getEastingFromChar static method Null safety

int getEastingFromChar(
  1. String e,
  2. int set
)

Given the first letter from a two-letter MGRS 100k zone, and given the MGRS table set for the zone number, figure out the easting value that should be added to the other, secondary easting value.

@private @param {string} e The first letter from a two-letter MGRS 100´k zone. @param {number} set The MGRS table set for the zone number. @return {number} The easting value for the given letter and set.

Implementation

static int getEastingFromChar(String e, int set) {
  // colOrigin is the letter at the origin of the set for the
  // column
  var curCol = unicode.toRune(SET_ORIGIN_COLUMN_LETTERS[set - 1]);
  var eastingValue = 100000;
  var rewindMarker = false;
  while (curCol != unicode.toRune(e[0])) {
    curCol++;
    if (curCol == I) {
      curCol++;
    }
    if (curCol == O) {
      curCol++;
    }
    if (curCol > Z) {
      if (rewindMarker) {
        throw Exception('Bad character: $e');
      }
      curCol = A;
      rewindMarker = true;
    }
    eastingValue += 100000;
  }
  return eastingValue;
}