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/*

FUNCTION

<<_mblen_r>>---reentrant minimal multibyte length function

INDEX

        _mblen_r

ANSI_SYNOPSIS

        #include <stdlib.h>

        int _mblen_r(struct _reent *<[r]>, const char *<[s]>, size_t <[n]>, int *<[state]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        int _mblen_r(<[r]>, <[s]>, <[n]>, <[state]>)

        struct _reent *<[r]>;

        const char *<[s]>;

        size_t <[n]>;

        int *<[state]>;

DESCRIPTION

When MB_CAPABLE is not defined, this is a minimal ANSI-conforming

implementation of <<_mblen_r>>.  In this case, the

only ``multi-byte character sequences'' recognized are single bytes,

and thus <<1>> is returned unless <[s]> is the null pointer or

has a length of 0 or is the empty string.

When MB_CAPABLE is defined, this routine calls <<_mbtowc_r>> to perform

the conversion, passing a state variable to allow state dependent

decoding.  The result is based on the locale setting which may

be restricted to a defined set of locales.

RETURNS

This implementation of <<_mblen_r>> returns <<0>> if

<[s]> is <<NULL>> or the empty string; it returns <<1>> if not MB_CAPABLE or

the character is a single-byte character; it returns <<-1>>

if the multi-byte character is invalid; otherwise it returns

the number of bytes in the multibyte character.

PORTABILITY

<<_mblen>> is required in the ANSI C standard.  However, the precise

effects vary with the locale.

<<_mblen_r>> requires no supporting OS subroutines.

*/

#include <stdlib.h>

int

_DEFUN (_mblen_r, (r, s, n, state),

        struct _reent *r    _AND

        const char *s _AND

        size_t n _AND

        int *state)

{

#ifdef MB_CAPABLE

        return _mbtowc_r (r, NULL, s, n, state);

#else /* not MB_CAPABLE */

        if (s == NULL || *s == '\0')

                return 0;

        if (n == 0)

                return -1;

        return 1;

#endif /* not MB_CAPABLE */

}