comparison DEPENDENCIES/generic/include/boost/next_prior.hpp @ 101:c530137014c0

Update Boost headers (1.58.0)

 
 #ifndef BOOST_NEXT_PRIOR_HPP_INCLUDED
 #define BOOST_NEXT_PRIOR_HPP_INCLUDED
 
 #include <iterator>
+#if defined(_MSC_VER) && _MSC_VER <= 1310
+#include <boost/mpl/and.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#endif
+#include <boost/type_traits/is_unsigned.hpp>
+#include <boost/type_traits/integral_promotion.hpp>
+#include <boost/type_traits/make_signed.hpp>
+#include <boost/type_traits/has_plus.hpp>
+#include <boost/type_traits/has_plus_assign.hpp>
+#include <boost/type_traits/has_minus.hpp>
+#include <boost/type_traits/has_minus_assign.hpp>
 
 namespace boost {
 
 //  Helper functions for classes like bidirectional iterators not supporting
 //  operator+ and operator-

 //    const std::list<T>::iterator prev = boost::prior(p);
 //    const std::list<T>::iterator next = boost::next(prev, 2);
 
 //  Contributed by Dave Abrahams
 
+namespace next_prior_detail {
+
+template< typename T, typename Distance, bool HasPlus = has_plus< T, Distance >::value >
+struct next_impl2
+{
+    static T call(T x, Distance n)
+    {
+        std::advance(x, n);
+        return x;
+    }
+};
+
+template< typename T, typename Distance >
+struct next_impl2< T, Distance, true >
+{
+    static T call(T x, Distance n)
+    {
+        return x + n;
+    }
+};
+
+
+template< typename T, typename Distance, bool HasPlusAssign = has_plus_assign< T, Distance >::value >
+struct next_impl1 :
+    public next_impl2< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct next_impl1< T, Distance, true >
+{
+    static T call(T x, Distance n)
+    {
+        x += n;
+        return x;
+    }
+};
+
+
+template<
+    typename T,
+    typename Distance,
+    typename PromotedDistance = typename integral_promotion< Distance >::type,
+#if !defined(_MSC_VER) || _MSC_VER > 1310
+    bool IsUInt = is_unsigned< PromotedDistance >::value
+#else
+    // MSVC 7.1 has problems with applying is_unsigned to non-integral types
+    bool IsUInt = mpl::and_< is_integral< PromotedDistance >, is_unsigned< PromotedDistance > >::value
+#endif
+>
+struct prior_impl3
+{
+    static T call(T x, Distance n)
+    {
+        std::advance(x, -n);
+        return x;
+    }
+};
+
+template< typename T, typename Distance, typename PromotedDistance >
+struct prior_impl3< T, Distance, PromotedDistance, true >
+{
+    static T call(T x, Distance n)
+    {
+        typedef typename make_signed< PromotedDistance >::type signed_distance;
+        std::advance(x, -static_cast< signed_distance >(static_cast< PromotedDistance >(n)));
+        return x;
+    }
+};
+
+
+template< typename T, typename Distance, bool HasMinus = has_minus< T, Distance >::value >
+struct prior_impl2 :
+    public prior_impl3< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct prior_impl2< T, Distance, true >
+{
+    static T call(T x, Distance n)
+    {
+        return x - n;
+    }
+};
+
+
+template< typename T, typename Distance, bool HasMinusAssign = has_minus_assign< T, Distance >::value >
+struct prior_impl1 :
+    public prior_impl2< T, Distance >
+{
+};
+
+template< typename T, typename Distance >
+struct prior_impl1< T, Distance, true >
+{
+    static T call(T x, Distance n)
+    {
+        x -= n;
+        return x;
+    }
+};
+
+} // namespace next_prior_detail
+
 template <class T>
 inline T next(T x) { return ++x; }
 
 template <class T, class Distance>
 inline T next(T x, Distance n)
 {
-    std::advance(x, n);
-    return x;
+    return next_prior_detail::next_impl1< T, Distance >::call(x, n);
 }
 
 template <class T>
 inline T prior(T x) { return --x; }
 
 template <class T, class Distance>
 inline T prior(T x, Distance n)
 {
-    std::advance(x, -n);
-    return x;
+    return next_prior_detail::prior_impl1< T, Distance >::call(x, n);
 }
 
 } // namespace boost
 
 #endif  // BOOST_NEXT_PRIOR_HPP_INCLUDED