1 files changed, 58 insertions, 0 deletions
diff --git a/libcxx/include/__iterator/size.h b/libcxx/include/__iterator/size.h
new file mode 100644
index 000000000000..259424f1d314
--- /dev/null
+++ b/libcxx/include/__iterator/size.h
@@ -0,0 +1,58 @@
+// -*- 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_SIZE_H
+#define _LIBCPP___ITERATOR_SIZE_H
+
+#include <__config>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Cont>
+_LIBCPP_INLINE_VISIBILITY
+constexpr auto size(const _Cont& __c)
+_NOEXCEPT_(noexcept(__c.size()))
+-> decltype        (__c.size())
+{ return            __c.size(); }
+
+template <class _Tp, size_t _Sz>
+_LIBCPP_INLINE_VISIBILITY
+constexpr size_t size(const _Tp (&)[_Sz]) noexcept { return _Sz; }
+
+#if _LIBCPP_STD_VER > 17
+template <class _Cont>
+_LIBCPP_INLINE_VISIBILITY
+constexpr auto ssize(const _Cont& __c)
+_NOEXCEPT_(noexcept(static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size())))
+->                              common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>
+{ return            static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size()); }
+
+template <class _Tp, ptrdiff_t _Sz>
+_LIBCPP_INLINE_VISIBILITY
+constexpr ptrdiff_t ssize(const _Tp (&)[_Sz]) noexcept { return _Sz; }
+#endif
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_SIZE_H