1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25 
  26 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
  27 /*        All Rights Reserved   */
  28 
  29 /*
  30  * Portions of this source code were derived from Berkeley 4.3 BSD
  31  * under license from the Regents of the University of California.
  32  */
  33 
  34 #include "lint.h"
  35 #include <sys/types.h>
  36 #include <strings.h>
  37 #include <ctype.h>
  38 
  39 int
  40 strncasecmp(const char *s1, const char *s2, size_t n)
  41 {
  42         extern int charset_is_ascii;
  43         extern int ascii_strncasecmp(const char *s1, const char *s2, size_t n);
  44         int *cm;
  45         const uchar_t *us1;
  46         const uchar_t *us2;
  47 
  48         /*
  49          * If we are in a locale that uses the ASCII character set
  50          * (C or POSIX), use the fast ascii_strncasecmp() function.
  51          */
  52         if (charset_is_ascii)
  53                 return (ascii_strncasecmp(s1, s2, n));
  54 
  55         cm = __trans_lower;
  56         us1 = (const uchar_t *)s1;
  57         us2 = (const uchar_t *)s2;
  58 
  59         while (n != 0 && cm[*us1] == cm[*us2++]) {
  60                 if (*us1++ == '\0')
  61                         return (0);
  62                 n--;
  63         }
  64         return (n == 0 ? 0 : cm[*us1] - cm[*(us2 - 1)]);
  65 }