Google Maps APIのPolyLineをデコードする関数(Python3)

以下のページを参考に作らせていただきました。感謝。
https://www.codeproject.com/Tips/312248/Google-Maps-Direction-API-V3-Polyline-Decoder

ビット演算とか全然やったことなかったので、勉強になりました。

def decode_polyline(enc: str):
"""
    Parameters
    ----------
    enc : str
        encoded string of polyline, which can be aquired via Google Maps API.

    Returns
    -------
    result : list
        each element in `result` contains pair of latitude and longitude.
"""
    if enc == None or enc == '':
        return [[0, 0]]

    result = []
    polyline_chars = list(enc.encode())
    current_latitude = 0
    current_longitude = 0
    try:
        index = 0
        while index < len(polyline_chars):
            # calculate next latitude
            total = 0
            shifter = 0

            while True:
                next5bits = int(polyline_chars[index]) - 63
                index += 1
                total |= (next5bits & 31) << shifter
                shifter += 5
                if not(next5bits >= 32 and index < len(polyline_chars)):
                    break

            if (index >= len(polyline_chars)):
                break

            if((total & 1) == 1):
                current_latitude += ~(total >> 1)
            else:
                current_latitude += (total >> 1)

            # calculate next longitude
            total = 0
            shifter = 0
            while True:
                next5bits = int(polyline_chars[index]) - 63
                index += 1
                total |= (next5bits & 31) << shifter
                shifter += 5
                if not(next5bits >= 32 and index < len(polyline_chars)):
                    break

            if (index >= len(polyline_chars) and next >= 32):
                break

            if((total & 1) == 1):
                current_longitude += ~(total >> 1)
            else:
                current_longitude += (total >> 1)

            # add to return value
            pair = [current_latitude / 100000, current_longitude / 100000]
            result.append(pair)

    except:
        pass
    return result