Update of /cvsroot/boost-sandbox/boost-sandbox/boost/units/detail
In directory sc8-pr-cvs3.sourceforge.net:/tmp/cvs-serv1466/boost-sandbox/boost/units/detail
Modified Files:
conversion_impl.hpp
Log Message:
Bug Fixes
Index: conversion_impl.hpp
===================================================================
RCS file: /cvsroot/boost-sandbox/boost-sandbox/boost/units/detail/conversion_impl.hpp,v
retrieving revision 1.1.1.1
retrieving revision 1.2
diff -u -d -r1.1.1.1 -r1.2
--- conversion_impl.hpp 16 Mar 2007 18:12:43 -0000 1.1.1.1
+++ conversion_impl.hpp 29 Mar 2007 00:31:27 -0000 1.2
@@ -14,7 +14,10 @@
#include <cmath>
#include <boost/type_traits/is_base_and_derived.hpp>
+#include <boost/type_traits/is_same.hpp>
+#include <boost/mpl/eval_if.hpp>
+#include <boost/mpl/if.hpp>
#include <boost/mpl/begin.hpp>
#include <boost/mpl/deref.hpp>
#include <boost/mpl/next.hpp>
@@ -89,14 +92,34 @@
static one value() { return one(); }
};
-template<class Tag,class System1,class System2> struct base_unit_converter;
+struct identity_conversion : trivial_conversion, implicitly_convertible {};
-/// base unit conversion from system to itself is a no-op
-template<class Tag,class System1>
-struct base_unit_converter<Tag, System1, System1> :
- public implicitly_convertible,
- public trivial_conversion
-{ };
+struct define_reverse_automatically {};
+
+struct undefined_conversion {};
+
+template<class Converter>
+struct reverse_conversion
+ : mpl::if_<is_base_and_derived<implicitly_convertible, Converter>, implicitly_convertible, undefined_conversion>::type {
+ typedef typename Converter::type type;
+ static type value() {
+ return(one()/Converter::value());
+ }
+};
+
+template<class Dimension, class Tag1, class Tag2>
+struct base_unit_converter :
+ mpl::eval_if<is_same<Tag1, Tag2>,
+ mpl::identity<identity_conversion>,
+ mpl::if_<
+ is_base_and_derived<
+ define_reverse_automatically,
+ base_unit_converter<Dimension,Tag2,Tag1>
+ >,
+ reverse_conversion<base_unit_converter<Dimension,Tag2,Tag1> >,
+ undefined_conversion
+ >
+ >::type {};
template<class Tag,class System1,class System2>
struct base_unit_is_implicitly_convertible :
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