forked from OSchip/llvm-project
62 lines
2.8 KiB
C++
62 lines
2.8 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___RANDOM_IS_VALID_H
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#define _LIBCPP___RANDOM_IS_VALID_H
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#include <__config>
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#include <cstdint>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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// [rand.req.genl]/1.5:
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// The effect of instantiating a template that has a template type parameter
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// named IntType is undefined unless the corresponding template argument is
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// cv-unqualified and is one of short, int, long, long long, unsigned short,
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// unsigned int, unsigned long, or unsigned long long.
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template<class> struct __libcpp_random_is_valid_inttype : false_type {};
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template<> struct __libcpp_random_is_valid_inttype<int8_t> : true_type {}; // extension
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template<> struct __libcpp_random_is_valid_inttype<short> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<int> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<long> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<long long> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<uint8_t> : true_type {}; // extension
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template<> struct __libcpp_random_is_valid_inttype<unsigned short> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<unsigned int> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<unsigned long> : true_type {};
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template<> struct __libcpp_random_is_valid_inttype<unsigned long long> : true_type {};
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#ifndef _LIBCPP_HAS_NO_INT128
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template<> struct __libcpp_random_is_valid_inttype<__int128_t> : true_type {}; // extension
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template<> struct __libcpp_random_is_valid_inttype<__uint128_t> : true_type {}; // extension
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#endif // _LIBCPP_HAS_NO_INT128
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// [rand.req.urng]/3:
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// A class G meets the uniform random bit generator requirements if G models
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// uniform_random_bit_generator, invoke_result_t<G&> is an unsigned integer type,
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// and G provides a nested typedef-name result_type that denotes the same type
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// as invoke_result_t<G&>.
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// (In particular, reject URNGs with signed result_types; our distributions cannot
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// handle such generator types.)
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template<class, class = void> struct __libcpp_random_is_valid_urng : false_type {};
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template<class _Gp> struct __libcpp_random_is_valid_urng<_Gp, __enable_if_t<
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is_unsigned<typename _Gp::result_type>::value &&
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_IsSame<decltype(declval<_Gp&>()()), typename _Gp::result_type>::value
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> > : true_type {};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANDOM_IS_VALID_H
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