1: /* c-strncasecmp.c -- case insensitive string comparator in C locale
    2:    Copyright (C) 1998-1999, 2005-2006 Free Software Foundation, Inc.
    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, or (at your option)
    7:    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 Foundation,
   16:    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
   17: 
   18: #include <config.h>
   19: 
   20: /* Specification.  */
   21: #include "c-strcase.h"
   22: 
   23: #include <limits.h>
   24: 
   25: #include "c-ctype.h"
   26: 
   27: int
   28: c_strncasecmp (const char *s1, const char *s2, size_t n)
   29: {
   30:   register const unsigned char *p1 = (const unsigned char *) s1;
   31:   register const unsigned char *p2 = (const unsigned char *) s2;
   32:   unsigned char c1, c2;
   33: 
   34:   if (p1 == p2 || n == 0)
   35:     return 0;
   36: 
   37:   do
   38:     {
   39:       c1 = c_tolower (*p1);
   40:       c2 = c_tolower (*p2);
   41: 
   42:       if (--n == 0 || c1 == '\0')
   43:         break;
   44: 
   45:       ++p1;
   46:       ++p2;
   47:     }
   48:   while (c1 == c2);
   49: 
   50:   if (UCHAR_MAX <= INT_MAX)
   51:     return c1 - c2;
   52:   else
   53:     /* On machines where 'char' and 'int' are types of the same size, the
   54:        difference of two 'unsigned char' values - including the sign bit -
   55:        doesn't fit in an 'int'.  */
   56:     return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
   57: }