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boost::make_variant_over cannot be trusted! 

Use my own naive implementation, with ugly meta-programming, instead
of using `boost::make_variant_over` and `boost::mpl::set`.
This commit is contained in:
Laurent Rineau 2018-10-08 14:53:48 +02:00
parent afde694d63
commit d50e70eee8
1 changed files with 54 additions and 6 deletions
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60
Mesh_3/include/CGAL/internal/Mesh_3/indices_management.h
View File

@ -33,7 +33,6 @@
#include <boost/type_traits/is_same.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/variant.hpp>
#include <boost/mpl/set/set10.hpp>
#include <CGAL/Mesh_3/Has_features.h>
#include <CGAL/IO/io.h>
@ -59,17 +58,66 @@ struct Index_generator<T, T>
typedef Index type;
};
// Nasty meta-programming to get a boost::variant of four types that
// may not be all different.
template <typename T0> struct seq1 {
typedef T0 type;
};
template <typename T0, typename T1> struct seq2 {
typedef boost::variant<T0, T1> type;
};
template <typename T0, typename T1, typename T2> struct seq3 {
typedef boost::variant<T0, T1, T2> type;
};
template <typename T0, typename T1, typename T2, typename T3> struct seq4 {
typedef boost::variant<T0, T1, T2, T3> type;
};
template <typename T, typename U> struct insert;
template <typename T, typename U> struct insert<seq1<T>, U> {
typedef seq2<T, U> type;
};
template <typename T, typename U, typename V> struct insert<seq2<T, U>, V> {
typedef seq3<T, U, V> type;
};
template <typename T, typename U, typename V, typename W>
struct insert<seq3<T, U, V>, W> {
typedef seq4<T, U, V, W> type;
};
template <typename T> struct insert<seq1<T>, T> {
typedef seq1<T> type;
};
template <typename T, typename U> struct insert<seq2<T, U>, T> {
typedef seq2<T, U> type;
};
template <typename T, typename U> struct insert<seq2<T, U>, U> {
typedef seq2<T, U> type;
};
template <typename T, typename U, typename V> struct insert<seq3<T, U, V>, T> {
typedef seq3<T, U, V> type;
};
template <typename T, typename U, typename V> struct insert<seq3<T, U, V>, U> {
typedef seq3<T, U, V> type;
};
template <typename T, typename U, typename V> struct insert<seq3<T, U, V>, V> {
typedef seq3<T, U, V> type;
};
template < typename Subdomain_index,
typename Surface_patch_index,
typename Curves_index,
typename Corner_index>
struct Index_generator_with_features
{
typedef boost::mpl::set4<Subdomain_index,
Surface_patch_index,
Curves_index,
Corner_index> Set;
typedef typename boost::make_variant_over<Set>::type Index;
typedef typename insert<
typename insert<
typename insert<seq1<Subdomain_index>,
Surface_patch_index
>::type,
Curves_index
>::type,
Corner_index>::type seq;
typedef typename seq::type Index;
typedef Index type;
};