/*

 * Copyright (C) 2001-2012 Free Software Foundation, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 2.1 of

 * the License, 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

#include "gnutls_int.h"

#include "auth/srp_kx.h"

#include "auth/anon.h"

#include "auth/cert.h"

#include "auth/psk.h"

#include "errors.h"

#include "auth.h"

#include "state.h"

#include "datum.h"

#include "algorithms.h"

/**

 * gnutls_fingerprint:

 * @algo: is a digest algorithm

 * @data: is the data

 * @result: is the place where the result will be copied (may be null).

 * @result_size: should hold the size of the result. The actual size

 * of the returned result will also be copied there.

 *

 * This function will calculate a fingerprint (actually a hash), of

 * the given data.  The result is not printable data.  You should

 * convert it to hex, or to something else printable.

 *

 * This is the usual way to calculate a fingerprint of an X.509 DER

 * encoded certificate.  Note however that the fingerprint of an

 * OpenPGP certificate is not just a hash and cannot be calculated with this

 * function.

 *

 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise

 *   an error code is returned.

 **/

int gnutls_fingerprint(gnutls_digest_algorithm_t algo,

           const gnutls_datum_t *data, void *result,

           size_t *result_size)

{

  int ret;

  int hash_len = _gnutls_hash_get_algo_len(hash_to_entry(algo));

  if (hash_len < 0 || (unsigned)hash_len > *result_size ||

      result == NULL) {

    *result_size = hash_len;

    return GNUTLS_E_SHORT_MEMORY_BUFFER;

  }

  *result_size = hash_len;

  if (result) {

    ret = _gnutls_hash_fast(algo, data->data, data->size, result);

    if (ret < 0)

      return gnutls_assert_val(ret);

  }

  return 0;

}