From 4c51534b6a19f5707e577c3e09a93bf44dfd2aa9 Mon Sep 17 00:00:00 2001
From: Rubidium <rubidium@openttd.org>
Date: Sat, 20 Jan 2024 15:59:53 +0100
Subject: [PATCH] Remove: LeastCommonMultiple / GreatestCommonDivisor

Use std::lcm / std::gcd instead.
---
 src/core/math_func.cpp  | 35 -----------------------------------
 src/core/math_func.hpp  |  2 --
 src/tests/math_func.cpp | 35 -----------------------------------
 3 files changed, 72 deletions(-)

diff --git a/src/core/math_func.cpp b/src/core/math_func.cpp
index db705092a8..f094e9ece8 100644
--- a/src/core/math_func.cpp
+++ b/src/core/math_func.cpp
@@ -12,41 +12,6 @@
 
 #include "../safeguards.h"
 
-/**
- * Compute least common multiple (lcm) of arguments \a a and \a b, the smallest
- * integer value that is a multiple of both \a a and \a b.
- * @param a First number.
- * @param b second number.
- * @return Least common multiple of values \a a and \a b.
- *
- * @note This function only works for non-negative values of \a a and \a b.
- */
-int LeastCommonMultiple(int a, int b)
-{
-	if (a == 0 || b == 0) return 0; // By definition.
-	if (a == 1 || a == b) return b;
-	if (b == 1) return a;
-
-	return a * b / GreatestCommonDivisor(a, b);
-}
-
-/**
- * Compute greatest common divisor (gcd) of \a a and \a b.
- * @param a First number.
- * @param b second number.
- * @return Greatest common divisor of \a a and \a b.
- */
-int GreatestCommonDivisor(int a, int b)
-{
-	while (b != 0) {
-		int t = b;
-		b = a % b;
-		a = t;
-	}
-	return a;
-
-}
-
 /**
  * Deterministic approximate division.
  * Cancels out division errors stemming from the integer nature of the division over multiple runs.
diff --git a/src/core/math_func.hpp b/src/core/math_func.hpp
index 6cf0567015..561f8fb754 100644
--- a/src/core/math_func.hpp
+++ b/src/core/math_func.hpp
@@ -309,8 +309,6 @@ inline uint ToPercent16(uint i)
 	return i * 101 >> 16;
 }
 
-int LeastCommonMultiple(int a, int b);
-int GreatestCommonDivisor(int a, int b);
 int DivideApprox(int a, int b);
 
 /**
diff --git a/src/tests/math_func.cpp b/src/tests/math_func.cpp
index 769e344145..1f53d005b7 100644
--- a/src/tests/math_func.cpp
+++ b/src/tests/math_func.cpp
@@ -13,41 +13,6 @@
 
 #include "../core/math_func.hpp"
 
-TEST_CASE("LeastCommonMultipleTest - Zero")
-{
-	CHECK(0 == LeastCommonMultiple(0, 0));
-	CHECK(0 == LeastCommonMultiple(0, 600));
-	CHECK(0 == LeastCommonMultiple(600, 0));
-}
-
-TEST_CASE("LeastCommonMultipleTest - FindLCM")
-{
-	CHECK(25 == LeastCommonMultiple(5, 25));
-	CHECK(25 == LeastCommonMultiple(25, 5));
-	CHECK(130 == LeastCommonMultiple(5, 26));
-	CHECK(130 == LeastCommonMultiple(26, 5));
-}
-
-TEST_CASE("GreatestCommonDivisorTest - Negative")
-{
-	CHECK(4 == GreatestCommonDivisor(4, -52));
-	// CHECK(3 == GreatestCommonDivisor(-27, 6)); // error - returns -3
-}
-
-TEST_CASE("GreatestCommonDivisorTest - Zero")
-{
-	CHECK(27 == GreatestCommonDivisor(0, 27));
-	CHECK(27 == GreatestCommonDivisor(27, 0));
-}
-
-TEST_CASE("GreatestCommonDivisorTest - FindGCD")
-{
-	CHECK(5 == GreatestCommonDivisor(5, 25));
-	CHECK(5 == GreatestCommonDivisor(25, 5));
-	CHECK(1 == GreatestCommonDivisor(7, 27));
-	CHECK(1 == GreatestCommonDivisor(27, 7));
-}
-
 TEST_CASE("DivideApproxTest - Negative")
 {
 	CHECK(-2 == DivideApprox(-5, 2));