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/*

FUNCTION

<<mblen>>---minimal multibyte length function

INDEX

        mblen

ANSI_SYNOPSIS

        #include <stdlib.h>

        int mblen(const char *<[s]>, size_t <[n]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        int mblen(<[s]>, <[n]>)

        const char *<[s]>;

        size_t <[n]>;

DESCRIPTION

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

implementation of <<mblen>>.  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>> 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>> requires no supporting OS subroutines.

*/

#include <stdlib.h>

int

_DEFUN (mblen, (s, n),

        const char *s _AND

        size_t n)

{

#ifdef MB_CAPABLE

        static int state;

        return _mbtowc_r (_REENT, 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 */

}