levels.rs

/// Returns the number of bits needed to store the given maximum definition or repetition level.
#[inline]
pub fn get_bit_width(max_level: i16) -> u32 {
    16 - max_level.leading_zeros()
}

#[cfg(test)]
mod tests {
    use super::get_bit_width;

    #[test]
    fn test_get_bit_width() {
        assert_eq!(0, get_bit_width(0));
        assert_eq!(1, get_bit_width(1));
        assert_eq!(2, get_bit_width(2));
        assert_eq!(2, get_bit_width(3));
        assert_eq!(3, get_bit_width(4));
        assert_eq!(3, get_bit_width(5));
        assert_eq!(3, get_bit_width(6));
        assert_eq!(3, get_bit_width(7));
        assert_eq!(4, get_bit_width(8));
        assert_eq!(4, get_bit_width(15));

        assert_eq!(8, get_bit_width(255));
        assert_eq!(9, get_bit_width(256));
    }
}