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/*

FUNCTION

<<mbstowcs>>---minimal multibyte string to wide char converter

INDEX

        mbstowcs

ANSI_SYNOPSIS

        #include <stdlib.h>

        int mbstowcs(wchar_t *<[pwc]>, const char *<[s]>, size_t <[n]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        int mbstowcs(<[pwc]>, <[s]>, <[n]>)

        wchar_t *<[pwc]>;

        const char *<[s]>;

        size_t <[n]>;

DESCRIPTION

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

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

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

and they are ``converted'' to wide-char versions simply by byte

extension.

When MB_CAPABLE is defined, this routine calls <<_mbstowcs_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 <<mbstowcs>> returns <<0>> if

<[s]> is <<NULL>> or is the empty string;

it returns <<-1>> if MB_CAPABLE and one of the

multi-byte characters is invalid or incomplete;

otherwise it returns the minimum of: <<n>> or the

number of multi-byte characters in <<s>> plus 1 (to

compensate for the nul character).

If the return value is -1, the state of the <<pwc>> string is

indeterminate.  If the input has a length of 0, the output

string will be modified to contain a wchar_t nul terminator.

PORTABILITY

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

effects vary with the locale.

<<mbstowcs>> requires no supporting OS subroutines.

*/

#include <stdlib.h>

size_t

_DEFUN (mbstowcs, (pwcs, s, n),

        wchar_t *pwcs _AND

        const char *s _AND

        size_t n)

{

#ifdef MB_CAPABLE

        int state = 0;

        return _mbstowcs_r (_REENT, pwcs, s, n, &state);

#else /* not MB_CAPABLE */

        int count = 0;

        if (n != 0) {

                do {

                        if ((*pwcs++ = (wchar_t) *s++) == 0)

                                break;

                        count++;

                } while (--n != 0);

        }

        return count;

#endif /* not MB_CAPABLE */

}