1 //===----------------------------------------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 #ifndef _LIBCPP___RANDOM_RANDOM_DEVICE_H
10 #define _LIBCPP___RANDOM_RANDOM_DEVICE_H
15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16 # pragma GCC system_header
20 #include <__undef_macros>
22 _LIBCPP_BEGIN_NAMESPACE_STD
24 #if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
26 class _LIBCPP_EXPORTED_FROM_ABI random_device
28 #ifdef _LIBCPP_USING_DEV_RANDOM
30 #elif !defined(_LIBCPP_ABI_NO_RANDOM_DEVICE_COMPATIBILITY_LAYOUT)
31 _LIBCPP_DIAGNOSTIC_PUSH
32 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-private-field")
34 // Apple platforms used to use the `_LIBCPP_USING_DEV_RANDOM` code path, and now
35 // use `arc4random()` as of this comment. In order to avoid breaking the ABI, we
36 // retain the same layout as before.
37 # if defined(__APPLE__)
38 int __padding_
; // padding to fake the `__f_` field above
41 // ... vendors can add workarounds here if they switch to a different representation ...
43 _LIBCPP_DIAGNOSTIC_POP
48 typedef unsigned result_type
;
50 // generator characteristics
51 static _LIBCPP_CONSTEXPR
const result_type _Min
= 0;
52 static _LIBCPP_CONSTEXPR
const result_type _Max
= 0xFFFFFFFFu
;
54 _LIBCPP_INLINE_VISIBILITY
55 static _LIBCPP_CONSTEXPR result_type
min() { return _Min
;}
56 _LIBCPP_INLINE_VISIBILITY
57 static _LIBCPP_CONSTEXPR result_type
max() { return _Max
;}
60 #ifndef _LIBCPP_CXX03_LANG
61 _LIBCPP_HIDE_FROM_ABI
random_device() : random_device("/dev/urandom") {}
62 explicit random_device(const string
& __token
);
64 explicit random_device(const string
& __token
= "/dev/urandom");
68 // generating functions
69 result_type
operator()();
72 double entropy() const _NOEXCEPT
;
74 random_device(const random_device
&) = delete;
75 void operator=(const random_device
&) = delete;
78 #endif // !_LIBCPP_HAS_NO_RANDOM_DEVICE
80 _LIBCPP_END_NAMESPACE_STD
84 #endif // _LIBCPP___RANDOM_RANDOM_DEVICE_H