From f5b9049421047f61cf9c139b7671564b04677de5 Mon Sep 17 00:00:00 2001
From: Jordan Woyak <jordan.woyak@gmail.com>
Date: Tue, 11 Oct 2022 15:13:33 -0500
Subject: [PATCH] Input: Add "abs" input expression function.

---
 .../Core/DolphinQt/Config/Mapping/IOWindow.cpp |  1 +
 .../ControlReference/FunctionExpression.cpp    | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/Source/Core/DolphinQt/Config/Mapping/IOWindow.cpp b/Source/Core/DolphinQt/Config/Mapping/IOWindow.cpp
index bf5d911afb..8bec82f015 100644
--- a/Source/Core/DolphinQt/Config/Mapping/IOWindow.cpp
+++ b/Source/Core/DolphinQt/Config/Mapping/IOWindow.cpp
@@ -303,6 +303,7 @@ void IOWindow::CreateMainLayout()
   m_functions_combo->addItem(QStringLiteral("min"));
   m_functions_combo->addItem(QStringLiteral("max"));
   m_functions_combo->addItem(QStringLiteral("clamp"));
+  m_functions_combo->addItem(QStringLiteral("abs"));
 
   m_variables_combo = new QComboBoxWithMouseWheelDisabled(this);
   m_variables_combo->addItem(tr("User Variables"));
diff --git a/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp b/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp
index 17ceae3bd0..46cfc37beb 100644
--- a/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp
+++ b/Source/Core/InputCommon/ControlReference/FunctionExpression.cpp
@@ -69,6 +69,22 @@ private:
   void SetValue(ControlState value) override { GetArg(0).SetValue(1.0 - value); }
 };
 
+// usage: abs(expression)
+class AbsExpression final : public FunctionExpression
+{
+private:
+  ArgumentValidation
+  ValidateArguments(const std::vector<std::unique_ptr<Expression>>& args) override
+  {
+    if (args.size() == 1)
+      return ArgumentsAreValid{};
+    else
+      return ExpectedArguments{"expression"};
+  }
+
+  ControlState GetValue() const override { return std::abs(GetArg(0).GetValue()); }
+};
+
 // usage: sin(expression)
 class SinExpression : public FunctionExpression
 {
@@ -641,6 +657,8 @@ std::unique_ptr<FunctionExpression> MakeFunctionExpression(std::string_view name
     return std::make_unique<NotExpression>();
   if (name == "if")
     return std::make_unique<IfExpression>();
+  if (name == "abs")
+    return std::make_unique<AbsExpression>();
   if (name == "sin")
     return std::make_unique<SinExpression>();
   if (name == "cos")