From 3d279e6c6d668d56db4722618ebc78580c542e71 Mon Sep 17 00:00:00 2001
From: Glen Fernandes <glenfe@live.com>
Date: Wed, 12 Feb 2014 13:45:28 -0800
Subject: [PATCH] Save additional sizeof(void*) bytes for arrays

---
 .../boost/smart_ptr/allocate_shared_array.hpp |  54 ++++----
 .../smart_ptr/detail/array_allocator.hpp      | 120 ++++++++++--------
 .../smart_ptr/detail/array_count_impl.hpp     |   2 +-
 include/boost/smart_ptr/make_shared_array.hpp |  42 +++---
 4 files changed, 120 insertions(+), 98 deletions(-)

diff --git a/include/boost/smart_ptr/allocate_shared_array.hpp b/include/boost/smart_ptr/allocate_shared_array.hpp
index e64047f..c91d4da 100644
--- a/include/boost/smart_ptr/allocate_shared_array.hpp
+++ b/include/boost/smart_ptr/allocate_shared_array.hpp
@@ -19,22 +19,23 @@ namespace boost {
         typedef typename boost::detail::array_inner<T>::type T1;
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef boost::detail::ms_init_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         std::size_t n1 = size * boost::detail::array_total<T1>::size;
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(allocator, size, &p2);
+        A1 a1(allocator, size);
         shared_ptr<T> s1(p1, d1, a1);
+        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
+        a2->swap(p2);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
         boost::detail::as_init(allocator, p2, n1);
 #else
         boost::detail::ms_init(p2, n1);
 #endif
-        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -44,7 +45,7 @@ namespace boost {
         typedef typename boost::detail::array_inner<T>::type T1;
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef boost::detail::ms_init_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         enum {
             N = boost::detail::array_total<T>::size
@@ -52,16 +53,17 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(allocator, &p2);
+        A1 a1(allocator);
         shared_ptr<T> s1(p1, d1, a1);
+        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
+        a2->swap(p2);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
         boost::detail::as_init(allocator, p2, N);
 #else
         boost::detail::ms_init(p2, N);
 #endif
-        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -73,7 +75,7 @@ namespace boost {
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef const T2 T3;
         typedef boost::detail::ms_init_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         enum {
             M = boost::detail::array_total<T1>::size
@@ -83,16 +85,17 @@ namespace boost {
         T2* p2 = 0;
         T3* p3 = reinterpret_cast<T3*>(&value);
         D1 d1;
-        A1 a1(allocator, size, &p2);
+        A1 a1(allocator, size);
         shared_ptr<T> s1(p1, d1, a1);
+        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
+        a2->swap(p2);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
         boost::detail::as_init<T2, A, M>(allocator, p2, n1, p3);
 #else
         boost::detail::ms_init<T2, M>(p2, n1, p3);
 #endif
-        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -104,7 +107,7 @@ namespace boost {
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef const T2 T3;
         typedef boost::detail::ms_init_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         enum {
             N = boost::detail::array_total<T>::size,
@@ -114,16 +117,17 @@ namespace boost {
         T2* p2 = 0;
         T3* p3 = reinterpret_cast<T3*>(&value);
         D1 d1;
-        A1 a1(allocator, &p2);
+        A1 a1(allocator);
         shared_ptr<T> s1(p1, d1, a1);
+        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
+        a2->swap(p2);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
         boost::detail::as_init<T2, A, M>(allocator, p2, N, p3);
 #else
         boost::detail::ms_init<T2,  M>(p2, N, p3);
 #endif
-        A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -133,18 +137,19 @@ namespace boost {
         typedef typename boost::detail::array_inner<T>::type T1;
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef boost::detail::ms_noinit_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         std::size_t n1 = size * boost::detail::array_total<T1>::size;
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(allocator, size, &p2);
+        A1 a1(allocator, size);
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_noinit(p2, n1);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_noinit(p2, n1);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -154,7 +159,7 @@ namespace boost {
         typedef typename boost::detail::array_inner<T>::type T1;
         typedef typename boost::detail::array_base<T1>::type T2;
         typedef boost::detail::ms_noinit_tag R1;
-        typedef boost::detail::ms_allocator<T, R1, A> A1;
+        typedef boost::detail::as_allocator<T, R1, A> A1;
         typedef boost::detail::ms_in_allocator_tag D1;
         enum {
             N = boost::detail::array_total<T>::size
@@ -162,12 +167,13 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(allocator, &p2);
+        A1 a1(allocator);
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_noinit(p2, N);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_noinit(p2, N);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 }
diff --git a/include/boost/smart_ptr/detail/array_allocator.hpp b/include/boost/smart_ptr/detail/array_allocator.hpp
index ce918b9..2289084 100644
--- a/include/boost/smart_ptr/detail/array_allocator.hpp
+++ b/include/boost/smart_ptr/detail/array_allocator.hpp
@@ -12,9 +12,7 @@
 #include <boost/smart_ptr/detail/array_traits.hpp>
 #include <boost/smart_ptr/detail/array_utility.hpp>
 #include <boost/type_traits/alignment_of.hpp>
-#if !defined(BOOST_NO_CXX11_ALLOCATOR)
-#include <memory>
-#endif
+#include <algorithm>
 
 namespace boost {
     namespace detail {
@@ -47,13 +45,13 @@ namespace boost {
         struct ms_init_tag   { };
         struct ms_noinit_tag { };
 
-        template<class T, class R, class A = void, class Y = char>
-        class ms_allocator
+        template<class T, class R, class A, class Y = char>
+        class as_allocator
             : as_size_base<T, A> {
             using as_size_base<T, A>::size;
 
             template<class T_, class R_, class A_, class Y_>
-            friend class ms_allocator;
+            friend class as_allocator;
 
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
             typedef typename std::allocator_traits<A>::
@@ -92,25 +90,36 @@ namespace boost {
 
             template<class U>
             struct rebind {
-                typedef ms_allocator<T, R, A, U> other;
+                typedef as_allocator<T, R, A, U> other;
             };
 
-            ms_allocator(const A& allocator, type** data_)
+            as_allocator(const A& allocator)
                 : as_size_base<T, A>(allocator),
-                  data(data_),
                   object(0) {
             }
 
-            ms_allocator(const A& allocator, std::size_t size_, type** data_)
+            as_allocator(const A& allocator, std::size_t size_)
                 : as_size_base<T, A>(allocator, size_),
-                  data(data_),
                   object(0) {
             }
 
             template<class U>
-            ms_allocator(const ms_allocator<T, R, A, U>& other)
+            as_allocator(const as_allocator& other, U* memory) 
+                : as_size_base<T, A>(other) {
+                enum {
+                    M = boost::alignment_of<type>::value
+                };
+                std::size_t n1 = sizeof(U) + M - 1;
+                char* p1 = reinterpret_cast<char*>(memory) + n1;
+                while (std::size_t(p1) % M != 0) {
+                    p1--;
+                }
+                object = reinterpret_cast<type*>(p1);
+            }
+
+            template<class U>
+            as_allocator(const as_allocator<T, R, A, U>& other)
                 : as_size_base<T, A>(other),
-                  data(other.data),
                   object(other.object) {
             }
 
@@ -129,29 +138,26 @@ namespace boost {
                 return ya.max_size();
             }
 
-            pointer allocate(size_type count, const void* value = 0) {
+            pointer allocate(size_type, const void* value = 0) {
                 enum {
                     M = boost::alignment_of<type>::value
                 };
-                std::size_t n1 = count * sizeof(value_type) + M - 1;
+                std::size_t n1 = sizeof(value_type) + M - 1;
                 std::size_t n2 = size * sizeof(type);
                 CA ca(*this);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
-                char* p1 = CT::allocate(ca, n1 + n2, value);
+                void* p1 = CT::allocate(ca, n1 + n2, value);
 #else
-                char* p1 = ca.allocate(n1 + n2, value);
+                void* p1 = ca.allocate(n1 + n2, value);
 #endif
-                char* p2 = p1 + n1;
-                while (std::size_t(p2) % M != 0) {
-                    p2--;
-                }
-                *data = reinterpret_cast<type*>(p2);
-                return reinterpret_cast<value_type*>(p1);
+                return static_cast<value_type*>(p1);
             }
 
-            void deallocate(pointer memory, size_type count) {
-                std::size_t a1 = boost::alignment_of<type>::value;
-                std::size_t n1 = count * sizeof(value_type) + a1 - 1;
+            void deallocate(pointer memory, size_type) {
+                enum {
+                    M = boost::alignment_of<type>::value
+                };
+                std::size_t n1 = sizeof(value_type) + M - 1;
                 char* p1 = reinterpret_cast<char*>(memory);
                 CA ca(*this);
 #if !defined(BOOST_NO_CXX11_ALLOCATOR)
@@ -193,17 +199,17 @@ namespace boost {
 #endif
 
             template<class U>
-            bool operator==(const ms_allocator<T, R, A, U>& other) const {
+            bool operator==(const as_allocator<T, R, A, U>& other) const {
                 return true;
             }
 
             template<class U>
-            bool operator!=(const ms_allocator<T, R, A, U>& other) const {
+            bool operator!=(const as_allocator<T, R, A, U>& other) const {
                 return !(*this == other);
             }
 
-            void set(type* memory) {
-                object = memory;
+            void swap(type*& other) {
+                std::swap(object, other);
             }
 
             void operator()() {
@@ -227,7 +233,6 @@ namespace boost {
                 ms_destroy(object, size);
             }
 
-            type** data;
             type* object;
         };
 
@@ -250,12 +255,12 @@ namespace boost {
             };
         };
 
-        template<class T, class R,  class Y>
-        class ms_allocator<T, R, void, Y>
+        template<class T, class R, class Y = char>
+        class ms_allocator
             : ms_size_base<T> {
             using ms_size_base<T>::size;
 
-            template<class T_, class R_, class A_, class Y_>
+            template<class T_, class R_, class Y_>
             friend class ms_allocator;
 
         public:
@@ -270,24 +275,35 @@ namespace boost {
 
             template<class U>
             struct rebind {
-                typedef ms_allocator<T, R, void, U> other;
+                typedef ms_allocator<T, R, U> other;
             };
 
-            ms_allocator(type** data_)
-                : data(data_),
-                  object(0) {
+            ms_allocator()
+                : object(0) {
             }
 
-            ms_allocator(std::size_t size_, type** data_)
+            ms_allocator(std::size_t size_)
                 : ms_size_base<T>(size_),
-                  data(data_),
                   object(0) {
             }
 
             template<class U>
-            ms_allocator(const ms_allocator<T, R, void, U>& other)
+            ms_allocator(const ms_allocator& other, U* memory)
+                : ms_size_base<T>(other) {
+                enum {
+                    M = boost::alignment_of<type>::value
+                };
+                std::size_t n1 = sizeof(U) + M - 1;
+                char* p1 = reinterpret_cast<char*>(memory) + n1;
+                while (std::size_t(p1) % M != 0) {
+                    p1--;
+                }
+                object = reinterpret_cast<type*>(p1);
+            }
+
+            template<class U>
+            ms_allocator(const ms_allocator<T, R, U>& other)
                 : ms_size_base<T>(other),
-                  data(other.data),
                   object(other.object) {
             }
 
@@ -306,19 +322,14 @@ namespace boost {
                 return N;
             }
 
-            pointer allocate(size_type count, const void* = 0) {
+            pointer allocate(size_type, const void* = 0) {
                 enum {
                     M = boost::alignment_of<type>::value
                 };
-                std::size_t n1 = count * sizeof(value_type) + M - 1;
+                std::size_t n1 = sizeof(value_type) + M - 1;
                 std::size_t n2 = size * sizeof(type);
                 void* p1 = ::operator new(n1 + n2);
-                char* p2 = static_cast<char*>(p1) + n1;
-                while (std::size_t(p2) % M != 0) {
-                    p2--;
-                }
-                *data = reinterpret_cast<type*>(p2);
-                return reinterpret_cast<value_type*>(p1);
+                return static_cast<value_type*>(p1);
             }
 
             void deallocate(pointer memory, size_type) {
@@ -348,17 +359,17 @@ namespace boost {
 #endif
 
             template<class U>
-            bool operator==(const ms_allocator<T, R, void, U>&) const {
+            bool operator==(const ms_allocator<T, R, U>&) const {
                 return true;
             }
 
             template<class U>
-            bool operator!=(const ms_allocator<T, R, void, U>& other) const {
+            bool operator!=(const ms_allocator<T, R, U>& other) const {
                 return !(*this == other);
             }
 
-            void set(type* memory) {
-                object = memory;
+            void swap(type*& other) {
+                std::swap(object, other);
             }
 
             void operator()() {
@@ -368,7 +379,6 @@ namespace boost {
             }
 
         private:
-            type** data;
             type* object;
         };
 
diff --git a/include/boost/smart_ptr/detail/array_count_impl.hpp b/include/boost/smart_ptr/detail/array_count_impl.hpp
index f81954d..da2d9dd 100644
--- a/include/boost/smart_ptr/detail/array_count_impl.hpp
+++ b/include/boost/smart_ptr/detail/array_count_impl.hpp
@@ -21,7 +21,7 @@ namespace boost {
             typedef sp_counted_impl_pda<P, D, A> Y;
         public:
             sp_counted_impl_pda(P, const D&, const A& allocator_)
-                : allocator(allocator_) {
+                : allocator(allocator_, this) {
             }
 
             virtual void dispose() {
diff --git a/include/boost/smart_ptr/make_shared_array.hpp b/include/boost/smart_ptr/make_shared_array.hpp
index 362c3f8..96a45dc 100644
--- a/include/boost/smart_ptr/make_shared_array.hpp
+++ b/include/boost/smart_ptr/make_shared_array.hpp
@@ -25,12 +25,13 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(size, &p2);
+        A1 a1(size);
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_init(p2, n1);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_init(p2, n1);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -48,12 +49,13 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(&p2);
+        A1 a1;
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_init(p2, N);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_init(p2, N);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -75,12 +77,13 @@ namespace boost {
         T2* p2 = 0;
         T3* p3 = reinterpret_cast<T3*>(&value);
         D1 d1;
-        A1 a1(size, &p2);
+        A1 a1(size);
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_init<T2, M>(p2, n1, p3);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_init<T2, M>(p2, n1, p3);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -101,12 +104,13 @@ namespace boost {
         T2* p2 = 0;
         T3* p3 = reinterpret_cast<T3*>(&value);
         D1 d1;
-        A1 a1(&p2);
+        A1 a1;
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_init<T2, M>(p2, N, p3);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_init<T2, M>(p2, N, p3);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -122,12 +126,13 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(size, &p2);
+        A1 a1(size);
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_noinit(p2, n1);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_noinit(p2, n1);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 
@@ -145,12 +150,13 @@ namespace boost {
         T1* p1 = 0;
         T2* p2 = 0;
         D1 d1;
-        A1 a1(&p2);
+        A1 a1;
         shared_ptr<T> s1(p1, d1, a1);
-        boost::detail::ms_noinit(p2, N);
         A1* a2 = static_cast<A1*>(s1._internal_get_untyped_deleter());
-        a2->set(p2);
+        a2->swap(p2);
+        boost::detail::ms_noinit(p2, N);
         p1 = reinterpret_cast<T1*>(p2);
+        a2->swap(p2);
         return shared_ptr<T>(s1, p1);
     }
 }