From dc17e01c9923b5af79b3ee1cea4435f6952c9a57 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 30 Jan 2021 13:49:03 +0100
Subject: [PATCH] AK: Allow Checked += Checked, and other such operations

The overflow state from both Checkeds is OR'ed in the result.
---
 AK/Checked.h | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/AK/Checked.h b/AK/Checked.h
index 9be8affdcb..efa6640344 100644
--- a/AK/Checked.h
+++ b/AK/Checked.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2011-2019 Apple Inc. All rights reserved.
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -186,24 +186,52 @@ public:
         m_value /= other;
     }
 
+    constexpr Checked& operator+=(const Checked& other)
+    {
+        m_overflow |= other.m_overflow;
+        add(other.value());
+        return *this;
+    }
+
     constexpr Checked& operator+=(T other)
     {
         add(other);
         return *this;
     }
 
+    constexpr Checked& operator-=(const Checked& other)
+    {
+        m_overflow |= other.m_overflow;
+        sub(other.value());
+        return *this;
+    }
+
     constexpr Checked& operator-=(T other)
     {
         sub(other);
         return *this;
     }
 
+    constexpr Checked& operator*=(const Checked& other)
+    {
+        m_overflow |= other.m_overflow;
+        mul(other.value());
+        return *this;
+    }
+
     constexpr Checked& operator*=(T other)
     {
         mul(other);
         return *this;
     }
 
+    constexpr Checked& operator/=(const Checked& other)
+    {
+        m_overflow |= other.m_overflow;
+        div(other.value());
+        return *this;
+    }
+
     constexpr Checked& operator/=(T other)
     {
         div(other);