src/system/libroot/posix/string/strcasecmp.c

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34
  35 #include <ctype.h>
  36 #include <strings.h>
  37
  38
  39 int
  40 strcasecmp(const char *s1, const char *s2)
  41 {
  42         const u_char *us1 = (const u_char *)s1;
  43         const u_char *us2 = (const u_char *)s2;
  44
  45         while (tolower(*us1) == tolower(*us2++)) {
  46                 if (*us1++ == '\0')
  47                         return 0;
  48         }
  49
  50         return tolower(*us1) - tolower(*--us2);
  51 }
  52
  53
  54 int
  55 strncasecmp(const char *s1, const char *s2, size_t n)
  56 {
  57         if (n != 0) {
  58                 const u_char *us1 = (const u_char *)s1;
  59                 const u_char *us2 = (const u_char *)s2;
  60
  61                 do {
  62                         if (tolower(*us1) != tolower(*us2++))
  63                                 return tolower(*us1) - tolower(*--us2);
  64                         if (*us1++ == '\0')
  65                                 break;
  66                 } while (--n != 0);
  67         }
  68         return 0;
  69 }
  70