Merge branch 'feature/FS1322-initialize-fieldvector'

cmake/modules/FindCXX11Features.cmake

@@ -288,4 +288,27 @@ CHECK_CXX_SOURCE_COMPILES("
   }
 " HAVE_RVALUE_REFERENCES
 )
+
+# initializer list
+CHECK_CXX_SOURCE_COMPILES("
+  #include <initializer_list>
+  #include <vector>
+
+  struct A
+  {
+    A(std::initializer_list<int> il)
+      : vec(il)
+    {}
+
+    std::vector<int> vec;
+  };
+
+  int main(void)
+  {
+    A a{1,3,4,5};
+    return 0;
+  }
+" HAVE_INITIALIZER_LIST
+)
+
 cmake_pop_check_state()

config.h.cmake

@@ -157,6 +157,9 @@
 /* Define to 1 if rvalue references are supported */
 #cmakedefine HAVE_RVALUE_REFERENCES 1
 
+/* Define to 1 if initializer list is supported */
+#cmakedefine HAVE_INITIALIZER_LIST 1
+
 /* Include always useful headers */
 #include <dune/common/deprecated.hh>
 #include <dune/common/unused.hh>

dune/common/fvector.hh

@@ -9,6 +9,7 @@
 #include <cstdlib>
 #include <complex>
 #include <cstring>
+#include <utility>
 
 #include "typetraits.hh"
 #include "exceptions.hh"
@@ -98,8 +99,22 @@ namespace Dune {
     typedef typename Base::size_type size_type;
     typedef typename Base::value_type value_type;
 
-    //! Constructor making uninitialized vector
-    FieldVector() {}
+    //! Constructor making default-initialized vector
+    FieldVector()
+    // Use C++11 unified initialization if available - tends to generate
+    // fastest code
+#if HAVE_INITIALIZER_LIST
+      : _data{}
+    {}
+#else
+    {
+      // fall back to library approach - this gives faster code than array placement
+      // new. Apart from that, placement new may create problems if K is a complex
+      // type. In that case, the default constructor of the _data elements has already
+      // been called and may have allocated memory.
+      std::fill(_data.begin(),_data.end(),K());
+    }
+#endif
 
     //! Constructor making vector with identical coordinates
     explicit FieldVector (const K& t)
@@ -205,7 +220,9 @@ namespace Dune {
     //===== construction
 
     /** \brief Default constructor */
-    FieldVector () {}
+    FieldVector ()
+      : _data()
+    {}
 
     /** \brief Constructor with a given scalar */
     FieldVector (const K& k) : _data(k) {}

m4/CMakeLists.txt

@@ -13,6 +13,7 @@ install(PROGRAMS
         cxx0x_static_assert.m4
         cxx0x_variadic.m4
         cxx0x_variadic_constructor_sfinae.m4
+        cxx11_initializer_list.m4
         cxx11_conditional.m4
         dune.m4
         dune_all.m4

m4/Makefile.am

@@ -17,6 +17,7 @@ ALLM4S = 					\
 	cxx0x_static_assert.m4			\
 	cxx0x_variadic.m4			\
 	cxx0x_variadic_constructor_sfinae.m4    \
+	cxx11_initializer_list.m4		\
 	cxx11_conditional.m4			\
 	dune.m4					\
 	dune_all.m4				\

m4/cxx11_initializer_list.m4

+# tests for C++11 initializer list support
+# the associated macro is called HAVE_INITIALIZER_LIST
+
+AC_DEFUN([INITIALIZER_LIST_CHECK],[
+  AC_CACHE_CHECK([whether std::initializer_list is supported], dune_cv_initializer_list_support, [
+    AC_REQUIRE([AC_PROG_CXX])
+    AC_REQUIRE([GXX0X])
+    AC_LANG_PUSH([C++])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([
+
+        #include <initializer_list>
+        #include <vector>
+
+        struct A
+        {
+
+          A(std::initializer_list<int> il)
+            : vec(il)
+          {}
+
+          std::vector<int> vec;
+        };
+
+        ],
+        [
+          A a{1,3,4,5};
+          return 0;
+        ])],
+      dune_cv_initializer_list_support=yes,
+      dune_cv_initializer_list_support=no)
+    AC_LANG_POP
+  ])
+  if test "x$dune_cv_initializer_list_support" = xyes; then
+    AC_DEFINE(HAVE_INITIALIZER_LIST, 1, [Define to 1 if std::initializer_list is supported])
+  fi
+])

m4/dune_common.m4

@@ -24,6 +24,7 @@ AC_DEFUN([DUNE_COMMON_CHECKS],
   AC_REQUIRE([SHARED_PTR])
   AC_REQUIRE([VARIADIC_TEMPLATES_CHECK])
   AC_REQUIRE([RVALUE_REFERENCES_CHECK])
+  AC_REQUIRE([INITIALIZER_LIST_CHECK])
   AC_REQUIRE([CXX11_CONDITIONAL_CHECK])
   AC_REQUIRE([DUNE_BOOST_BASE])
   AC_REQUIRE([MAKE_SHARED])
@@ -78,7 +79,7 @@ AC_DEFUN([DUNE_COMMON_CHECKS],
 AC_DEFUN([DUNE_COMMON_CHECK_MODULE],
 [
     DUNE_CHECK_MODULES([dune-common], [common/stdstreams.hh],
-	[#ifndef DUNE_MINIMAL_DEBUG_LEVEL 
+	[#ifndef DUNE_MINIMAL_DEBUG_LEVEL
    #define DUNE_MINIMAL_DEBUG_LEVEL 1
    #endif
 	Dune::derr.active();])