From e92f7d86c1599dde290ac5c70f8ca44bbcd0c96f Mon Sep 17 00:00:00 2001
From: Daniel James <daniel@calamity.org.uk>
Date: Sun, 14 Aug 2016 20:55:40 +0100
Subject: [PATCH] Remove array_constructor.

I was using SFINAE for everything because some old compilers had issues.
But that's hopefully in the distant past now.
---
 include/boost/unordered/detail/allocate.hpp | 71 +--------------------
 include/boost/unordered/detail/table.hpp    | 65 ++++++++++++-------
 2 files changed, 43 insertions(+), 93 deletions(-)

diff --git a/include/boost/unordered/detail/allocate.hpp b/include/boost/unordered/detail/allocate.hpp
index d56bcaa0..a83edad2 100644
--- a/include/boost/unordered/detail/allocate.hpp
+++ b/include/boost/unordered/detail/allocate.hpp
@@ -31,6 +31,7 @@
 #include <boost/tuple/tuple.hpp>
 #include <boost/utility/enable_if.hpp>
 #include <boost/utility/addressof.hpp>
+#include <boost/detail/no_exceptions_support.hpp>
 #include <boost/detail/select_type.hpp>
 #include <boost/swap.hpp>
 #include <boost/assert.hpp>
@@ -1248,76 +1249,6 @@ namespace boost { namespace unordered { namespace detail { namespace func {
     }
 }}}}
 
-namespace boost { namespace unordered { namespace detail {
-
-    ////////////////////////////////////////////////////////////////////////////
-    //
-    // array_constructor
-    //
-    // Allocate and construct an array in an exception safe manner, and
-    // clean up if an exception is thrown before the container takes charge
-    // of it.
-
-    template <typename Allocator>
-    struct array_constructor
-    {
-        typedef boost::unordered::detail::allocator_traits<Allocator> traits;
-        typedef typename traits::pointer pointer;
-
-        Allocator& alloc_;
-        pointer ptr_;
-        pointer constructed_;
-        std::size_t length_;
-
-        array_constructor(Allocator& a)
-            : alloc_(a), ptr_(), constructed_(), length_(0)
-        {
-            constructed_ = pointer();
-            ptr_ = pointer();
-        }
-
-        ~array_constructor() {
-            if (ptr_) {
-                for(pointer p = ptr_; p != constructed_; ++p) {
-                    boost::unordered::detail::func::destroy(
-                            boost::addressof(*p));
-                }
-
-                traits::deallocate(alloc_, ptr_, length_);
-            }
-        }
-
-        template <typename V>
-        void construct(V const& v, std::size_t l)
-        {
-            BOOST_ASSERT(!ptr_);
-            length_ = l;
-            ptr_ = traits::allocate(alloc_, length_);
-            pointer end = ptr_ + static_cast<std::ptrdiff_t>(length_);
-            for(constructed_ = ptr_; constructed_ != end; ++constructed_) {
-                new ((void*) boost::addressof(*constructed_)) V(v);
-            }
-        }
-
-        pointer get() const
-        {
-            return ptr_;
-        }
-
-        pointer release()
-        {
-            pointer p(ptr_);
-            ptr_ = pointer();
-            return p;
-        }
-
-    private:
-
-        array_constructor(array_constructor const&);
-        array_constructor& operator=(array_constructor const&);
-    };
-}}}
-
 #if defined(BOOST_MSVC)
 #pragma warning(pop)
 #endif
diff --git a/include/boost/unordered/detail/table.hpp b/include/boost/unordered/detail/table.hpp
index de7baa57..ab4000b4 100644
--- a/include/boost/unordered/detail/table.hpp
+++ b/include/boost/unordered/detail/table.hpp
@@ -345,34 +345,53 @@ namespace boost { namespace unordered { namespace detail {
 
         void create_buckets(std::size_t new_count)
         {
-            boost::unordered::detail::array_constructor<bucket_allocator>
-                constructor(bucket_alloc());
-    
-            // Creates an extra bucket to act as the start node.
-            constructor.construct(bucket(), new_count + 1);
+            std::size_t length = new_count + 1;
+            bucket_pointer new_buckets = bucket_allocator_traits::allocate(
+                    bucket_alloc(), length);
+            bucket_pointer constructed = new_buckets;
 
-            if (buckets_)
-            {
-                // Copy the nodes to the new buckets, including the dummy
-                // node if there is one.
-                (constructor.get() +
-                    static_cast<std::ptrdiff_t>(new_count))->next_ =
-                        (buckets_ + static_cast<std::ptrdiff_t>(
-                            bucket_count_))->next_;
-                destroy_buckets();
-            }
-            else if (bucket::extra_node)
-            {
-                node_constructor a(node_alloc());
-                a.create_node();
+            BOOST_TRY {
+                bucket_pointer end = new_buckets
+                    + static_cast<std::ptrdiff_t>(length);
+                for(; constructed != end; ++constructed) {
+                    new ((void*) boost::addressof(*constructed)) bucket();
+                }
 
-                (constructor.get() +
-                    static_cast<std::ptrdiff_t>(new_count))->next_ =
-                        a.release();
+                if (buckets_)
+                {
+                    // Copy the nodes to the new buckets, including the dummy
+                    // node if there is one.
+                    (new_buckets +
+                        static_cast<std::ptrdiff_t>(new_count))->next_ =
+                            (buckets_ + static_cast<std::ptrdiff_t>(
+                                bucket_count_))->next_;
+                    destroy_buckets();
+                }
+                else if (bucket::extra_node)
+                {
+                    node_constructor a(node_alloc());
+                    a.create_node();
+
+                    (new_buckets +
+                        static_cast<std::ptrdiff_t>(new_count))->next_ =
+                            a.release();
+                }
             }
+            BOOST_CATCH(...) {
+                for(bucket_pointer p = new_buckets; p != constructed; ++p) {
+                    boost::unordered::detail::func::destroy(
+                            boost::addressof(*p));
+                }
+
+                bucket_allocator_traits::deallocate(bucket_alloc(),
+                        new_buckets, length);
+
+                BOOST_RETHROW;
+            }
+            BOOST_CATCH_END
 
             bucket_count_ = new_count;
-            buckets_ = constructor.release();
+            buckets_ = new_buckets;
             recalculate_max_load();
         }