Add get_allocator_pointer

doc/smart_ptr/allocate_unique.adoc

@@ -1,5 +1,5 @@
 ////
-Copyright 2019 Glen Joseph Fernandes (glenjofe@gmail.com)
+Copyright 2019-2021 Glen Joseph Fernandes (glenjofe@gmail.com)
 
 Distributed under the Boost Software License, Version 1.0.
 
@@ -85,6 +85,11 @@ namespace boost {
   template<class T, class A>
     std::unique_ptr<remove_extent_t<T>[], alloc_noinit_deleter<T, A>>
       allocate_unique_noinit(const A& a);
+
+  template<class T, class U, class A>
+    allocator_pointer_t<allocator_rebind_t<A, remove_cv_t<remove_extent_t<T>>>>
+      get_allocator_pointer(const std::unique_ptr<T,
+        alloc_deleter<U, A>>& p) noexcept;
 }
 ```
 
@@ -269,6 +274,18 @@ Returns:: A `std::unique_ptr` to a sequence of `extent_v<T>`
 default-initialized objects of type `remove_extent_t<T>`.
 Example:: `auto p = allocate_unique_noinit<double[1024]>(a);`
 
+```
+template<class T, class U, class A>
+  allocator_pointer_t<allocator_rebind_t<A, remove_cv_t<remove_extent_t<T>>>>
+    get_allocator_pointer(const std::unique_ptr<T,
+      alloc_deleter<U, A>>& p) noexcept;
+```
+[none]
+* {blank}
++
+Returns:: The allocator pointer to the allocation.
+Example:: `auto r = boost::get_allocator_ptr(p.release());`
+
 ## Deleter
 
 Class template `alloc_deleter` is the deleter used by the `allocate_unique`

include/boost/smart_ptr/allocate_unique.hpp

@@ -1,5 +1,5 @@
 /*
-Copyright 2019 Glen Joseph Fernandes
+Copyright 2019-2021 Glen Joseph Fernandes
 (glenjofe@gmail.com)
 
 Distributed under the Boost Software License, Version 1.0.
@@ -477,6 +477,15 @@ allocate_unique(const A& alloc,
     return c.release();
 }
 
+template<class T, class U, class A>
+inline typename allocator_pointer<typename allocator_rebind<A,
+    typename detail::sp_alloc_value<T>::type>::type>::type
+get_allocator_pointer(const std::unique_ptr<T,
+    alloc_deleter<U, A> >& p) BOOST_NOEXCEPT
+{
+    return p.get().ptr();
+}
+
 } /* boost */
 
 #endif

test/Jamfile

@@ -352,6 +352,7 @@ run allocate_unique_noinit_test.cpp ;
 run allocate_unique_test.cpp ;
 run allocate_unique_throws_test.cpp ;
 run allocate_unique_value_test.cpp ;
+run get_allocator_pointer_test.cpp ;
 
 run sp_guides_test.cpp ;
 run sp_guides_test2.cpp ;

test/get_allocator_pointer_test.cpp

@@ -0,0 +1,250 @@
+/*
+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/config.hpp>
+#if (!defined(BOOST_LIBSTDCXX_VERSION) || \
+    BOOST_LIBSTDCXX_VERSION >= 46000) && \
+    !defined(BOOST_NO_CXX11_SMART_PTR)
+#include <boost/smart_ptr/allocate_unique.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+template<class T>
+class point {
+public:
+    point()
+        : state_()
+        , ptr_() { }
+
+    point(int count, T* value)
+        : state_(count)
+        , ptr_(value) { }
+
+    operator bool() const {
+        return static_cast<bool>(ptr_);
+    }
+
+    T* operator->() const {
+        return ptr_;
+    }
+
+    int state() const {
+        return state_;
+    }
+
+private:
+    int state_;
+    T* ptr_;
+};
+
+template<class T = void>
+class creator {
+public:
+    typedef T value_type;
+    typedef point<T> pointer;
+    typedef std::ptrdiff_t difference_type;
+
+    creator()
+        : state_() { }
+
+    explicit creator(int value)
+        : state_(value) { }
+
+    template<class U>
+    creator(const creator<U>& other)
+        : state_(other.state()) { }
+
+    pointer allocate(std::size_t size) {
+        return pointer(state_,
+            static_cast<T*>(::operator new(sizeof(T) * size)));
+    }
+
+    void deallocate(pointer ptr, std::size_t) {
+        ::operator delete(ptr.operator->());
+    }
+
+    int state() const {
+        return state_;
+    }
+
+private:
+    int state_;
+};
+
+template<class T, class U>
+inline bool
+operator==(const creator<T>&, const creator<U>&)
+{
+    return true;
+}
+
+template<class T, class U>
+inline bool
+operator!=(const creator<T>&, const creator<U>&)
+{
+    return false;
+}
+
+int main()
+{
+    {
+        std::unique_ptr<int,
+            boost::alloc_deleter<int, creator<> > > result =
+            boost::allocate_unique<int>(creator<>(1));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 1);
+    }
+    {
+        std::unique_ptr<const int,
+            boost::alloc_deleter<const int, creator<> > > result =
+            boost::allocate_unique<const int>(creator<>(2));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 2);
+    }
+    {
+        std::unique_ptr<int[],
+            boost::alloc_deleter<int[], creator<> > > result =
+            boost::allocate_unique<int[]>(creator<>(3), 3);
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 3);
+    }
+    {
+        std::unique_ptr<int[],
+            boost::alloc_deleter<int[3], creator<> > > result =
+            boost::allocate_unique<int[3]>(creator<>(4));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 4);
+    }
+    {
+        std::unique_ptr<int[][2],
+            boost::alloc_deleter<int[][2], creator<> > > result =
+            boost::allocate_unique<int[][2]>(creator<>(5), 2);
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 5);
+    }
+    {
+        std::unique_ptr<int[][2],
+            boost::alloc_deleter<int[2][2], creator<> > > result =
+            boost::allocate_unique<int[2][2]>(creator<>(6));
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 6);
+    }
+    {
+        std::unique_ptr<const int[],
+            boost::alloc_deleter<const int[], creator<> > > result =
+            boost::allocate_unique<const int[]>(creator<>(7), 3);
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 7);
+    }
+    {
+        std::unique_ptr<const int[],
+            boost::alloc_deleter<const int[3], creator<> > > result =
+            boost::allocate_unique<const int[3]>(creator<>(8));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 8);
+    }
+    {
+        std::unique_ptr<const int[][2],
+            boost::alloc_deleter<const int[][2], creator<> > > result =
+            boost::allocate_unique<const int[][2]>(creator<>(9), 2);
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 9);
+    }
+    {
+        std::unique_ptr<const int[][2],
+            boost::alloc_deleter<const int[2][2], creator<> > > result =
+            boost::allocate_unique<const int[2][2]>(creator<>(10));
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 10);
+    }
+    {
+        std::unique_ptr<int,
+            boost::alloc_deleter<int,
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<int>(creator<>(11));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 11);
+    }
+    {
+        std::unique_ptr<const int,
+            boost::alloc_deleter<const int,
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<const int>(creator<>(12));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 12);
+    }
+    {
+        std::unique_ptr<int[],
+            boost::alloc_deleter<int[],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<int[]>(creator<>(13), 3);
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 13);
+    }
+    {
+        std::unique_ptr<int[],
+            boost::alloc_deleter<int[3],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<int[3]>(creator<>(14));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 14);
+    }
+    {
+        std::unique_ptr<int[][2],
+            boost::alloc_deleter<int[][2],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<int[][2]>(creator<>(15), 2);
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 15);
+    }
+    {
+        std::unique_ptr<int[][2],
+            boost::alloc_deleter<int[2][2],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<int[2][2]>(creator<>(16));
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 16);
+    }
+    {
+        std::unique_ptr<const int[],
+            boost::alloc_deleter<const int[],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<const int[]>(creator<>(17), 3);
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 17);
+    }
+    {
+        std::unique_ptr<const int[],
+            boost::alloc_deleter<const int[3],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<const int[3]>(creator<>(18));
+        point<int> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 18);
+    }
+    {
+        std::unique_ptr<const int[][2],
+            boost::alloc_deleter<const int[][2],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<const int[][2]>(creator<>(19), 2);
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 19);
+    }
+    {
+        std::unique_ptr<const int[][2],
+            boost::alloc_deleter<const int[2][2],
+            boost::noinit_adaptor<creator<> > > > result =
+            boost::allocate_unique_noinit<const int[2][2]>(creator<>(20));
+        point<int[2]> ptr = boost::get_allocator_pointer(result);
+        BOOST_TEST_EQ(ptr.state(), 20);
+    }
+    return boost::report_errors();
+}
+#else
+int main()
+{
+    return 0;
+}
+#endif