1pub trait Math {
 2  fn square_root(self) -> usize;
 3  fn pow2(self) -> usize;
 4  fn get_bits(self, num_bits: usize) -> Vec<bool>;
 5  fn log_2(self) -> usize;
 6}
 7
 8impl Math for usize {
 9  #[inline]
10  fn square_root(self) -> usize {
11    (self as f64).sqrt() as usize
12  }
13
14  #[inline]
15  fn pow2(self) -> usize {
16    let base: usize = 2;
17    base.pow(self as u32)
18  }
19
20  /// Returns the num_bits from n in a canonical order
21  fn get_bits(self, num_bits: usize) -> Vec<bool> {
22    (0..num_bits)
23      .map(|shift_amount| ((self & (1 << (num_bits - shift_amount - 1))) > 0))
24      .collect::<Vec<bool>>()
25  }
26
27  fn log_2(self) -> usize {
28    assert_ne!(self, 0);
29
30    if self.is_power_of_two() {
31      (1usize.leading_zeros() - self.leading_zeros()) as usize
32    } else {
33      (0usize.leading_zeros() - self.leading_zeros()) as usize
34    }
35  }
36}