functional.h

/* ScummVM - Graphic Adventure Engine
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/********************************************
   DISCLAIMER:

   This is a wrapper code to mimic the relevant std:: class
   Please use it ONLY when porting an existing code e.g. from the original sources

   For all new development please use classes from Common::
 *********************************************/

#ifndef COMMON_STD_FUNCTIONAL_H
#define COMMON_STD_FUNCTIONAL_H

namespace Std {

template <class _Arg, class _Result>
struct unary_function { // base class for unary functions
    using argument_type = _Arg;
    using result_type = _Result;
};

template <class _Arg1, class _Arg2, class _Result>
struct binary_function { // base class for binary functions
    using first_argument_type = _Arg1;
    using second_argument_type = _Arg2;
    using result_type = _Result;
};

template <typename _Fty>
struct function {
    _Fty *_fn;

    function() : _fn(nullptr) {}
    function(_Fty *fn) : _fn(fn) {}

    operator _Fty &() {
        return *_fn;
    }

    operator bool() const {
        return _fn != nullptr;
    }
};

} // namespace Std

#endif