decodePoly function

List<List<double>> decodePoly(
  1. String encoded
)

Implementation

List<List<double>> decodePoly(String encoded) {
  List<List<double>> poly = [];
  int index = 0, len = encoded.length;
  int lat = 0, lng = 0;

  while (index < len) {
    int b, shift = 0, result = 0;
    do {
      b = encoded[index++].codeUnitAt(0) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lat += dlat;

    shift = 0;
    result = 0;
    do {
      b = encoded[index++].codeUnitAt(0) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lng += dlng;
    List<double> p = [lat / 1e5, lng / 1e5];

    poly.add(p);
  }

  return poly;
}