1*946379e7Schristos /* c-strncasecmp.c -- case insensitive string comparator in C locale
2*946379e7Schristos Copyright (C) 1998-1999, 2005-2006 Free Software Foundation, Inc.
3*946379e7Schristos
4*946379e7Schristos This program is free software; you can redistribute it and/or modify
5*946379e7Schristos it under the terms of the GNU General Public License as published by
6*946379e7Schristos the Free Software Foundation; either version 2, or (at your option)
7*946379e7Schristos any later version.
8*946379e7Schristos
9*946379e7Schristos This program is distributed in the hope that it will be useful,
10*946379e7Schristos but WITHOUT ANY WARRANTY; without even the implied warranty of
11*946379e7Schristos MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12*946379e7Schristos GNU General Public License for more details.
13*946379e7Schristos
14*946379e7Schristos You should have received a copy of the GNU General Public License
15*946379e7Schristos along with this program; if not, write to the Free Software Foundation,
16*946379e7Schristos Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
17*946379e7Schristos
18*946379e7Schristos #include <config.h>
19*946379e7Schristos
20*946379e7Schristos /* Specification. */
21*946379e7Schristos #include "c-strcase.h"
22*946379e7Schristos
23*946379e7Schristos #include <limits.h>
24*946379e7Schristos
25*946379e7Schristos #include "c-ctype.h"
26*946379e7Schristos
27*946379e7Schristos int
c_strncasecmp(const char * s1,const char * s2,size_t n)28*946379e7Schristos c_strncasecmp (const char *s1, const char *s2, size_t n)
29*946379e7Schristos {
30*946379e7Schristos register const unsigned char *p1 = (const unsigned char *) s1;
31*946379e7Schristos register const unsigned char *p2 = (const unsigned char *) s2;
32*946379e7Schristos unsigned char c1, c2;
33*946379e7Schristos
34*946379e7Schristos if (p1 == p2 || n == 0)
35*946379e7Schristos return 0;
36*946379e7Schristos
37*946379e7Schristos do
38*946379e7Schristos {
39*946379e7Schristos c1 = c_tolower (*p1);
40*946379e7Schristos c2 = c_tolower (*p2);
41*946379e7Schristos
42*946379e7Schristos if (--n == 0 || c1 == '\0')
43*946379e7Schristos break;
44*946379e7Schristos
45*946379e7Schristos ++p1;
46*946379e7Schristos ++p2;
47*946379e7Schristos }
48*946379e7Schristos while (c1 == c2);
49*946379e7Schristos
50*946379e7Schristos if (UCHAR_MAX <= INT_MAX)
51*946379e7Schristos return c1 - c2;
52*946379e7Schristos else
53*946379e7Schristos /* On machines where 'char' and 'int' are types of the same size, the
54*946379e7Schristos difference of two 'unsigned char' values - including the sign bit -
55*946379e7Schristos doesn't fit in an 'int'. */
56*946379e7Schristos return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
57*946379e7Schristos }
58