memory.hpp

#ifndef ENTT_CORE_MEMORY_HPP
#define ENTT_CORE_MEMORY_HPP
 
#include <cstddef>
#include <limits>
#include <memory>
#include <type_traits>
#include <utility>
#include "../config/config.h"
 
namespace entt {
 
template<typename Type>
[[nodiscard]] constexpr auto to_address(Type &&ptr) ENTT_NOEXCEPT {
    if constexpr(std::is_pointer_v<std::remove_const_t<std::remove_reference_t<Type>>>) {
        return ptr;
    } else {
        return to_address(std::forward<Type>(ptr).operator->());
    }
}
 
template<typename Allocator>
constexpr void propagate_on_container_copy_assignment([[maybe_unused]] Allocator &lhs, [[maybe_unused]] Allocator &rhs) ENTT_NOEXCEPT {
    if constexpr(std::allocator_traits<Allocator>::propagate_on_container_copy_assignment::value) {
        lhs = rhs;
    }
}
 
template<typename Allocator>
constexpr void propagate_on_container_move_assignment([[maybe_unused]] Allocator &lhs, [[maybe_unused]] Allocator &rhs) ENTT_NOEXCEPT {
    if constexpr(std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value) {
        lhs = std::move(rhs);
    }
}
 
template<typename Allocator>
constexpr void propagate_on_container_swap([[maybe_unused]] Allocator &lhs, [[maybe_unused]] Allocator &rhs) ENTT_NOEXCEPT {
    ENTT_ASSERT(std::allocator_traits<Allocator>::propagate_on_container_swap::value || lhs == rhs, "Cannot swap the containers");
 
    if constexpr(std::allocator_traits<Allocator>::propagate_on_container_swap::value) {
        using std::swap;
        swap(lhs, rhs);
    }
}
 
[[nodiscard]] inline constexpr bool is_power_of_two(const std::size_t value) ENTT_NOEXCEPT {
    return value && ((value & (value - 1)) == 0);
}
 
[[nodiscard]] inline constexpr std::size_t next_power_of_two(const std::size_t value) ENTT_NOEXCEPT {
    ENTT_ASSERT(value < (std::size_t{1u} << (std::numeric_limits<std::size_t>::digits - 1)), "Numeric limits exceeded");
    std::size_t curr = value - (value != 0u);
 
    for(int next = 1; next < std::numeric_limits<std::size_t>::digits; next = next * 2) {
        curr |= curr >> next;
    }
 
    return ++curr;
}
 
[[nodiscard]] inline constexpr std::size_t fast_mod(const std::size_t value, const std::size_t mod) ENTT_NOEXCEPT {
    ENTT_ASSERT(is_power_of_two(mod), "Value must be a power of two");
    return value & (mod - 1u);
}
 
} // namespace entt
 
#endif