/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
 *  Copyright 2007 Sun Microsystems, Inc.
 *  Copyright (C) 2009  Vladimir Serbinenko <phcoder@gmail.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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <grub/err.h>
#include <grub/file.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/types.h>
#include <grub/zfs/zfs.h>
#include <grub/zfs/zio.h>
#include <grub/zfs/dnode.h>
#include <grub/zfs/uberblock_impl.h>
#include <grub/zfs/vdev_impl.h>
#include <grub/zfs/zio_checksum.h>
#include <grub/zfs/zap_impl.h>
#include <grub/zfs/zap_leaf.h>
#include <grub/zfs/zfs_znode.h>
#include <grub/zfs/dmu.h>
#include <grub/zfs/dmu_objset.h>
#include <grub/zfs/dsl_dir.h>
#include <grub/zfs/dsl_dataset.h>

void
fletcher_2(const void *buf, grub_uint64_t size, grub_zfs_endian_t endian, 
	   zio_cksum_t *zcp)
{
  const grub_uint64_t *ip = buf;
  const grub_uint64_t *ipend = ip + (size / sizeof (grub_uint64_t));
  grub_uint64_t a0, b0, a1, b1;
  
  for (a0 = b0 = a1 = b1 = 0; ip < ipend; ip += 2) 
    {
      a0 += grub_zfs_to_cpu64 (ip[0], endian);
      a1 += grub_zfs_to_cpu64 (ip[1], endian);
      b0 += a0;
      b1 += a1;
    }

  zcp->zc_word[0] = grub_cpu_to_zfs64 (a0, endian);
  zcp->zc_word[1] = grub_cpu_to_zfs64 (a1, endian);
  zcp->zc_word[2] = grub_cpu_to_zfs64 (b0, endian);
  zcp->zc_word[3] = grub_cpu_to_zfs64 (b1, endian);
}

void
fletcher_4 (const void *buf, grub_uint64_t size, grub_zfs_endian_t endian, 
	    zio_cksum_t *zcp)
{
  const grub_uint32_t *ip = buf;
  const grub_uint32_t *ipend = ip + (size / sizeof (grub_uint32_t));
  grub_uint64_t a, b, c, d;
  
  for (a = b = c = d = 0; ip < ipend; ip++) 
    {
      a += grub_zfs_to_cpu32 (ip[0], endian);;
      b += a;
      c += b;
      d += c;
    }

  zcp->zc_word[0] = grub_cpu_to_zfs64 (a, endian);
  zcp->zc_word[1] = grub_cpu_to_zfs64 (b, endian);
  zcp->zc_word[2] = grub_cpu_to_zfs64 (c, endian);
  zcp->zc_word[3] = grub_cpu_to_zfs64 (d, endian);
}