chore: add UntypedStorage

src/ll/api/base/Alias.h

@@ -1,5 +1,10 @@
 #pragma once
 
+#include <bit>
+#include <cstddef>
+#include <type_traits>
+#include <utility>
+
 namespace ll {
 template <class T, size_t N>
 struct CArray {
@@ -11,4 +16,27 @@ struct CArray<T, 0> {
 };
 template <class T, size_t N = 0>
 using CArrayT = typename CArray<T, N>::type;
+
+template <size_t Len, size_t Align = (std::min)((1ull << std::countr_zero(Len)), 8ull)>
+struct UntypedStorage {
+    alignas(Align) std::byte data[Len];
+
+    template <class T>
+    [[nodiscard]] T& as() & {
+        return *reinterpret_cast<T*>(this);
+    }
+    template <class T>
+    [[nodiscard]] T const& as() const& {
+        return *reinterpret_cast<T const*>(this);
+    }
+    template <class T>
+    [[nodiscard]] T&& as() && {
+        return std::move(*reinterpret_cast<T*>(this));
+    }
+    template <class T>
+    [[nodiscard]] T const&& as() const&& {
+        return std::move(*reinterpret_cast<T const*>(this));
+    }
+};
+
 } // namespace ll

src/ll/api/coro/Generator.h

@@ -12,7 +12,7 @@ template <class T>
 struct Generator {
     using value     = std::remove_cvref_t<T>;
     using reference = T&&;
-    using yielded   = std::conditional_t<std::is_reference_v<reference>, reference, reference const&>;
+    using yielded   = reference;
 
 
     struct promise_type {
@@ -60,8 +60,8 @@ struct Generator {
     struct iterator {
         using iterator_category = std::input_iterator_tag;
         using difference_type   = ptrdiff_t;
-        using value_type        = value;
-        using reference         = reference;
+        using value_type        = Generator::value;
+        using reference         = Generator::reference;
         using pointer           = std::add_pointer_t<yielded>;
 
         std::coroutine_handle<promise_type> handle = nullptr;