[WIP] Introduce ArrayOfStructsView

teslamotors · Jul 1, 2024 · 1c49cfc · 1c49cfc
1 parent 2ec72ac
commit 1c49cfc
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diff --git a/include/fixed_containers/sub_struct_view.hpp b/include/fixed_containers/sub_struct_view.hpp
@@ -76,4 +76,43 @@ void sub_struct_view_of(Super& super_struct,
                               sub_struct_field_properties);
 }
 
+template <typename SuperStruct, typename SubStruct>
+class StridedArrayView
+{
+    FixedMap<std::string_view, FieldProperties, reflection::field_count_of<SuperStruct>()>
+        super_struct_field_properties_;
+    FixedMap<std::string_view, FieldProperties, reflection::field_count_of<SubStruct>()>
+        sub_struct_field_properties_;
+    std::byte* base_array_super_struct_ptr_;
+    std::size_t size_;
+
+public:
+    StridedArrayView()
+      : super_struct_field_properties_(extract_field_properties_of<SuperStruct>())
+      , sub_struct_field_properties_(extract_field_properties_of<SubStruct>())
+      , base_array_super_struct_ptr_{nullptr}
+    {
+    }
+
+public:
+    template <typename ArrayOfSuperStruct>
+    void update(ArrayOfSuperStruct& super_struct_instance)
+    {
+        base_array_super_struct_ptr_ = memory::addressof_as_mutable_byte_ptr(super_struct_instance);
+        size_ = super_struct_instance.size();
+    }
+
+    SubStruct at(const std::size_t i) const
+    {
+        SubStruct instance{};
+        std::byte* base_of_ith_entry = std::next(
+            base_array_super_struct_ptr_, static_cast<std::ptrdiff_t>(i * sizeof(SuperStruct)));
+        sub_struct_view::sub_struct_view_of(base_of_ith_entry,
+                                            super_struct_field_properties_,
+                                            memory::addressof_as_mutable_byte_ptr(instance),
+                                            sub_struct_field_properties_);
+        return instance;
+    }
+};
+
 }  // namespace fixed_containers::sub_struct_view
diff --git a/test/sub_struct_view_test.cpp b/test/sub_struct_view_test.cpp
@@ -75,6 +75,53 @@ TEST(SubStructView, SubStructViewOf)
     ASSERT_EQ(flat_sub_struct_1.retain1, &flat_super_struct_1.retain1);
     ASSERT_EQ(flat_sub_struct_1.retain2, &flat_super_struct_1.retain2);
 }
+
+namespace
+{
+struct PointXYZ
+{
+    double x{};
+    double y{};
+    double z{};
+};
+
+struct FlatSuperStruct2
+{
+    int ignore1{};
+    std::array<PointXYZ, 3> retain1{};
+    float ignore2{};
+};
+
+struct PointXZ
+{
+    const double* z{};
+    const double* x{};
+};
+
+struct FlatSubStruct2
+{
+    StridedArrayView<PointXYZ, PointXZ> retain1{};
+};
+
+}  // namespace
+
+TEST(SubStructView, ArraysOfStructs)
+{
+    FlatSuperStruct2 flat_super_struct_2{};
+    FlatSubStruct2 flat_sub_struct_2{};
+
+    flat_sub_struct_2.retain1.update(flat_super_struct_2.retain1);
+
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(0).x, &flat_super_struct_2.retain1.at(0).x);
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(0).z, &flat_super_struct_2.retain1.at(0).z);
+
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(1).x, &flat_super_struct_2.retain1.at(1).x);
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(1).z, &flat_super_struct_2.retain1.at(1).z);
+
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(2).x, &flat_super_struct_2.retain1.at(2).x);
+    ASSERT_EQ(flat_sub_struct_2.retain1.at(2).z, &flat_super_struct_2.retain1.at(2).z);
+}
+
 }  // namespace fixed_containers::sub_struct_view
 
 #endif