source: trunk/libs/newlib/src/newlib/libc/string/wcsncpy.c @ 444

/*
FUNCTION
        <<wcsncpy>>---copy part of a wide-character string 

SYNOPSIS
        #include <wchar.h>
        wchar_t *wcsncpy(wchar_t *__restrict <[s1]>,
                        const wchar_t *__restrict <[s2]>, size_t <[n]>);

DESCRIPTION
        The <<wcsncpy>> function copies not more than <[n]> wide-character codes
        (wide-character codes that follow a null wide-character code are not
        copied) from the array pointed to by <[s2]> to the array pointed to
        by <[s1]>. If copying takes place between objects that overlap, the
        behaviour is undefined.  Note that if <[s1]> contains more than <[n]>
        wide characters before its terminating null, the result is not
        null-terminated.

        If the array pointed to by <[s2]> is a wide-character string that is
        shorter than <[n]> wide-character codes, null wide-character codes are
        appended to the copy in the array pointed to by <[s1]>, until <[n]>
        wide-character codes in all are written. 

RETURNS
        The <<wcsncpy>> function returns <[s1]>; no return value is reserved to
        indicate an error. 

PORTABILITY
ISO/IEC 9899; POSIX.1.

No supporting OS subroutines are required.
*/

#include <_ansi.h>
#include <wchar.h>

wchar_t *
wcsncpy (wchar_t *__restrict s1,
        const wchar_t *__restrict s2,
        size_t n)
{
  wchar_t *dscan=s1;

  while(n > 0)
    {
      --n;
      if((*dscan++ = *s2++) == L'\0')  break;
    }
  while(n-- > 0)  *dscan++ = L'\0';

  return s1;
}