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___RANDOM_RANDOM_DEVICE_H
10#define _LIBCPP___RANDOM_RANDOM_DEVICE_H
11
12#include <__config>
13#include <string>
14
15#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16#  pragma GCC system_header
17#endif
18
19_LIBCPP_PUSH_MACROS
20#include <__undef_macros>
21
22_LIBCPP_BEGIN_NAMESPACE_STD
23
24#if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
25
26class _LIBCPP_EXPORTED_FROM_ABI random_device {
27#  ifdef _LIBCPP_USING_DEV_RANDOM
28  int __f_;
29#  elif !defined(_LIBCPP_ABI_NO_RANDOM_DEVICE_COMPATIBILITY_LAYOUT)
30  _LIBCPP_DIAGNOSTIC_PUSH
31  _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-private-field")
32
33  // Apple platforms used to use the `_LIBCPP_USING_DEV_RANDOM` code path, and now
34  // use `arc4random()` as of this comment. In order to avoid breaking the ABI, we
35  // retain the same layout as before.
36#    if defined(__APPLE__)
37  int __padding_; // padding to fake the `__f_` field above
38#    endif
39
40  // ... vendors can add workarounds here if they switch to a different representation ...
41
42  _LIBCPP_DIAGNOSTIC_POP
43#  endif
44
45public:
46  // types
47  typedef unsigned result_type;
48
49  // generator characteristics
50  static _LIBCPP_CONSTEXPR const result_type _Min = 0;
51  static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
52
53  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
54  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
55
56  // constructors
57#  ifndef _LIBCPP_CXX03_LANG
58  _LIBCPP_HIDE_FROM_ABI random_device() : random_device("/dev/urandom") {}
59  explicit random_device(const string& __token);
60#  else
61  explicit random_device(const string& __token = "/dev/urandom");
62#  endif
63  ~random_device();
64
65  // generating functions
66  result_type operator()();
67
68  // property functions
69  double entropy() const _NOEXCEPT;
70
71  random_device(const random_device&)  = delete;
72  void operator=(const random_device&) = delete;
73};
74
75#endif // !_LIBCPP_HAS_NO_RANDOM_DEVICE
76
77_LIBCPP_END_NAMESPACE_STD
78
79_LIBCPP_POP_MACROS
80
81#endif // _LIBCPP___RANDOM_RANDOM_DEVICE_H
82