Add new Arena Allocator for optimized dynamic memory allocations with a shared lifetime

Source/Engine/Core/Memory/Allocation.cpp

@@ -0,0 +1,44 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#include "ArenaAllocation.h"
+#include "../Math/Math.h"
+
+void ArenaAllocator::Free()
+{
+    // Free all pages
+    Page* page = _first;
+    while (page)
+    {
+        Allocator::Free(page->Memory);
+        Page* next = page->Next;
+        Allocator::Free(page);
+        page = next;
+    }
+}
+
+void* ArenaAllocator::Allocate(uint64 size, uint64 alignment)
+{
+    // Find the first page that has some space left
+    Page* page = _first;
+    while (page && page->Offset + size + alignment > page->Size)
+        page = page->Next;
+
+    // Create a new page if need to
+    if (!page)
+    {
+        uint64 pageSize = Math::Max<uint64>(_pageSize, size);
+        page = (Page*)Allocator::Allocate(sizeof(Page));
+        page->Memory = Allocator::Allocate(pageSize);
+        page->Next = _first;
+        page->Offset = 0;
+        page->Size = pageSize;
+        _first = page;
+    }
+
+    // Allocate within a page
+    page->Offset = Math::AlignUp(page->Offset, (uint32)alignment);
+    void* mem = (byte*)page->Memory + page->Offset;
+    page->Offset += size;
+
+    return mem;
+}