malachite_nz/integer_polynomial/conversion/
natural_polynomial_from_integer_polynomial.rs

1// Copyright © 2026 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::integer_polynomial::IntegerPolynomial;
10use crate::natural::Natural;
11use crate::natural_polynomial::NaturalPolynomial;
12use alloc::vec::Vec;
13use malachite_base::num::conversion::traits::ConvertibleFrom;
14use malachite_base::polynomial::Polynomial;
15
16/// The error returned when an [`IntegerPolynomial`] with a negative coefficient is converted to a
17/// [`NaturalPolynomial`].
18#[derive(Clone, Copy, Debug, Eq, PartialEq)]
19pub struct NaturalPolynomialFromIntegerPolynomialError;
20
21impl TryFrom<IntegerPolynomial> for NaturalPolynomial {
22    type Error = NaturalPolynomialFromIntegerPolynomialError;
23
24    /// Converts an [`IntegerPolynomial`] to a [`NaturalPolynomial`], taking the
25    /// [`IntegerPolynomial`] by value and returning an error if any coefficient is negative.
26    ///
27    /// Each coefficient's limbs are reused rather than copied. A successful conversion keeps the
28    /// degree.
29    ///
30    /// # Worst-case complexity
31    /// $T(n) = O(n)$
32    ///
33    /// $M(n) = O(n)$
34    ///
35    /// where $T$ is time, $M$ is additional memory, and $n$ is the number of coefficients.
36    ///
37    /// # Examples
38    /// See [here](super::natural_polynomial_from_integer_polynomial#try_from).
39    fn try_from(p: IntegerPolynomial) -> Result<Self, Self::Error> {
40        Ok(Self::from_coefficients_asc(
41            p.coefficients
42                .into_iter()
43                .map(|c| {
44                    Natural::try_from(c).map_err(|_| NaturalPolynomialFromIntegerPolynomialError)
45                })
46                .collect::<Result<Vec<Natural>, _>>()?,
47        ))
48    }
49}
50
51impl TryFrom<&IntegerPolynomial> for NaturalPolynomial {
52    type Error = NaturalPolynomialFromIntegerPolynomialError;
53
54    /// Converts an [`IntegerPolynomial`] to a [`NaturalPolynomial`], taking the
55    /// [`IntegerPolynomial`] by reference and returning an error if any coefficient is negative.
56    ///
57    /// A successful conversion keeps the degree.
58    ///
59    /// # Worst-case complexity
60    /// $T(n) = O(n)$
61    ///
62    /// $M(n) = O(n)$
63    ///
64    /// where $T$ is time, $M$ is additional memory, and $n$ is the total number of bits in the
65    /// coefficients.
66    ///
67    /// # Examples
68    /// See [here](super::natural_polynomial_from_integer_polynomial#try_from).
69    fn try_from(p: &IntegerPolynomial) -> Result<Self, Self::Error> {
70        Ok(Self::from_coefficients_asc(
71            p.coefficients
72                .iter()
73                .map(|c| {
74                    Natural::try_from(c).map_err(|_| NaturalPolynomialFromIntegerPolynomialError)
75                })
76                .collect::<Result<Vec<Natural>, _>>()?,
77        ))
78    }
79}
80
81impl ConvertibleFrom<&IntegerPolynomial> for NaturalPolynomial {
82    /// Determines whether an [`IntegerPolynomial`] can be converted to a [`NaturalPolynomial`]
83    /// (when none of its coefficients is negative). Takes the [`IntegerPolynomial`] by reference.
84    ///
85    /// Unlike checking whether [`TryFrom`] succeeds, this allocates nothing.
86    ///
87    /// # Worst-case complexity
88    /// $T(n) = O(n)$
89    ///
90    /// $M(n) = O(1)$
91    ///
92    /// where $T$ is time, $M$ is additional memory, and $n$ is the number of coefficients.
93    ///
94    /// # Examples
95    /// See [here](super::natural_polynomial_from_integer_polynomial#convertible_from).
96    #[inline]
97    fn convertible_from(p: &IntegerPolynomial) -> bool {
98        p.coefficients.iter().all(Natural::convertible_from)
99    }
100}
malachite_nz/integer_polynomial/conversion/natural_polynomial_from_integer_polynomial.rs

malachite_nz/integer_polynomial/conversion/
natural_polynomial_from_integer_polynomial.rs
