From 63b8c6913cea1bca0507e8d11e17afbe7560721b Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Wed, 15 Apr 2020 17:14:18 +0200
Subject: [PATCH] AK: Add Checked<T>::multiplication_would_overflow()

This allows you to comfortably test if multiply 2 or 3 values would
cause arithmetic overflow.
---
 AK/Checked.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/AK/Checked.h b/AK/Checked.h
index 062fb962f4..9514a8fb9d 100644
--- a/AK/Checked.h
+++ b/AK/Checked.h
@@ -234,6 +234,25 @@ public:
         return *this;
     }
 
+    template<typename U, typename V, typename X>
+    static bool multiplication_would_overflow(U u, V v)
+    {
+        Checked checked;
+        checked = u;
+        checked *= v;
+        return checked.has_overflow();
+    }
+
+    template<typename U, typename V, typename X>
+    static bool multiplication_would_overflow(U u, V v, X x)
+    {
+        Checked checked;
+        checked = u;
+        checked *= v;
+        checked *= x;
+        return checked.has_overflow();
+    }
+
 private:
     T m_value;
     bool m_overflow { false };