1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___ITERATOR_SIZE_H
11#define _LIBCPP___ITERATOR_SIZE_H
12
13#include <__config>
14#include <__type_traits/common_type.h>
15#include <__type_traits/make_signed.h>
16#include <cstddef>
17
18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19#  pragma GCC system_header
20#endif
21
22_LIBCPP_BEGIN_NAMESPACE_STD
23
24#if _LIBCPP_STD_VER >= 17
25
26template <class _Cont>
27_LIBCPP_HIDE_FROM_ABI constexpr auto size(const _Cont& __c) _NOEXCEPT_(noexcept(__c.size())) -> decltype(__c.size()) {
28  return __c.size();
29}
30
31template <class _Tp, size_t _Sz>
32_LIBCPP_HIDE_FROM_ABI constexpr size_t size(const _Tp (&)[_Sz]) noexcept {
33  return _Sz;
34}
35
36#  if _LIBCPP_STD_VER >= 20
37template <class _Cont>
38_LIBCPP_HIDE_FROM_ABI constexpr auto ssize(const _Cont& __c)
39    _NOEXCEPT_(noexcept(static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size())))
40        -> common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>> {
41  return static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size());
42}
43
44// GCC complains about the implicit conversion from ptrdiff_t to size_t in
45// the array bound.
46_LIBCPP_DIAGNOSTIC_PUSH
47_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wsign-conversion")
48template <class _Tp, ptrdiff_t _Sz>
49_LIBCPP_HIDE_FROM_ABI constexpr ptrdiff_t ssize(const _Tp (&)[_Sz]) noexcept {
50  return _Sz;
51}
52_LIBCPP_DIAGNOSTIC_POP
53#  endif
54
55#endif // _LIBCPP_STD_VER >= 17
56
57_LIBCPP_END_NAMESPACE_STD
58
59#endif // _LIBCPP___ITERATOR_SIZE_H
60