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___ALGORITHM_COMP_REF_TYPE_H 10 #define _LIBCPP___ALGORITHM_COMP_REF_TYPE_H 11 12 #include <__config> 13 #include <__debug> 14 #include <__utility/declval.h> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 # pragma GCC system_header 18 #endif 19 20 _LIBCPP_BEGIN_NAMESPACE_STD 21 22 template <class _Compare> 23 struct __debug_less 24 { 25 _Compare &__comp_; 26 _LIBCPP_CONSTEXPR_SINCE_CXX14 __debug_less__debug_less27 __debug_less(_Compare& __c) : __comp_(__c) {} 28 29 template <class _Tp, class _Up> 30 _LIBCPP_CONSTEXPR_SINCE_CXX14 operator__debug_less31 bool operator()(const _Tp& __x, const _Up& __y) 32 { 33 bool __r = __comp_(__x, __y); 34 if (__r) 35 __do_compare_assert(0, __y, __x); 36 return __r; 37 } 38 39 template <class _Tp, class _Up> 40 _LIBCPP_CONSTEXPR_SINCE_CXX14 operator__debug_less41 bool operator()(_Tp& __x, _Up& __y) 42 { 43 bool __r = __comp_(__x, __y); 44 if (__r) 45 __do_compare_assert(0, __y, __x); 46 return __r; 47 } 48 49 template <class _LHS, class _RHS> 50 _LIBCPP_CONSTEXPR_SINCE_CXX14 51 inline _LIBCPP_INLINE_VISIBILITY 52 decltype((void)std::declval<_Compare&>()( 53 std::declval<_LHS &>(), std::declval<_RHS &>())) __do_compare_assert__debug_less54 __do_compare_assert(int, _LHS & __l, _RHS & __r) { 55 _LIBCPP_DEBUG_ASSERT(!__comp_(__l, __r), 56 "Comparator does not induce a strict weak ordering"); 57 (void)__l; 58 (void)__r; 59 } 60 61 template <class _LHS, class _RHS> 62 _LIBCPP_CONSTEXPR_SINCE_CXX14 63 inline _LIBCPP_INLINE_VISIBILITY __do_compare_assert__debug_less64 void __do_compare_assert(long, _LHS &, _RHS &) {} 65 }; 66 67 // Pass the comparator by lvalue reference. Or in debug mode, using a 68 // debugging wrapper that stores a reference. 69 #ifdef _LIBCPP_ENABLE_DEBUG_MODE 70 template <class _Comp> 71 using __comp_ref_type = __debug_less<_Comp>; 72 #else 73 template <class _Comp> 74 using __comp_ref_type = _Comp&; 75 #endif 76 77 _LIBCPP_END_NAMESPACE_STD 78 79 #endif // _LIBCPP___ALGORITHM_COMP_REF_TYPE_H 80