From d99628981d1ff7181bee652bc5177342d79aaf4e Mon Sep 17 00:00:00 2001
From: Christopher Wecht <christopher.wecht@student.kit.edu>
Date: Fri, 1 Sep 2017 17:53:46 +0200
Subject: [PATCH] push_back: added support for not-copyable but moveable
 value-types like e.g. unique_ptr

---
 .../boost/range/algorithm_ext/push_back.hpp   | 43 ++++++++++-
 test/algorithm_ext_test/push_back.cpp         | 74 +++++++++++++++++++
 2 files changed, 116 insertions(+), 1 deletion(-)

diff --git a/include/boost/range/algorithm_ext/push_back.hpp b/include/boost/range/algorithm_ext/push_back.hpp
index 6fb9b9b..d741b62 100644
--- a/include/boost/range/algorithm_ext/push_back.hpp
+++ b/include/boost/range/algorithm_ext/push_back.hpp
@@ -20,9 +20,37 @@
 
 namespace boost
 {
-    namespace range
+#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
+    namespace range_detail
     {
 
+template < class Container, class Range >
+inline Container& push_back_impl( Container& on, Range&& from, std::false_type)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<Range> ));
+    BOOST_ASSERT_MSG(!range_detail::is_same_object(on, from),
+        "cannot move from a container to itself");
+    on.insert( on.end(),
+               std::make_move_iterator(boost::begin(from)),
+               std::make_move_iterator(boost::end(from)));
+    return on;
+}
+
+template < class Container, class Range >
+inline Container& push_back_impl( Container& on, const Range& from, std::true_type)
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const Range> ));
+    BOOST_ASSERT_MSG(!range_detail::is_same_object(on, from),
+        "cannot copy from a container to itself");
+    on.insert( on.end(), boost::begin(from), boost::end(from));
+    return on;
+}
+
+    } //namespace range_detail
+#endif
+
+    namespace range {
+#if defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
 template< class Container, class Range >
 inline Container& push_back( Container& on, const Range& from )
 {
@@ -34,6 +62,19 @@ inline Container& push_back( Container& on, const Range& from )
     return on;
 }
 
+#else
+
+template< class Container, class Range >
+inline Container& push_back( Container& on, Range&& from )
+{
+    BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<Container> ));
+    range_detail::push_back_impl(on,
+                                 std::forward<Range>(from),
+                                 std::is_lvalue_reference<Range>() );
+    return on;
+}
+
+#endif
     } // namespace range
     using range::push_back;
 } // namespace boost
diff --git a/test/algorithm_ext_test/push_back.cpp b/test/algorithm_ext_test/push_back.cpp
index 7e9d539..b3e4754 100644
--- a/test/algorithm_ext_test/push_back.cpp
+++ b/test/algorithm_ext_test/push_back.cpp
@@ -19,6 +19,7 @@
 #include <list>
 #include <vector>
 
+
 namespace
 {
     template< class Container >
@@ -58,6 +59,76 @@ namespace
         test_push_back_impl< std::vector<std::size_t> >();
         test_push_back_impl< std::list<std::size_t> >();
     }
+
+#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
+    // test type which is not copyable by moveable.
+    class noncopyable_int : boost::noncopyable {
+      private:
+        int i;
+      public:
+        noncopyable_int(int x) : i(x) {}
+        noncopyable_int(const noncopyable_int&) = delete;
+        noncopyable_int& operator=(const noncopyable_int&) = delete;
+        noncopyable_int(noncopyable_int&& o) : i(o.i) {}
+        noncopyable_int& operator=(noncopyable_int&& o) { return o; }
+        bool operator!=(const noncopyable_int &rhs) { return i != rhs.i; }
+        friend std::ostream &operator<<(std::ostream &os, const noncopyable_int& x);
+    };
+
+    std::ostream & operator<<(std::ostream &os, const noncopyable_int& x)
+    {
+       return os << x.i;
+    }
+
+    template< class Container >
+    void test_push_back_move_impl(std::size_t n)
+    {
+        Container test;
+        Container reference;
+        for (std::size_t i = 0; i < n; ++i)
+            reference.push_back(noncopyable_int(i));
+
+        {
+            Container to_push_back;
+            for (std::size_t i = 0; i < n; ++i)
+                to_push_back.push_back(noncopyable_int(i));
+
+            boost::push_back(test, std::move(to_push_back));
+
+            BOOST_CHECK_EQUAL_COLLECTIONS( reference.begin(), reference.end(),
+                test.begin(), test.end() );
+        }
+        // Do it again to push onto non-empty container
+        for (std::size_t i = 0; i < n; ++i)
+            reference.push_back(noncopyable_int(i));
+
+        {
+            Container to_push_back;
+            for (std::size_t i = 0; i < n; ++i)
+                to_push_back.push_back(noncopyable_int(i));
+
+            boost::push_back(test, std::move(to_push_back));
+
+            BOOST_CHECK_EQUAL_COLLECTIONS( reference.begin(), reference.end(),
+                test.begin(), test.end() );
+        }
+    }
+
+    template< class Container >
+    void test_push_back_move_impl()
+    {
+        test_push_back_move_impl< Container >(0);
+        test_push_back_move_impl< Container >(1);
+        test_push_back_move_impl< Container >(2);
+        test_push_back_move_impl< Container >(100);
+    }
+
+    void test_push_back_move()
+    {
+        test_push_back_move_impl< std::vector<noncopyable_int> >();
+        test_push_back_move_impl< std::list<noncopyable_int> >();
+    }
+#endif
 }
 
 boost::unit_test::test_suite*
@@ -67,6 +138,9 @@ init_unit_test_suite(int argc, char* argv[])
         = BOOST_TEST_SUITE( "RangeTestSuite.algorithm_ext.push_back" );
 
     test->add( BOOST_TEST_CASE( &test_push_back ) );
+#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
+    test->add( BOOST_TEST_CASE( &test_push_back_move ) );
+#endif
 
     return test;
 }