/* Copyright (c) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1997.

   The GNU C Library 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.

   The GNU C 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 the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <nss.h>

/* This is from libc/db/hash/hash_func.c, hash3 is static there */

/*

 * This is INCREDIBLY ugly, but fast.  We break the string up into 8 byte

 * units.  On the first time through the loop we get the "leftover bytes"

 * (strlen % 8).  On every other iteration, we perform 8 HASHC's so we handle

 * all 8 bytes.  Essentially, this saves us 7 cmp & branch instructions.  If

 * this routine is heavily used enough, it's worth the ugly coding.

 *

 * OZ's original sdbm hash

 */

uint32_t

__nss_hash (const void *keyarg, size_t len)

{

  const unsigned char *key;

  size_t loop;

  uint32_t h;

#define HASHC   h = *key++ + 65599 * h

  h = 0;

  key = keyarg;

  if (len > 0)

    {

      loop = (len + 8 - 1) >> 3;

      switch (len & (8 - 1))

        {

        case 0:

          do

            {

              HASHC;

              /* FALLTHROUGH */

            case 7:

              HASHC;

              /* FALLTHROUGH */

            case 6:

              HASHC;

              /* FALLTHROUGH */

            case 5:

              HASHC;

              /* FALLTHROUGH */

            case 4:

              HASHC;

              /* FALLTHROUGH */

            case 3:

              HASHC;

              /* FALLTHROUGH */

            case 2:

              HASHC;

              /* FALLTHROUGH */

            case 1:

              HASHC;

            }

	  while (--loop);

        }

    }

  return h;

}

libc_hidden_def (__nss_hash)