Document block_size option in deque_options.

Author: igaztanaga

include/boost/container/deque.hpp

@@ -1318,28 +1318,13 @@ class deque : protected deque_base<typename real_allocator<T, Allocator>::type,
                                   || allocator_traits_type::is_always_equal::value)
    {
       if (BOOST_LIKELY(this != &x)) {
-         allocator_type &this_alloc = this->alloc();
-         allocator_type &x_alloc    = x.alloc();
-         const bool propagate_alloc = allocator_traits_type::
-               propagate_on_container_move_assignment::value;
-         dtl::bool_<propagate_alloc> flag;
-         const bool allocators_equal = this_alloc == x_alloc; (void)allocators_equal;
-         //Resources can be transferred if both allocators are
-         //going to be equal after this function (either propagated or already equal)
-         if(propagate_alloc || allocators_equal){
-            //Destroy objects but retain memory in case x reuses it in the future
-            this->clear();
-            //Move allocator if needed
-            dtl::move_alloc(this_alloc, x_alloc, flag);
-            dtl::move_alloc(this->ptr_alloc(), x.ptr_alloc(), flag);
-            //Nothrow swap
-            this->swap_members(x);
-         }
-         //Else do a one by one move
-         else{
-            this->assign( boost::make_move_iterator(x.begin())
-                        , boost::make_move_iterator(x.end()));
-         }
+         //We know resources can be transferred at comiple time if both allocators are
+         //always equal or the allocator is going to be propagated
+         const bool can_steal_resources_alloc
+            =  allocator_traits_type::propagate_on_container_move_assignment::value
+            || allocator_traits_type::is_always_equal::value;
+         dtl::bool_<can_steal_resources_alloc> flag;
+         this->priv_move_assign(boost::move(x), flag);
       }
       return *this;
    }
@@ -2378,6 +2363,30 @@ class deque : protected deque_base<typename real_allocator<T, Allocator>::type,
    #ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
    private:
 
+   void priv_move_assign(BOOST_RV_REF(deque) x, dtl::bool_<true> /*steal_resources*/)
+   {
+      //Destroy objects but retain memory in case x reuses it in the future
+      this->clear();
+      //Move allocator if needed
+      dtl::bool_<allocator_traits_type::propagate_on_container_move_assignment::value> flag;
+      dtl::move_alloc(this->alloc(), x.alloc(), flag);
+      dtl::move_alloc(this->ptr_alloc(), x.ptr_alloc(), flag);
+      //Nothrow swap
+      this->swap_members(x);
+   }
+
+   void priv_move_assign(BOOST_RV_REF(deque) x, dtl::bool_<false> /*steal_resources*/)
+   {
+      //We can't guarantee a compile-time equal allocator or propagation so fallback to runtime
+      //Resources can be transferred if both allocators are equal
+      if (this->alloc() == x.alloc()) {
+         this->priv_move_assign(boost::move(x), dtl::true_());
+      }
+      else {
+         this->assign(boost::make_move_iterator(x.begin()), boost::make_move_iterator(x.end()));
+      }
+   }
+
    inline size_type priv_index_of(const_iterator p) const
    {
       BOOST_ASSERT(this->cbegin() <= p);
@@ -2493,7 +2502,8 @@ class deque : protected deque_base<typename real_allocator<T, Allocator>::type,
 
    void priv_destroy_range(iterator p, iterator p2)
    {
-      if(!Base::traits_t::trivial_dctr){
+      (void)p; (void)p2;
+      BOOST_IF_CONSTEXPR(!Base::traits_t::trivial_dctr){
          for(;p != p2; ++p){
             allocator_traits_type::destroy(this->alloc(), boost::movelib::iterator_to_raw_pointer(p));
          }
@@ -2502,7 +2512,8 @@ class deque : protected deque_base<typename real_allocator<T, Allocator>::type,
 
    void priv_destroy_range(pointer p, pointer p2)
    {
-      if(!Base::traits_t::trivial_dctr){
+      (void)p; (void)p2;
+      BOOST_IF_CONSTEXPR(!Base::traits_t::trivial_dctr){
          for(;p != p2; ++p){
             allocator_traits_type::destroy(this->alloc(), boost::movelib::iterator_to_raw_pointer(p));
          }

include/boost/container/detail/tree.hpp

@@ -688,40 +688,13 @@ class tree
                            boost::container::dtl::is_nothrow_move_assignable<Compare>::value)
    {
       if (BOOST_LIKELY(this != &x)) {
-         NodeAlloc &this_alloc = this->node_alloc();
-         NodeAlloc &x_alloc    = x.node_alloc();
-         const bool propagate_alloc = allocator_traits<NodeAlloc>::
-               propagate_on_container_move_assignment::value;
-         const bool allocators_equal = this_alloc == x_alloc; (void)allocators_equal;
-         //Resources can be transferred if both allocators are
-         //going to be equal after this function (either propagated or already equal)
-         if(propagate_alloc || allocators_equal){
-            //Destroy
-            this->clear();
-            //Move allocator if needed
-            this->AllocHolder::move_assign_alloc(x);
-            //Obtain resources
-            this->icont() = boost::move(x.icont());
-         }
-         //Else do a one by one move
-         else{
-            //Transfer all the nodes to a temporary tree
-            //If anything goes wrong, all the nodes will be destroyed
-            //automatically
-            Icont other_tree(::boost::move(this->icont()));
-
-            //Now recreate the source tree reusing nodes stored by other_tree
-            this->icont().clone_from
-               (::boost::move(x.icont())
-               , RecyclingCloner<AllocHolder, true>(*this, other_tree)
-               , Destroyer(this->node_alloc()));
-
-            //If there are remaining nodes, destroy them
-            NodePtr p;
-            while((p = other_tree.unlink_leftmost_without_rebalance())){
-               AllocHolder::destroy_node(p);
-            }
-         }
+         //We know resources can be transferred at comiple time if both allocators are
+         //always equal or the allocator is going to be propagated
+         const bool can_steal_resources_alloc
+            =  allocator_traits_type::propagate_on_container_move_assignment::value
+            || allocator_traits_type::is_always_equal::value;
+         dtl::bool_<can_steal_resources_alloc> flag;
+         this->priv_move_assign(boost::move(x), flag);
       }
       return *this;
    }
@@ -895,6 +868,42 @@ class tree
 
 
    private:
+   void priv_move_assign(BOOST_RV_REF(tree) x, dtl::bool_<true> /*steal_resources*/)
+   {
+      //Destroy objects but retain memory in case x reuses it in the future
+      this->clear();
+      //Move allocator if needed
+      this->AllocHolder::move_assign_alloc(x);
+      //Obtain resources
+      this->icont() = boost::move(x.icont());
+   }
+
+   void priv_move_assign(BOOST_RV_REF(tree) x, dtl::bool_<false> /*steal_resources*/)
+   {
+      //We can't guarantee a compile-time equal allocator or propagation so fallback to runtime
+      //Resources can be transferred if both allocators are equal
+      if (this->node_alloc() == x.node_alloc()) {
+         this->priv_move_assign(boost::move(x), dtl::true_());
+      }
+      else {
+         //Transfer all the nodes to a temporary tree
+         //If anything goes wrong, all the nodes will be destroyed
+         //automatically
+         Icont other_tree(::boost::move(this->icont()));
+
+         //Now recreate the source tree reusing nodes stored by other_tree
+         this->icont().clone_from
+         (::boost::move(x.icont())
+            , RecyclingCloner<AllocHolder, true>(*this, other_tree)
+            , Destroyer(this->node_alloc()));
+
+         //If there are remaining nodes, destroy them
+         NodePtr p;
+         while ((p = other_tree.unlink_leftmost_without_rebalance())) {
+            AllocHolder::destroy_node(p);
+         }
+      }
+   }
 
    template<class KeyConvertible, class M>
    iiterator priv_insert_or_assign_commit