xref: /freebsd/contrib/llvm-project/libcxx/include/__utility/is_pointer_in_range.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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 #include <__utility/is_valid_range.h>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 template <class _Tp, class _Up, class = void>
29 struct __is_less_than_comparable : false_type {};
30 
31 template <class _Tp, class _Up>
32 struct __is_less_than_comparable<_Tp, _Up, __void_t<decltype(std::declval<_Tp>() < std::declval<_Up>())> > : true_type {
33 };
34 
35 template <class _Tp, class _Up, __enable_if_t<__is_less_than_comparable<const _Tp*, const _Up*>::value, int> = 0>
36 _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_SANITIZE("address") bool
37 __is_pointer_in_range(const _Tp* __begin, const _Tp* __end, const _Up* __ptr) {
38   _LIBCPP_ASSERT_VALID_INPUT_RANGE(std::__is_valid_range(__begin, __end), "[__begin, __end) is not a valid range");
39 
40   if (__libcpp_is_constant_evaluated()) {
41     // If this is not a constant during constant evaluation we know that __ptr is not part of the allocation where
42     // [__begin, __end) is.
43     if (!__builtin_constant_p(__begin <= __ptr && __ptr < __end))
44       return false;
45   }
46 
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
52 __is_pointer_in_range(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