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 _LIBCPP_HAS_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_RANDOM_DEVICE
76
77_LIBCPP_END_NAMESPACE_STD
78
79_LIBCPP_POP_MACROS
80
81#endif // _LIBCPP___RANDOM_RANDOM_DEVICE_H
82