newlib-cygwin/newlib/libc/string/wcslcat.c

87 lines
3.0 KiB
C

/*
FUNCTION
<<wcslcat>>---concatenate wide-character strings to specified length
SYNOPSIS
#include <wchar.h>
size_t wcslcat(wchar_t *<[dst]>, const wchar_t *<[src]>, size_t <[siz]>);
DESCRIPTION
The <<wcslcat>> function appends wide characters from <[src]> to
end of the <[dst]> wide-character string so that the resultant
wide-character string is not more than <[siz]> wide characters
including the terminating null wide-character code. A terminating
null wide character is always added unless <[siz]> is 0. Thus,
the maximum number of wide characters that can be appended from
<[src]> is <[siz]> - 1. If copying takes place between objects
that overlap, the behaviour is undefined.
RETURNS
Wide-character string length of initial <[dst]> plus the
wide-character string length of <[src]> (does not include
terminating null wide-characters). If the return value is
greater than or equal to <[siz]>, then truncation occurred and
not all wide characters from <[src]> were appended.
PORTABILITY
No supporting OS subroutines are required.
*/
/* $OpenBSD: wcslcat.c,v 1.7 2019/01/25 00:19:25 millert Exp $ */
/*
* Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <wchar.h>
/*
* Appends src to string dst of size dsize (unlike strncat, dsize is the
* full size of dst, not space left). At most dsize-1 characters
* will be copied. Always NUL terminates (unless dsize <= wcslen(dst)).
* Returns wcslen(src) + MIN(dsize, wcslen(initial dst)).
* If retval >= siz, truncation occurred.
*/
size_t
wcslcat (wchar_t *dst,
const wchar_t *src,
size_t dsize)
{
const wchar_t *odst = dst;
const wchar_t *osrc = src;
size_t n = dsize;
size_t dlen;
/* Find the end of dst and adjust bytes left but don't go past end. */
while (n-- != 0 && *dst != L'\0')
dst++;
dlen = dst - odst;
n = dsize - dlen;
if (n-- == 0)
return(dlen + wcslen(src));
while (*src != L'\0') {
if (n != 0) {
*dst++ = *src;
n--;
}
src++;
}
*dst = L'\0';
return(dlen + (src - osrc)); /* count does not include NUL */
}