math.hpp

// Copyright (C) 2022-2023 by Camden Mannett.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include <type_traits>
 
namespace arg_router::math
{
template <typename T>
[[nodiscard]] constexpr T abs(T value) noexcept
{
    static_assert(std::is_integral_v<T>, "T must be an integral");
    if constexpr (std::is_signed_v<T>) {
        return value < T{0} ? -value : value;
    } else {
        return value;
    }
}
 
template <typename T>
[[nodiscard]] constexpr T num_digits(T value) noexcept
{
    static_assert(std::is_integral_v<T>, "T must be an integral");
 
    constexpr auto base = T{10};
 
    value = abs(value);
    auto i = T{1};
    while (value /= base) {
        ++i;
    }
 
    return i;
}
 
template <auto Base, typename T>
[[nodiscard]] constexpr T pow(T exp) noexcept
{
    static_assert(std::is_integral_v<T>, "T must be an integral");
    static_assert(Base > 0, "Base must be greater than zero");
 
    return exp <= T{0} ? T{1} : Base * pow<Base>(exp - T{1});
}
}  // namespace arg_router::math