From baadde122b9bf3e77e51b003670d68bbd477afe2 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 3 May 2020 18:38:16 +0200
Subject: [PATCH] AK: Add Vector::resize_and_keep_capacity()

This function is just like resize() except it does not deallocate the
vector buffer when shrinking.
---
 AK/Vector.h | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/AK/Vector.h b/AK/Vector.h
index a6218d1461..1b40a8f509 100644
--- a/AK/Vector.h
+++ b/AK/Vector.h
@@ -539,14 +539,17 @@ public:
         m_capacity = new_capacity;
     }
 
-    void shrink(size_t new_size)
+    void shrink(size_t new_size, bool keep_capacity = false)
     {
         ASSERT(new_size <= size());
         if (new_size == size())
             return;
 
         if (!new_size) {
-            clear();
+            if (keep_capacity)
+                clear_with_capacity();
+            else
+                clear();
             return;
         }
 
@@ -555,10 +558,10 @@ public:
         m_size = new_size;
     }
 
-    void resize(size_t new_size)
+    void resize(size_t new_size, bool keep_capacity = false)
     {
         if (new_size <= size())
-            return shrink(new_size);
+            return shrink(new_size, keep_capacity);
 
         ensure_capacity(new_size);
         for (size_t i = size(); i < new_size; ++i)
@@ -566,6 +569,11 @@ public:
         m_size = new_size;
     }
 
+    void resize_and_keep_capacity(size_t new_size)
+    {
+        return resize(new_size, true);
+    }
+
     using Iterator = VectorIterator<Vector, T>;
     Iterator begin() { return Iterator(*this, 0); }
     Iterator end() { return Iterator(*this, size()); }