Files
opendht/src/infohash.cpp
T

102 lines
3.1 KiB
C++

/*
* Copyright (C) 2014-2015 Savoir-Faire Linux Inc.
* Author : Adrien Béraud <adrien.beraud@savoirfairelinux.com>
*
* 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 3 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.
*
* Additional permission under GNU GPL version 3 section 7:
*
* If you modify this program, or any covered work, by linking or
* combining it with the OpenSSL project's OpenSSL library (or a
* modified version of that library), containing parts covered by the
* terms of the OpenSSL or SSLeay licenses, Savoir-Faire Linux Inc.
* grants you additional permission to convey the resulting work.
* Corresponding Source for a non-source form of such a combination
* shall include the source code for the parts of OpenSSL used as well
* as that of the covered work.
*/
#include "infohash.h"
#include "rng.h"
extern "C" {
#include <gnutls/gnutls.h>
}
#include <functional>
#include <sstream>
#include <cstdio>
namespace dht {
InfoHash::InfoHash(const std::string& hex) {
if (hex.size() < 2*HASH_LEN) {
fill(0);
return;
}
const auto p = (const char*)hex.data();
for (size_t i = 0; i < HASH_LEN; i++) {
unsigned res = 0;
sscanf(p + 2*i, "%02x", &res);
(*this)[i] = res;
}
}
InfoHash
InfoHash::get(const uint8_t* data, size_t data_len)
{
InfoHash h;
size_t s = h.size();
const gnutls_datum_t gnudata = {(uint8_t*)data, (unsigned)data_len};
const gnutls_digest_algorithm_t algo = (HASH_LEN == 64) ? GNUTLS_DIG_SHA512 : (
(HASH_LEN == 32) ? GNUTLS_DIG_SHA256 : (
(HASH_LEN == 20) ? GNUTLS_DIG_SHA1 :
GNUTLS_DIG_NULL ));
static_assert(algo != GNUTLS_DIG_NULL, "Can't find hash function to use.");
int rc = gnutls_fingerprint(algo, &gnudata, h.data(), &s);
if (rc == 0 && s == HASH_LEN)
return h;
throw std::string("Error while hashing");
}
InfoHash
InfoHash::getRandom()
{
InfoHash h;
crypto::random_device rdev;
std::uniform_int_distribution<uint8_t> rand_byte;
std::generate(h.begin(), h.end(), std::bind(rand_byte, std::ref(rdev)));
return h;
}
std::string
InfoHash::toString() const
{
std::stringstream ss;
ss << *this;
return ss.str();
}
std::ostream& operator<< (std::ostream& s, const InfoHash& h)
{
s << std::hex;
for (unsigned i=0; i<HASH_LEN; i++)
s << std::setfill('0') << std::setw(2) << (unsigned)h[i];
s << std::dec;
return s;
}
}