encode static method

int encode(Iterable<int> week)

Encodes the days of a week into a bitfield. The length of week should be less than or equal to 7 with elements ranging from 1 to 7.

Behaviour is undefined if the given week is invalid.

Implementation

static int encode(Iterable<int> week) {
  assert(week.length <= 7, 'Number of days is "${week.length}", should be less than 7');
  assert(week.every((day) => day >= 1 && day <= 7), 'Invalid day in week, should be between 1 and 7');

  var encoded = 0;
  for (var day = 7; day >= 1; day--) {
    encoded <<= 1;
    if (week.contains(day)) {
      encoded += 1;
    }
  }

  return encoded;
}