1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___UTILITY_IS_POINTER_IN_RANGE_H 10 #define _LIBCPP___UTILITY_IS_POINTER_IN_RANGE_H 11 12 #include <__algorithm/comp.h> 13 #include <__assert> 14 #include <__config> 15 #include <__type_traits/enable_if.h> 16 #include <__type_traits/integral_constant.h> 17 #include <__type_traits/is_constant_evaluated.h> 18 #include <__type_traits/void_t.h> 19 #include <__utility/declval.h> 20 21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22 # pragma GCC system_header 23 #endif 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 template <class _Tp, class _Up, class = void> 28 struct __is_less_than_comparable : false_type {}; 29 30 template <class _Tp, class _Up> 31 struct __is_less_than_comparable<_Tp, _Up, __void_t<decltype(std::declval<_Tp>() < std::declval<_Up>())> > : true_type { 32 }; 33 34 template <class _Tp, class _Up, __enable_if_t<__is_less_than_comparable<const _Tp*, const _Up*>::value, int> = 0> 35 _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_SANITIZE("address") bool __is_pointer_in_range( 36 const _Tp* __begin, const _Tp* __end, const _Up* __ptr) { 37 if (__libcpp_is_constant_evaluated()) { 38 _LIBCPP_ASSERT_UNCATEGORIZED(__builtin_constant_p(__begin <= __end), "__begin and __end do not form a range"); 39 40 // If this is not a constant during constant evaluation we know that __ptr is not part of the allocation where 41 // [__begin, __end) is. 42 if (!__builtin_constant_p(__begin <= __ptr && __ptr < __end)) 43 return false; 44 } 45 46 // Checking this for unrelated pointers is technically UB, but no compiler optimizes based on it (currently). 47 return !__less<>()(__ptr, __begin) && __less<>()(__ptr, __end); 48 } 49 50 template <class _Tp, class _Up, __enable_if_t<!__is_less_than_comparable<const _Tp*, const _Up*>::value, int> = 0> 51 _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_SANITIZE("address") bool __is_pointer_in_range( 52 const _Tp* __begin, const _Tp* __end, const _Up* __ptr) { 53 if (__libcpp_is_constant_evaluated()) 54 return false; 55 56 return reinterpret_cast<const char*>(__begin) <= reinterpret_cast<const char*>(__ptr) && 57 reinterpret_cast<const char*>(__ptr) < reinterpret_cast<const char*>(__end); 58 } 59 60 _LIBCPP_END_NAMESPACE_STD 61 62 #endif // _LIBCPP___UTILITY_IS_POINTER_IN_RANGE_H 63