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OpenVPNAdapter/Sources/OpenVPN3/openvpn/random/randbytestore.hpp

68 lines
1.8 KiB
C++

// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012-2017 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// as published by the Free Software Foundation.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
#ifndef OPENVPN_RANDOM_RANDBYTESTORE_H
#define OPENVPN_RANDOM_RANDBYTESTORE_H
#include <openvpn/common/size.hpp>
namespace openvpn {
template <typename RAND_TYPE>
class RandomByteStore
{
public:
static constexpr size_t SIZE = sizeof(typename RAND_TYPE::result_type);
unsigned char get_byte(RAND_TYPE& rng)
{
if (n_bytes == 0)
{
res.rt = rng();
n_bytes = SIZE;
}
unsigned char ret = res.bytes[0];
res.rt >>= 8;
--n_bytes;
return ret;
}
template <typename T>
void fill(T& obj, RAND_TYPE& rng)
{
unsigned char *data = reinterpret_cast<unsigned char *>(&obj);
for (size_t i = 0; i < sizeof(obj); ++i)
data[i] = get_byte(rng);
}
private:
union Result {
unsigned char bytes[SIZE];
typename RAND_TYPE::result_type rt;
};
Result res;
unsigned int n_bytes = 0;
};
}
#endif