1 files changed, 51 insertions, 0 deletions
diff --git a/compat/borrowed-ptr-fwd.hpp b/compat/borrowed-ptr-fwd.hpp
new file mode 100644
index 00000000..b28c6a71
--- /dev/null
+++ b/compat/borrowed-ptr-fwd.hpp
@@ -0,0 +1,51 @@
+#pragma once
+
+namespace floormat::detail_borrowed_ptr {
+
+struct control_block_;
+
+template<typename From, typename To>
+concept StaticCastable = requires(From* ptr) {
+    static_cast<To*>(ptr);
+};
+
+} // namespace floormat::detail_borrowed_ptr
+
+namespace floormat {
+
+template<typename T>
+class bptr final // NOLINT(*-special-member-functions)
+{
+    T* ptr; // todo add simple_bptr that doesn't allow casting. should only have the control block member variable.
+    detail_borrowed_ptr::control_block_* blk;
+
+public:
+    template<typename... Ts>
+    requires std::is_constructible_v<T, Ts&&...>
+    explicit bptr(InPlaceInitT, Ts&&... args) noexcept;
+
+    constexpr bptr(std::nullptr_t) noexcept; // NOLINT(*-explicit-conversions)
+    constexpr bptr() noexcept;
+    explicit constexpr bptr(NoInitT) noexcept;
+    explicit bptr(T* ptr) noexcept;
+    ~bptr() noexcept;
+
+    template<typename Y> requires std::is_convertible_v<Y*, T*> bptr(const bptr<Y>&) noexcept;
+    template<typename Y> requires std::is_convertible_v<Y*, T*> bptr(bptr<Y>&&) noexcept;
+    template<typename Y> requires std::is_convertible_v<Y*, T*> bptr& operator=(const bptr<Y>&) noexcept;
+    template<typename Y> requires std::is_convertible_v<Y*, T*> bptr& operator=(bptr<Y>&&) noexcept;
+
+    void swap() noexcept;
+    T* get() noexcept;
+    const T* get() const noexcept;
+    T& operator*() const noexcept;
+    T* operator->() const noexcept;
+    uint32_t use_count() const noexcept;
+    explicit operator bool() const noexcept;
+
+    template<typename U>
+    requires detail_borrowed_ptr::StaticCastable<T, U>
+    bptr<U> static_pointer_cast() noexcept;
+};
+
+} // namespace floormat