From 6da6ca64d23287d0797fe9f2da38cc9e547d32c7 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Wed, 7 Aug 2019 15:25:34 +0200
Subject: [PATCH] Vector: Use TypedTransfer in more parts of Vector

Make more Vector-of-trivial-type operations go fast :^)
---
 AK/Tests/TestVector.cpp | 14 ++++++++++++++
 AK/Vector.h             | 19 ++++++++++---------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/AK/Tests/TestVector.cpp b/AK/Tests/TestVector.cpp
index 88a53ba9fe..ab619cc688 100644
--- a/AK/Tests/TestVector.cpp
+++ b/AK/Tests/TestVector.cpp
@@ -167,4 +167,18 @@ TEST_CASE(vector_compare)
     EXPECT_EQ(strings, same_strings);
 }
 
+BENCHMARK_CASE(vector_append_trivial)
+{
+    // This should be super fast thanks to Vector using memmove.
+    Vector<int> ints;
+    for (int i = 0; i < 1000000; ++i) {
+        ints.append(i);
+    }
+    for (int i = 0; i < 100; ++i) {
+        Vector<int> tmp;
+        tmp.append(ints);
+        EXPECT_EQ(tmp.size(), 1000000);
+    }
+}
+
 TEST_MAIN(Vector)
diff --git a/AK/Vector.h b/AK/Vector.h
index 631efdb064..025ac96ba9 100644
--- a/AK/Vector.h
+++ b/AK/Vector.h
@@ -142,8 +142,8 @@ public:
     Vector(const Vector& other)
     {
         ensure_capacity(other.size());
-        for (int i = 0; i < other.size(); ++i)
-            unchecked_append(other[i]);
+        TypedTransfer<T>::copy(data(), other.data(), other.size());
+        m_size = other.size();
     }
 
     // FIXME: What about assigning from a vector with lower inline capacity?
@@ -311,8 +311,8 @@ public:
         if (this != &other) {
             clear();
             ensure_capacity(other.size());
-            for (const auto& v : other)
-                unchecked_append(v);
+            TypedTransfer<T>::copy(data(), other.data(), other.size());
+            m_size = other.size();
         }
         return *this;
     }
@@ -323,17 +323,18 @@ public:
             *this = move(other);
             return;
         }
+        auto other_size = other.size();
         Vector tmp = move(other);
-        grow_capacity(size() + tmp.size());
-        for (auto&& v : tmp)
-            unchecked_append(move(v));
+        grow_capacity(size() + other_size);
+        TypedTransfer<T>::move(data() + m_size, tmp.data(), other_size);
+        m_size += other_size;
     }
 
     void append(const Vector& other)
     {
         grow_capacity(size() + other.size());
-        for (auto& value : other)
-            unchecked_append(value);
+        TypedTransfer<T>::copy(data() + m_size, other.data(), other.size());
+        m_size += other.m_size;
     }
 
     template<typename Callback>