malachite_base/num/arithmetic/
power_of_2.rs

1// Copyright © 2025 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::num::arithmetic::traits::PowerOf2;
10use crate::num::basic::signeds::PrimitiveSigned;
11use crate::num::basic::unsigneds::PrimitiveUnsigned;
12use crate::num::conversion::traits::IntegerMantissaAndExponent;
13
14fn power_of_2_unsigned<T: PrimitiveUnsigned>(pow: u64) -> T {
15    assert!(pow < T::WIDTH);
16    T::ONE << pow
17}
18
19macro_rules! impl_power_of_2_unsigned {
20    ($t:ident) => {
21        impl PowerOf2<u64> for $t {
22            /// Raises 2 to an integer power.
23            ///
24            /// $f(k) = 2^k$.
25            ///
26            /// # Worst-case complexity
27            /// Constant time and additional memory.
28            ///
29            /// # Panics
30            /// Panics if the result is not representable.
31            ///
32            /// # Examples
33            /// See [here](super::power_of_2#power_of_2).
34            #[inline]
35            fn power_of_2(pow: u64) -> $t {
36                power_of_2_unsigned(pow)
37            }
38        }
39    };
40}
41apply_to_unsigneds!(impl_power_of_2_unsigned);
42
43fn power_of_2_signed<T: PrimitiveSigned>(pow: u64) -> T {
44    assert!(pow < T::WIDTH - 1);
45    T::ONE << pow
46}
47
48macro_rules! impl_power_of_2_signed {
49    ($t:ident) => {
50        impl PowerOf2<u64> for $t {
51            /// Raises 2 to an integer power.
52            ///
53            /// $f(k) = 2^k$.
54            ///
55            /// # Worst-case complexity
56            /// Constant time and additional memory.
57            ///
58            /// # Panics
59            /// Panics if the result is not representable.
60            ///
61            /// # Examples
62            /// See [here](super::power_of_2#power_of_2).
63            #[inline]
64            fn power_of_2(pow: u64) -> $t {
65                power_of_2_signed(pow)
66            }
67        }
68    };
69}
70apply_to_signeds!(impl_power_of_2_signed);
71
72macro_rules! impl_power_of_2_primitive_float {
73    ($t:ident) => {
74        impl PowerOf2<i64> for $t {
75            /// Raises 2 to an integer power.
76            ///
77            /// $f(k) = 2^k$.
78            ///
79            /// # Worst-case complexity
80            /// Constant time and additional memory.
81            ///
82            /// # Panics
83            /// Panics if the power is smaller than `Self::MIN_EXPONENT` or greater than
84            /// `Self::MAX_EXPONENT`.
85            ///
86            /// # Examples
87            /// See [here](super::power_of_2#power_of_2).
88            #[inline]
89            fn power_of_2(pow: i64) -> $t {
90                $t::from_integer_mantissa_and_exponent(1, pow).unwrap()
91            }
92        }
93    };
94}
95apply_to_primitive_floats!(impl_power_of_2_primitive_float);
malachite_base/num/arithmetic/power_of_2.rs

malachite_base/num/arithmetic/
power_of_2.rs
