smart_callable.hpp

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#ifndef EAGINE_SMART_CALLABLE_HPP
#define EAGINE_SMART_CALLABLE_HPP
 
#include "args_within_limits.hpp"
#include "assert.hpp"
#include "valid_if/decl.hpp"
 
namespace eagine {
//------------------------------------------------------------------------------
template <bool Asserting, typename Callable>
class smart_callable;
//------------------------------------------------------------------------------
template <bool Asserting, typename RV, typename... Params>
class smart_callable_base;
//------------------------------------------------------------------------------
template <typename RV, typename... Params>
class smart_callable_base<false, RV, Params...> {
protected:
    template <typename Callable, typename... Args>
    static constexpr auto _invoke(Callable& callable, Args&&... args) {
#ifdef __clang__
        EAGINE_DIAG_PUSH()
        EAGINE_DIAG_OFF(conversion)
        EAGINE_DIAG_OFF(sign-conversion)
#endif
        using ORV = optionally_valid<RV>;
        return args_within_limits_of<Params...>(args...)
                 ? ORV{callable(std::forward<Args>(args)...)}
                 : ORV{};
#ifdef __clang__
        EAGINE_DIAG_POP()
#endif
    }
};
//------------------------------------------------------------------------------
template <typename RV, typename... Params>
class smart_callable_base<true, RV, Params...> {
protected:
    template <typename Callable, typename... Args>
    static constexpr auto _invoke(Callable& callable, Args&&... args) {
#ifdef __clang__
        EAGINE_DIAG_PUSH()
        EAGINE_DIAG_OFF(conversion)
        EAGINE_DIAG_OFF(sign-conversion)
#endif
        EAGINE_ASSERT(args_within_limits_of<Params...>(args...));
        return callable(std::forward<Args>(args)...);
#ifdef __clang__
        EAGINE_DIAG_POP()
#endif
    }
};
//------------------------------------------------------------------------------
template <bool Asseting, typename RV, typename... Params>
class smart_callable<Asseting, RV (*)(Params...)>
  : public smart_callable_base<Asseting, RV, Params...> {
public:
    constexpr smart_callable(RV (*function)(Params...)) noexcept
      : _function{function} {}
 
    template <typename... Args>
    constexpr auto operator()(Args&&... args) const {
        this->_invoke(_function, std::forward<Args>(args)...);
    }
 
private:
    RV (*_function)(Params...) = nullptr;
};
//------------------------------------------------------------------------------
template <typename RV, typename... Params>
static constexpr smart_callable<false, RV (*)(Params...)>
smart_call(RV (*function)(Params...)) noexcept {
    return {function};
}
//------------------------------------------------------------------------------
template <typename RV, typename... Params>
static constexpr smart_callable<true, RV (*)(Params...)>
safe_call(RV (*function)(Params...)) noexcept {
    return {function};
}
//------------------------------------------------------------------------------
} // namespace eagine
 
#endif // EAGINE_SMART_CALLABLE_HPP