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___CXX03___ITERATOR_DISTANCE_H
11 #define _LIBCPP___CXX03___ITERATOR_DISTANCE_H
12
13 #include <__cxx03/__config>
14 #include <__cxx03/__iterator/iterator_traits.h>
15 #include <__cxx03/__type_traits/decay.h>
16 #include <__cxx03/__type_traits/remove_cvref.h>
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 template <class _InputIter>
25 inline _LIBCPP_HIDE_FROM_ABI typename iterator_traits<_InputIter>::difference_type
__distance(_InputIter __first,_InputIter __last,input_iterator_tag)26 __distance(_InputIter __first, _InputIter __last, input_iterator_tag) {
27 typename iterator_traits<_InputIter>::difference_type __r(0);
28 for (; __first != __last; ++__first)
29 ++__r;
30 return __r;
31 }
32
33 template <class _RandIter>
34 inline _LIBCPP_HIDE_FROM_ABI typename iterator_traits<_RandIter>::difference_type
__distance(_RandIter __first,_RandIter __last,random_access_iterator_tag)35 __distance(_RandIter __first, _RandIter __last, random_access_iterator_tag) {
36 return __last - __first;
37 }
38
39 template <class _InputIter>
40 inline _LIBCPP_HIDE_FROM_ABI typename iterator_traits<_InputIter>::difference_type
distance(_InputIter __first,_InputIter __last)41 distance(_InputIter __first, _InputIter __last) {
42 return std::__distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());
43 }
44
45 _LIBCPP_END_NAMESPACE_STD
46
47 #endif // _LIBCPP___CXX03___ITERATOR_DISTANCE_H
48