1*61cfbce3SDimitry Andric //===----------------------------------------------------------------------===// 2*61cfbce3SDimitry Andric // 3*61cfbce3SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*61cfbce3SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*61cfbce3SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*61cfbce3SDimitry Andric // 7*61cfbce3SDimitry Andric //===----------------------------------------------------------------------===// 8*61cfbce3SDimitry Andric 9*61cfbce3SDimitry Andric #ifndef _LIBCPP___ALGORITHM_RANGES_UNIFORM_RANDOM_BIT_GENERATOR_ADAPTOR_H 10*61cfbce3SDimitry Andric #define _LIBCPP___ALGORITHM_RANGES_UNIFORM_RANDOM_BIT_GENERATOR_ADAPTOR_H 11*61cfbce3SDimitry Andric 12*61cfbce3SDimitry Andric #include <__config> 13*61cfbce3SDimitry Andric #include <__functional/invoke.h> 14*61cfbce3SDimitry Andric #include <type_traits> 15*61cfbce3SDimitry Andric 16*61cfbce3SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17*61cfbce3SDimitry Andric # pragma GCC system_header 18*61cfbce3SDimitry Andric #endif 19*61cfbce3SDimitry Andric 20*61cfbce3SDimitry Andric #if _LIBCPP_STD_VER > 17 21*61cfbce3SDimitry Andric 22*61cfbce3SDimitry Andric _LIBCPP_PUSH_MACROS 23*61cfbce3SDimitry Andric #include <__undef_macros> 24*61cfbce3SDimitry Andric 25*61cfbce3SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 26*61cfbce3SDimitry Andric 27*61cfbce3SDimitry Andric // Range versions of random algorithms (e.g. `std::shuffle`) are less constrained than their classic counterparts. 28*61cfbce3SDimitry Andric // Range algorithms only require the given generator to satisfy the `std::uniform_random_bit_generator` concept. 29*61cfbce3SDimitry Andric // Classic algorithms require the given generator to meet the uniform random bit generator requirements; these 30*61cfbce3SDimitry Andric // requirements include satisfying `std::uniform_random_bit_generator` and add a requirement for the generator to 31*61cfbce3SDimitry Andric // provide a nested `result_type` typedef (see `[rand.req.urng]`). 32*61cfbce3SDimitry Andric // 33*61cfbce3SDimitry Andric // To be able to reuse classic implementations, make the given generator meet the classic requirements by wrapping 34*61cfbce3SDimitry Andric // it into an adaptor type that forwards all of its interface and adds the required typedef. 35*61cfbce3SDimitry Andric template <class _Gen> 36*61cfbce3SDimitry Andric class _ClassicGenAdaptor { 37*61cfbce3SDimitry Andric private: 38*61cfbce3SDimitry Andric // The generator is not required to be copyable or movable, so it has to be stored as a reference. 39*61cfbce3SDimitry Andric _Gen& __gen; 40*61cfbce3SDimitry Andric 41*61cfbce3SDimitry Andric public: 42*61cfbce3SDimitry Andric using result_type = invoke_result_t<_Gen&>; 43*61cfbce3SDimitry Andric 44*61cfbce3SDimitry Andric _LIBCPP_HIDE_FROM_ABI 45*61cfbce3SDimitry Andric static constexpr auto min() { return __uncvref_t<_Gen>::min(); } 46*61cfbce3SDimitry Andric _LIBCPP_HIDE_FROM_ABI 47*61cfbce3SDimitry Andric static constexpr auto max() { return __uncvref_t<_Gen>::max(); } 48*61cfbce3SDimitry Andric 49*61cfbce3SDimitry Andric _LIBCPP_HIDE_FROM_ABI 50*61cfbce3SDimitry Andric constexpr explicit _ClassicGenAdaptor(_Gen& __g) : __gen(__g) {} 51*61cfbce3SDimitry Andric 52*61cfbce3SDimitry Andric _LIBCPP_HIDE_FROM_ABI 53*61cfbce3SDimitry Andric constexpr auto operator()() const { return __gen(); } 54*61cfbce3SDimitry Andric }; 55*61cfbce3SDimitry Andric 56*61cfbce3SDimitry Andric _LIBCPP_END_NAMESPACE_STD 57*61cfbce3SDimitry Andric 58*61cfbce3SDimitry Andric _LIBCPP_POP_MACROS 59*61cfbce3SDimitry Andric 60*61cfbce3SDimitry Andric #endif // _LIBCPP_STD_VER > 17 61*61cfbce3SDimitry Andric 62*61cfbce3SDimitry Andric #endif // _LIBCPP___ALGORITHM_RANGES_UNIFORM_RANDOM_BIT_GENERATOR_ADAPTOR_H 63