aria2/src/SimpleRandomizer.cc

129 lines
3.6 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "SimpleRandomizer.h"
#include <sys/types.h>
#include <unistd.h>
#include <cstdlib>
#include <cassert>
#include <cstring>
#include "a2time.h"
namespace aria2 {
std::unique_ptr<SimpleRandomizer> SimpleRandomizer::randomizer_;
const std::unique_ptr<SimpleRandomizer>& SimpleRandomizer::getInstance()
{
if(!randomizer_) {
randomizer_.reset(new SimpleRandomizer());
}
return randomizer_;
}
void SimpleRandomizer::init()
{
#ifndef __MINGW32__
// Just in case std::random_device() is fixed, add time and pid too.
eng_.seed(std::random_device()()^time(nullptr)^getpid());
#endif // !__MINGW32__
}
SimpleRandomizer::SimpleRandomizer()
{
#ifdef __MINGW32__
BOOL r = CryptAcquireContext(&cryProvider_, 0, 0, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT|CRYPT_SILENT);
assert(r);
#endif // __MINGW32__
}
SimpleRandomizer::~SimpleRandomizer()
{
#ifdef __MINGW32__
CryptReleaseContext(cryProvider_, 0);
#endif // __MINGW32__
}
long int SimpleRandomizer::getRandomNumber(long int to)
{
assert(to > 0);
#ifdef __MINGW32__
int32_t val;
BOOL r = CryptGenRandom(cryProvider_, sizeof(val),
reinterpret_cast<BYTE*>(&val));
assert(r);
if(val == INT32_MIN) {
val = INT32_MAX;
} else if(val < 0) {
val = -val;
}
return val % to;
#else // !__MINGW32__
return std::uniform_int_distribution<long int>(0, to - 1)(eng_);
#endif // !__MINGW32__
}
long int SimpleRandomizer::operator()(long int to)
{
return getRandomNumber(to);
}
void SimpleRandomizer::getRandomBytes(unsigned char *buf, size_t len)
{
#ifdef __MINGW32__
if (!CryptGenRandom(cryProvider_, len, (PBYTE)buf)) {
throw std::bad_alloc();
}
#else
uint32_t val;
size_t q = len / sizeof(val);
size_t r = len % sizeof(val);
auto gen = std::bind(std::uniform_int_distribution<uint32_t>
(0, std::numeric_limits<uint32_t>::max()),
eng_);
for(; q > 0; --q) {
val = gen();
memcpy(buf, &val, sizeof(val));
buf += sizeof(val);
}
val = gen();
memcpy(buf, &val, r);
#endif
}
} // namespace aria2