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Boost-Commit : |
Subject: [Boost-commit] svn:boost r62111 - sandbox/chrono/boost/type_traits
From: vicente.botet_at_[hidden]
Date: 2010-05-20 10:21:29
Author: viboes
Date: 2010-05-20 10:21:28 EDT (Thu, 20 May 2010)
New Revision: 62111
URL: http://svn.boost.org/trac/boost/changeset/62111
Log:
Boost.Chrono 0.5:
* Change common_type to take advantage of C++0x individual features
Text files modified:
sandbox/chrono/boost/type_traits/common_type.hpp | 118 ++++++++++++++++++++++++---------------
1 files changed, 73 insertions(+), 45 deletions(-)
Modified: sandbox/chrono/boost/type_traits/common_type.hpp
==============================================================================
--- sandbox/chrono/boost/type_traits/common_type.hpp (original)
+++ sandbox/chrono/boost/type_traits/common_type.hpp 2010-05-20 10:21:28 EDT (Thu, 20 May 2010)
@@ -9,10 +9,30 @@
#ifndef BOOST_COMMON_TYPE_HPP
#define BOOST_COMMON_TYPE_HPP
-#define BOOST_VARIADIC_COMMON_TYPE 0
+#include <boost/config.hpp>
+//----------------------------------------------------------------------------//
+#if defined(BOOST_NO_VARIADIC_TEMPLATES)
+#define BOOST_COMMON_TYPE_ARITY 3
+#endif
+
+//----------------------------------------------------------------------------//
+#if defined(BOOST_NO_RVALUE_REFERENCES) \
+ || defined(BOOST_NO_DECLTYPE)
#define BOOST_TYPEOF_SILENT
#include <boost/typeof/typeof.hpp> // boost wonders never cease!
+#endif
+
+//----------------------------------------------------------------------------//
+#if !defined(BOOST_NO_STATIC_ASSERT)
+#define BOOST_COMMON_TYPE_STATIC_ASSERT(CND,MSG) \
+ static_assert(CND, MSG)
+#else
+#include <boost/static_assert.hpp> // boost wonders never cease!
+#define BOOST_COMMON_TYPE_STATIC_ASSERT(CND,MSG) \
+ BOOST_STATIC_ASSERT(CND)
+#endif
+
//----------------------------------------------------------------------------//
// //
@@ -23,63 +43,71 @@
// //
//----------------------------------------------------------------------------//
-namespace boost
-{
-#ifndef BOOST_NO_VARIADIC_TEMPLATES
+namespace boost {
+
+// prototype
+#if !defined(BOOST_NO_VARIADIC_TEMPLATES)
template<typename... T>
struct common_type;
+#else // or no specialization
+ template <class T, class U = void, class V = void>
+ struct common_type
+ {
+ public:
+ typedef typename common_type<typename common_type<T, U>::type, V>::type type;
+ };
+#endif
+
+// 1 arg
template<typename T>
- struct common_type<T> {
- static_assert(sizeof(T) > 0, "must be complete type");
+#if !defined(BOOST_NO_VARIADIC_TEMPLATES)
+ struct common_type<T>
+#else
+ struct common_type<T, void, void>
+
+#endif
+ {
+ BOOST_COMMON_TYPE_STATIC_ASSERT(sizeof(T) > 0, "must be complete type");
+ public:
typedef T type;
};
- template<typename T, typename U>
- class common_type<T, U> {
- static_assert(sizeof(T) > 0, "must be complete type");
- static_assert(sizeof(U) > 0, "must be complete type");
- static T&& m_t();
- static U&& m_u();
-
+// 2 args
+
+#if !defined(BOOST_NO_VARIADIC_TEMPLATES)
+ template <class T, class U>
+ struct common_type<T, U>
+#else
+ template <class T, class U>
+ struct common_type<T, U, void>
+#endif
+ {
+ BOOST_COMMON_TYPE_STATIC_ASSERT(sizeof(T) > 0, "must be complete type");
+ BOOST_COMMON_TYPE_STATIC_ASSERT(sizeof(U) > 0, "must be complete type");
static bool m_f(); // workaround gcc bug; not required by std
+#if !defined(BOOST_NO_RVALUE_REFERENCES) \
+ && !defined(BOOST_NO_DECLTYPE)
+ static T&& m_t();
+ static U&& m_u();
- public:
- typedef decltype(m_true_or_false() ? m_t() : m_u()) type;
+ public:
+ typedef decltype(m_f() ? m_t() : m_u()) type;
+#else
+ static T m_t();
+ static U m_u();
+ public:
+ typedef BOOST_TYPEOF_TPL(m_f() ? m_t() : m_u()) type;
+#endif
};
-
+
+// 3 or more args
+#if !defined(BOOST_NO_VARIADIC_TEMPLATES)
template<typename T, typename U, typename... V>
struct common_type<T, U, V...> {
- typedef typename
- common_type<typename common_type<T, U>::type, V...>::type type;
+ public:
+ typedef typename common_type<typename common_type<T, U>::type, V...>::type type;
};
-#else
-
- template <class T, class U = void, class V = void>
- struct common_type
- {
- public:
- typedef typename common_type<typename common_type<T, U>::type, V>::type type;
- };
-
- template <class T>
- struct common_type<T, void, void>
- {
- public:
- typedef T type;
- };
-
- template <class T, class U>
- struct common_type<T, U, void>
- {
- private:
- static T m_t();
- static U m_u();
- static bool m_f(); // workaround gcc bug; not required by std
- public:
-
- typedef BOOST_TYPEOF_TPL(m_f() ? m_t() : m_u()) type;
- };
#endif
} // namespace boost
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