src/strcasecmp.c

   1 /* portable case insensitive string compare */
   2 /* Copyright (C) Olly Betts 1994,1999
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include <ctype.h>
  20
  21 /* What about top bit set chars? */
  22 int strcasecmp(const char *s1, const char *s2) {
  23    register c1, c2;
  24    do {
  25       c1 = *s1++;
  26       c2 = *s2++;
  27    } while (c1 && toupper(c1) == toupper(c2));
  28    /* now calculate real difference */
  29    return c1 - c2;
  30 }