1 files changed, 75 insertions, 0 deletions
diff --git a/lib/libcxx/include/__iterator/front_insert_iterator.h b/lib/libcxx/include/__iterator/front_insert_iterator.h
new file mode 100644
index 0000000000..0421dd5c4b
--- /dev/null
+++ b/lib/libcxx/include/__iterator/front_insert_iterator.h
@@ -0,0 +1,75 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
+#define _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__utility/move.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Container>
+class _LIBCPP_TEMPLATE_VIS front_insert_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+protected:
+    _Container* container;
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t difference_type;
+#else
+    typedef void difference_type;
+#endif
+    typedef void pointer;
+    typedef void reference;
+    typedef _Container container_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator=(const typename _Container::value_type& __value_)
+        {container->push_front(__value_); return *this;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator=(typename _Container::value_type&& __value_)
+        {container->push_front(_VSTD::move(__value_)); return *this;}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator*()     {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator++()    {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator  operator++(int) {return *this;}
+};
+
+template <class _Container>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+front_insert_iterator<_Container>
+front_inserter(_Container& __x)
+{
+    return front_insert_iterator<_Container>(__x);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H