.BOM_UTF8.startswith(input):
+            # not enough data to decide if this is a BOM
+            # => try again on the next call
+            return (u"", 0)
+        self.decode = codecs.utf_8_decode
+        return decode(input, errors)
+
+### encodings module API
+
+def getregentry():
+    return codecs.CodecInfo(
+        name='utf-8-sig',
+        encode=encode,
+        decode=decode,
+        incrementalencoder=IncrementalEncoder,
+        incrementaldecoder=IncrementalDecoder,
+        streamreader=StreamReader,
+        streamwriter=StreamWriter,
+    )