From f5ef1937eafb3d96b3683d92639a193694210c70 Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Tue, 19 Nov 2024 23:30:55 +0100
Subject: More work on asl::box

---
 asl/box.hpp | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

(limited to 'asl/box.hpp')

diff --git a/asl/box.hpp b/asl/box.hpp
index 0cab66b..d8ccd36 100644
--- a/asl/box.hpp
+++ b/asl/box.hpp
@@ -1,7 +1,10 @@
 #pragma once
 
 #include "asl/allocator.hpp"
+#include "asl/assert.hpp"
 #include "asl/annotations.hpp"
+#include "asl/memory.hpp"
+#include "asl/utility.hpp"
 
 namespace asl
 {
@@ -13,7 +16,87 @@ class box
     ASL_NO_UNIQUE_ADDRESS Allocator m_alloc;
     
 public:
+    explicit constexpr box(T* ptr = nullptr)
+        requires default_constructible<Allocator>
+        : m_ptr{ptr}
+    {}
+    
+    constexpr box(T* ptr, Allocator alloc)
+        : m_ptr{ptr}
+        , m_alloc{ASL_MOVE(alloc)}
+    {}
+
+    constexpr box(box&& other)
+        : m_ptr{exchange(other.m_ptr, nullptr)}
+        , m_alloc{ASL_MOVE(other.m_alloc)}
+    {}
+
+    constexpr box& operator=(box&& other)
+    {
+        if (this == &other) { return *this; }
+
+        if (m_ptr != nullptr) { reset(); }
+
+        m_ptr = exchange(other.m_ptr, nullptr);
+        m_alloc = ASL_MOVE(other.m_alloc);
+
+        return *this;
+    }
+
+    box(const box&) = delete;
+    box& operator=(const box&) = delete;
+
+    constexpr ~box()
+    {
+        reset();
+    }
+
+    constexpr void reset()
+    {
+        if (m_ptr != nullptr)
+        {
+            if constexpr (!trivially_destructible<T>)
+            {
+                m_ptr->~T();
+            }
+            m_alloc.dealloc(m_ptr, layout::of<T>());
+            m_ptr = nullptr;
+        }
+    }
+
+    constexpr T* get() const { return m_ptr; }
+
+    constexpr T& operator*() const
+    {
+        ASL_ASSERT(m_ptr != nullptr);
+        return *m_ptr;
+    }
+
+    constexpr T* operator->() const
+    {
+        ASL_ASSERT(m_ptr != nullptr);
+        return m_ptr;
+    }
 };
 
+template<is_object T, allocator Allocator = DefaultAllocator, typename... Args>
+constexpr box<T, Allocator> make_box_in(Allocator allocator, Args&&... args)
+    requires constructible_from<T, Args&&...>
+{
+    void* raw_ptr = allocator.alloc(layout::of<T>());
+    T* ptr = new (raw_ptr) T(ASL_FWD(args)...);
+    return box(ptr, ASL_MOVE(allocator));
+}
+
+template<is_object T, allocator Allocator = DefaultAllocator, typename... Args>
+constexpr box<T, Allocator> make_box(Args&&... args)
+    requires default_constructible<Allocator> && constructible_from<T, Args&&...>
+{
+    Allocator allocator{};
+    void* raw_ptr = allocator.alloc(layout::of<T>());
+    T* ptr = new (raw_ptr) T{ ASL_FWD(args)... };
+    return box<T>(ptr, ASL_MOVE(allocator));
+}
+
 } // namespace asl
 
-- 
cgit