/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * 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 2

 * 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. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/nonce.c#3 $

 */

#include "nonce.h"

#include "murmur/MurmurHash3.h"

#include "numeric.h"

#include "random.h"

#include "stringUtils.h"

#include "timeUtils.h"

/*****************************************************************************/

static uint64_t hashStuff(uint64_t start, const void *data, size_t len)

{

  uint32_t seed = start ^ (start >> 27);

  byte hashBuffer[16];

  MurmurHash3_x64_128(data, len, seed, hashBuffer);

  return getUInt64LE(hashBuffer + 4);

}

/*****************************************************************************/

static void *memput(void *buf, void *end, const void *data, size_t len)

{

  byte *bp = buf;

  byte *be = end;

  size_t chunk = minSizeT(len, be - bp);

  memcpy(bp, data, chunk);

  return bp + chunk;

}

/*****************************************************************************/

size_t createUniqueNonceData(byte *buffer, size_t length)

{

  AbsTime now = currentTime(CLOCK_REALTIME);

  byte *be = buffer + length;

  byte *bp = memput(buffer, be, &now, sizeof(now));

  uint32_t rand = randomInRange(1, (1<<30) - 1);

  bp = memput(bp, be, &rand, sizeof(rand));

  while (bp < be) {

    size_t n = minSizeT(be - bp, bp - buffer);

    memcpy(bp, buffer, n);

    bp += n;

  }

  return bp - buffer;

}

/*****************************************************************************/

uint64_t generateMasterNonce(const void *data, size_t len)

{

  return hashStuff(0xa1b1e0fc, data, len);

}

/*****************************************************************************/

uint64_t generateSecondaryNonce(uint64_t    nonce,

                                const void *data,

                                size_t      len)

{

  return hashStuff(nonce + 1, data, len);

}