整理

include/boost/core/default_allocator.hpp

@@ -0,0 +1,159 @@
+/*
+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_DEFAULT_ALLOCATOR_HPP
+#define BOOST_CORE_DEFAULT_ALLOCATOR_HPP
+
+#include <boost/config.hpp>
+#include <new>
+#include <cstddef>
+
+namespace boost {
+
+#if defined(BOOST_NO_EXCEPTIONS)
+BOOST_NORETURN void throw_exception(const std::exception&);
+#endif
+
+namespace default_ {
+
+template<bool V>
+struct bool_constant {
+    typedef bool value_type;
+    typedef bool_constant type;
+
+    static const bool value = V;
+
+    operator bool() const BOOST_NOEXCEPT {
+        return V;
+    }
+
+    bool operator()() const BOOST_NOEXCEPT {
+        return V;
+    }
+};
+
+template<bool V>
+const bool bool_constant<V>::value;
+
+template<class T>
+struct add_reference {
+    typedef T& type;
+};
+
+template<>
+struct add_reference<void> {
+    typedef void type;
+};
+
+template<>
+struct add_reference<const void> {
+    typedef const void type;
+};
+
+template<class T>
+struct default_allocator {
+    typedef T value_type;
+    typedef T* pointer;
+    typedef const T* const_pointer;
+    typedef typename add_reference<T>::type reference;
+    typedef typename add_reference<const T>::type const_reference;
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef bool_constant<true> propagate_on_container_move_assignment;
+    typedef bool_constant<true> is_always_equal;
+
+    template<class U>
+    struct rebind {
+        typedef default_allocator<U> other;
+    };
+
+#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
+    default_allocator() = default;
+#else
+    BOOST_CONSTEXPR default_allocator() BOOST_NOEXCEPT { }
+#endif
+
+    template<class U>
+    BOOST_CONSTEXPR default_allocator(const default_allocator<U>&)
+        BOOST_NOEXCEPT { }
+
+    BOOST_CONSTEXPR std::size_t max_size() const BOOST_NOEXCEPT {
+        return static_cast<std::size_t>(-1) / (2 < sizeof(T) ? sizeof(T) : 2);
+    }
+
+#if !defined(BOOST_NO_EXCEPTIONS)
+    T* allocate(std::size_t n) {
+        if (n > max_size()) {
+            throw std::bad_alloc();
+        }
+        return static_cast<T*>(::operator new(sizeof(T) * n));
+    }
+
+    void deallocate(T* p, std::size_t) {
+        ::operator delete(p);
+    }
+#else
+    T* allocate(std::size_t n) {
+        if (n > max_size()) {
+            boost::throw_exception(std::bad_alloc());
+        }
+        void* p = ::operator new(sizeof(T) * n, std::nothrow);
+        if (!p) {
+            boost::throw_exception(std::bad_alloc());
+        }
+        return static_cast<T*>(p);
+    }
+
+    void deallocate(T* p, std::size_t) {
+        ::operator delete(p, std::nothrow);
+    }
+#endif
+
+#if defined(BOOST_NO_CXX11_ALLOCATOR)
+    T* allocate(std::size_t n, const void*) {
+        return allocate(n);
+    }
+#endif
+
+#if (defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 60000) || \
+    defined(BOOST_NO_CXX11_ALLOCATOR)
+    template<class U, class V>
+    void construct(U* p, const V& v) {
+        ::new(p) U(v);
+    }
+
+    template<class U>
+    void destroy(U* p) {
+        p->~U();
+        (void)p;
+    }
+#endif
+};
+
+template<class T, class U>
+BOOST_CONSTEXPR inline bool
+operator==(const default_allocator<T>&,
+    const default_allocator<U>&) BOOST_NOEXCEPT
+{
+    return true;
+}
+
+template<class T, class U>
+BOOST_CONSTEXPR inline bool
+operator!=(const default_allocator<T>&,
+    const default_allocator<U>&) BOOST_NOEXCEPT
+{
+    return false;
+}
+
+} /* default_ */
+
+using default_::default_allocator;
+
+} /* boost */
+
+#endif