Add allocator_traits that uses allocator_access

doc/allocator_traits.qbk

@@ -0,0 +1,116 @@
+[/
+Copyright 2021 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+]
+
+[section:allocator_traits allocator_traits]
+
+[simplesect Authors]
+
+* Glen Fernandes
+
+[endsimplesect]
+
+[section Overview]
+
+This header <boost/core/allocator_traits.hpp> provides an implementation of the
+C++ standard library class template `allocator_traits` based on the facilities
+in [link core.allocator_access Allocator Access]. Users should still prefer the
+individual traits, but this utility exists to simplify migration.
+
+[endsect]
+
+[section Reference]
+
+```
+namespace boost {
+
+template<class A>
+struct allocator_traits {
+    using allocator_type = A;
+
+    using value_type = allocator_value_type_t<A>;
+
+    using pointer = allocator_pointer_t<A>;
+
+    using const_pointer = allocator_const_pointer_t<A>;
+
+    using void_pointer = allocator_void_pointer_t<A>;
+
+    using const_pointer = allocator_const_void_pointer_t<A>;
+
+    using difference_type = allocator_difference_type_t<A>;
+
+    using size_type = allocator_size_type_t<A>;
+
+    using propagate_on_container_copy_assignment =
+        allocator_propagate_on_container_copy_assignment_t<A>;
+
+    using propagate_on_container_move_assignment =
+        allocator_propagate_on_container_move_assignment_t<A>;
+
+    using propagate_on_container_swap =
+        allocator_propagate_on_container_swap_t<A>;
+
+    using is_always_equal = allocator_is_always_equal_t<A>;
+
+    template<class T>
+    using rebind_traits = allocator_traits<allocator_rebind_t<A, T> >;
+
+    static pointer allocate(A& a, size_type n);
+
+    static pointer allocate(A& a, size_type n, const_void_pointer h);
+
+    static void deallocate(A& a, pointer p, size_type n);
+
+    template<class T, class... Args>
+    static void construct(A& a, T* p, Args&&... args);
+
+    static void destroy(A& a, T* p);
+
+    static size_type max_size(const A& a) noexcept;
+
+    static A select_on_container_copy_construction(const A& a);
+};
+
+} /* boost */
+```
+
+[section Static member functions]
+
+[variablelist
+[[`static pointer allocate(A& a, size_type n);`]
+[Equivalent to: `return boost::allocator_allocate(a, n);`]]
+[[`static pointer allocate(A& a, size_type n, const_void_pointer h);`]
+[Equivalent to: `return boost::allocator_allocate(a, n, h);`]]
+[[`static void deallocate(A& a, pointer p, size_type n);`]
+[Equivalent to: `return boost::allocator_deallocate(a, n, h);`]]
+[[`template<class T, class... Args>
+static void construct(A& a, T* p, Args&&... args);`]
+[Equivalent to:
+`return boost::allocator_construct(a, p, std::forward<Args>(args)...);`]]
+[[`static void destroy(A& a, T* p);`]
+[Equivalent to: `return boost::allocator_destroy(a, p);`]]
+[[`static size_type max_size(const A& a);`]
+[Equivalent to: `return boost::allocator_max_size(a);`]]
+[[`static A select_on_container_copy_construction(const A& a);`]
+[Equivalent to:
+`return boost::allocator_select_on_container_copy_construction(a);`]]]
+
+[endsect]
+
+[section Notes]
+
+# The member `rebind_alloc` is not provided for parity with C++03 where it is
+unimplementable. Instead of `allocator_traits<A>::rebind_alloc<U>` you can
+express the same with `allocator_traits<A>::rebind_traits<U>::allocator_type`
+or more simply with `allocator_rebind_t<A, T>`.
+
+[endsect]
+
+[endsect]
+
+[endsect]

doc/changes.qbk

@@ -6,6 +6,12 @@
 
 [section Revision History]
 
+[section Changes in 1.79.0]
+
+* Added `boost::allocator_traits`, an implementation of `std::allocator_traits`.
+
+[endsect]
+
 [section Changes in 1.78.0]
 
 * Added a generic implementation to `boost/core/cmath.hpp`, enabled when `BOOST_CORE_USE_GENERIC_CMATH`

doc/core.qbk

@@ -42,6 +42,7 @@ criteria for inclusion is that the utility component be:
 
 [include addressof.qbk]
 [include allocator_access.qbk]
+[include allocator_traits.qbk]
 [include alloc_construct.qbk]
 [include bit.qbk]
 [include checked_delete.qbk]

include/boost/core/allocator_traits.hpp

@@ -0,0 +1,112 @@
+/*
+Copyright 2021 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_ALLOCATOR_TRAITS_HPP
+#define BOOST_CORE_ALLOCATOR_TRAITS_HPP
+
+#include <boost/core/allocator_access.hpp>
+
+namespace boost {
+
+template<class A>
+struct allocator_traits {
+    typedef A allocator_type;
+
+    typedef typename allocator_value_type<A>::type value_type;
+
+    typedef typename allocator_pointer<A>::type pointer;
+
+    typedef typename allocator_const_pointer<A>::type const_pointer;
+
+    typedef typename allocator_void_pointer<A>::type void_pointer;
+
+    typedef typename allocator_const_void_pointer<A>::type const_void_pointer;
+
+    typedef typename allocator_difference_type<A>::type difference_type;
+
+    typedef typename allocator_size_type<A>::type size_type;
+
+    typedef typename allocator_propagate_on_container_copy_assignment<A>::type
+        propagate_on_container_copy_assignment;
+
+    typedef typename allocator_propagate_on_container_move_assignment<A>::type
+        propagate_on_container_move_assignment;
+
+    typedef typename allocator_propagate_on_container_swap<A>::type
+        propagate_on_container_swap;
+
+    typedef typename allocator_is_always_equal<A>::type is_always_equal;
+
+#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
+    template<class T>
+    using rebind_traits = allocator_traits<typename
+        allocator_rebind<A, T>::type>;
+#else
+    template<class T>
+    struct rebind_traits
+        : allocator_traits<typename allocator_rebind<A, T>::type> { };
+#endif
+
+    static pointer allocate(A& a, size_type n) {
+        return boost::allocator_allocate(a, n);
+    }
+
+    static pointer allocate(A& a, size_type n, const_void_pointer h) {
+        return boost::allocator_allocate(a, n, h);
+    }
+
+    static void deallocate(A& a, pointer p, size_type n) {
+        return boost::allocator_deallocate(a, p, n);
+    }
+
+    template<class T>
+    static void construct(A& a, T* p) {
+        boost::allocator_construct(a, p);
+    }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+    template<class T, class V, class... Args>
+    static void construct(A& a, T* p, V&& v, Args&&... args) {
+        boost::allocator_construct(a, p, std::forward<V>(v),
+            std::forward<Args>(args)...);
+    }
+#else
+    template<class T, class V>
+    static void construct(A& a, T* p, V&& v) {
+        boost::allocator_construct(a, p, std::forward<V>(v));
+    }
+#endif
+#else
+    template<class T, class V>
+    static void construct(A& a, T* p, const V& v) {
+        boost::allocator_construct(a, p, v);
+    }
+
+    template<class T, class V>
+    static void construct(A& a, T* p, V& v) {
+        boost::allocator_construct(a, p, v);
+    }
+#endif
+
+    template<class T>
+    static void destroy(A& a, T* p) {
+        boost::allocator_destroy(a, p);
+    }
+
+    static size_type max_size(const A& a) BOOST_NOEXCEPT {
+        return boost::allocator_max_size(a);
+    }
+
+    static A select_on_container_copy_construction(const A& a) {
+        return boost::allocator_select_on_container_copy_construction(a);
+    }
+};
+
+} /* boost */
+
+#endif

test/Jamfile.v2

@@ -236,6 +236,7 @@ run allocator_allocate_hint_test.cpp ;
 run allocator_deallocate_test.cpp ;
 run allocator_max_size_test.cpp ;
 run allocator_soccc_test.cpp ;
+run allocator_traits_test.cpp ;
 
 lib lib_typeid : lib_typeid.cpp : <link>shared:<define>LIB_TYPEID_DYN_LINK=1 ;
 

test/allocator_traits_test.cpp

@@ -0,0 +1,114 @@
+/*
+Copyright 2021 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/allocator_traits.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+template<class T>
+class creator {
+public:
+    typedef T value_type;
+    typedef T* pointer;
+    typedef const T* const_pointer;
+    typedef void* void_pointer;
+    typedef const void* const_void_pointer;
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+
+    template<class U>
+    struct rebind {
+        typedef creator<U> other;
+    };
+
+    explicit creator(int value) BOOST_NOEXCEPT
+        : state_(value) { }
+
+    template<class U>
+    creator(const creator<U>& other) BOOST_NOEXCEPT
+        : state_(other.state) { }
+
+    std::size_t max_size() const BOOST_NOEXCEPT {
+        return static_cast<std::size_t>(-1) / sizeof(T);
+    }
+
+    T* allocate(std::size_t n, const void* = 0) {
+        return static_cast<T*>(::operator new(sizeof(T) * n));
+    }
+
+    void deallocate(T* p, std::size_t) {
+        ::operator delete(p);
+    }
+
+    int state() const {
+        return state_;
+    }
+
+private:
+    int state_;
+};
+
+template<class T, class U>
+inline bool operator==(const creator<T>& lhs,
+    const creator<U>& rhs) BOOST_NOEXCEPT
+{
+    return lhs.state() == rhs.state();
+}
+
+template<class T, class U>
+inline bool operator!=(const creator<T>& lhs,
+    const creator<U>& rhs) BOOST_NOEXCEPT
+{
+    return !(lhs == rhs);
+}
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME(creator<int>,
+        boost::allocator_traits<creator<int> >::allocator_type);
+    BOOST_TEST_TRAIT_SAME(int,
+        boost::allocator_traits<creator<int> >::value_type);
+    BOOST_TEST_TRAIT_SAME(int*,
+        boost::allocator_traits<creator<int> >::pointer);
+    BOOST_TEST_TRAIT_SAME(const int*,
+        boost::allocator_traits<creator<int> >::const_pointer);
+    BOOST_TEST_TRAIT_SAME(void*,
+        boost::allocator_traits<creator<int> >::void_pointer);
+    BOOST_TEST_TRAIT_SAME(const void*,
+        boost::allocator_traits<creator<int> >::const_void_pointer);
+    BOOST_TEST_TRAIT_SAME(std::ptrdiff_t,
+        boost::allocator_traits<creator<int> >::difference_type);
+    BOOST_TEST_TRAIT_SAME(std::size_t,
+        boost::allocator_traits<creator<int> >::size_type);
+    BOOST_TEST_TRAIT_FALSE((boost::allocator_traits<creator<int> >::
+        propagate_on_container_copy_assignment));
+    BOOST_TEST_TRAIT_FALSE((boost::allocator_traits<creator<int> >::
+        propagate_on_container_move_assignment));
+    BOOST_TEST_TRAIT_FALSE((boost::allocator_traits<creator<int> >::
+        propagate_on_container_swap));
+    BOOST_TEST_TRAIT_FALSE((boost::allocator_traits<creator<int> >::
+        is_always_equal));
+    BOOST_TEST_TRAIT_SAME(creator<char>,
+        boost::allocator_traits<creator<int> >::
+            rebind_traits<char>::allocator_type);
+    creator<int> a(1);
+    int* p1 = boost::allocator_traits<creator<int> >::allocate(a, 1);
+    if (BOOST_TEST(p1)) {
+        int* p2 = boost::allocator_traits<creator<int> >::allocate(a, 1, p1);
+        if (BOOST_TEST(p2)) {
+            boost::allocator_traits<creator<int> >::deallocate(a, p2, 1);
+        }
+        boost::allocator_traits<creator<int> >::construct(a, p1, 5);
+        BOOST_TEST_EQ(*p1, 5);
+        boost::allocator_traits<creator<int> >::destroy(a, p1);
+        boost::allocator_traits<creator<int> >::deallocate(a, p1, 1);
+    }
+    BOOST_TEST_EQ(boost::allocator_traits<creator<int> >::max_size(a),
+        static_cast<std::size_t>(-1) / sizeof(int));
+    BOOST_TEST(boost::allocator_traits<creator<int> >::
+        select_on_container_copy_construction(a) == a);
+    return boost::report_errors();
+}