Update of /cvsroot/boost-sandbox/boost-sandbox/boost/units
In directory sc8-pr-cvs3.sourceforge.net:/tmp/cvs-serv20927/boost-sandbox/boost/units
Modified Files:
quantity.hpp
Log Message:
Made quantity_cast able to cast to the value_type
Index: quantity.hpp
===================================================================
RCS file: /cvsroot/boost-sandbox/boost-sandbox/boost/units/quantity.hpp,v
retrieving revision 1.5
retrieving revision 1.6
diff -u -d -r1.5 -r1.6
--- quantity.hpp 29 Mar 2007 18:24:44 -0000 1.5
+++ quantity.hpp 29 Mar 2007 18:51:36 -0000 1.6
@@ -349,12 +349,21 @@
{
typedef quantity<Unit,X> type;
- type operator()(const Y& source) { return type::from_value(source); }
+ type operator()(Y& source) { return type::from_value(source); }
};
/// specialization for casting from one value_type to another
template<class Unit,class X,class Y>
-struct quantity_cast_helper< X,quantity<Unit,Y> >
+struct quantity_cast_helper< quantity<Unit,X>,quantity<Unit,Y> >
+{
+ typedef quantity<Unit,X> type;
+
+ type operator()(quantity<Unit,Y>& source) { return type::from_value(source.value()); }
+};
+
+/// specialization for casting from one value_type to another
+template<class Unit,class X,class Y>
+struct quantity_cast_helper< quantity<Unit,X>,const quantity<Unit,Y> >
{
typedef quantity<Unit,X> type;
@@ -362,31 +371,67 @@
};
/// specialization for casting from one unit system to another
-template<class X,class System,class Dim,class Unit2>
-struct quantity_cast_helper< unit<Dim,System>,quantity<Unit2,X> >
+template<class Y,class X,class Unit1,class Unit2>
+struct quantity_cast_helper< quantity<Unit1,Y>,quantity<Unit2,X> >
{
- typedef quantity<unit<Dim,System>,X> type;
+ typedef quantity<Unit1,Y> type;
+
+ type operator()(quantity<Unit2,X>& source) { return type(source); }
+};
+
+/// specialization for casting from one unit system to another
+template<class Y,class X,class Unit1,class Unit2>
+struct quantity_cast_helper< quantity<Unit1,Y>,const quantity<Unit2,X> >
+{
+ typedef quantity<Unit1,Y> type;
type operator()(const quantity<Unit2,X>& source) { return type(source); }
};
+/// specialization for casting to the value type
+template<class Y,class X,class Unit2>
+struct quantity_cast_helper<Y,quantity<Unit2,X> >
+{
+ typedef Y type;
+
+ type operator()(quantity<Unit2,X>& source) { return const_cast<X&>(source.value()); }
+};
+
+/// specialization for casting to the value type
+template<class Y,class X,class Unit2>
+struct quantity_cast_helper<Y,const quantity<Unit2,X> >
+{
+ typedef Y type;
+
+ type operator()(const quantity<Unit2,X>& source) { return source.value(); }
+};
+
/// quantity_cast supporting three types of casting:
///
/// 1) Casting from a @c value_type to a @c quantity :
/// @verbatim quantity<Unit,X> q = quantity_cast< quantity<Unit,X> >(const X&); @endverbatim
/// 2) Casting from one @c value_type to another @c value_type :
-/// @verbatim quantity<Unit,X> q = quantity_cast<X>(const quantity<Unit,Y>&); @endverbatim
+/// @verbatim quantity<Unit,X> q = quantity_cast<quantity<Unit,X> >(const quantity<Unit,Y>&); @endverbatim
/// 3) Casting from one unit system to another :
-/// @verbatim quantity<unit,X> q = quantity_cast< unit<Dim,System1> >(const quantity<unit<Dim,System2> >,X>&); @endverbatim
+/// @verbatim quantity<unit,X> q = quantity_cast< quantity<unit<Dim,System1>,X> >(const quantity<unit<Dim,System2> >,Y>&); @endverbatim
template<class X,class Y>
inline
typename quantity_cast_helper<X,Y>::type
-quantity_cast(const Y& source)
+quantity_cast(Y& source)
{
quantity_cast_helper<X,Y> qch;
return qch(source);
}
+template<class X,class Y>
+inline
+typename quantity_cast_helper<X,const Y>::type
+quantity_cast(const Y& source)
+{
+ quantity_cast_helper<X,const Y> qch;
+
+ return qch(source);
+}
/// specialize unary plus typeof helper
template<class Unit,class Y>
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