File strcasecmp.c

File List > base > posix > strcasecmp.c
/*  $OpenBSD: strcasecmp.c,v 1.6 2005/08/08 08:05:37 espie Exp $    */
/*
 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <string.h>
typedef unsigned char u_char;
/*
 * This array is designed for mapping upper and lower case letter
 * together for a case independent comparison.  The mappings are
 * based upon ascii character sequences.
 */
static const u_char charmap[] = {
    '\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
    '\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
    '\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
    '\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
    '\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
    '\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
    '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
    '\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
    '\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
    '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
    '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
    '\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
    '\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
    '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
    '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
    '\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
    '\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
    '\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
    '\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
    '\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
    '\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
    '\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
    '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
    '\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
    '\300', '\301', '\302', '\303', '\304', '\305', '\306', '\307',
    '\310', '\311', '\312', '\313', '\314', '\315', '\316', '\317',
    '\320', '\321', '\322', '\323', '\324', '\325', '\326', '\327',
    '\330', '\331', '\332', '\333', '\334', '\335', '\336', '\337',
    '\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
    '\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
    '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
    '\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
};
int
strcasecmp(const char *s1, const char *s2)
{
    const u_char *cm = charmap;
    const u_char *us1 = (const u_char *)s1;
    const u_char *us2 = (const u_char *)s2;
    while (cm[*us1] == cm[*us2++])
        if (*us1++ == '\0')
            return (0);
    return (cm[*us1] - cm[*--us2]);
}
int
strncasecmp(const char *s1, const char *s2, size_t n)
{
    if (n != 0) {
        const u_char *cm = charmap;
        const u_char *us1 = (const u_char *)s1;
        const u_char *us2 = (const u_char *)s2;
        do {
            if (cm[*us1] != cm[*us2++])
                return (cm[*us1] - cm[*--us2]);
            if (*us1++ == '\0')
                break;
        } while (--n != 0);
    }
    return (0);
}