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

57 lines
1.4 KiB
C

/*
FUNCTION
<<wcswidth>>---number of column positions of a wide-character string
INDEX
wcswidth
ANSI_SYNOPSIS
#include <wchar.h>
int wcswidth(const wchar_t *<[pwcs]>, size_t <[n]>);
TRAD_SYNOPSIS
#include <wchar.h>
int wcswidth(<[pwcs]>, <[n]>)
wchar_t *<[wc]>;
size_t <[n]>;
DESCRIPTION
The <<wcswidth>> function shall determine the number of column
positions required for <[n]> wide-character codes (or fewer than <[n]>
wide-character codes if a null wide-character code is encountered
before <[n]> wide-character codes are exhausted) in the string pointed
to by <[pwcs]>.
RETURNS
The <<wcswidth>> function either shall return 0 (if <[pwcs]> points to a
null wide-character code), or return the number of column positions
to be occupied by the wide-character string pointed to by <[pwcs]>, or
return -1 (if any of the first <[n]> wide-character codes in the
wide-character string pointed to by <[pwcs]> is not a printable
wide-character code).
PORTABILITY
<<wcswidth>> has been introduced in the Single UNIX Specification Volume 2.
<<wcswidth>> has been marked as an extension in the Single UNIX Specification Volume 3.
*/
#include <_ansi.h>
#include <wchar.h>
int
_DEFUN (wcswidth, (pwcs, n),
_CONST wchar_t *pwcs _AND
size_t n)
{
int w, len = 0;
if (!pwcs || n == 0)
return 0;
do {
if ((w = wcwidth (*pwcs)) < 0)
return -1;
len += w;
} while (*pwcs++ && --n > 0);
return len;
}