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 27int 28c_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} 58