llvm-project/libcxx/include/__random/random_device.h

85 lines
2.3 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANDOM_RANDOM_DEVICE_H
#define _LIBCPP___RANDOM_RANDOM_DEVICE_H
#include <__config>
#include <string>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
class _LIBCPP_TYPE_VIS random_device
{
#ifdef _LIBCPP_USING_DEV_RANDOM
int __f_;
#elif !defined(_LIBCPP_ABI_NO_RANDOM_DEVICE_COMPATIBILITY_LAYOUT)
_LIBCPP_DIAGNOSTIC_PUSH
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-private-field")
// Apple platforms used to use the `_LIBCPP_USING_DEV_RANDOM` code path, and now
// use `arc4random()` as of this comment. In order to avoid breaking the ABI, we
// retain the same layout as before.
# if defined(__APPLE__)
int __padding_; // padding to fake the `__f_` field above
# endif
// ... vendors can add workarounds here if they switch to a different representation ...
_LIBCPP_DIAGNOSTIC_POP
#endif
public:
// types
typedef unsigned result_type;
// generator characteristics
static _LIBCPP_CONSTEXPR const result_type _Min = 0;
static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
_LIBCPP_INLINE_VISIBILITY
static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
_LIBCPP_INLINE_VISIBILITY
static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
// constructors
#ifndef _LIBCPP_CXX03_LANG
random_device() : random_device("/dev/urandom") {}
explicit random_device(const string& __token);
#else
explicit random_device(const string& __token = "/dev/urandom");
#endif
~random_device();
// generating functions
result_type operator()();
// property functions
double entropy() const _NOEXCEPT;
random_device(const random_device&) = delete;
void operator=(const random_device&) = delete;
};
#endif // !_LIBCPP_HAS_NO_RANDOM_DEVICE
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANDOM_RANDOM_DEVICE_H