From f8c0bc3d1cbb93169be6d515b6833fc16510a301 Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@gmx.com>
Date: Fri, 12 Oct 2018 19:38:58 +0100
Subject: [PATCH] Hardcode -'0' subtraction.

---
 include/duckhandy/int_conv.hpp | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/duckhandy/int_conv.hpp b/include/duckhandy/int_conv.hpp
index c8fa5c2..ec3d7df 100644
--- a/include/duckhandy/int_conv.hpp
+++ b/include/duckhandy/int_conv.hpp
@@ -133,25 +133,32 @@ namespace dhandy {
 				using RetType = ReversedSizedArray<std::decay_t<decltype(std::declval<Tr>().to_digit(1))>, implem::int_info<I, 10>::max_len + 1>;
 				using Num = implem::NumberAdaptation<I, 10>;
 
-				const constexpr char lookup[201] = "000102030405060708091011121314"
-					"1516171819202122232425262728293031323334353637383940414243"
-					"4445464748495051525354555657585960616263646566676869707172"
-					"737475767778798081828384858687888990919293949596979899";
+				const constexpr char lookup[200] = {
+					0,0,0,1,0,2,0,3,0,4,0,5,0,6,0,7,0,8,0,9,1,0,1,1,1,2,1,3,1,4,
+					1,5,1,6,1,7,1,8,1,9,2,0,2,1,2,2,2,3,2,4,2,5,2,6,2,7,2,8,2,9,
+					3,0,3,1,3,2,3,3,3,4,3,5,3,6,3,7,3,8,3,9,4,0,4,1,4,2,4,3,4,4,
+					4,5,4,6,4,7,4,8,4,9,5,0,5,1,5,2,5,3,5,4,5,5,5,6,5,7,5,8,5,9,
+					6,0,6,1,6,2,6,3,6,4,6,5,6,6,6,7,6,8,6,9,7,0,7,1,7,2,7,3,7,4,
+					7,5,7,6,7,7,7,8,7,9,8,0,8,1,8,2,8,3,8,4,8,5,8,6,8,7,8,8,8,9,
+					9,0,9,1,9,2,9,3,9,4,9,5,9,6,9,7,9,8,9,9
+				};
 				const bool was_negative = implem::is_negative<I, 10>(in);
 
 				RetType arr;
 				arr.push_front('\0');
 				while (Num::abs(in) >= static_cast<I>(100)) {
-					arr.push_front(Tr::to_digit(static_cast<int>(lookup[(Num::abs(in) % 100) * 2 + 1] - '0')));
-					arr.push_front(Tr::to_digit(static_cast<int>(lookup[(Num::abs(in) % 100) * 2 + 0] - '0')));
+					const auto index = (Num::abs(in) % 100) * 2;
+					arr.push_front(Tr::to_digit(static_cast<int>(lookup[index + 1])));
+					arr.push_front(Tr::to_digit(static_cast<int>(lookup[index + 0])));
 					in = static_cast<I>(in / static_cast<I>(100));
 				};
 				if (Num::abs(in) < static_cast<I>(10)) {
 					arr.push_front(Tr::to_digit(static_cast<int>(Num::abs(in))));
 				}
 				else {
-					arr.push_front(Tr::to_digit(static_cast<int>(lookup[Num::abs(in) * 2 + 1] - '0')));
-					arr.push_front(Tr::to_digit(static_cast<int>(lookup[Num::abs(in) * 2 + 0] - '0')));
+					const auto index = Num::abs(in) * 2;
+					arr.push_front(Tr::to_digit(static_cast<int>(lookup[index + 1])));
+					arr.push_front(Tr::to_digit(static_cast<int>(lookup[index + 0])));
 				}
 				if (was_negative)
 					arr.push_front(Tr::Minus);