/* Case-insensitive buffer comparator.

   Copyright (C) 1996-1997, 2000, 2003, 2006, 2009-2018 Free Software

   Foundation, 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 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, see <https://www.gnu.org/licenses/>.  */

/* Written by Jim Meyering.  */

#include <config.h>

#include "memcasecmp.h"

#include <ctype.h>

#include <limits.h>

/* Like memcmp, but ignore differences in case.

   Convert to upper case (not lower) before comparing so that

   join -i works with sort -f.  */

int

memcasecmp (const void *vs1, const void *vs2, size_t n)

{

  size_t i;

  char const *s1 = vs1;

  char const *s2 = vs2;

  for (i = 0; i < n; i++)

    {

      unsigned char u1 = s1[i];

      unsigned char u2 = s2[i];

      int U1 = toupper (u1);

      int U2 = toupper (u2);

      int diff = (UCHAR_MAX <= INT_MAX ? U1 - U2

                  : U1 < U2 ? -1 : U2 < U1);

      if (diff)

        return diff;

    }

  return 0;

}