def determineEncoding()

in bleach/_vendor/html5lib/_inputstream.py [0:0]
43 lines of code
17 McCabe index (conditional complexity)

    def determineEncoding(self, chardet=True):
        # BOMs take precedence over everything
        # This will also read past the BOM if present
        charEncoding = self.detectBOM(), "certain"
        if charEncoding[0] is not None:
            return charEncoding

        # If we've been overridden, we've been overridden
        charEncoding = lookupEncoding(self.override_encoding), "certain"
        if charEncoding[0] is not None:
            return charEncoding

        # Now check the transport layer
        charEncoding = lookupEncoding(self.transport_encoding), "certain"
        if charEncoding[0] is not None:
            return charEncoding

        # Look for meta elements with encoding information
        charEncoding = self.detectEncodingMeta(), "tentative"
        if charEncoding[0] is not None:
            return charEncoding

        # Parent document encoding
        charEncoding = lookupEncoding(self.same_origin_parent_encoding), "tentative"
        if charEncoding[0] is not None and not charEncoding[0].name.startswith("utf-16"):
            return charEncoding

        # "likely" encoding
        charEncoding = lookupEncoding(self.likely_encoding), "tentative"
        if charEncoding[0] is not None:
            return charEncoding

        # Guess with chardet, if available
        if chardet:
            try:
                from chardet.universaldetector import UniversalDetector
            except ImportError:
                pass
            else:
                buffers = []
                detector = UniversalDetector()
                while not detector.done:
                    buffer = self.rawStream.read(self.numBytesChardet)
                    assert isinstance(buffer, bytes)
                    if not buffer:
                        break
                    buffers.append(buffer)
                    detector.feed(buffer)
                detector.close()
                encoding = lookupEncoding(detector.result['encoding'])
                self.rawStream.seek(0)
                if encoding is not None:
                    return encoding, "tentative"

        # Try the default encoding
        charEncoding = lookupEncoding(self.default_encoding), "tentative"
        if charEncoding[0] is not None:
            return charEncoding

        # Fallback to html5lib's default if even that hasn't worked
        return lookupEncoding("windows-1252"), "tentative"