//  tuple_basic.hpp -----------------------------------------------------



// Copyright (C) 1999, 2000 Jaakko Järvi (jaakko.jarvi@cs.utu.fi)

//

// Permission to copy, use, sell and distribute this software is granted

// provided this copyright notice appears in all copies. 

// Permission to modify the code and to distribute modified code is granted

// provided this copyright notice appears in all copies, and a notice 

// that the code was modified is included with the copyright notice.

//

// This software is provided "as is" without express or implied warranty, 

// and with no claim as to its suitability for any purpose.



// For more information, see http://www.boost.org



// Outside help:

// This and that, Gary Powell.

// Fixed return types for get_head/get_tail 

// ( and other bugs ) per suggestion of Jens Maurer

// simplified element type accessors + bug fix  (Jeremy Siek)

// Several changes/additions according to suggestions by Doug Gregor, 

// William Kempf, Vesa Karvonen, John Max Skaller, Ed Brey, Beman Davis,

// David Abrahams.



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



#ifndef BOOST_TUPLE_BASIC_HPP

#define BOOST_TUPLE_BASIC_HPP





#include <utility> // needed for the assignment from pair to tuple



#include "boost/type_traits/cv_traits.hpp"

							    

namespace boost {



// -- null_type --------------------------------------------------------

struct null_type {};



// a helper function to provide a const null_type type temporary

namespace detail {

namespace tuples {

  inline const null_type cnull_type() { return null_type(); }

} // end tuples

} // end detail



// - cons forward declaration -----------------------------------------------

template <class HT, class TT>

struct cons;



// - tuple forward declaration -----------------------------------------------

template <

  class T0 = null_type, class T1 = null_type, class T2 = null_type, 

  class T3 = null_type, class T4 = null_type, class T5 = null_type, 

  class T6 = null_type, class T7 = null_type, class T8 = null_type, 

  class T9 = null_type>

class tuple; 



// tuple_length forward declaration

template<class T> struct tuple_length;







namespace detail {

namespace tuples {



// -- generate error template, referencing to non-existing members of this 

// template is used to produce compilation errors intentionally

template<class T>

class generate_error;



// tuple default argument wrappers ---------------------------------------

// Work for non-reference types, intentionally not for references

template <class T>

struct default_arg {



// Non-class temporaries cannot have qualifiers.

// To prevent f to return for example const int, we remove cv-qualifiers

// from all temporaries. 

     static typename boost::remove_cv<T>::type f() { return T(); }

};

   

template <class T>

struct default_arg<T&> {

  static T& f() { 

    return generate_error<T>::no_default_values_for_reference_types;

  }

};



// - cons getters --------------------------------------------------------

// called: element<N>::get<RETURN_TYPE>(aTuple)



template< int N >

struct element {

  template<class RET, class HT, class TT >

  inline static RET get(const cons<HT, TT>& t)

  {

    return element<N-1>::template get<RET>(t.tail);

  }

  template<class RET, class HT, class TT >

  inline static RET get(cons<HT, TT>& t)

  {

    return element<N-1>::template get<RET>(t.tail);

  }

};



template<>

struct element<0> {

  template<class RET, class HT, class TT> 

  inline static RET get(const cons<HT, TT>& t)

  {

    return t.head;

  }

  template<class RET, class HT, class TT> 

  inline static RET get(cons<HT, TT>& t)

  {

    return t.head;

  }

};



} // end of namespace tuples

} // end of namespace detail





// -cons type accessors ----------------------------------------

// typename tuple_element<N,T>::type gets the type of the 

// Nth element ot T, first element is at index 0

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



template<int N, class T>

struct tuple_element

{

private:

  typedef typename T::tail_type Next;

public:

  typedef typename tuple_element<N-1, Next>::type type;

};

template<class T>

struct tuple_element<0,T>

{

  typedef typename T::head_type type;

};



// -get function templates -----------------------------------------------

// Usage: get<N>(aTuple)



// -- some traits classes for get functions



// access traits lifted from detail namespace to be part of the interface,

// (Joel de Guzman's suggestion). Rationale: get functions are part of the

// interface, so should the way to express their return types be.



template <class T> struct tuple_access_traits {

  typedef const T& const_type;

  typedef T& non_const_type;



  typedef const typename boost::remove_cv<T>::type& parameter_type;

// used as the tuple constructors parameter types

// Rationale: non-reference tuple element types can be cv-qualified.

// It should be possible to initialize such types with temporaries,

// and when binding temporaries to references, the reference must

// be non-volatile and const. 8.5.3. (5)

};



template <class T> struct tuple_access_traits<T&> {



  typedef T& const_type;

  typedef T& non_const_type;

   

  typedef T& parameter_type;   

};





// get function for non-const cons-lists, returns a reference to the element



template<int N, class HT, class TT>

inline typename tuple_access_traits<

                  typename tuple_element<N, cons<HT, TT> >::type

                >::non_const_type

get(cons<HT, TT>& c) { 

  return detail::tuples::element<N>::template 

         get<

           typename tuple_access_traits<

             typename tuple_element<N, cons<HT, TT> >::type

           >::non_const_type>(c); 

} 



// get function for const cons-lists, returns a const reference to

// the element. If the element is a reference, returns the reference

// as such (that is, can return a non-const reference)

template<int N, class HT, class TT>

inline typename tuple_access_traits<

                  typename tuple_element<N, cons<HT, TT> >::type

                >::const_type

get(const cons<HT, TT>& c) { 

  return detail::tuples::element<N>::template 

         get<

           typename tuple_access_traits<

             typename tuple_element<N, cons<HT, TT> >::type

         >::const_type>(c);

} 









// -- the cons template  --------------------------------------------------



template <class HT, class TT>

struct cons {



  typedef HT head_type;

  typedef TT tail_type;



  head_type head;

  tail_type tail;



  typename tuple_access_traits<head_type>::non_const_type get_head() { return head; }

  typename tuple_access_traits<tail_type>::non_const_type get_tail() { return tail; }  



  typename tuple_access_traits<head_type>::const_type get_head() const { return head; }

  typename tuple_access_traits<tail_type>::const_type get_tail() const { return tail; }  

   

  template <class T1, class T2, class T3, class T4, class T5, 

            class T6, class T7, class T8, class T9, class T10>

  cons( T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, 

        T6& t6, T7& t7, T8& t8, T9& t9, T10& t10 ) 

    : head (t1) , tail (t2, t3, t4, t5, t6, t7, t8, t9, t10, detail::tuples::cnull_type()) {}



   template <class HT2, class TT2>

   cons( const cons<HT2, TT2>& u ) : head(u.head), tail(u.tail) {}



  template <class HT2, class TT2>

  cons& operator=( const cons<HT2, TT2>& u ) { 

    head=u.head; tail=u.tail; return *this; 

  }



  // must define assignment operator explicitly, implicit version is 

  // illformed if HT is a reference (12.8. (12))

  cons& operator=(const cons& u) { 

    head = u.head; tail = u.tail;  return *this; 

  }



  template <class T1, class T2>

  cons& operator=( const std::pair<T1, T2>& u ) { 

    BOOST_STATIC_ASSERT(tuple_length<cons>::value == 2); // check length = 2

    head = u.first; tail.head = u.second; return *this;

  }



  // get member functions (non-const and const)

  template <int N>

  typename tuple_access_traits<

             typename tuple_element<N, cons<HT, TT> >::type

           >::non_const_type

  get() {

    return boost::get<N>(*this); // delegate to non-member get

  }



  template <int N>

  typename tuple_access_traits<

             typename tuple_element<N, cons<HT, TT> >::type

           >::const_type

  get() const {

    return boost::get<N>(*this); // delegate to non-member get

  }

};



template <class HT>

struct cons<HT, null_type> {



  typedef HT head_type;

  typedef null_type tail_type;



  head_type head;

 

  typename tuple_access_traits<head_type>::non_const_type get_head() { return head; }

  null_type get_tail() { return null_type(); }  



  typename tuple_access_traits<head_type>::const_type get_head() const { return head; }

  const null_type get_tail() const { return null_type(); }  

   

  template<class T1>

  cons( T1& t1, const null_type&, const null_type&, const null_type&, const null_type&, 

        const null_type&, const null_type&, const null_type&, const null_type&, const null_type&)

  : head (t1) {}



  template <class HT2>

  cons( const cons<HT2, null_type>& u ) : head(u.head) {}

  

  template <class HT2>

  cons& operator=(const cons<HT2, null_type>& u ) {  head = u.head; return *this; }



  // must define assignment operator explicitely, implicit version 

  // is illformed if HT is a reference

  cons& operator=(const cons& u) { head = u.head; return *this; }



  template <int N>

  typename tuple_access_traits<

             typename tuple_element<N, cons>::type

            >::non_const_type

  get() {

    return boost::get<N>(*this);

  }



  template <int N>

  typename tuple_access_traits<

             typename tuple_element<N, cons>::type

           >::const_type

  get() const {

    return boost::get<N>(*this);

  }



};



// templates for finding out the length of the tuple -------------------



template<class T>

struct tuple_length  {

  BOOST_STATIC_CONSTANT(int, value = 1 + tuple_length<typename T::tail_type>::value);

};



template<>

struct tuple_length<null_type> {

  BOOST_STATIC_CONSTANT(int, value = 0);

};





namespace detail {

namespace tuples {



// Tuple to cons mapper --------------------------------------------------

template <class T0, class T1, class T2, class T3, class T4, 

          class T5, class T6, class T7, class T8, class T9>

struct map_tuple_to_cons

{

  typedef cons<T0, 

               typename map_tuple_to_cons<T1, T2, T3, T4, T5, 

                                          T6, T7, T8, T9, null_type>::type

              > type;

};



template <class T0>

struct map_tuple_to_cons<T0, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type>

{

  typedef cons<T0, null_type> type;

};



// The empty tuple is a null_type

template <>

struct map_tuple_to_cons<null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type>

{

  typedef null_type type;

};



} // end tuples

} // end detail



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

// -- tuple ------------------------------------------------------

template <class T0, class T1, class T2, class T3, class T4, 

          class T5, class T6, class T7, class T8, class T9>



class tuple : 

  public detail::tuples::map_tuple_to_cons<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type   

{

public:

  typedef typename 

    detail::tuples::map_tuple_to_cons<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type inherited;

  typedef typename inherited::head_type head_type;

  typedef typename inherited::tail_type tail_type;  





// tuple_access_traits<T>::parameter_type takes non-reference types as const T& 

  explicit tuple(

    typename tuple_access_traits<T0>::parameter_type t0 

      = detail::tuples::default_arg<T0>::f(),

    typename tuple_access_traits<T1>::parameter_type t1 

      = detail::tuples::default_arg<T1>::f(),

    typename tuple_access_traits<T2>::parameter_type t2 

      = detail::tuples::default_arg<T2>::f(),

    typename tuple_access_traits<T3>::parameter_type t3 

      = detail::tuples::default_arg<T3>::f(),

    typename tuple_access_traits<T4>::parameter_type t4 

      = detail::tuples::default_arg<T4>::f(),

    typename tuple_access_traits<T5>::parameter_type t5 

      = detail::tuples::default_arg<T5>::f(),

    typename tuple_access_traits<T6>::parameter_type t6 

      = detail::tuples::default_arg<T6>::f(),

    typename tuple_access_traits<T7>::parameter_type t7 

      = detail::tuples::default_arg<T7>::f(),

    typename tuple_access_traits<T8>::parameter_type t8 

      = detail::tuples::default_arg<T8>::f(),

    typename tuple_access_traits<T9>::parameter_type t9 

      = detail::tuples::default_arg<T9>::f())



        : inherited(t0, t1, t2, t3, t4, t5, t6, t7, t8, t9) {}



  template<class U1, class U2>

  tuple(const cons<U1, U2>& p) : inherited(p) {}



  template <class U1, class U2>

  tuple& operator=(const cons<U1, U2>& k) { 

    inherited::operator=(k); 

    return *this;

  }



  template <class U1, class U2>

  tuple& operator=(const std::pair<U1, U2>& k) { 

    BOOST_STATIC_ASSERT(tuple_length<tuple>::value == 2);// check_length = 2

    this->head = k.first;

    this->tail.head = k.second; 

    return *this;

  }



};



// Swallows any assignment   (by Doug Gregor)

namespace detail {

namespace tuples {



struct swallow_assign {

      

  template<typename T>

  swallow_assign& operator=(const T&) {

    return *this;

  }

};

} // namespace tuples

} // namespace detail



// "ignore" allows tuple positions to be ignored when using "tie". 

namespace {

 detail::tuples::swallow_assign ignore;

}



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

// The call_traits for make_tuple

// Honours the reference_wrapper class.



// Must be instantiated with plain or const plain types (not with references)



// from template<class T> foo(const T& t) : make_tuple_traits<const T>::type

// from template<class T> foo(T& t) : make_tuple_traits<T>::type



// Conversions:

// T -> T, 

// references -> compile_time_error

// reference_wrapper<T> -> T&

// const reference_wrapper<T> -> T&

// array -> const ref array





template<class T>

struct make_tuple_traits {

  typedef T type; 



  // commented away, see below  (JJ)

  //  typedef typename IF<                 

  //  boost::is_function<T>::value,

  //  T&,

  //  T>::RET type;



};

 

// The is_function test was there originally for plain function types, 

// which can't be stored as such (we must either store them as references or

// pointers). Such a type could be formed if make_tuple was called with a 

// reference to a function.

// But this would mean that a const qualified function type was formed in

// the make_tuple function and hence make_tuple can't take a function

// reference as a parameter, and thus T can't be a function type.

// So is_function test was removed.

// (14.8.3. says that type deduction fails if a cv-qualified function type

// is created. (It only applies for the case of explicitly specifying template

// args, though?)) (JJ)



template<class T>

struct make_tuple_traits<T&> {

  typedef typename

     detail::tuples::generate_error<T&>::

       do_not_use_with_reference_type error;

}; 



// Arrays can't be stored as plain types; convert them to references.

// All arrays are converted to const. This is because make_tuple takes its

// parameters as const T& and thus the knowledge of the potential 

// non-constness of actual argument is lost.

template<class T, int n>  struct make_tuple_traits <T[n]> {

  typedef const T (&type)[n];

};



template<class T, int n> 

struct make_tuple_traits<const T[n]> {

  typedef const T (&type)[n];

};



template<class T, int n>  struct make_tuple_traits<volatile T[n]> {

  typedef const volatile T (&type)[n];

};



template<class T, int n> 

struct make_tuple_traits<const volatile T[n]> {

  typedef const volatile T (&type)[n];

};



template<class T> 

struct make_tuple_traits<reference_wrapper<T> >{

  typedef T& type;

};



template<class T> 

struct make_tuple_traits<const reference_wrapper<T> >{

  typedef T& type;

};









namespace detail {

namespace tuples {



// a helper traits to make the make_tuple functions shorter (Vesa Karvonen's

// suggestion)

template <

  class T0 = null_type, class T1 = null_type, class T2 = null_type, 

  class T3 = null_type, class T4 = null_type, class T5 = null_type, 

  class T6 = null_type, class T7 = null_type, class T8 = null_type, 

  class T9 = null_type

>

struct make_tuple_mapper {

  typedef

    tuple<typename make_tuple_traits<T0>::type, 

          typename make_tuple_traits<T1>::type, 

          typename make_tuple_traits<T2>::type, 

          typename make_tuple_traits<T3>::type, 

          typename make_tuple_traits<T4>::type, 

          typename make_tuple_traits<T5>::type, 

          typename make_tuple_traits<T6>::type, 

          typename make_tuple_traits<T7>::type,

          typename make_tuple_traits<T8>::type,

          typename make_tuple_traits<T9>::type> type;

};



} // end tuples

} // end detail



// -make_tuple function templates -----------------------------------

//tuple<> inline make_tuple() {

//  return tuple<>(); 

//}



template<class T0>

boost::detail::tuples::make_tuple_mapper<T0>::type

inline make_tuple(const T0& t0) {

  return boost::detail::tuples::make_tuple_mapper<T0>::type(t0); 

}



template<class T0, class T1>

boost::detail::tuples::make_tuple_mapper<T0, T1>::type

inline make_tuple(const T0& t0, const T1& t1) {

  return boost::detail::tuples::make_tuple_mapper<T0, T1>::type(t0, t1); 

}



template<class T0, class T1, class T2>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2) {

  return boost::detail::tuples::make_tuple_mapper<T0, T1, T2>::type(t0, t1, t2); 

}



template<class T0, class T1, class T2, class T3>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3) {

  return boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3>::type

           (t0, t1, t2, t3); 

}



template<class T0, class T1, class T2, class T3, class T4>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4) {

  return boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4>::type

           (t0, t1, t2, t3, t4); 

}



template<class T0, class T1, class T2, class T3, class T4, class T5>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4, T5>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4, const T5& t5) {

  return boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4, T5>::type

           (t0, t1, t2, t3, t4, t5); 

}



template<class T0, class T1, class T2, class T3, class T4, class T5, class T6>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4, T5, T6>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4, const T5& t5, const T6& t6) {

  return boost::detail::tuples::make_tuple_mapper

           <T0, T1, T2, T3, T4, T5, T6>::type

           (t0, t1, t2, t3, t4, t5, t6); 

}



template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,

         class T7>

boost::detail::tuples::make_tuple_mapper<T0, T1, T2, T3, T4, T5, T6, T7>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4, const T5& t5, const T6& t6, const T7& t7) {

  return boost::detail::tuples::make_tuple_mapper

           <T0, T1, T2, T3, T4, T5, T6, T7>::type

           (t0, t1, t2, t3, t4, t5, t6, t7); 

}



template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,

         class T7, class T8>

boost::detail::tuples::make_tuple_mapper

  <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4, const T5& t5, const T6& t6, const T7& t7,

                  const T8& t8) {

  return boost::detail::tuples::make_tuple_mapper

           <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type

           (t0, t1, t2, t3, t4, t5, t6, t7, t8); 

}



template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,

         class T7, class T8, class T9>

boost::detail::tuples::make_tuple_mapper

  <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type

inline make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,

                  const T4& t4, const T5& t5, const T6& t6, const T7& t7,

                  const T8& t8, const T9& t9) {

  return boost::detail::tuples::make_tuple_mapper

           <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type

           (t0, t1, t2, t3, t4, t5, t6, t7, t8, t9); 

}







// Tie function templates -------------------------------------------------

template<class T1>

tuple<T1&> inline tie(T1& t1) {

  return tuple<T1&> (t1);

}



template<class T1, class T2>

tuple<T1&, T2&> inline tie(T1& t1, T2& t2) {

  return tuple<T1&, T2&> (t1, t2);

}



template<class T1, class T2, class T3>

tuple<T1&, T2&, T3&> inline tie(T1& t1, T2& t2, T3& t3) {

  return tuple<T1&, T2&, T3&> (t1, t2, t3);

}



template<class T1, class T2, class T3, class T4>

tuple<T1&, T2&, T3&, T4&> inline tie(T1& t1, T2& t2, T3& t3, T4& t4) {

  return tuple<T1&, T2&, T3&, T4&> (t1, t2, t3, t4);

}



template<class T1, class T2, class T3, class T4, class T5>

tuple<T1&, T2&, T3&, T4&, T5&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5) {

  return tuple<T1&, T2&, T3&, T4&, T5&> (t1, t2, t3, t4, t5);

}



template<class T1, class T2, class T3, class T4, class T5, class T6>

tuple<T1&, T2&, T3&, T4&, T5&, T6&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6) {

  return tuple<T1&, T2&, T3&, T4&, T5&, T6&> (t1, t2, t3, t4, t5, t6);

}



template<class T1, class T2, class T3, class T4, class T5, class T6, class T7>

tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7) {

  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&> (t1, t2, t3, t4, t5, t6, t7);

}



template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 

         class T8>

tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8) {

  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&> 

           (t1, t2, t3, t4, t5, t6, t7, t8);

}



template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 

         class T8, class T9>

tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8, 

           T9& t9) {

  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&> 

            (t1, t2, t3, t4, t5, t6, t7, t8, t9);

}



template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 

         class T8, class T9, class T10>

tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&, T10&> 

inline tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8, 

           T9& t9, T10& t10) {

  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&, T10&> 

           (t1, t2, t3, t4, t5, t6, t7, t8, t9, t10);

}



} // end of namespace boost





#endif	// BOOST_TUPLE_BASIC_HPP





