1 files changed, 163 insertions, 0 deletions
diff --git a/lib/glAllocator.h b/lib/glAllocator.h
new file mode 100644
index 0000000..02690c3
--- /dev/null
+++ b/lib/glAllocator.h
@@ -0,0 +1,163 @@
+#include "special_members.h"
+#include <glad/gl.h>
+#include <iterator>
+#include <memory>
+#include <vector>
+
+namespace Detail {
+	template<typename T> class glPointer {
+	public:
+		constexpr glPointer(const glPointer<std::remove_const_t<T>> & other)
+			requires(std::is_const_v<T>)
+			: ptr {other.get()}, name {other.bufferName()}
+		{
+		}
+
+		DEFAULT_MOVE_COPY(glPointer);
+
+		constexpr glPointer() : ptr {nullptr}, name {0} { }
+
+		constexpr glPointer(T * ptr, GLuint name) : ptr {ptr}, name {name} { }
+
+		auto operator<=>(const glPointer &) const noexcept = default;
+
+		operator T *() const noexcept
+		{
+			return ptr;
+		}
+
+		operator bool() const noexcept
+		{
+			return ptr;
+		}
+
+		std::ptrdiff_t
+		operator-(const glPointer & other) const noexcept
+		{
+			return ptr - other.ptr;
+		}
+
+		T *
+		get() const noexcept
+		{
+			return ptr;
+		}
+
+		T &
+		operator*() const noexcept
+		{
+			return *ptr;
+		}
+
+		[[nodiscard]]
+		T &
+		operator[](std::unsigned_integral auto index) const noexcept
+		{
+			return ptr[index];
+		}
+
+		T *
+		operator->() const noexcept
+		{
+			return ptr;
+		}
+
+		glPointer<T> &
+		operator++() noexcept
+		{
+			++ptr;
+			return *this;
+		}
+
+		glPointer<T> &
+		operator--() noexcept
+		{
+			--ptr;
+			return *this;
+		}
+
+		[[nodiscard]] glPointer<T>
+		operator+(std::integral auto offset) const noexcept
+		{
+			return {ptr + offset, name};
+		}
+
+		[[nodiscard]] glPointer<T>
+		operator-(std::integral auto offset) const noexcept
+		{
+			return {ptr - offset, name};
+		}
+
+		[[nodiscard]] glPointer<T>
+		operator+=(std::integral auto offset) const noexcept
+		{
+			return {ptr += offset, name};
+		}
+
+		[[nodiscard]] glPointer<T>
+		operator-=(std::integral auto offset) const noexcept
+		{
+			return {ptr -= offset, name};
+		}
+
+		[[nodiscard]] GLuint
+		bufferName() const noexcept
+		{
+			return name;
+		}
+
+	private:
+		T * ptr;
+		GLuint name;
+	};
+
+	std::pair<void *, GLuint> allocateBuffer(size_t count, size_t objSize);
+	void deallocateBuffer(GLuint name);
+
+	template<typename T> class glAllocator {
+	public:
+		// NOLINTBEGIN(readability-identifier-naming) - STL like
+		using pointer = glPointer<T>;
+		using const_pointer = glPointer<const T>;
+		using value_type = T;
+
+		// NOLINTEND(readability-identifier-naming)
+
+		pointer
+		allocate(size_t count)
+		{
+			auto allocated = allocateBuffer(count, sizeof(T));
+			return {static_cast<T *>(allocated.first), allocated.second};
+		}
+
+#if (__cpp_lib_allocate_at_least >= 202302L)
+		std::allocation_result<pointer>
+		allocate_at_least(size_t count)
+		{
+			count = std::min(count, 32ZU);
+			return {allocate(count), count};
+		}
+#endif
+
+		void
+		deallocate(pointer ptr, size_t)
+		{
+			deallocateBuffer(ptr.bufferName());
+		}
+
+		using is_always_equal = std::true_type;
+	};
+}
+
+template<typename T> struct std::iterator_traits<Detail::glPointer<T>> {
+	using iterator_category = std::random_access_iterator_tag;
+	using iterator_concept = std::contiguous_iterator_tag;
+	using value_type = T;
+	using difference_type = std::ptrdiff_t;
+	using reference = T &;
+	using pointer = T *;
+};
+
+template<typename T>
+// NOLINTNEXTLINE(readability-identifier-naming) - OpenGL like
+using glVector = std::vector<T, typename std::allocator_traits<Detail::glAllocator<T>>::allocator_type>;