/*
    Copyright (C) 2014-2021 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic 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.

    DCP-o-matic 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 DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/


#include "digester.h"
#include "dcpomatic_assert.h"
#include <nettle/md5.h>
#include <nettle/version.h>
#include <iomanip>
#include <cstdio>


using std::string;
using std::hex;
using std::setfill;
using std::setw;


Digester::Digester()
{
	md5_init(&_context);
}


Digester::~Digester()
{
	get();
}


void
Digester::add(void const * data, size_t size)
{
	md5_update(&_context, size, reinterpret_cast<uint8_t const *>(data));
}


void
Digester::add(string const & s)
{
	add(s.c_str(), s.length());
}


string
Digester::get() const
{
	if (!_digest) {
		unsigned char digest[MD5_DIGEST_SIZE];
#if NETTLE_VERSION_MAJOR >= 4
		md5_digest(&_context, digest);
#else
		md5_digest(&_context, MD5_DIGEST_SIZE, digest);
#endif

		char hex[MD5_DIGEST_SIZE * 2 + 1];
		for (int i = 0; i < MD5_DIGEST_SIZE; ++i) {
			snprintf(hex + i * 2, 3, "%02x", digest[i]);
		}

		_digest = hex;
	}

	return _digest.get();
}


void
Digester::get(uint8_t* buffer) const
{
#if NETTLE_VERSION_MAJOR >= 4
	md5_digest(&_context, buffer);
#else
	md5_digest(&_context, MD5_DIGEST_SIZE, buffer);
#endif
}


int
Digester::size() const
{
	return MD5_DIGEST_SIZE;
}