common.hpp

/*
 * This file is part of libtcspc
 * Copyright 2019-2026 Board of Regents of the University of Wisconsin System
 * SPDX-License-Identifier: MIT
 */
 
#pragma once
 
#include <cassert>
#include <concepts>
#include <cstdint>
#include <type_traits>
 
namespace tcspc::internal {
 
// Disable inlining; Must be placed _after_ standard attributes such as
// [[noreturn]], for MSVC.
#if defined(__GNUC__)
#define LIBTCSPC_NOINLINE [[gnu::noinline]]
#elif defined(_MSC_VER)
#define LIBTCSPC_NOINLINE [[msvc::noinline]]
#else
#define LIBTCSPC_NOINLINE
#endif
 
// Run-time check for actual alignment.
template <typename T>
inline auto is_aligned(void const *ptr) noexcept -> bool {
    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast)
    auto const start = reinterpret_cast<uintptr_t>(ptr);
    return start % alignof(T) == 0;
}
 
// C++23 std::unreachable(), but safe in debug build.
[[noreturn]] inline void unreachable() {
    assert(false);
#if defined(__GNUC__)
    __builtin_unreachable();
#elif defined(_MSC_VER)
    __assume(false);
#endif
}
 
// A "false" template metafunction that can be used with static_assert in
// constexpr-if branches (by pretending that it may not always be false).
template <typename T> struct always_false : std::false_type {};
 
template <typename T>
inline constexpr bool always_false_v = always_false<T>::value;
 
template <typename T, typename... U>
concept same_as_any_of = (std::same_as<T, U> || ...);
 
// Overloaded idiom for std::visit
template <typename... Ts> struct overloaded : Ts... {
    using Ts::operator()...;
};
template <typename... Ts> overloaded(Ts...) -> overloaded<Ts...>;
 
} // namespace tcspc::internal