fixed span for ref types, copy_from with spans

src/polymesh/attributes.hh

@@ -7,6 +7,7 @@
 #include <polymesh/cursors.hh>
 #include <polymesh/detail/unique_array.hh>
 #include <polymesh/ranges.hh>
+#include <polymesh/span.hh>
 #include <polymesh/tmp.hh>
 #include <polymesh/view.hh>
 
@@ -121,8 +122,8 @@ public:
     // template <class ReadT, class WriteT>
     // void view(ReadT&& r, WriteT&& w) && = delete;
 
-    /// copies as much data as possible from the given vector
-    void copy_from(std::vector<AttrT> const& data);
+    /// copies as much data as possible from the given range of data
+    void copy_from(span<AttrT const> data);
     /// copies as much data as possible from the given array
     void copy_from(AttrT const* data, int cnt);
     /// copies as much data as possible from the given attribute

src/polymesh/impl/impl_attributes.hh

@@ -63,7 +63,7 @@ AttrT const& edge_attribute<AttrT>::operator()(halfedge_handle h) const
 }
 
 template <class tag, class AttrT>
-void primitive_attribute<tag, AttrT>::copy_from(std::vector<AttrT> const& data)
+void primitive_attribute<tag, AttrT>::copy_from(span<AttrT const> data)
 {
     std::copy_n(data.data(), std::min(int(data.size()), this->size()), this->data());
 }

src/polymesh/tmp.hh

@@ -103,9 +103,11 @@ struct constant_rational
 namespace detail
 {
 template <class Container, class ElementT>
-auto contiguous_range_test(Container* c) -> decltype(static_cast<ElementT*>(c->data()), static_cast<size_t>(c->size()), 0);
+auto contiguous_range_test(int) -> decltype(static_cast<ElementT*>(std::declval<Container>().data()), //
+                                            static_cast<size_t>(std::declval<Container>().size()),
+                                            std::true_type{});
 template <class Container, class ElementT>
-char contiguous_range_test(...);
+std::false_type contiguous_range_test(char);
 
 template <class Container, class ElementT, class = void>
 struct is_range_t : std::false_type
@@ -139,7 +141,7 @@ struct is_range_t<Container,
 }
 
 template <class Container, class ElementT>
-static constexpr bool is_contiguous_range = sizeof(detail::contiguous_range_test<Container, ElementT>(nullptr)) == sizeof(int);
+static constexpr bool is_contiguous_range = decltype(detail::contiguous_range_test<Container, ElementT>(0))::value;
 
 template <class Container, class ElementT>
 static constexpr bool is_range = detail::is_range_t<Container, ElementT>::value;