// ------------------------------------------------------------------------------

// Copyright (c) 2000 Cadenza New Zealand Ltd

// Distributed under the Boost Software License, Version 1.0. (See accompany-

// ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

// ------------------------------------------------------------------------------

// Boost functional.hpp header file

// See http://www.boost.org/libs/functional for documentation.

// ------------------------------------------------------------------------------

// $Id$

// ------------------------------------------------------------------------------

#ifndef BOOST_FUNCTIONAL_HPP

#define BOOST_FUNCTIONAL_HPP

#include <boost/config.hpp>

#include <boost/call_traits.hpp>

#include <functional>

namespace boost

{

    namespace functional

    {

        namespace detail {

#if defined(_HAS_AUTO_PTR_ETC) && !_HAS_AUTO_PTR_ETC

            // std::unary_function and std::binary_function were both removed

            // in C++17.

            template <typename Arg1, typename Result>

            struct unary_function

            {

                typedef Arg1 argument_type;

                typedef Result result_type;

            };

            template <typename Arg1, typename Arg2, typename Result>

            struct binary_function

            {

                typedef Arg1 first_argument_type;

                typedef Arg2 second_argument_type;

                typedef Result result_type;

            };

#else

            // Use the standard objects when we have them.

            using std::unary_function;

            using std::binary_function;

#endif

        }

    }

#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    // --------------------------------------------------------------------------

    // The following traits classes allow us to avoid the need for ptr_fun

    // because the types of arguments and the result of a function can be 

    // deduced.

    //

    // In addition to the standard types defined in unary_function and 

    // binary_function, we add

    //

    // - function_type, the type of the function or function object itself.

    //

    // - param_type, the type that should be used for passing the function or

    //   function object as an argument.

    // --------------------------------------------------------------------------

    namespace detail

    {

        template <class Operation>

        struct unary_traits_imp;

        template <class Operation>

        struct unary_traits_imp<Operation*>

        {

            typedef Operation                         function_type;

            typedef const function_type &             param_type;

            typedef typename Operation::result_type   result_type;

            typedef typename Operation::argument_type argument_type;

        };

        template <class R, class A>

        struct unary_traits_imp<R(*)(A)>

        {

            typedef R (*function_type)(A);

            typedef R (*param_type)(A);

            typedef R result_type;

            typedef A argument_type;

        };

        template <class Operation>

        struct binary_traits_imp;

        template <class Operation>

        struct binary_traits_imp<Operation*>

        {

            typedef Operation                                function_type;

            typedef const function_type &                    param_type;

            typedef typename Operation::result_type          result_type;

            typedef typename Operation::first_argument_type  first_argument_type;

            typedef typename Operation::second_argument_type second_argument_type;

        };

        template <class R, class A1, class A2>

        struct binary_traits_imp<R(*)(A1,A2)>

        {

            typedef R (*function_type)(A1,A2);

            typedef R (*param_type)(A1,A2);

            typedef R result_type;

            typedef A1 first_argument_type;

            typedef A2 second_argument_type;

        };

    } // namespace detail

    template <class Operation>

    struct unary_traits

    {

        typedef typename detail::unary_traits_imp<Operation*>::function_type function_type;

        typedef typename detail::unary_traits_imp<Operation*>::param_type    param_type;

        typedef typename detail::unary_traits_imp<Operation*>::result_type   result_type;

        typedef typename detail::unary_traits_imp<Operation*>::argument_type argument_type;

    }; 

    template <class R, class A>

    struct unary_traits<R(*)(A)>

    {

        typedef R (*function_type)(A);

        typedef R (*param_type)(A);

        typedef R result_type;

        typedef A argument_type;

    };

    template <class Operation>

    struct binary_traits

    {

        typedef typename detail::binary_traits_imp<Operation*>::function_type        function_type;

        typedef typename detail::binary_traits_imp<Operation*>::param_type           param_type;

        typedef typename detail::binary_traits_imp<Operation*>::result_type          result_type;

        typedef typename detail::binary_traits_imp<Operation*>::first_argument_type  first_argument_type;

        typedef typename detail::binary_traits_imp<Operation*>::second_argument_type second_argument_type;

    };

    template <class R, class A1, class A2>

    struct binary_traits<R(*)(A1,A2)>

    {

        typedef R (*function_type)(A1,A2);

        typedef R (*param_type)(A1,A2);

        typedef R result_type;

        typedef A1 first_argument_type;

        typedef A2 second_argument_type;

    };

#else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    // --------------------------------------------------------------------------

    // If we have no partial specialisation available, decay to a situation

    // that is no worse than in the Standard, i.e., ptr_fun will be required.

    // --------------------------------------------------------------------------

    template <class Operation>

    struct unary_traits

    {

        typedef Operation                         function_type;

        typedef const Operation&                  param_type;

        typedef typename Operation::result_type   result_type;

        typedef typename Operation::argument_type argument_type;

    }; 

    template <class Operation>

    struct binary_traits

    {

        typedef Operation                                function_type;

        typedef const Operation &                        param_type;

        typedef typename Operation::result_type          result_type;

        typedef typename Operation::first_argument_type  first_argument_type;

        typedef typename Operation::second_argument_type second_argument_type;

    };    

#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    // --------------------------------------------------------------------------

    // unary_negate, not1

    // --------------------------------------------------------------------------

    template <class Predicate>

    class unary_negate

        : public boost::functional::detail::unary_function<typename unary_traits<Predicate>::argument_type,bool>

    {

      public:

        explicit unary_negate(typename unary_traits<Predicate>::param_type x)

            :

            pred(x)

        {}

        bool operator()(typename call_traits<typename unary_traits<Predicate>::argument_type>::param_type x) const

        {

            return !pred(x);

        }

      private:

        typename unary_traits<Predicate>::function_type pred;

    };

    template <class Predicate>

    unary_negate<Predicate> not1(const Predicate &pred)

    {

        // The cast is to placate Borland C++Builder in certain circumstances.

        // I don't think it should be necessary.

        return unary_negate<Predicate>((typename unary_traits<Predicate>::param_type)pred);

    }

    template <class Predicate>

    unary_negate<Predicate> not1(Predicate &pred)

    {

        return unary_negate<Predicate>(pred);

    }

    // --------------------------------------------------------------------------

    // binary_negate, not2

    // --------------------------------------------------------------------------

    template <class Predicate>

    class binary_negate

        : public boost::functional::detail::binary_function<

                                      typename binary_traits<Predicate>::first_argument_type,

                                      typename binary_traits<Predicate>::second_argument_type,

                                      bool>

    {

      public:

        explicit binary_negate(typename binary_traits<Predicate>::param_type x)

            :

            pred(x)

        {}

        bool operator()(typename call_traits<typename binary_traits<Predicate>::first_argument_type>::param_type x,

                        typename call_traits<typename binary_traits<Predicate>::second_argument_type>::param_type y) const

        {

            return !pred(x,y);

        }

      private:

        typename binary_traits<Predicate>::function_type pred;

    };

    template <class Predicate>

    binary_negate<Predicate> not2(const Predicate &pred)

    {

        // The cast is to placate Borland C++Builder in certain circumstances.

        // I don't think it should be necessary.

        return binary_negate<Predicate>((typename binary_traits<Predicate>::param_type)pred);

    }

    template <class Predicate>

    binary_negate<Predicate> not2(Predicate &pred)

    {

        return binary_negate<Predicate>(pred);

    }

    // --------------------------------------------------------------------------

    // binder1st, bind1st

    // --------------------------------------------------------------------------

    template <class Operation>

    class binder1st

        : public boost::functional::detail::unary_function<

                                     typename binary_traits<Operation>::second_argument_type,

                                     typename binary_traits<Operation>::result_type>

    {       

      public:

        binder1st(typename binary_traits<Operation>::param_type x,

                  typename call_traits<typename binary_traits<Operation>::first_argument_type>::param_type y)

            :

            op(x), value(y)

        {}

        typename binary_traits<Operation>::result_type

        operator()(typename call_traits<typename binary_traits<Operation>::second_argument_type>::param_type x) const

        {

            return op(value, x);

        }

      protected:

        typename binary_traits<Operation>::function_type op;

        typename binary_traits<Operation>::first_argument_type value;

    };

    template <class Operation>

    inline binder1st<Operation> bind1st(const Operation &op,

                                        typename call_traits<

                                                    typename binary_traits<Operation>::first_argument_type

                                        >::param_type x)

    {

        // The cast is to placate Borland C++Builder in certain circumstances.

        // I don't think it should be necessary.

        return binder1st<Operation>((typename binary_traits<Operation>::param_type)op, x);

    }

    template <class Operation>

    inline binder1st<Operation> bind1st(Operation &op,

                                        typename call_traits<

                                                    typename binary_traits<Operation>::first_argument_type

                                        >::param_type x)

    {

        return binder1st<Operation>(op, x);

    }

    // --------------------------------------------------------------------------

    // binder2nd, bind2nd

    // --------------------------------------------------------------------------

    template <class Operation>

    class binder2nd

        : public boost::functional::detail::unary_function<

                                     typename binary_traits<Operation>::first_argument_type,

                                     typename binary_traits<Operation>::result_type>

    {

      public:

        binder2nd(typename binary_traits<Operation>::param_type x,

                  typename call_traits<typename binary_traits<Operation>::second_argument_type>::param_type y)

            :

            op(x), value(y)

        {}

        typename binary_traits<Operation>::result_type

        operator()(typename call_traits<typename binary_traits<Operation>::first_argument_type>::param_type x) const

        {

            return op(x, value);

        }               

      protected:

        typename binary_traits<Operation>::function_type op;

        typename binary_traits<Operation>::second_argument_type value;

    };

    template <class Operation>

    inline binder2nd<Operation> bind2nd(const Operation &op,

                                        typename call_traits<

                                                    typename binary_traits<Operation>::second_argument_type

                                        >::param_type x)

    {

        // The cast is to placate Borland C++Builder in certain circumstances.

        // I don't think it should be necessary.

        return binder2nd<Operation>((typename binary_traits<Operation>::param_type)op, x);

    }

    template <class Operation>

    inline binder2nd<Operation> bind2nd(Operation &op,

                                        typename call_traits<

                                                    typename binary_traits<Operation>::second_argument_type

                                        >::param_type x)

    {

        return binder2nd<Operation>(op, x);

    }

    // --------------------------------------------------------------------------

    // mem_fun, etc

    // --------------------------------------------------------------------------

    template <class S, class T>

    class mem_fun_t : public boost::functional::detail::unary_function<T*, S>

    {

      public:

        explicit mem_fun_t(S (T::*p)())

            :

            ptr(p)

        {}

        S operator()(T* p) const

        {

            return (p->*ptr)();

        }

      private:

        S (T::*ptr)();

    };

    template <class S, class T, class A>

    class mem_fun1_t : public boost::functional::detail::binary_function<T*, A, S>

    {

      public:   

        explicit mem_fun1_t(S (T::*p)(A))

            :

            ptr(p)

        {}

        S operator()(T* p, typename call_traits::param_type x) const

        {

            return (p->*ptr)(x);

        }

      private:

        S (T::*ptr)(A);

    };

    template <class S, class T>

    class const_mem_fun_t : public boost::functional::detail::unary_function<const T*, S>

    {

      public:

        explicit const_mem_fun_t(S (T::*p)() const)

            :

            ptr(p)

        {}

        S operator()(const T* p) const

        {

            return (p->*ptr)();

        }

      private:

        S (T::*ptr)() const;        

    };

    template <class S, class T, class A>

    class const_mem_fun1_t : public boost::functional::detail::binary_function<const T*, A, S>

    {

      public:

        explicit const_mem_fun1_t(S (T::*p)(A) const)

            :

            ptr(p)

        {}

        S operator()(const T* p, typename call_traits::param_type x) const

        {

            return (p->*ptr)(x);

        }

      private:

        S (T::*ptr)(A) const;

    };

    template<class S, class T>

    inline mem_fun_t<S,T> mem_fun(S (T::*f)())

    {

        return mem_fun_t<S,T>(f);

    }

    template<class S, class T, class A>

    inline mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A))

    {

        return mem_fun1_t<S,T,A>(f);

    }

#ifndef BOOST_NO_POINTER_TO_MEMBER_CONST

    template<class S, class T>

    inline const_mem_fun_t<S,T> mem_fun(S (T::*f)() const)

    {

        return const_mem_fun_t<S,T>(f);

    }

    template<class S, class T, class A>

    inline const_mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A) const)

    {

        return const_mem_fun1_t<S,T,A>(f);

    }

#endif // BOOST_NO_POINTER_TO_MEMBER_CONST

    // --------------------------------------------------------------------------

    // mem_fun_ref, etc

    // --------------------------------------------------------------------------

    template <class S, class T>

    class mem_fun_ref_t : public boost::functional::detail::unary_function<T&, S>

    {

      public:

        explicit mem_fun_ref_t(S (T::*p)())

            :

            ptr(p)

        {}

        S operator()(T& p) const

        {

            return (p.*ptr)();

        }

      private:

        S (T::*ptr)();

    };

    template <class S, class T, class A>

    class mem_fun1_ref_t : public boost::functional::detail::binary_function<T&, A, S>

    {

      public:

        explicit mem_fun1_ref_t(S (T::*p)(A))

            :

            ptr(p)

        {}

        S operator()(T& p, typename call_traits::param_type x) const

        {

            return (p.*ptr)(x);

        }

      private:

        S (T::*ptr)(A);

    };

    template <class S, class T>

    class const_mem_fun_ref_t : public boost::functional::detail::unary_function<const T&, S>

    {

      public:

        explicit const_mem_fun_ref_t(S (T::*p)() const)

            :

            ptr(p)

        {}

        S operator()(const T &p) const

        {

            return (p.*ptr)();

        }

      private:

        S (T::*ptr)() const;

    };

    template <class S, class T, class A>

    class const_mem_fun1_ref_t : public boost::functional::detail::binary_function<const T&, A, S>

    {

      public:

        explicit const_mem_fun1_ref_t(S (T::*p)(A) const)

            :

            ptr(p)

        {}

        S operator()(const T& p, typename call_traits::param_type x) const

        {

            return (p.*ptr)(x);

        }

      private:

        S (T::*ptr)(A) const;

    };

    template<class S, class T>

    inline mem_fun_ref_t<S,T> mem_fun_ref(S (T::*f)())

    {

        return mem_fun_ref_t<S,T>(f);

    }

    template<class S, class T, class A>

    inline mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A))

    {

        return mem_fun1_ref_t<S,T,A>(f);

    }

#ifndef BOOST_NO_POINTER_TO_MEMBER_CONST

    template<class S, class T>

    inline const_mem_fun_ref_t<S,T> mem_fun_ref(S (T::*f)() const)

    {

        return const_mem_fun_ref_t<S,T>(f);

    }

    template<class S, class T, class A>

    inline const_mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A) const)

    {

        return const_mem_fun1_ref_t<S,T,A>(f);

    }   

#endif // BOOST_NO_POINTER_TO_MEMBER_CONST

    // --------------------------------------------------------------------------

    // ptr_fun

    // --------------------------------------------------------------------------

    template <class Arg, class Result>

    class pointer_to_unary_function : public boost::functional::detail::unary_function<Arg,Result>

    {

      public:

        explicit pointer_to_unary_function(Result (*f)(Arg))

            :

            func(f)

        {}

        Result operator()(typename call_traits<Arg>::param_type x) const

        {

            return func(x);

        }

      private:

        Result (*func)(Arg);

    };

    template <class Arg, class Result>

    inline pointer_to_unary_function<Arg,Result> ptr_fun(Result (*f)(Arg))

    {

        return pointer_to_unary_function<Arg,Result>(f);

    }

    template <class Arg1, class Arg2, class Result>

    class pointer_to_binary_function : public boost::functional::detail::binary_function<Arg1,Arg2,Result>

    {

      public:

        explicit pointer_to_binary_function(Result (*f)(Arg1, Arg2))

            :

            func(f)

        {}

        Result operator()(typename call_traits<Arg1>::param_type x, typename call_traits<Arg2>::param_type y) const

        {

            return func(x,y);

        }

      private:

        Result (*func)(Arg1, Arg2);

    };

    template <class Arg1, class Arg2, class Result>

    inline pointer_to_binary_function<Arg1,Arg2,Result> ptr_fun(Result (*f)(Arg1, Arg2))

    {

        return pointer_to_binary_function<Arg1,Arg2,Result>(f);

    }

} // namespace boost

#endif