1 /* c-strncasecmp.c -- case insensitive string comparator in C locale 2 Copyright (C) 1998-1999, 2005-2006, 2009-2012 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 3, 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, see <http://www.gnu.org/licenses/>. */ 16 17 #include <config.h> 18 19 /* Specification. */ 20 #include "c-strcase.h" 21 22 #include <limits.h> 23 24 #include "c-ctype.h" 25 26 int 27 c_strncasecmp (const char *s1, const char *s2, size_t n) 28 { 29 register const unsigned char *p1 = (const unsigned char *) s1; 30 register const unsigned char *p2 = (const unsigned char *) s2; 31 unsigned char c1, c2; 32 33 if (p1 == p2 || n == 0) 34 return 0; 35 36 do 37 { 38 c1 = c_tolower (*p1); 39 c2 = c_tolower (*p2); 40 41 if (--n == 0 || c1 == '\0') 42 break; 43 44 ++p1; 45 ++p2; 46 } 47 while (c1 == c2); 48 49 if (UCHAR_MAX <= INT_MAX) 50 return c1 - c2; 51 else 52 /* On machines where 'char' and 'int' are types of the same size, the 53 difference of two 'unsigned char' values - including the sign bit - 54 doesn't fit in an 'int'. */ 55 return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0); 56 } 57
