Fixed OffsetPointer and OffsetArray being nonstandard layout

nicholas477 · Nov 22, 2023 · 49f44f5 · 49f44f5
1 parent c350ad2
commit 49f44f5
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Showing 3 changed files with 30 additions and 11 deletions.
diff --git a/dependencies/egg-library/include/egg/mesh_header.hpp b/dependencies/egg-library/include/egg/mesh_header.hpp
@@ -27,4 +27,10 @@ struct MeshFileHeader
 	OffsetArray<MeshTriangleStripHeader> strips;
 };
 
+static_assert(std::is_standard_layout_v<Vector> == true);
+static_assert(std::is_standard_layout_v<OffsetArray<Vector>> == true);
+static_assert(std::is_standard_layout_v<OffsetArray<Vector2>> == true);
+static_assert(std::is_standard_layout_v<OffsetArray<MeshTriangleStripHeader>> == true);
+static_assert(std::is_standard_layout_v<MeshFileHeader> == true);
+
 #pragma pack(pop)
diff --git a/dependencies/egg-library/include/egg/offset_pointer.hpp b/dependencies/egg-library/include/egg/offset_pointer.hpp
@@ -8,12 +8,12 @@
 #include <span>
 #endif
 
-template <typename T, typename size_type_T = uint32_t>
+template <typename T>
 struct OffsetPointer
 {
 	// Offset (in bytes)
 	// This is generally an offset from the first byte of THIS OffsetPointer
-	size_type_T offset;
+	int32_t offset;
 
 	T* get_ptr()
 	{
@@ -26,14 +26,27 @@ struct OffsetPointer
 	}
 
 	using elem_T = T;
-	static_assert(std::is_arithmetic_v<size_type_T> == true);
 };
 
-template <typename T, typename size_type_T = uint32_t>
-struct OffsetArray: public OffsetPointer<T, size_type_T>
+template <typename T>
+struct OffsetArray
 {
+	// Offset (in bytes)
+	// This is generally an offset from the first byte of THIS OffsetPointer
+	int32_t offset;
+
 	// Length of the array (in bytes)
-	size_type_T length;
+	int32_t length;
+
+	T* get_ptr()
+	{
+		return reinterpret_cast<T*>(((uint8_t*)this) + offset);
+	}
+
+	const T* get_ptr() const
+	{
+		return reinterpret_cast<const T*>(((const uint8_t*)this) + offset);
+	}
 
 	T* get_array()
 	{
@@ -45,13 +58,13 @@ struct OffsetArray: public OffsetPointer<T, size_type_T>
 		return this->get_ptr();
 	}
 
-	T& operator[](size_t index)
+	T& operator[](int32_t index)
 	{
 		assert(index >= 0 && index < num_elements());
 		return get_array()[index];
 	}
 
-	const T& operator[](size_t index) const
+	const T& operator[](int32_t index) const
 	{
 		assert(index >= 0 && index < num_elements());
 		return get_array()[index];
@@ -77,20 +90,19 @@ struct OffsetArray: public OffsetPointer<T, size_type_T>
 		return &get_array()[num_elements()];
 	}
 
-
 #ifdef __cpp_lib_span
 	std::span<T> get_span()
 	{
 		return std::span<T>(get_array(), num_elements());
 	}
 #endif
 
-	size_type_T num_elements() const
+	int32_t num_elements() const
 	{
 		return length / sizeof(T);
 	}
 
-	void set_num_elements(size_type_T num_elements)
+	void set_num_elements(int32_t num_elements)
 	{
 		length = num_elements * sizeof(T);
 	}

diff --git a/dependencies/egg-library/src/egg.cpp b/dependencies/egg-library/src/egg.cpp
@@ -1,4 +1,5 @@
 #include "egg/math_types.hpp"
+#include "egg/mesh_header.hpp"
 
 #include <sstream>