newlib/libc/string/wcsnlen.c

   1 /*
   2 FUNCTION
   3         <<wcsnlen>>---get fixed-size wide-character string length
   4
   5 INDEX
   6         wcsnlen
   7
   8 SYNOPSIS
   9         #include <wchar.h>
  10         size_t wcsnlen(const wchar_t *<[s]>, size_t <[maxlen]>);
  11
  12 DESCRIPTION
  13         The <<wcsnlen>> function computes the number of wide-character codes
  14         in the wide-character string pointed to by <[s]> not including the
  15         terminating L'\0' wide character but at most <[maxlen]> wide
  16         characters.
  17
  18 RETURNS
  19         <<wcsnlen>> returns the length of <[s]> if it is less then <[maxlen]>,
  20         or <[maxlen]> if there is no L'\0' wide character in first <[maxlen]>
  21         characters.
  22
  23 PORTABILITY
  24 <<wcsnlen>> is a GNU extension.
  25
  26 <<wcsnlen>> requires no supporting OS subroutines.
  27 */
  28
  29 /*
  30  * Copyright (c) 2003, Artem B. Bityuckiy (dedekind@mail.ru).
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the above copyright notice,
  34  * this condition statement, and the following disclaimer are retained
  35  * in any redistributions of the source code.
  36  *
  37  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  38  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  39  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  40  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  41  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  42  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  43  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  45  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  46  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  47  * SUCH DAMAGE.
  48  */
  49
  50 #include <_ansi.h>
  51 #include <sys/types.h>
  52 #include <wchar.h>
  53
  54 size_t
  55 wcsnlen (const wchar_t *s,
  56                  size_t maxlen)
  57 {
  58   const wchar_t *p;
  59
  60   p = s;
  61   while (*p && maxlen-- > 0)
  62     p++;
  63
  64   return (size_t)(p - s);
  65 }
  66
  67
  68