external/bsd/libc++/dist/libcxx/src/random.cpp

   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 #if !defined(_WIN32)
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #endif // defined(_WIN32)
  26 #include <errno.h>
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 #if defined(_WIN32)
  31 random_device::random_device(const string&)
  32 {
  33 }
  34
  35 random_device::~random_device()
  36 {
  37 }
  38
  39 unsigned
  40 random_device::operator()()
  41 {
  42     unsigned r;
  43     errno_t err = rand_s(&r);
  44     if (err)
  45         __throw_system_error(err, "random_device rand_s failed.");
  46     return r;
  47 }
  48 #else
  49 random_device::random_device(const string& __token)
  50     : __f_(open(__token.c_str(), O_RDONLY))
  51 {
  52     if (__f_ <= 0)
  53         __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
  54 }
  55
  56 random_device::~random_device()
  57 {
  58     close(__f_);
  59 }
  60
  61 unsigned
  62 random_device::operator()()
  63 {
  64     unsigned r;
  65     read(__f_, &r, sizeof(r));
  66     return r;
  67 }
  68 #endif // defined(_WIN32)
  69
  70 double
  71 random_device::entropy() const _NOEXCEPT
  72 {
  73     return 0;
  74 }
  75
  76 _LIBCPP_END_NAMESPACE_STD