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_DISTANCE_H 11 #define _LIBCPP___ITERATOR_DISTANCE_H 12 13 #include <__config> 14 #include <__iterator/iterator_traits.h> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 #pragma GCC system_header 18 #endif 19 20 _LIBCPP_PUSH_MACROS 21 #include <__undef_macros> 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 template <class _InputIter> 26 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 27 typename iterator_traits<_InputIter>::difference_type 28 __distance(_InputIter __first, _InputIter __last, input_iterator_tag) 29 { 30 typename iterator_traits<_InputIter>::difference_type __r(0); 31 for (; __first != __last; ++__first) 32 ++__r; 33 return __r; 34 } 35 36 template <class _RandIter> 37 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 38 typename iterator_traits<_RandIter>::difference_type 39 __distance(_RandIter __first, _RandIter __last, random_access_iterator_tag) 40 { 41 return __last - __first; 42 } 43 44 template <class _InputIter> 45 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 46 typename iterator_traits<_InputIter>::difference_type 47 distance(_InputIter __first, _InputIter __last) 48 { 49 return _VSTD::__distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category()); 50 } 51 52 _LIBCPP_END_NAMESPACE_STD 53 54 _LIBCPP_POP_MACROS 55 56 #endif // _LIBCPP___ITERATOR_DISTANCE_H 57