1 files changed, 150 insertions, 0 deletions
diff --git a/modules/core/templates.h b/modules/core/templates.h
new file mode 100644
index 0000000..2eb0f7e
--- /dev/null
+++ b/modules/core/templates.h
@@ -0,0 +1,150 @@
+#pragma once
+
+#include "string_literal.h"
+
+namespace saw {
+
+template <class T, class... TL> struct parameter_pack_index;
+
+template <class T, class... TL> struct parameter_pack_index<T, T, TL...> {
+	static constexpr size_t value = 0u;
+};
+
+template <class T, class TL0, class... TL>
+struct parameter_pack_index<T, TL0, TL...> {
+	static constexpr size_t value =
+		1u + parameter_pack_index<T, TL...>::value;
+};
+
+template <size_t N, class... T> struct parameter_pack_type {
+	static_assert(always_false<T...>, "Should've been caught by the specializations");
+};
+
+template <class TN, class... T> struct parameter_pack_type<0, TN, T...> {
+	using type = TN;
+};
+
+template <size_t N, class TN, class... T>
+struct parameter_pack_type<N, TN, T...> {
+	static_assert(sizeof...(T) > 0, "Exhausted parameters");
+	static_assert(N > 0, "Invalid number. Should've been caught");
+	using type = typename parameter_pack_type<N - 1, T...>::type;
+};
+/*
+ * Nightmare inducing compiler problems found here. Somehow non-type
+ * string_literals cannot be resolved as non-type primitive template values can.
+ * This is the workaround
+ */
+template <string_literal V, string_literal Key0, string_literal... Keys>
+struct parameter_key_pack_index_helper {
+	static constexpr size_t value =
+		(V == Key0)
+			? (0u)
+			: (1u + parameter_key_pack_index_helper<V, Keys...>::value);
+};
+
+template <string_literal V, string_literal Key0>
+struct parameter_key_pack_index_helper<V, Key0> {
+	static constexpr size_t value = (V == Key0) ? (0u) : (1u);
+};
+
+template <string_literal V, string_literal... Keys>
+struct parameter_key_pack_index {
+	static constexpr size_t value =
+		parameter_key_pack_index_helper<V, Keys...>::value;
+	static_assert(value < sizeof...(Keys),
+				  "Provided string_literal doesn't exist in searched list");
+};
+
+template <size_t i, size_t s, string_literal Key0, string_literal... Keys>
+struct parameter_key_pack_type_helper {
+	static constexpr string_literal literal = parameter_key_pack_type_helper<i, s+1, Keys...>::literal;
+};
+
+template <size_t i, string_literal Key0, string_literal... Keys>
+struct parameter_key_pack_type_helper<i, i, Key0, Keys...> {
+	static constexpr string_literal literal = Key0;
+};
+
+template <size_t i, string_literal... Keys>
+struct parameter_key_pack_type {
+	static constexpr string_literal literal = parameter_key_pack_type_helper<i, 0, Keys...>::literal;
+
+	static_assert(i < sizeof...(Keys), "Provided index is too large for list");
+};
+
+template<std::size_t i, std::size_t s, typename T, T V0, T... VN>
+struct parameter_pack_value_helper {
+	static constexpr T value = parameter_pack_value_helper<i, s+1, T, VN...>::value;
+};
+
+template<std::size_t i, typename T, T V0, T... VN>
+struct parameter_pack_value_helper<i, i, T, V0, VN...> {
+	static constexpr T value = V0;
+};
+
+template<std::size_t i, typename T, T... Values>
+struct parameter_pack_value {
+	static constexpr T value = parameter_pack_value_helper<i, 0, T, Values...>::value;
+	static_assert(i < sizeof...(Values), "Provided index is too large for list");
+};
+
+template<typename T, T... V>
+struct ct_multiply;
+
+template<typename T>
+struct ct_multiply<T> {
+	static constexpr T value = 1;
+};
+
+template<typename T, T V0, T... VN>
+struct ct_multiply<T, V0, VN...> {
+	static constexpr T value = V0 * ct_multiply<T,VN...>::value;
+};
+
+namespace impl {
+template<typename T, size_t i>
+struct ct_convert_digits_table_helper {
+		static_assert(i <= 15, "Only conversion up to hex is supported");
+
+		static constexpr std::array<T, 16> table = {
+				'0', '1', '2', '3',
+				'4', '5', '6', '7',
+				'8', '9', 'A', 'B',
+				'C', 'D', 'E', 'F'
+		};
+
+		static constexpr T value = table[i];
+};
+
+template<uint64_t Num, uint64_t Base, uint64_t... Digs>
+struct ct_convert_digits_helper {
+		static constexpr size_t size = ct_convert_digits_helper<Num / Base, Base, Num % Base, Digs...>::size;
+		static constexpr std::array<uint64_t, size> value = ct_convert_digits_helper<Num / Base, Base, Num % Base, Digs...>::value;
+		static constexpr string_literal literal = ct_convert_digits_helper<Num / Base, Base, Num % Base, Digs...>::literal;
+};
+
+template<uint64_t Base, uint64_t... Digs>
+struct ct_convert_digits_helper<0, Base, Digs...> {
+		static constexpr size_t size = sizeof...(Digs);
+		static constexpr std::array<uint64_t, size> value = {Digs...};
+		static constexpr string_literal literal = {{ct_convert_digits_table_helper<char, Digs>::value..., '\0'}};
+};
+
+template<uint64_t Base>
+struct ct_convert_digits_helper<0, Base> {
+		static constexpr size_t size = 0;
+		static constexpr std::array<uint64_t, 1> value = {0};
+		static constexpr string_literal literal = "0"_sl;
+};
+}
+
+template<uint64_t Num, uint64_t Base>
+struct ct_convert_to_digits {
+		static_assert(Base <= 16, "Only conversion up to hex is supported");
+
+		static constexpr size_t size = impl::ct_convert_digits_helper<Num, Base>::size;
+		static constexpr std::array<uint64_t, size> value = impl::ct_convert_digits_helper<Num, Base>::value;
+		static constexpr string_literal literal = impl::ct_convert_digits_helper<Num,Base>::literal;
+};
+}