Iterator

const Iterator = struct {
    size: usize,
    power_of_two: usize,
    numerator: usize,
    decimal: usize,
    denominator: usize,
    decimal_step: usize,
    numerator_step: usize,

    fn init(size2: usize, min_level: usize) Iterator {
        const power_of_two = math.floorPowerOfTwo(usize, size2);
        const denominator = power_of_two / min_level;
        return Iterator{
            .numerator = 0,
            .decimal = 0,
            .size = size2,
            .power_of_two = power_of_two,
            .denominator = denominator,
            .decimal_step = size2 / denominator,
            .numerator_step = size2 % denominator,
        };
    }

    fn begin(self: *Iterator) void {
        self.numerator = 0;
        self.decimal = 0;
    }

    fn nextRange(self: *Iterator) Range {
        const start = self.decimal;

        self.decimal += self.decimal_step;
        self.numerator += self.numerator_step;
        if (self.numerator >= self.denominator) {
            self.numerator -= self.denominator;
            self.decimal += 1;
        }

        return Range{
            .start = start,
            .end = self.decimal,
        };
    }

    fn finished(self: *Iterator) bool {
        return self.decimal >= self.size;
    }

    fn nextLevel(self: *Iterator) bool {
        self.decimal_step += self.decimal_step;
        self.numerator_step += self.numerator_step;
        if (self.numerator_step >= self.denominator) {
            self.numerator_step -= self.denominator;
            self.decimal_step += 1;
        }

        return (self.decimal_step < self.size);
    }

    fn length(self: *Iterator) usize {
        return self.decimal_step;
    }
}