From 94ef1ac3916d2bc1296efc7dd4d1a50c859bfb68 Mon Sep 17 00:00:00 2001
From: Daniel James <daniel@calamity.org.uk>
Date: Mon, 17 Sep 2012 18:59:29 +0000
Subject: [PATCH] Unordered: Support empty containers in node_holder.

[SVN r80562]
---
 include/boost/unordered/detail/buckets.hpp | 12 +++++++-----
 include/boost/unordered/detail/table.hpp   |  9 +++------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/include/boost/unordered/detail/buckets.hpp b/include/boost/unordered/detail/buckets.hpp
index 4bfae1c9..def5c7c7 100644
--- a/include/boost/unordered/detail/buckets.hpp
+++ b/include/boost/unordered/detail/buckets.hpp
@@ -444,10 +444,12 @@ namespace boost { namespace unordered { namespace detail {
             base(b.node_alloc()),
             nodes_()
         {
-            typename Table::previous_pointer prev = b.get_previous_start();
-            nodes_ = static_cast<node_pointer>(prev->next_);
-            prev->next_ = link_pointer();
-            b.size_ = 0;
+            if (b.size_) {
+                typename Table::previous_pointer prev = b.get_previous_start();
+                nodes_ = static_cast<node_pointer>(prev->next_);
+                prev->next_ = link_pointer();
+                b.size_ = 0;
+            }
         }
 
         ~node_holder();
@@ -508,7 +510,7 @@ namespace boost { namespace unordered { namespace detail {
             }
         }
 
-        iterator get_start() const
+        iterator begin() const
         {
             return iterator(nodes_);
         }
diff --git a/include/boost/unordered/detail/table.hpp b/include/boost/unordered/detail/table.hpp
index 3713d063..a1c4dd69 100644
--- a/include/boost/unordered/detail/table.hpp
+++ b/include/boost/unordered/detail/table.hpp
@@ -400,7 +400,7 @@ namespace boost { namespace unordered { namespace detail {
 
                 move_nodes<node_allocator> move(node_alloc());
                 node_holder<node_allocator> nodes(x);
-                table_impl::fill_buckets(nodes.get_start(), *this, move);
+                table_impl::fill_buckets(nodes.begin(), *this, move);
             }
         }
 
@@ -765,11 +765,8 @@ namespace boost { namespace unordered { namespace detail {
                 // elements, assigning to them if possible, and deleting
                 // any that are left over.
                 move_assign_nodes<table> assign(*this);
-
-                if (x.size_) {
-                    node_holder<node_allocator> nodes(x);
-                    table_impl::fill_buckets(nodes.get_start(), *this, assign);
-                }
+                node_holder<node_allocator> nodes(x);
+                table_impl::fill_buckets(nodes.begin(), *this, assign);
             }
         }