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// random -*- C++ -*-
// Copyright (C) 2012-2019 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#define _GLIBCXX_USE_CXX11_ABI 1
#include <random>
#ifdef _GLIBCXX_USE_C99_STDINT_TR1
#if defined __i386__ || defined __x86_64__
# include <cpuid.h>
#endif
#include <cerrno>
#include <cstdio>
#ifdef _GLIBCXX_HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#ifdef _GLIBCXX_HAVE_LINUX_TYPES_H
# include <linux/types.h>
#endif
#ifdef _GLIBCXX_HAVE_LINUX_RANDOM_H
# include <linux/random.h>
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
namespace
{
static unsigned long
_M_strtoul(const std::string& __str)
{
unsigned long __ret = 5489UL;
if (__str != "mt19937")
{
const char* __nptr = __str.c_str();
char* __endptr;
__ret = std::strtoul(__nptr, &__endptr, 0);
if (*__nptr == '\0' || *__endptr != '\0')
std::__throw_runtime_error(__N("random_device::_M_strtoul"
"(const std::string&)"));
}
return __ret;
}
#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
unsigned int
__attribute__ ((target("rdrnd")))
__x86_rdrand(void)
{
unsigned int retries = 100;
unsigned int val;
while (__builtin_ia32_rdrand32_step(&val) == 0)
if (--retries == 0)
std::__throw_runtime_error(__N("random_device::__x86_rdrand(void)"));
return val;
}
#endif
}
void
random_device::_M_init(const std::string& token)
{
const char *fname = token.c_str();
if (token == "default")
{
#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
unsigned int eax, ebx, ecx, edx;
// Check availability of cpuid and, for now at least, also the
// CPU signature for Intel's
if (__get_cpuid_max(0, &ebx) > 0 && ebx == signature_INTEL_ebx)
{
__cpuid(1, eax, ebx, ecx, edx);
if (ecx & bit_RDRND)
{
_M_file = nullptr;
return;
}
}
#endif
fname = "/dev/urandom";
}
else if (token != "/dev/urandom" && token != "/dev/random")
fail:
std::__throw_runtime_error(__N("random_device::"
"random_device(const std::string&)"));
_M_file = static_cast<void*>(std::fopen(fname, "rb"));
if (!_M_file)
goto fail;
}
void
random_device::_M_init_pretr1(const std::string& token)
{
_M_mt.seed(_M_strtoul(token));
}
void
random_device::_M_fini()
{
if (_M_file)
std::fclose(static_cast<FILE*>(_M_file));
}
random_device::result_type
random_device::_M_getval()
{
#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
if (!_M_file)
return __x86_rdrand();
#endif
result_type __ret;
void* p = &__ret;
size_t n = sizeof(result_type);
#ifdef _GLIBCXX_HAVE_UNISTD_H
do
{
const int e = read(fileno(static_cast<FILE*>(_M_file)), p, n);
if (e > 0)
{
n -= e;
p = static_cast<char*>(p) + e;
}
else if (e != -1 || errno != EINTR)
__throw_runtime_error(__N("random_device could not be read"));
}
while (n > 0);
#else
const size_t e = std::fread(p, n, 1, static_cast<FILE*>(_M_file));
if (e != 1)
__throw_runtime_error(__N("random_device could not be read"));
#endif
return __ret;
}
random_device::result_type
random_device::_M_getval_pretr1()
{
return _M_mt();
}
double
random_device::_M_getentropy() const noexcept
{
#if defined _GLIBCXX_HAVE_SYS_IOCTL_H && defined RNDGETENTCNT
if (!_M_file)
return 0.0;
const int fd = fileno(static_cast<FILE*>(_M_file));
if (fd < 0)
return 0.0;
int ent;
if (ioctl(fd, RNDGETENTCNT, &ent) < 0)
return 0.0;
if (ent < 0)
return 0.0;
const int max = sizeof(result_type) * __CHAR_BIT__;
if (ent > max)
ent = max;
return static_cast<double>(ent);
#else
return 0.0;
#endif
}
template class mersenne_twister_engine<
uint_fast32_t,
32, 624, 397, 31,
0x9908b0dfUL, 11,
0xffffffffUL, 7,
0x9d2c5680UL, 15,
0xefc60000UL, 18, 1812433253UL>;
}
#endif
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