From 422b475ce3aa1da8d50ea29620ed221497cf7738 Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@gmx.com>
Date: Fri, 28 May 2021 02:06:28 +0200
Subject: [PATCH] Add support for constexpr string_view creation

---
 include/duckhandy/implem/int_conv.hpp |  8 ++++
 include/duckhandy/int_conv.hpp        | 63 ++++++++++++++++++---------
 test/unit/int_conv_test.cpp           | 24 ++++++++++
 3 files changed, 74 insertions(+), 21 deletions(-)

diff --git a/include/duckhandy/implem/int_conv.hpp b/include/duckhandy/implem/int_conv.hpp
index d7c8782..5dc8903 100644
--- a/include/duckhandy/implem/int_conv.hpp
+++ b/include/duckhandy/implem/int_conv.hpp
@@ -168,6 +168,9 @@ namespace dhandy {
 			}
 		};
 
+		template <typename I, I In, unsigned int Base, typename Tr>
+		inline constexpr const auto g_int_to_str = IntConversion<std::remove_cvref_t<I>, Base, Tr>::to_ary(In);
+
 		template <typename T>
 		[[gnu::always_inline,gnu::pure]]
 		constexpr inline T negated_ifn (T n, bool negate) {
@@ -293,6 +296,11 @@ namespace dhandy {
 	template <typename C>
 	using ASCIITranslatorUpcase = ASCIITranslator<C, '0', 'A'>;
 
+	template <typename I, I In, unsigned int Base=10, typename Tr=ASCIITranslator<char>>
+	constexpr inline const auto& buildtime_int_to_ary() {
+		return implem::g_int_to_str<I, In, Base, Tr>;
+	}
+
 	template <typename I, unsigned int Base=10, typename Tr=ASCIITranslator<char>>
 	constexpr inline auto int_to_ary (I in) {
 		return implem::IntConversion<std::remove_cvref_t<I>, Base, Tr>::to_ary(in);
diff --git a/include/duckhandy/int_conv.hpp b/include/duckhandy/int_conv.hpp
index a9fd3a7..6fb4b16 100644
--- a/include/duckhandy/int_conv.hpp
+++ b/include/duckhandy/int_conv.hpp
@@ -26,47 +26,68 @@
 
 namespace dhandy {
 	namespace implem {
-		template <typename T, typename F, bool SafeRetval>
+		template <typename T, typename F, bool SafeRetval, typename Tr>
 		struct IntConv;
 
-		template <typename F, bool SafeRetval>
-		struct IntConv<std::enable_if_t<std::is_integral_v<F>, std::string>, F, SafeRetval> {
-			static std::string conv (const F& in) {
-				auto retval = dhandy::int_to_ary(in);
-				return std::string(retval.begin(), retval.end() - 1);
+		template <typename Tr>
+		using IntConvString = std::basic_string<typename Tr::char_type>;
+
+		template <typename Tr>
+		using IntConvStringView = std::basic_string_view<typename Tr::char_type>;
+
+		template <typename F, bool SafeRetval, typename Tr>
+		struct IntConv<std::enable_if_t<std::is_integral_v<F>, IntConvString<Tr>>, F, SafeRetval, Tr> {
+			static IntConvString<Tr> conv (const F& in) {
+				auto retval = dhandy::int_to_ary<F, 10, Tr>(in);
+				return IntConvString<Tr>{retval.begin(), retval.end() - 1};
 			}
 		};
-		template <typename F, bool SafeRetval>
-		struct IntConv<std::enable_if_t<std::is_integral_v<F>, std::string_view>, F, SafeRetval> {
-			constexpr static std::string_view conv (const F& in) {
+		template <typename F, bool SafeRetval, typename Tr>
+		struct IntConv<std::enable_if_t<std::is_integral_v<F>, IntConvStringView<Tr>>, F, SafeRetval, Tr> {
+			constexpr static IntConvStringView<Tr> conv (const F& in) {
 				if (std::is_constant_evaluated() or not SafeRetval)
-					return dhandy::int_to_ary(in).to_string_view();
+					return dhandy::int_to_ary<F, 10, Tr>(in).to_string_view();
 				else
 					throw std::logic_error("Only callable in a constexpr context, call int_conv_temporary() instead if you know what you're doing");
 			}
 		};
-		template <typename T, bool SafeRetval>
-		struct IntConv<T, std::enable_if_t<std::is_integral_v<T>, std::string>, SafeRetval> {
-			constexpr static T conv (const std::string& in) {
-				return dhandy::ary_to_int<T>(in.data(), in.data() + in.size());
+		template <typename T, bool SafeRetval, typename Tr>
+		struct IntConv<T, std::enable_if_t<std::is_integral_v<T>, IntConvString<Tr>>, SafeRetval, Tr> {
+			constexpr static T conv (const IntConvString<Tr>& in) {
+				return dhandy::ary_to_int<T, char, 10, Tr>(
+					in.data(),
+					in.data() + in.size()
+				);
 			}
 		};
-		template <typename T, bool SafeRetval>
-		struct IntConv<T, std::enable_if_t<std::is_integral_v<T>, std::string_view>, SafeRetval> {
-			constexpr static T conv (const std::string_view& in) {
-				return dhandy::ary_to_int<T>(in.data(), in.data() + in.size());
+		template <typename T, bool SafeRetval, typename Tr>
+		struct IntConv<T, std::enable_if_t<std::is_integral_v<T>, IntConvStringView<Tr>>, SafeRetval, Tr> {
+			constexpr static T conv (const IntConvStringView<Tr>& in) {
+				return dhandy::ary_to_int<T, char, 10, Tr>(
+					in.data(),
+					in.data() + in.size()
+				);
+			}
+		};
+		template <typename T, typename F, F In, bool SafeRetval, typename Tr>
+		struct IntConv<T, std::integral_constant<F, In>, SafeRetval, Tr> {
+			constexpr static T conv (const std::integral_constant<F, In>&) {
+				return dhandy::buildtime_int_to_ary<F, In, 10, Tr>().to_string_view();
 			}
 		};
 	} //namespace implem
 
 	template <typename To, typename From>
-	constexpr inline To int_conv (const From& from) {
-		return implem::IntConv<To, From, true>::conv(from);
+	constexpr inline To int_conv (const From& from, bool all_caps=false) {
+		if (all_caps)
+			return implem::IntConv<To, From, true, ASCIITranslatorUpcase<char>>::conv(from);
+		else
+			return implem::IntConv<To, From, true, ASCIITranslator<char>>::conv(from);
 	}
 
 	template <typename To, typename From>
 	constexpr inline To int_conv_temporary (const From& from) {
-		return implem::IntConv<To, From, false>::conv(from);
+		return implem::IntConv<To, From, false, ASCIITranslator<char>>::conv(from);
 	}
 } //namespace dhandy
 
diff --git a/test/unit/int_conv_test.cpp b/test/unit/int_conv_test.cpp
index ebbe445..cfe9276 100644
--- a/test/unit/int_conv_test.cpp
+++ b/test/unit/int_conv_test.cpp
@@ -171,3 +171,27 @@ TEST_CASE ("Check char array to int conversions", "[i2s][int_conv]") {
 	AryConversionTestHelper<std::int64_t, 10>("-1", -1, false);
 	AryConversionTestHelper<std::int64_t, 10>("-510123123123", -510123123123, false);
 }
+
+TEST_CASE ("Check upcase/downcase int to array conversions", "[i2s][int_conv]") {
+	using dhandy::int_conv;
+	using std::string_view;
+	using std::integral_constant;
+
+	constexpr auto bool1 = int_conv<string_view>(integral_constant<bool, true>{});
+	CHECK("1" == bool1);
+
+	constexpr auto bool2 = int_conv<string_view>(integral_constant<bool, false>{});
+	CHECK("0" == bool2);
+
+	constexpr auto int1 = int_conv<string_view>(integral_constant<int, 42>{});
+	CHECK("42" == int1);
+
+	constexpr auto int2 = int_conv<string_view>(integral_constant<unsigned int, 7777777>{});
+	CHECK("7777777" == int2);
+
+	constexpr auto int3 = int_conv<string_view>(integral_constant<int, -1234>{});
+	CHECK("-1234" == int3);
+
+	constexpr auto int4 = int_conv<string_view>(integral_constant<short int, -256>{});
+	CHECK("-256" == int4);
+}