Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2004-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: 
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: // Contains the definition of the class template 
Chris@16: // boost::iostreams::detail::double_object, which is similar to compressed pair
Chris@16: // except that both members of the pair have the same type, and 
Chris@16: // compression occurs only if requested using a boolean template
Chris@16: // parameter.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_DETAIL_DOUBLE_OBJECT_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_DETAIL_DOUBLE_OBJECT_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif              
Chris@16: 
Chris@16: #include <algorithm>              // swap.
Chris@16: #include <boost/detail/workaround.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #if BOOST_WORKAROUND(__MWERKS__, > 0x3003)
Chris@16: # include <msl_utility>
Chris@16: #else
Chris@16: # include <boost/call_traits.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost { namespace iostreams { namespace detail {
Chris@16: 
Chris@16: template<typename T>
Chris@16: class single_object_holder {
Chris@16: public:
Chris@16: #if BOOST_WORKAROUND(__MWERKS__, > 0x3003)
Chris@16:     typedef Metrowerks::call_traits<T>             traits_type;
Chris@16: #else
Chris@16:     typedef boost::call_traits<T>                  traits_type;
Chris@16: #endif
Chris@16:     typedef typename traits_type::param_type       param_type;
Chris@16:     typedef typename traits_type::reference        reference;
Chris@16:     typedef typename traits_type::const_reference  const_reference;
Chris@16:     single_object_holder() { }
Chris@16:     single_object_holder(param_type t) : first_(t) { }
Chris@16:     reference first() { return first_; }
Chris@16:     const_reference first() const { return first_; }
Chris@16:     reference second() { return first_; }
Chris@16:     const_reference second() const { return first_; }
Chris@16:     void swap(single_object_holder& o)
Chris@16:     { std::swap(first_, o.first_); }
Chris@16: private:
Chris@16:     T first_;
Chris@16: };
Chris@16: 
Chris@16: template<typename T>
Chris@16: struct double_object_holder {
Chris@16: public:
Chris@16: #if BOOST_WORKAROUND(__MWERKS__, > 0x3003)
Chris@16:     typedef Metrowerks::call_traits<T>             traits_type;
Chris@16: #else
Chris@16:     typedef boost::call_traits<T>                  traits_type;
Chris@16: #endif
Chris@16:     typedef typename traits_type::param_type       param_type;
Chris@16:     typedef typename traits_type::reference        reference;
Chris@16:     typedef typename traits_type::const_reference  const_reference;
Chris@16:     double_object_holder() { }
Chris@16:     double_object_holder(param_type t1, param_type t2)
Chris@16:         : first_(t1), second_(t2) { }
Chris@16:     reference first() { return first_; }
Chris@16:     const_reference first() const { return first_; }
Chris@16:     reference second() { return second_; }
Chris@16:     const_reference second() const { return second_; }
Chris@16:     void swap(double_object_holder& d)
Chris@16:     { 
Chris@16:         std::swap(first_, d.first_); 
Chris@16:         std::swap(second_, d.second_); 
Chris@16:     }
Chris@16: private:
Chris@16:     T first_, second_;
Chris@16: };
Chris@16: 
Chris@16: template<typename T, typename IsDouble>
Chris@16: class double_object 
Chris@16:     : public mpl::if_<
Chris@16:                  IsDouble, 
Chris@16:                  double_object_holder<T>, 
Chris@16:                  single_object_holder<T>
Chris@16:              >::type
Chris@16: {
Chris@16: private:
Chris@16:     typedef typename 
Chris@16:             mpl::if_<
Chris@16:                 IsDouble, 
Chris@16:                 double_object_holder<T>, 
Chris@16:                 single_object_holder<T>
Chris@16:             >::type                                base_type;
Chris@16: public:
Chris@16: #if BOOST_WORKAROUND(__MWERKS__, > 0x3003)
Chris@16:     typedef Metrowerks::call_traits<T>             traits_type;
Chris@16: #else
Chris@16:     typedef boost::call_traits<T>                  traits_type;
Chris@16: #endif
Chris@16:     typedef typename traits_type::param_type       param_type;
Chris@16:     typedef typename traits_type::reference        reference;
Chris@16:     typedef typename traits_type::const_reference  const_reference;
Chris@16:     double_object() : base_type() {}
Chris@16:     double_object(param_type t1, param_type t2)
Chris@16:         : base_type(t1, t2) { }
Chris@16:     bool is_double() const { return IsDouble::value; }
Chris@16: };
Chris@16: 
Chris@16: } } } // End namespaces detail, iostreams, boost.
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_DETAIL_DOUBLE_OBJECT_HPP_INCLUDED