kms++util: New template based conversion & testpat code

New templated conversion and test pattern code.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

1 files changed, 177 insertions, 0 deletions

diff --git a/kms++util/src/conv-common.h b/kms++util/src/conv-common.h
new file mode 100644
index 0000000..837668f
--- /dev/null
+++ b/kms++util/src/conv-common.h
@@ -0,0 +1,177 @@
+#pragma once
+
+#include <algorithm>
+#include <array>
+
+#define MDSPAN_IMPL_STANDARD_NAMESPACE md
+#define MDSPAN_IMPL_PROPOSED_NAMESPACE exp
+
+#include <mdspan/mdspan.hpp>
+
+namespace kms
+{
+
+/*
+ * Helpers
+ */
+
+template<class T>
+constexpr auto make_strided_view(T* data, size_t rows, size_t cols, size_t row_stride_bytes)
+{
+	assert(row_stride_bytes % sizeof(T) == 0 && "Row stride must be aligned to element size");
+
+	size_t row_stride = row_stride_bytes / sizeof(T);
+	std::array<size_t, 2> strides = { row_stride, 1 };
+
+	auto layout = md::layout_stride::mapping(md::dextents<size_t, 2>(rows, cols), strides);
+
+	return md::mdspan<T, md::dextents<size_t, 2>, md::layout_stride>(data, layout);
+}
+
+template<class T>
+constexpr auto make_strided_fb_view(void* data, size_t rows, size_t cols, size_t row_stride_bytes)
+{
+	return make_strided_view(reinterpret_cast<T*>(data), rows, cols, row_stride_bytes);
+}
+
+// Helper for static loop unrolling
+template<size_t Begin, size_t End, typename F>
+constexpr void static_for(F&& f)
+{
+	[&]<size_t... I>(std::index_sequence<I...>) {
+		(f(std::integral_constant<size_t, Begin + I>{}), ...);
+	}(std::make_index_sequence<End - Begin>{});
+}
+
+template<typename T, typename TElement>
+concept HasIndexOperatorReturning = requires(T t) {
+	{ t[0] } -> std::convertible_to<const TElement&>;
+};
+
+template<typename T, typename TElement>
+concept Is2Dspan = std::convertible_to<T, md::mdspan<TElement, md::dextents<size_t, 2>>>;
+
+/*
+ * Packing and Layouts
+ */
+
+/* This type must be big enough to hold any of the components' value */
+using component_storage_type = uint16_t;
+
+enum class ComponentType {
+	X, A,
+	R, G, B,
+	Y, Cb, Cr,
+	Y0, Y1, Y2,
+	Cb0, Cb1, Cb2,
+	Cr0, Cr1, Cr2,
+};
+
+// Describes a single component's bit layout
+template<ComponentType Type, size_t BitSize, size_t BitOffset>
+struct ComponentLayout {
+	static constexpr size_t size = BitSize;
+	static constexpr size_t offset = BitOffset;
+	static constexpr ComponentType type = Type;
+
+	static_assert(sizeof(component_storage_type) * 8 >= size);
+
+	static constexpr auto get_mask() { return ((1ull << BitSize) - 1) << BitOffset; }
+
+	template<typename TStorage>
+	static constexpr TStorage pack_value(TStorage value)
+	{
+		return (value & ((1ull << BitSize) - 1)) << BitOffset;
+	}
+
+	template<typename TStorage>
+	static constexpr component_storage_type unpack_value(TStorage value)
+	{
+		return (value >> BitOffset) & ((1ull << BitSize) - 1);
+	}
+};
+
+// Describes N components packed into a storage type
+template<typename TStorage, typename... Components>
+struct PlaneLayout {
+	using components_tuple = std::tuple<Components...>;
+
+	static constexpr size_t num_components = sizeof...(Components);
+
+	static constexpr size_t total_bits = (Components::size + ...);
+	static constexpr size_t storage_bits = sizeof(TStorage) * 8;
+	static_assert(total_bits <= storage_bits, "Components don't fit in storage type");
+
+	template<size_t N>
+	static constexpr size_t component_size = std::tuple_element_t<N, components_tuple>::size;
+
+	using storage_type = TStorage;
+
+	static constexpr std::array<ComponentType, sizeof...(Components)> order = {
+		Components::type...
+	};
+
+	template<ComponentType C>
+	static constexpr size_t component_count()
+	{
+		return std::ranges::count(order, C);
+	}
+
+	template<ComponentType C>
+	static constexpr size_t find_pos()
+	{
+		return std::ranges::find(order, C) - order.begin();
+	}
+
+	template<ComponentType C>
+	static constexpr size_t find_nth_pos(size_t n = 0)
+	{
+		auto it = std::ranges::find_if(
+			order, [&n](ComponentType type) mutable {
+				return type == C && n-- == 0;
+			});
+		return it - order.begin();
+	}
+
+	// Pack values into storage type (separate parameters version)
+	template<typename... Values>
+	static constexpr TStorage pack(Values... values)
+	{
+		static_assert(sizeof...(values) == num_components,
+			      "Number of values must match number of components");
+		return (Components::template pack_value<TStorage>(values) | ...);
+	}
+
+	// Pack values into storage type (std:array version)
+	template<typename T, size_t N>
+	static constexpr TStorage pack(const std::array<T, N>& values)
+	{
+		static_assert(N == num_components,
+			      "Number of values must match number of components");
+		return [&]<size_t... I>(std::index_sequence<I...>) {
+			return (Components::template pack_value<TStorage>(values[I]) | ...);
+		}(std::make_index_sequence<N>{});
+	}
+
+	static constexpr std::array<component_storage_type, num_components>
+	unpack(TStorage value)
+	{
+		return [&]<size_t... I>(std::index_sequence<I...>) {
+			return std::array{
+				std::tuple_element_t<I, components_tuple>::template unpack_value<
+					TStorage>(value)...
+			};
+		}(std::make_index_sequence<num_components>{});
+	}
+};
+
+template<typename... Planes>
+class FormatLayout
+{
+public:
+	static constexpr size_t num_planes = sizeof...(Planes);
+
+	template<size_t N> using plane = std::tuple_element_t<N, std::tuple<Planes...>>;
+};
+
+} // namespace kms