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// Copyright © 2026 Mikhail Hogrefe
//
// This file is part of Malachite.
//
// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
use crate::num::arithmetic::traits::PowerOf2;
use crate::num::basic::signeds::PrimitiveSigned;
use crate::num::basic::unsigneds::PrimitiveUnsigned;
use crate::num::conversion::traits::{IntegerMantissaAndExponent, SaturatingFrom};
fn power_of_2_unsigned<T: PrimitiveUnsigned>(pow: u64) -> T {
assert!(pow < T::WIDTH);
T::ONE << pow
}
macro_rules! impl_power_of_2_unsigned {
($t:ident) => {
impl PowerOf2<u64> for $t {
/// Raises 2 to an integer power.
///
/// $f(k) = 2^k$.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Panics
/// Panics if the result is not representable.
///
/// # Examples
/// See [here](super::power_of_2#power_of_2).
#[inline]
fn power_of_2(pow: u64) -> $t {
power_of_2_unsigned(pow)
}
}
};
}
apply_to_unsigneds!(impl_power_of_2_unsigned);
fn power_of_2_signed<T: PrimitiveSigned>(pow: u64) -> T {
assert!(pow < T::WIDTH - 1);
T::ONE << pow
}
macro_rules! impl_power_of_2_signed {
($t:ident) => {
impl PowerOf2<u64> for $t {
/// Raises 2 to an integer power.
///
/// $f(k) = 2^k$.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Panics
/// Panics if the result is not representable.
///
/// # Examples
/// See [here](super::power_of_2#power_of_2).
#[inline]
fn power_of_2(pow: u64) -> $t {
power_of_2_signed(pow)
}
}
};
}
apply_to_signeds!(impl_power_of_2_signed);
macro_rules! impl_power_of_2_primitive_float {
($t:ident) => {
impl PowerOf2<u64> for $t {
/// Raises 2 to an integer power.
///
/// $f(k) = 2^k$.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Panics
/// Panics if the power is greater than `Self::MAX_EXPONENT`.
///
/// # Examples
/// See [here](super::power_of_2#power_of_2).
#[inline]
fn power_of_2(pow: u64) -> $t {
$t::from_integer_mantissa_and_exponent(1, i64::saturating_from(pow)).unwrap()
}
}
impl PowerOf2<i64> for $t {
/// Raises 2 to an integer power.
///
/// $f(k) = 2^k$.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Panics
/// Panics if the power is smaller than `Self::MIN_EXPONENT` or greater than
/// `Self::MAX_EXPONENT`.
///
/// # Examples
/// See [here](super::power_of_2#power_of_2).
#[inline]
fn power_of_2(pow: i64) -> $t {
$t::from_integer_mantissa_and_exponent(1, pow).unwrap()
}
}
};
}
apply_to_primitive_floats!(impl_power_of_2_primitive_float);