group: extended_group_iterator::base to return the underlying iterator

TODO

@@ -15,7 +15,6 @@ TODO (high prio):
 * check natvis files (periodically :)
 * remove the static storage from the const assure in the registry
 * pop_if to improve further destroying entities (drastically)
-* add iterator_type/base to extended storage iterators (group)
 
 WIP:
 * get rid of observers, storage based views made them pointless - document alternatives

src/entt/entity/group.hpp

@@ -36,6 +36,7 @@ class extended_group_iterator<It, owned_t<Owned...>, get_t<Get...>> {
     }
 
 public:
+    using iterator_type = It;
     using difference_type = std::ptrdiff_t;
     using value_type = decltype(std::tuple_cat(std::make_tuple(*std::declval<It>()), std::declval<Owned>().get_as_tuple({})..., std::declval<Get>().get_as_tuple({})...));
     using pointer = input_iterator_pointer<value_type>;
@@ -67,6 +68,10 @@ public:
         return operator*();
     }
 
+    constexpr iterator_type base() const noexcept {
+        return it;
+    }
+
     template<typename... Lhs, typename... Rhs>
     friend constexpr bool operator==(const extended_group_iterator<Lhs...> &, const extended_group_iterator<Rhs...> &) noexcept;
 

test/entt/entity/group.cpp

@@ -201,7 +201,9 @@ TEST(NonOwningGroup, Each) {
 
     auto it = iterable.begin();
 
+    ASSERT_EQ(it.base(), group.begin());
     ASSERT_EQ((it++, ++it), iterable.end());
+    ASSERT_EQ(it.base(), group.end());
 
     group.each([expected = 1](auto entt, int &ivalue, char &cvalue) mutable {
         ASSERT_EQ(static_cast<int>(entt::to_integral(entt)), expected);
@@ -875,7 +877,9 @@ TEST(OwningGroup, Each) {
 
     auto it = iterable.begin();
 
+    ASSERT_EQ(it.base(), group.begin());
     ASSERT_EQ((it++, ++it), iterable.end());
+    ASSERT_EQ(it.base(), group.end());
 
     group.each([expected = 1](auto entt, int &ivalue, char &cvalue) mutable {
         ASSERT_EQ(static_cast<int>(entt::to_integral(entt)), expected);