整理

include/boost/core/noinit_adaptor.hpp

@@ -0,0 +1,90 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_CORE_NOINIT_ADAPTOR_HPP
+#define BOOST_CORE_NOINIT_ADAPTOR_HPP
+
+#include <boost/core/allocator_access.hpp>
+
+namespace boost {
+
+template<class A>
+struct noinit_adaptor
+    : A {
+    typedef void _default_construct_destroy;
+
+    template<class U>
+    struct rebind {
+        typedef noinit_adaptor<typename allocator_rebind<A, U>::type> other;
+    };
+
+    noinit_adaptor()
+        : A() { }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+    template<class U>
+    noinit_adaptor(U&& u) BOOST_NOEXCEPT
+        : A(std::forward<U>(u)) { }
+#else
+    template<class U>
+    noinit_adaptor(const U& u) BOOST_NOEXCEPT
+        : A(u) { }
+
+    template<class U>
+    noinit_adaptor(U& u) BOOST_NOEXCEPT
+        : A(u) { }
+#endif
+
+    template<class U>
+    noinit_adaptor(const noinit_adaptor<U>& u) BOOST_NOEXCEPT
+        : A(static_cast<const A&>(u)) { }
+
+    template<class U>
+    void construct(U* p) {
+        ::new((void*)p) U;
+    }
+
+#if defined(BOOST_NO_CXX11_ALLOCATOR)
+    template<class U, class V>
+    void construct(U* p, const V& v) {
+        ::new((void*)p) U(v);
+    }
+#endif
+
+    template<class U>
+    void destroy(U* p) {
+        p->~U();
+        (void)p;
+    }
+};
+
+template<class T, class U>
+inline bool
+operator==(const noinit_adaptor<T>& lhs,
+    const noinit_adaptor<U>& rhs) BOOST_NOEXCEPT
+{
+    return static_cast<const T&>(lhs) == static_cast<const U&>(rhs);
+}
+
+template<class T, class U>
+inline bool
+operator!=(const noinit_adaptor<T>& lhs,
+    const noinit_adaptor<U>& rhs) BOOST_NOEXCEPT
+{
+    return !(lhs == rhs);
+}
+
+template<class A>
+inline noinit_adaptor<A>
+noinit_adapt(const A& a) BOOST_NOEXCEPT
+{
+    return noinit_adaptor<A>(a);
+}
+
+} /* boost */
+
+#endif