1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
use crate::natural::Natural;
use malachite_base::num::arithmetic::traits::ModPowerOf2IsReduced;
use malachite_base::num::logic::traits::SignificantBits;
impl ModPowerOf2IsReduced for Natural {
/// Returns whether a [`Natural`] is reduced modulo 2^k$; in other words, whether it has no
/// more than $k$ significant bits.
///
/// $f(x, k) = (x < 2^k)$.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// extern crate malachite_base;
///
/// use malachite_base::num::arithmetic::traits::{ModPowerOf2IsReduced, Pow};
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::natural::Natural;
///
/// assert_eq!(Natural::ZERO.mod_power_of_2_is_reduced(5), true);
/// assert_eq!(Natural::from(10u32).pow(12).mod_power_of_2_is_reduced(39), false);
/// assert_eq!(Natural::from(10u32).pow(12).mod_power_of_2_is_reduced(40), true);
/// ```
#[inline]
fn mod_power_of_2_is_reduced(&self, pow: u64) -> bool {
self.significant_bits() <= pow
}
}