comparison DEPENDENCIES/generic/include/boost/units/quantity.hpp @ 16:2665513ce2d3

Add boost headers

+// Boost.Units - A C++ library for zero-overhead dimensional analysis and 
+// unit/quantity manipulation and conversion
+//
+// Copyright (C) 2003-2008 Matthias Christian Schabel
+// Copyright (C) 2007-2008 Steven Watanabe
+//
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNITS_QUANTITY_HPP
+#define BOOST_UNITS_QUANTITY_HPP
+
+#include <algorithm>
+
+#include <boost/config.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/mpl/bool.hpp>
+#include <boost/mpl/and.hpp>
+#include <boost/mpl/not.hpp>
+#include <boost/mpl/or.hpp>
+#include <boost/mpl/assert.hpp>
+#include <boost/utility/enable_if.hpp>
+#include <boost/type_traits/is_arithmetic.hpp>
+#include <boost/type_traits/is_convertible.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#include <boost/type_traits/is_same.hpp>
+
+#include <boost/units/conversion.hpp>
+#include <boost/units/dimensionless_type.hpp>
+#include <boost/units/homogeneous_system.hpp>
+#include <boost/units/operators.hpp>
+#include <boost/units/static_rational.hpp>
+#include <boost/units/units_fwd.hpp>
+#include <boost/units/detail/dimensionless_unit.hpp>
+
+namespace boost {
+
+namespace units {
+
+namespace detail {
+
+template<class T, class Enable = void>
+struct is_base_unit : mpl::false_ {};
+
+template<class T>
+struct is_base_unit<T, typename T::boost_units_is_base_unit_type> : mpl::true_ {};
+
+template<class Source, class Destination>
+struct is_narrowing_conversion_impl : mpl::bool_<(sizeof(Source) > sizeof(Destination))> {};
+
+template<class Source, class Destination>
+struct is_non_narrowing_conversion :
+    mpl::and_<
+        boost::is_convertible<Source, Destination>,
+        mpl::not_<
+            mpl::and_<
+                boost::is_arithmetic<Source>,
+                boost::is_arithmetic<Destination>,
+                mpl::or_<
+                    mpl::and_<
+                        is_integral<Destination>,
+                        mpl::not_<is_integral<Source> >
+                    >,
+                    is_narrowing_conversion_impl<Source, Destination>
+                >
+            >
+        >
+    >
+{};
+
+template<>
+struct is_non_narrowing_conversion<long double, double> : mpl::false_ {};
+
+// msvc 7.1 needs extra disambiguation
+template<class T, class U>
+struct disable_if_is_same
+{
+    typedef void type;
+};
+
+template<class T>
+struct disable_if_is_same<T, T> {};
+
+}
+ 
+/// class declaration
+template<class Unit,class Y = double>
+class quantity
+{
+        // base units are not the same as units.
+        BOOST_MPL_ASSERT_NOT((detail::is_base_unit<Unit>));
+        enum { force_instantiation_of_unit = sizeof(Unit) };
+        typedef void (quantity::*unspecified_null_pointer_constant_type)(int*******);
+    public:
+        typedef quantity<Unit,Y>                        this_type;
+        
+        typedef Y                                       value_type;
+        typedef Unit        unit_type;
+ 
+        quantity() : val_() 
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        quantity(unspecified_null_pointer_constant_type) : val_() 
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+        
+        quantity(const this_type& source) : val_(source.val_) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+        
+        // Need to make sure that the destructor of
+        // Unit which contains the checking is instantiated,
+        // on sun.
+        #ifdef __SUNPRO_CC
+        ~quantity() {
+            unit_type force_unit_instantiation;
+        }
+        #endif
+        
+        //~quantity() { }
+        
+        this_type& operator=(const this_type& source) 
+        { 
+             val_ = source.val_; 
+             
+             return *this; 
+        }
+
+        #ifndef BOOST_NO_SFINAE
+
+        /// implicit conversion between value types is allowed if allowed for value types themselves
+        template<class YY>
+        quantity(const quantity<Unit,YY>& source,
+            typename boost::enable_if<detail::is_non_narrowing_conversion<YY, Y> >::type* = 0) :
+            val_(source.value())
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        /// implicit conversion between value types is not allowed if not allowed for value types themselves
+        template<class YY>
+        explicit quantity(const quantity<Unit,YY>& source,
+            typename boost::disable_if<detail::is_non_narrowing_conversion<YY, Y> >::type* = 0) :
+            val_(static_cast<Y>(source.value()))
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        #else
+
+        /// implicit conversion between value types is allowed if allowed for value types themselves
+        template<class YY>
+        quantity(const quantity<Unit,YY>& source) :
+            val_(source.value())
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY, Y>::value == true));
+        }
+
+        #endif
+        
+        /// implicit assignment between value types is allowed if allowed for value types themselves
+        template<class YY>
+        this_type& operator=(const quantity<Unit,YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY, Y>::value == true));
+
+            *this = this_type(source);
+            
+            return *this;
+        }
+
+        #ifndef BOOST_NO_SFINAE
+
+        /// explicit conversion between different unit systems is allowed if implicit conversion is disallowed
+        template<class Unit2,class YY> 
+        explicit
+        quantity(const quantity<Unit2,YY>& source, 
+                 typename boost::disable_if<
+                    mpl::and_<
+                        //is_implicitly_convertible should be undefined when the
+                        //units are not convertible at all
+                        typename is_implicitly_convertible<Unit2,Unit>::type,
+                        detail::is_non_narrowing_conversion<YY, Y>
+                    >,
+                    typename detail::disable_if_is_same<Unit, Unit2>::type
+                 >::type* = 0)
+             : val_(conversion_helper<quantity<Unit2,YY>,this_type>::convert(source).value())
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY,Y>::value == true));
+        }
+
+        /// implicit conversion between different unit systems is allowed if each fundamental dimension is implicitly convertible
+        template<class Unit2,class YY> 
+        quantity(const quantity<Unit2,YY>& source, 
+                 typename boost::enable_if<
+                     mpl::and_<
+                         typename is_implicitly_convertible<Unit2,Unit>::type,
+                         detail::is_non_narrowing_conversion<YY, Y>
+                     >,
+                     typename detail::disable_if_is_same<Unit, Unit2>::type
+                 >::type* = 0)
+             : val_(conversion_helper<quantity<Unit2,YY>,this_type>::convert(source).value())
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY,Y>::value == true));
+        }
+
+        #else
+
+        /// without SFINAE we can't distinguish between explicit and implicit conversions so 
+        /// the conversion is always explicit
+        template<class Unit2,class YY> 
+        explicit quantity(const quantity<Unit2,YY>& source)
+             : val_(conversion_helper<quantity<Unit2,YY>,this_type>::convert(source).value())
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY,Y>::value == true));
+        }
+
+        #endif
+        
+        /// implicit assignment between different unit systems is allowed if each fundamental dimension is implicitly convertible 
+        template<class Unit2,class YY>
+        this_type& operator=(const quantity<Unit2,YY>& source)
+        {
+            
+            BOOST_STATIC_ASSERT((is_implicitly_convertible<Unit2,unit_type>::value == true));
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY,Y>::value == true));
+            
+            *this = this_type(source);
+            
+            return *this;
+        }
+
+        const value_type& value() const                     { return val_; }                        ///< constant accessor to value
+        
+        ///< can add a quantity of the same type if add_typeof_helper<value_type,value_type>::type is convertible to value_type
+        template<class Unit2, class YY>
+        this_type& operator+=(const quantity<Unit2, YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_same<typename add_typeof_helper<Unit, Unit2>::type, Unit>::value));
+            val_ += source.value();
+            return *this;
+        }  
+
+        ///< can subtract a quantity of the same type if subtract_typeof_helper<value_type,value_type>::type is convertible to value_type
+        template<class Unit2, class YY>
+        this_type& operator-=(const quantity<Unit2, YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_same<typename subtract_typeof_helper<Unit, Unit2>::type, Unit>::value));
+            val_ -= source.value();
+            return *this;
+        }  
+
+        template<class Unit2, class YY>
+        this_type& operator*=(const quantity<Unit2, YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_same<typename multiply_typeof_helper<Unit, Unit2>::type, Unit>::value));
+            val_ *= source.value();
+            return *this;
+        }  
+        
+        template<class Unit2, class YY>
+        this_type& operator/=(const quantity<Unit2, YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_same<typename divide_typeof_helper<Unit, Unit2>::type, Unit>::value));
+            val_ /= source.value();
+            return *this;
+        }
+
+        ///< can multiply a quantity by a scalar value_type if multiply_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator*=(const value_type& source) { val_ *= source; return *this; }
+        ///< can divide a quantity by a scalar value_type if divide_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator/=(const value_type& source) { val_ /= source; return *this; }
+    
+        /// Construct quantity directly from @c value_type (potentially dangerous).
+        static this_type from_value(const value_type& val)  { return this_type(val, 0); }
+
+    protected:
+        explicit quantity(const value_type& val, int) : val_(val) { }
+        
+    private:
+        value_type    val_;
+};
+
+/// Specialization for dimensionless quantities. Implicit conversions between 
+/// unit systems are allowed because all dimensionless quantities are equivalent.
+/// Implicit construction and assignment from and conversion to @c value_type is
+/// also allowed.
+template<class System,class Y>
+class quantity<BOOST_UNITS_DIMENSIONLESS_UNIT(System),Y>
+{
+    public:
+        typedef quantity<unit<dimensionless_type,System>,Y>     this_type;
+                                   
+        typedef Y                                               value_type;
+        typedef System                                          system_type;
+        typedef dimensionless_type                              dimension_type;
+        typedef unit<dimension_type,system_type>                unit_type;
+         
+        quantity() : val_() 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+        
+        /// construction from raw @c value_type is allowed
+        quantity(value_type val) : val_(val) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        } 
+                           
+        quantity(const this_type& source) : val_(source.val_) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+        
+        //~quantity() { }
+        
+        this_type& operator=(const this_type& source) 
+        { 
+            val_ = source.val_; 
+                
+            return *this; 
+        }
+        
+        #ifndef BOOST_NO_SFINAE
+
+        /// implicit conversion between value types is allowed if allowed for value types themselves
+        template<class YY>
+        quantity(const quantity<unit<dimension_type,system_type>,YY>& source,
+            typename boost::enable_if<detail::is_non_narrowing_conversion<YY, Y> >::type* = 0) :
+            val_(source.value())
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        /// implicit conversion between value types is not allowed if not allowed for value types themselves
+        template<class YY>
+        explicit quantity(const quantity<unit<dimension_type,system_type>,YY>& source,
+            typename boost::disable_if<detail::is_non_narrowing_conversion<YY, Y> >::type* = 0) :
+            val_(static_cast<Y>(source.value()))
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        #else
+
+        /// implicit conversion between value types is allowed if allowed for value types themselves
+        template<class YY>
+        quantity(const quantity<unit<dimension_type,system_type>,YY>& source) :
+            val_(source.value())
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY, Y>::value == true));
+        }
+
+        #endif
+        
+        /// implicit assignment between value types is allowed if allowed for value types themselves
+        template<class YY>
+        this_type& operator=(const quantity<unit<dimension_type,system_type>,YY>& source)
+        {
+            BOOST_STATIC_ASSERT((boost::is_convertible<YY,Y>::value == true));
+
+            *this = this_type(source);
+            
+            return *this;
+        }
+
+        #if 1
+
+        /// implicit conversion between different unit systems is allowed
+        template<class System2, class Y2> 
+        quantity(const quantity<unit<dimensionless_type, System2>,Y2>& source,
+        #ifdef __SUNPRO_CC
+            typename boost::enable_if<
+                boost::mpl::and_<
+                    detail::is_non_narrowing_conversion<Y2, Y>,
+                    detail::is_dimensionless_system<System2>
+                > 
+            >::type* = 0
+        #else
+            typename boost::enable_if<detail::is_non_narrowing_conversion<Y2, Y> >::type* = 0,
+            typename detail::disable_if_is_same<System, System2>::type* = 0,
+            typename boost::enable_if<detail::is_dimensionless_system<System2> >::type* = 0
+        #endif
+            ) :
+            val_(source.value()) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        /// implicit conversion between different unit systems is allowed
+        template<class System2, class Y2> 
+        explicit quantity(const quantity<unit<dimensionless_type, System2>,Y2>& source,
+        #ifdef __SUNPRO_CC
+            typename boost::enable_if<
+                boost::mpl::and_<
+                    boost::mpl::not_<detail::is_non_narrowing_conversion<Y2, Y> >,
+                    detail::is_dimensionless_system<System2>
+                > 
+            >::type* = 0
+        #else
+            typename boost::disable_if<detail::is_non_narrowing_conversion<Y2, Y> >::type* = 0,
+            typename detail::disable_if_is_same<System, System2>::type* = 0,
+            typename boost::enable_if<detail::is_dimensionless_system<System2> >::type* = 0
+        #endif
+            ) :
+            val_(static_cast<Y>(source.value())) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+
+        #else
+
+        /// implicit conversion between different unit systems is allowed
+        template<class System2, class Y2> 
+        quantity(const quantity<unit<dimensionless_type,homogeneous_system<System2> >,Y2>& source) :
+            val_(source.value()) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+            BOOST_STATIC_ASSERT((boost::is_convertible<Y2, Y>::value == true));
+        }
+
+        #endif
+
+        /// conversion between different unit systems is explicit when
+        /// the units are not equivalent.
+        template<class System2, class Y2> 
+        explicit quantity(const quantity<unit<dimensionless_type, System2>,Y2>& source,
+            typename boost::disable_if<detail::is_dimensionless_system<System2> >::type* = 0) :
+            val_(conversion_helper<quantity<unit<dimensionless_type, System2>,Y2>, this_type>::convert(source).value()) 
+        {
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
+        
+        #ifndef __SUNPRO_CC
+
+        /// implicit assignment between different unit systems is allowed
+        template<class System2>
+        this_type& operator=(const quantity<BOOST_UNITS_DIMENSIONLESS_UNIT(System2),Y>& source)
+        {
+            *this = this_type(source);
+            
+            return *this;
+        }
+        
+        #endif
+        
+        /// implicit conversion to @c value_type is allowed
+        operator value_type() const                         { return val_; }
+        
+        const value_type& value() const                     { return val_; }                        ///< constant accessor to value
+        
+        ///< can add a quantity of the same type if add_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator+=(const this_type& source)      { val_ += source.val_; return *this; }  
+        
+        ///< can subtract a quantity of the same type if subtract_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator-=(const this_type& source)      { val_ -= source.val_; return *this; }  
+        
+        ///< can multiply a quantity by a scalar value_type if multiply_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator*=(const value_type& val)        { val_ *= val; return *this; }          
+
+        ///< can divide a quantity by a scalar value_type if divide_typeof_helper<value_type,value_type>::type is convertible to value_type
+        this_type& operator/=(const value_type& val)        { val_ /= val; return *this; }          
+
+        /// Construct quantity directly from @c value_type.
+        static this_type from_value(const value_type& val)  { return this_type(val); }
+
+   private:
+        value_type    val_;
+};
+
+#ifdef BOOST_MSVC
+// HACK: For some obscure reason msvc 8.0 needs these specializations
+template<class System, class T>
+class quantity<unit<int, System>, T> {};
+template<class T>
+class quantity<int, T> {};
+#endif
+
+} // namespace units
+
+} // namespace boost
+
+#if BOOST_UNITS_HAS_BOOST_TYPEOF
+
+#include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
+
+BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::quantity, 2)
+
+#endif
+
+namespace boost {
+
+namespace units {
+
+namespace detail {
+
+/// helper class for quantity_cast
+template<class X,class Y> struct quantity_cast_helper;
+
+/// specialization for casting to the value type
+template<class Y,class X,class Unit>
+struct quantity_cast_helper<Y,quantity<Unit,X> >
+{
+    typedef Y type;
+    
+    type operator()(quantity<Unit,X>& source)           { return const_cast<X&>(source.value()); }
+};
+
+/// specialization for casting to the value type
+template<class Y,class X,class Unit>
+struct quantity_cast_helper<Y,const quantity<Unit,X> >
+{
+    typedef Y type;
+    
+    type operator()(const quantity<Unit,X>& source)     { return source.value(); }
+};
+
+} // namespace detail
+
+/// quantity_cast provides mutating access to underlying quantity value_type
+template<class X,class Y>
+inline 
+X
+quantity_cast(Y& source)
+{
+    detail::quantity_cast_helper<X,Y>   qch;
+    
+    return qch(source);
+}
+
+template<class X,class Y>
+inline 
+X
+quantity_cast(const Y& source)
+{
+    detail::quantity_cast_helper<X,const Y>   qch;
+    
+    return qch(source);
+}
+
+/// swap quantities
+template<class Unit,class Y>
+inline void swap(quantity<Unit,Y>& lhs, quantity<Unit,Y>& rhs)
+{
+    using std::swap;
+    swap(quantity_cast<Y&>(lhs),quantity_cast<Y&>(rhs));
+}
+
+/// specialize unary plus typeof helper
+/// INTERNAL ONLY
+template<class Unit,class Y>
+struct unary_plus_typeof_helper< quantity<Unit,Y> >
+{
+    typedef typename unary_plus_typeof_helper<Y>::type      value_type;
+    typedef typename unary_plus_typeof_helper<Unit>::type   unit_type;
+    typedef quantity<unit_type,value_type>                  type;
+};
+
+/// specialize unary minus typeof helper
+/// INTERNAL ONLY
+template<class Unit,class Y>
+struct unary_minus_typeof_helper< quantity<Unit,Y> >
+{
+    typedef typename unary_minus_typeof_helper<Y>::type     value_type;
+    typedef typename unary_minus_typeof_helper<Unit>::type  unit_type;
+    typedef quantity<unit_type,value_type>                  type;
+};
+
+/// specialize add typeof helper
+/// INTERNAL ONLY
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+struct add_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >
+{
+    typedef typename add_typeof_helper<X,Y>::type           value_type;
+    typedef typename add_typeof_helper<Unit1,Unit2>::type   unit_type;
+    typedef quantity<unit_type,value_type>                  type;
+};
+
+/// for sun CC we need to invoke SFINAE at
+/// the top level, otherwise it will silently
+/// return int.
+template<class Dim1, class System1,
+         class Dim2, class System2,
+         class X,
+         class Y>
+struct add_typeof_helper< quantity<unit<Dim1, System1>,X>,quantity<unit<Dim2, System2>,Y> >
+{
+};
+
+template<class Dim,
+         class System,
+         class X,
+         class Y>
+struct add_typeof_helper< quantity<unit<Dim, System>,X>,quantity<unit<Dim, System>,Y> >
+{
+    typedef typename add_typeof_helper<X,Y>::type  value_type;
+    typedef unit<Dim, System>                      unit_type;
+    typedef quantity<unit_type,value_type>         type;
+};
+
+/// specialize subtract typeof helper
+/// INTERNAL ONLY
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+struct subtract_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >
+{
+    typedef typename subtract_typeof_helper<X,Y>::type          value_type;
+    typedef typename subtract_typeof_helper<Unit1,Unit2>::type  unit_type;
+    typedef quantity<unit_type,value_type>                      type;
+};
+
+// Force adding different units to fail on sun.
+template<class Dim1, class System1,
+         class Dim2, class System2,
+         class X,
+         class Y>
+struct subtract_typeof_helper< quantity<unit<Dim1, System1>,X>,quantity<unit<Dim2, System2>,Y> >
+{
+};
+
+template<class Dim,
+         class System,
+         class X,
+         class Y>
+struct subtract_typeof_helper< quantity<unit<Dim, System>,X>,quantity<unit<Dim, System>,Y> >
+{
+    typedef typename subtract_typeof_helper<X,Y>::type  value_type;
+    typedef unit<Dim, System>                           unit_type;
+    typedef quantity<unit_type,value_type>              type;
+};
+
+/// scalar times unit typeof helper
+/// INTERNAL ONLY
+template<class System,
+         class Dim,
+         class X>
+struct multiply_typeof_helper< X,unit<Dim,System> >
+{
+    typedef X                               value_type;
+    typedef unit<Dim,System>                unit_type;
+    typedef quantity<unit_type,value_type>  type;
+};
+
+/// unit times scalar typeof helper
+/// INTERNAL ONLY
+template<class System,
+         class Dim,
+         class X>
+struct multiply_typeof_helper< unit<Dim,System>,X >
+{
+    typedef X                               value_type;
+    typedef unit<Dim,System>                unit_type;
+    typedef quantity<unit_type,value_type>  type;
+};
+
+/// scalar times quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class X,
+         class Y>
+struct multiply_typeof_helper< X,quantity<Unit,Y> >
+{
+    typedef typename multiply_typeof_helper<X,Y>::type  value_type;
+    typedef Unit                                        unit_type;
+    typedef quantity<unit_type,value_type>              type;
+};
+
+/// disambiguate
+/// INTERNAL ONLY
+template<class Unit,
+         class Y>
+struct multiply_typeof_helper< one,quantity<Unit,Y> >
+{
+    typedef quantity<Unit,Y> type;
+};
+
+/// quantity times scalar typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class X,
+         class Y>
+struct multiply_typeof_helper< quantity<Unit,X>,Y >
+{
+    typedef typename multiply_typeof_helper<X,Y>::type  value_type;
+    typedef Unit                                        unit_type;
+    typedef quantity<unit_type,value_type>              type;
+};
+
+/// disambiguate
+/// INTERNAL ONLY
+template<class Unit,
+         class X>
+struct multiply_typeof_helper< quantity<Unit,X>,one >
+{
+    typedef quantity<Unit,X> type;
+};
+
+/// unit times quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class System,
+         class Dim,
+         class X>
+struct multiply_typeof_helper< unit<Dim,System>,quantity<Unit,X> >
+{
+    typedef X                                                               value_type;
+    typedef typename multiply_typeof_helper< unit<Dim,System>,Unit >::type  unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+};
+
+/// quantity times unit typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class System,
+         class Dim,
+         class X>
+struct multiply_typeof_helper< quantity<Unit,X>,unit<Dim,System> >
+{
+    typedef X                                                               value_type;
+    typedef typename multiply_typeof_helper< Unit,unit<Dim,System> >::type  unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+};
+
+/// quantity times quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+struct multiply_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >
+{
+    typedef typename multiply_typeof_helper<X,Y>::type          value_type;
+    typedef typename multiply_typeof_helper<Unit1,Unit2>::type  unit_type;
+    typedef quantity<unit_type,value_type>                      type;
+};
+
+/// scalar divided by unit typeof helper
+/// INTERNAL ONLY
+template<class System,
+         class Dim,
+         class X>
+struct divide_typeof_helper< X,unit<Dim,System> >
+{
+    typedef X                                                                           value_type;
+    typedef typename power_typeof_helper< unit<Dim,System>,static_rational<-1> >::type  unit_type;
+    typedef quantity<unit_type,value_type>                                              type;
+};
+
+/// unit divided by scalar typeof helper
+/// INTERNAL ONLY
+template<class System,
+         class Dim,
+         class X>
+struct divide_typeof_helper< unit<Dim,System>,X >
+{
+    typedef typename divide_typeof_helper<X,X>::type    value_type;
+    typedef unit<Dim,System>                            unit_type;
+    typedef quantity<unit_type,value_type>              type;
+};
+
+/// scalar divided by quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class X,
+         class Y>
+struct divide_typeof_helper< X,quantity<Unit,Y> >
+{
+    typedef typename divide_typeof_helper<X,Y>::type                        value_type;
+    typedef typename power_typeof_helper< Unit,static_rational<-1> >::type  unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+};
+
+/// disambiguate
+/// INTERNAL ONLY
+template<class Unit,
+         class Y>
+struct divide_typeof_helper< one,quantity<Unit,Y> >
+{
+    typedef quantity<Unit,Y> type;
+};
+
+/// quantity divided by scalar typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class X,
+         class Y>
+struct divide_typeof_helper< quantity<Unit,X>,Y >
+{
+    typedef typename divide_typeof_helper<X,Y>::type    value_type;
+    typedef Unit                                        unit_type;
+    typedef quantity<unit_type,value_type>              type;
+};
+
+/// disambiguate
+/// INTERNAL ONLY
+template<class Unit,
+         class X>
+struct divide_typeof_helper< quantity<Unit,X>,one >
+{
+    typedef quantity<Unit,X> type;
+};
+
+/// unit divided by quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class System,
+         class Dim,
+         class X>
+struct divide_typeof_helper< unit<Dim,System>,quantity<Unit,X> >
+{
+    typedef typename divide_typeof_helper<X,X>::type                        value_type;
+    typedef typename divide_typeof_helper< unit<Dim,System>,Unit >::type    unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+};
+
+/// quantity divided by unit typeof helper
+/// INTERNAL ONLY
+template<class Unit,
+         class System,
+         class Dim,
+         class X>
+struct divide_typeof_helper< quantity<Unit,X>,unit<Dim,System> >
+{
+    typedef X                                                               value_type;
+    typedef typename divide_typeof_helper< Unit,unit<Dim,System> >::type    unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+};
+
+/// quantity divided by quantity typeof helper
+/// INTERNAL ONLY
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+struct divide_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >
+{
+    typedef typename divide_typeof_helper<X,Y>::type            value_type;
+    typedef typename divide_typeof_helper<Unit1,Unit2>::type    unit_type;
+    typedef quantity<unit_type,value_type>                      type;
+};
+
+/// specialize power typeof helper
+/// INTERNAL ONLY
+template<class Unit,long N,long D,class Y> 
+struct power_typeof_helper< quantity<Unit,Y>,static_rational<N,D> >                
+{ 
+    typedef typename power_typeof_helper<Y,static_rational<N,D> >::type     value_type;
+    typedef typename power_typeof_helper<Unit,static_rational<N,D> >::type  unit_type;
+    typedef quantity<unit_type,value_type>                                  type; 
+    
+    static type value(const quantity<Unit,Y>& x)  
+    { 
+        return type::from_value(power_typeof_helper<Y,static_rational<N,D> >::value(x.value()));
+    }
+};
+
+/// specialize root typeof helper
+/// INTERNAL ONLY
+template<class Unit,long N,long D,class Y> 
+struct root_typeof_helper< quantity<Unit,Y>,static_rational<N,D> >                
+{ 
+    typedef typename root_typeof_helper<Y,static_rational<N,D> >::type      value_type;
+    typedef typename root_typeof_helper<Unit,static_rational<N,D> >::type   unit_type;
+    typedef quantity<unit_type,value_type>                                  type;
+    
+    static type value(const quantity<Unit,Y>& x)  
+    { 
+        return type::from_value(root_typeof_helper<Y,static_rational<N,D> >::value(x.value()));
+    }
+};
+
+/// runtime unit times scalar
+/// INTERNAL ONLY
+template<class System,
+         class Dim,
+         class Y>
+inline
+typename multiply_typeof_helper< unit<Dim,System>,Y >::type
+operator*(const unit<Dim,System>&,const Y& rhs)
+{
+    typedef typename multiply_typeof_helper< unit<Dim,System>,Y >::type type;
+    
+    return type::from_value(rhs);
+}
+
+/// runtime unit divided by scalar
+template<class System,
+         class Dim,
+         class Y>
+inline
+typename divide_typeof_helper< unit<Dim,System>,Y >::type
+operator/(const unit<Dim,System>&,const Y& rhs)
+{
+    typedef typename divide_typeof_helper<unit<Dim,System>,Y>::type type;
+    
+    return type::from_value(Y(1)/rhs);
+}
+
+/// runtime scalar times unit
+template<class System,
+         class Dim,
+         class Y>
+inline
+typename multiply_typeof_helper< Y,unit<Dim,System> >::type
+operator*(const Y& lhs,const unit<Dim,System>&)
+{
+    typedef typename multiply_typeof_helper< Y,unit<Dim,System> >::type type;
+    
+    return type::from_value(lhs);
+}
+
+/// runtime scalar divided by unit
+template<class System,
+         class Dim,
+         class Y>
+inline
+typename divide_typeof_helper< Y,unit<Dim,System> >::type
+operator/(const Y& lhs,const unit<Dim,System>&)
+{
+    typedef typename divide_typeof_helper< Y,unit<Dim,System> >::type   type;
+    
+    return type::from_value(lhs);
+}
+
+///// runtime quantity times scalar
+//template<class Unit,
+//         class X,
+//         class Y>
+//inline
+//typename multiply_typeof_helper< quantity<Unit,X>,Y >::type
+//operator*(const quantity<Unit,X>& lhs,const Y& rhs)
+//{
+//    typedef typename multiply_typeof_helper< quantity<Unit,X>,Y >::type type;
+//    
+//    return type::from_value(lhs.value()*rhs);
+//}
+//
+///// runtime scalar times quantity
+//template<class Unit,
+//         class X,
+//         class Y>
+//inline
+//typename multiply_typeof_helper< X,quantity<Unit,Y> >::type
+//operator*(const X& lhs,const quantity<Unit,Y>& rhs)
+//{
+//    typedef typename multiply_typeof_helper< X,quantity<Unit,Y> >::type type;
+//    
+//    return type::from_value(lhs*rhs.value());
+//}
+
+/// runtime quantity times scalar
+template<class Unit,
+         class X>
+inline
+typename multiply_typeof_helper< quantity<Unit,X>,X >::type
+operator*(const quantity<Unit,X>& lhs,const X& rhs)
+{
+    typedef typename multiply_typeof_helper< quantity<Unit,X>,X >::type type;
+    
+    return type::from_value(lhs.value()*rhs);
+}
+
+/// runtime scalar times quantity
+template<class Unit,
+         class X>
+inline
+typename multiply_typeof_helper< X,quantity<Unit,X> >::type
+operator*(const X& lhs,const quantity<Unit,X>& rhs)
+{
+    typedef typename multiply_typeof_helper< X,quantity<Unit,X> >::type type;
+    
+    return type::from_value(lhs*rhs.value());
+}
+
+///// runtime quantity divided by scalar
+//template<class Unit,
+//         class X,
+//         class Y>
+//inline
+//typename divide_typeof_helper< quantity<Unit,X>,Y >::type
+//operator/(const quantity<Unit,X>& lhs,const Y& rhs)
+//{
+//    typedef typename divide_typeof_helper< quantity<Unit,X>,Y >::type   type;
+//    
+//    return type::from_value(lhs.value()/rhs);
+//}
+//
+///// runtime scalar divided by quantity
+//template<class Unit,
+//         class X,
+//         class Y>
+//inline
+//typename divide_typeof_helper< X,quantity<Unit,Y> >::type
+//operator/(const X& lhs,const quantity<Unit,Y>& rhs)
+//{
+//    typedef typename divide_typeof_helper< X,quantity<Unit,Y> >::type   type;
+//    
+//    return type::from_value(lhs/rhs.value());
+//}
+
+/// runtime quantity divided by scalar
+template<class Unit,
+         class X>
+inline
+typename divide_typeof_helper< quantity<Unit,X>,X >::type
+operator/(const quantity<Unit,X>& lhs,const X& rhs)
+{
+    typedef typename divide_typeof_helper< quantity<Unit,X>,X >::type   type;
+    
+    return type::from_value(lhs.value()/rhs);
+}
+
+/// runtime scalar divided by quantity
+template<class Unit,
+         class X>
+inline
+typename divide_typeof_helper< X,quantity<Unit,X> >::type
+operator/(const X& lhs,const quantity<Unit,X>& rhs)
+{
+    typedef typename divide_typeof_helper< X,quantity<Unit,X> >::type   type;
+    
+    return type::from_value(lhs/rhs.value());
+}
+
+/// runtime unit times quantity
+template<class System1,
+         class Dim1,
+         class Unit2,
+         class Y>
+inline
+typename multiply_typeof_helper< unit<Dim1,System1>,quantity<Unit2,Y> >::type
+operator*(const unit<Dim1,System1>&,const quantity<Unit2,Y>& rhs)
+{
+    typedef typename multiply_typeof_helper< unit<Dim1,System1>,quantity<Unit2,Y> >::type  type;
+    
+    return type::from_value(rhs.value());
+}
+
+/// runtime unit divided by quantity
+template<class System1,
+         class Dim1,
+         class Unit2,
+         class Y>
+inline
+typename divide_typeof_helper< unit<Dim1,System1>,quantity<Unit2,Y> >::type
+operator/(const unit<Dim1,System1>&,const quantity<Unit2,Y>& rhs)
+{
+    typedef typename divide_typeof_helper< unit<Dim1,System1>,quantity<Unit2,Y> >::type    type;
+    
+    return type::from_value(Y(1)/rhs.value());
+}
+
+/// runtime quantity times unit
+template<class Unit1,
+         class System2,
+         class Dim2,
+         class Y>
+inline
+typename multiply_typeof_helper< quantity<Unit1,Y>,unit<Dim2,System2> >::type
+operator*(const quantity<Unit1,Y>& lhs,const unit<Dim2,System2>&)
+{
+    typedef typename multiply_typeof_helper< quantity<Unit1,Y>,unit<Dim2,System2> >::type  type;
+    
+    return type::from_value(lhs.value());
+}
+
+/// runtime quantity divided by unit
+template<class Unit1,
+         class System2,
+         class Dim2,
+         class Y>
+inline
+typename divide_typeof_helper< quantity<Unit1,Y>,unit<Dim2,System2> >::type
+operator/(const quantity<Unit1,Y>& lhs,const unit<Dim2,System2>&)
+{
+    typedef typename divide_typeof_helper< quantity<Unit1,Y>,unit<Dim2,System2> >::type    type;
+    
+    return type::from_value(lhs.value());
+}
+
+/// runtime unary plus quantity
+template<class Unit,class Y>
+typename unary_plus_typeof_helper< quantity<Unit,Y> >::type
+operator+(const quantity<Unit,Y>& val)
+{ 
+    typedef typename unary_plus_typeof_helper< quantity<Unit,Y> >::type     type;
+    
+    return type::from_value(+val.value());
+}
+
+/// runtime unary minus quantity
+template<class Unit,class Y>
+typename unary_minus_typeof_helper< quantity<Unit,Y> >::type
+operator-(const quantity<Unit,Y>& val)
+{ 
+    typedef typename unary_minus_typeof_helper< quantity<Unit,Y> >::type    type;
+    
+    return type::from_value(-val.value());
+}
+
+/// runtime quantity plus quantity
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+inline
+typename add_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type
+operator+(const quantity<Unit1,X>& lhs,
+          const quantity<Unit2,Y>& rhs)
+{
+    typedef typename add_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type     type;
+    
+    return type::from_value(lhs.value()+rhs.value());
+}
+
+/// runtime quantity minus quantity
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+inline
+typename subtract_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type
+operator-(const quantity<Unit1,X>& lhs,
+          const quantity<Unit2,Y>& rhs)
+{
+    typedef typename subtract_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type    type;
+    
+    return type::from_value(lhs.value()-rhs.value());
+}
+
+/// runtime quantity times quantity
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+inline
+typename multiply_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type
+operator*(const quantity<Unit1,X>& lhs,
+          const quantity<Unit2,Y>& rhs)
+{
+    typedef typename multiply_typeof_helper< quantity<Unit1,X>,
+                                             quantity<Unit2,Y> >::type type;
+    
+    return type::from_value(lhs.value()*rhs.value());
+}
+
+/// runtime quantity divided by quantity
+template<class Unit1,
+         class Unit2,
+         class X,
+         class Y>
+inline
+typename divide_typeof_helper< quantity<Unit1,X>,quantity<Unit2,Y> >::type
+operator/(const quantity<Unit1,X>& lhs,
+          const quantity<Unit2,Y>& rhs)
+{
+    typedef typename divide_typeof_helper< quantity<Unit1,X>,
+                                           quantity<Unit2,Y> >::type   type;
+    
+    return type::from_value(lhs.value()/rhs.value());
+}
+
+/// runtime operator==
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator==(const quantity<Unit,X>& val1,
+           const quantity<Unit,Y>& val2)
+{
+    return val1.value() == val2.value();
+}
+
+/// runtime operator!=
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator!=(const quantity<Unit,X>& val1,
+           const quantity<Unit,Y>& val2)
+{
+    return val1.value() != val2.value();
+}
+
+/// runtime operator<
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator<(const quantity<Unit,X>& val1,
+          const quantity<Unit,Y>& val2)
+{
+    return val1.value() < val2.value();
+}
+
+/// runtime operator<=
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator<=(const quantity<Unit,X>& val1,
+           const quantity<Unit,Y>& val2)
+{
+    return val1.value() <= val2.value();
+}
+
+/// runtime operator>
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator>(const quantity<Unit,X>& val1,
+          const quantity<Unit,Y>& val2)
+{
+    return val1.value() > val2.value();
+}
+
+/// runtime operator>=
+template<class Unit,
+         class X,
+         class Y>
+inline
+bool 
+operator>=(const quantity<Unit,X>& val1,
+           const quantity<Unit,Y>& val2)
+{
+    return val1.value() >= val2.value();
+}
+
+} // namespace units
+
+} // namespace boost
+
+#endif // BOOST_UNITS_QUANTITY_HPP