/*
     This file is part of GNUnet.
     Copyright (C) 2002, 2003, 2004, 2006, 2013 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @author Christian Grothoff
 * @file nse/perf_kdf.c
 * @brief measure performance of KDF hash function
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include <gcrypt.h>
#include <gauger.h>



/**
 * Calculate the 'proof-of-work' hash (an expensive hash).
 *
 * @param buf data to hash
 * @param buf_len number of bytes in 'buf'
 * @param result where to write the resulting hash
 */
static void
pow_hash (const void *buf,
	  size_t buf_len,
	  struct GNUNET_HashCode *result)
{
  GNUNET_break (0 ==
		gcry_kdf_derive (buf, buf_len,
				 GCRY_KDF_SCRYPT,
				 1 /* subalgo */,
				 "gnunet-proof-of-work", strlen ("gnunet-proof-of-work"),
				 2 /* iterations; keep cost of individual op small */,
				 sizeof (struct GNUNET_HashCode), result));
}


static void
perfHash ()
{
  struct GNUNET_HashCode hc;
  unsigned int i;
  char buf[64];

  memset (buf, 1,  sizeof (buf));
  for (i = 0; i < 1024; i++)
    pow_hash (buf, sizeof (buf), &hc);
}


int
main (int argc, char *argv[])
{
  struct GNUNET_TIME_Absolute start;

  start = GNUNET_TIME_absolute_get ();
  perfHash ();
  printf ("Hash perf took %s\n",
          GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (start),
						  GNUNET_YES));
  GAUGER ("NSE", "Proof-of-work hashing",
          1024.0 / (1.0 +
		  GNUNET_TIME_absolute_get_duration
		  (start).rel_value_us / 1000.0), "hashes/ms");
  return 0;
}

/* end of perf_kdf.c */