1/* strcasecmp.c -- case insensitive string comparator 2 Copyright (C) 1998, 1999 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 St - Fifth Floor, Boston, MA 02110-1301, USA. */ 17 18#if HAVE_CONFIG_H 19# include <config.h> 20#endif 21 22#ifdef LENGTH_LIMIT 23# define STRXCASECMP_FUNCTION strncasecmp 24# define STRXCASECMP_DECLARE_N , size_t n 25# define LENGTH_LIMIT_EXPR(Expr) Expr 26#else 27# define STRXCASECMP_FUNCTION strcasecmp 28# define STRXCASECMP_DECLARE_N /* empty */ 29# define LENGTH_LIMIT_EXPR(Expr) 0 30#endif 31 32#include <stddef.h> 33#include <ctype.h> 34 35#define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch)) 36 37/* Compare {{no more than N characters of }}strings S1 and S2, 38 ignoring case, returning less than, equal to or 39 greater than zero if S1 is lexicographically less 40 than, equal to or greater than S2. */ 41 42int 43STRXCASECMP_FUNCTION (const char *s1, const char *s2 STRXCASECMP_DECLARE_N) 44{ 45 register const unsigned char *p1 = (const unsigned char *) s1; 46 register const unsigned char *p2 = (const unsigned char *) s2; 47 unsigned char c1, c2; 48 49 if (p1 == p2 || LENGTH_LIMIT_EXPR (n == 0)) 50 return 0; 51 52 do 53 { 54 c1 = TOLOWER (*p1); 55 c2 = TOLOWER (*p2); 56 57 if (LENGTH_LIMIT_EXPR (--n == 0) || c1 == '\0') 58 break; 59 60 ++p1; 61 ++p2; 62 } 63 while (c1 == c2); 64 65 return c1 - c2; 66} 67