Function compute_precision_for_length

3party/open-location-code/openlocationcode.cc:66–71

Compute the latitude precision value for a given code length. Lengths <= 10 have the same precision for latitude and longitude, but lengths > 10 have different precisions due to the grid method having fewer columns than rows.

// have the same precision for latitude and longitude, but lengths > 10 have
// different precisions due to the grid method having fewer columns than rows.
double compute_precision_for_length(int code_length) {
  if (code_length <= 10) {
    return pow_neg(internal::kEncodingBase, floor((code_length / -2) + 2));
  }
  return pow_neg(internal::kEncodingBase, -3) / pow(5, code_length - 10);
}

// Returns the position of a char in the encoding alphabet, or -1 if invalid.
int get_alphabet_position(char c) {