1 //===-------------------------- random.cpp --------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #if defined(_WIN32) 11 // Must be defined before including stdlib.h to enable rand_s(). 12 #define _CRT_RAND_S 13 #include <stdio.h> 14 #endif 15 16 #include "random" 17 #include "system_error" 18 19 #ifdef __sun__ 20 #define rename solaris_headers_are_broken 21 #endif 22 #include <fcntl.h> 23 #include <unistd.h> 24 #include <errno.h> 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 #if defined(_WIN32) 29 random_device::random_device(const string&) 30 { 31 } 32 33 random_device::~random_device() 34 { 35 } 36 37 unsigned 38 random_device::operator()() 39 { 40 unsigned r; 41 errno_t err = rand_s(&r); 42 if (err) 43 __throw_system_error(err, "random_device rand_s failed."); 44 return r; 45 } 46 #else 47 random_device::random_device(const string& __token) 48 : __f_(open(__token.c_str(), O_RDONLY)) 49 { 50 if (__f_ <= 0) 51 __throw_system_error(errno, ("random_device failed to open " + __token).c_str()); 52 } 53 54 random_device::~random_device() 55 { 56 close(__f_); 57 } 58 59 unsigned 60 random_device::operator()() 61 { 62 unsigned r; 63 read(__f_, &r, sizeof(r)); 64 return r; 65 } 66 #endif // defined(_WIN32) 67 68 double 69 random_device::entropy() const _NOEXCEPT 70 { 71 return 0; 72 } 73 74 _LIBCPP_END_NAMESPACE_STD 75