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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::integer::Integer;
use crate::integer_polynomial::IntegerPolynomial;
use core::ops::{Shl, ShlAssign};
// Shifts every coefficient left by `bits`. A nonzero coefficient stays nonzero, and keeps its sign,
// so the result is normalized.
//
// This is equivalent to `fmpz_poly_scalar_mul_2exp` from `fmpz_poly/scalar.c`, FLINT 3.6.0.
fn shl_ref<T: Copy>(p: &IntegerPolynomial, bits: T) -> IntegerPolynomial
where
for<'a> &'a Integer: Shl<T, Output = Integer>,
{
IntegerPolynomial {
coefficients: p.coefficients.iter().map(|c| c << bits).collect(),
}
}
// Shifts every coefficient left by `bits`, in place.
//
// This is equivalent to `fmpz_poly_scalar_mul_2exp` from `fmpz_poly/scalar.c`, FLINT 3.6.0.
fn shl_assign<T: Copy>(p: &mut IntegerPolynomial, bits: T)
where
Integer: ShlAssign<T>,
{
for c in &mut p.coefficients {
*c <<= bits;
}
}
macro_rules! impl_integer_polynomial_shl_unsigned {
($t:ident) => {
impl Shl<$t> for IntegerPolynomial {
type Output = IntegerPolynomial;
/// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), taking it by
/// value. Every coefficient is shifted.
///
/// $f(p, k) = 2^kp$.
///
/// # Worst-case complexity
/// $T(n, m, k) = O(n + km)$
///
/// $M(n, m, k) = O(n + km)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
/// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
///
/// # Examples
/// See [here](super::shl#shl).
#[inline]
fn shl(mut self, bits: $t) -> IntegerPolynomial {
self <<= bits;
self
}
}
impl Shl<$t> for &IntegerPolynomial {
type Output = IntegerPolynomial;
/// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), taking it by
/// reference. Every coefficient is shifted.
///
/// $f(p, k) = 2^kp$.
///
/// # Worst-case complexity
/// $T(n, m, k) = O(n + km)$
///
/// $M(n, m, k) = O(n + km)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
/// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
///
/// # Examples
/// See [here](super::shl#shl).
#[inline]
fn shl(self, bits: $t) -> IntegerPolynomial {
shl_ref(self, bits)
}
}
impl ShlAssign<$t> for IntegerPolynomial {
/// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), in place.
/// Every coefficient is shifted.
///
/// $p \gets 2^kp$.
///
/// # Worst-case complexity
/// $T(n, m, k) = O(n + km)$
///
/// $M(n, m, k) = O(n + km)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
/// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
///
/// # Examples
/// See [here](super::shl#shl_assign).
#[inline]
fn shl_assign(&mut self, bits: $t) {
shl_assign(self, bits);
}
}
};
}
apply_to_unsigneds!(impl_integer_polynomial_shl_unsigned);