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use crate::num::arithmetic::traits::{Parity, Pow, PowAssign};
use crate::num::conversion::traits::ExactFrom;
macro_rules! impl_pow_unsigned {
($t:ident) => {
impl Pow<u64> for $t {
type Output = $t;
/// This is a wrapper over the `pow` functions in the standard library, for example
/// [this one](u32::pow).
#[inline]
fn pow(self, exp: u64) -> $t {
if exp == 0 {
1
} else if self < 2 {
self
} else {
self.pow(u32::exact_from(exp))
}
}
}
};
}
apply_to_unsigneds!(impl_pow_unsigned);
macro_rules! impl_pow_signed {
($t:ident) => {
impl Pow<u64> for $t {
type Output = $t;
/// This is a wrapper over the `pow` functions in the standard library, for example
/// [this one](i32::pow).
#[inline]
fn pow(self, exp: u64) -> $t {
if exp == 0 {
1
} else if self == 0 || self == 1 {
self
} else if self == -1 {
if exp.even() {
1
} else {
-1
}
} else {
self.pow(u32::exact_from(exp))
}
}
}
};
}
apply_to_signeds!(impl_pow_signed);
macro_rules! impl_pow_primitive_int {
($t:ident) => {
impl PowAssign<u64> for $t {
/// Raises a number to a power, in place.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `exp.significant_bits()`.
///
/// # Examples
/// See [here](super::pow#pow_assign).
#[inline]
fn pow_assign(&mut self, exp: u64) {
*self = Pow::pow(*self, exp);
}
}
};
}
apply_to_primitive_ints!(impl_pow_primitive_int);
macro_rules! impl_pow_primitive_float {
($t:ident) => {
impl Pow<i64> for $t {
type Output = $t;
/// This is a wrapper over the `powi` functions in the standard library, for example
/// [this one](f32::powi).
#[inline]
fn pow(self, exp: i64) -> $t {
libm::Libm::<$t>::pow(self, exp as $t)
}
}
impl PowAssign<i64> for $t {
/// Raises a number to a power, in place.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::pow#pow_assign).
#[inline]
fn pow_assign(&mut self, exp: i64) {
*self = libm::Libm::<$t>::pow(*self, exp as $t);
}
}
impl Pow<$t> for $t {
type Output = $t;
/// This is a wrapper over the `powf` functions in the standard library, for example
/// [this one](f32::powf).
#[inline]
fn pow(self, exp: $t) -> $t {
libm::Libm::<$t>::pow(self, exp)
}
}
impl PowAssign<$t> for $t {
/// Raises a number to a power, in place.
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::pow#pow_assign).
#[inline]
fn pow_assign(&mut self, exp: $t) {
*self = libm::Libm::<$t>::pow(*self, exp);
}
}
};
}
apply_to_primitive_floats!(impl_pow_primitive_float);