From 64778f9e69bbdc40f62ba10e78c635147de31014 Mon Sep 17 00:00:00 2001
From: creator1creeper1 <creator1creeper1@airmail.cc>
Date: Wed, 12 Jan 2022 16:39:31 +0100
Subject: [PATCH] AK: Add a constructor from Span for FixedArray

This is particularly useful in the Kernel, where the physical pages of
a VMObject are stored as a FixedArray but often passed around as a Span
from which a new FixedArray should be cloned.
---
 AK/FixedArray.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/AK/FixedArray.h b/AK/FixedArray.h
index 8f0d1a9b418..92593e5ffaf 100644
--- a/AK/FixedArray.h
+++ b/AK/FixedArray.h
@@ -55,6 +55,19 @@ public:
         return FixedArray<T>(N, elements);
     }
 
+    template<typename U>
+    static ErrorOr<FixedArray<T>> try_create(Span<U> span)
+    {
+        if (span.size() == 0)
+            return FixedArray<T>();
+        T* elements = static_cast<T*>(kmalloc_array(span.size(), sizeof(T)));
+        if (!elements)
+            return Error::from_errno(ENOMEM);
+        for (size_t i = 0; i < span.size(); ++i)
+            new (&elements[i]) T(span[i]);
+        return FixedArray<T>(span.size(), elements);
+    }
+
     ErrorOr<FixedArray<T>> try_clone() const
     {
         if (m_size == 0)