From a171faa95d30c5d84a7aa46620ace38c21e933de Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@gmx.com>
Date: Mon, 7 Jun 2021 20:02:07 +0200
Subject: [PATCH] Revert lookup removal, but keep the speed test cpp

This reverts commit 4f1c0f8d6df21d7c3b404d41512bba0b60ba7689.
---
 include/duckhandy/implem/int_conv.hpp | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/include/duckhandy/implem/int_conv.hpp b/include/duckhandy/implem/int_conv.hpp
index 2fd9239..9c6a661 100644
--- a/include/duckhandy/implem/int_conv.hpp
+++ b/include/duckhandy/implem/int_conv.hpp
@@ -159,6 +159,15 @@ namespace dhandy {
 				using RetType = RevArray<I, 10, Tr>;
 				using Num = implem::NumberAdaptation<I, 10>;
 
+				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;
@@ -167,21 +176,18 @@ namespace dhandy {
 				arr.push_front(Tr::NullChar);
 				in = Num::abs(in);
 				while (in >= static_cast<I>(100)) {
-					const auto last_two = in % 100;
-					const auto digit_low = in % 10;
+					const auto index = (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));
-					const auto digit_high = last_two / 10;
-					arr.push_front(Tr::to_digit(static_cast<int>(digit_low)));
-					arr.push_front(Tr::to_digit(static_cast<int>(digit_high)));
 				};
 				if (in < static_cast<I>(10)) {
 					arr.push_front(Tr::to_digit(static_cast<int>(in)));
 				}
 				else {
-					const auto digit_low = in % 10;
-					const auto digit_high = (in / 10) % 10;
-					arr.push_front(Tr::to_digit(static_cast<int>(digit_low)));
-					arr.push_front(Tr::to_digit(static_cast<int>(digit_high)));
+					const auto index = 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);