/***
*_mbslen.c - Return number of multibyte characters in a multibyte string
*
*	Copyright (c) 1989-1995, Microsoft Corporation.	All rights reserved.
*
*Purpose:
*	Return number of multibyte characters in a multibyte string
*	excluding the terminal null.  Locale-dependent.
*
*Revision History:
*	10-01-91  ETC	Created.
*	12-08-91  ETC	Add multithread lock.
*	12-18-92  CFW	Ported to Cuda tree, changed _CALLTYPE1 to _CRTAPI1.
*	04-29-93  CFW	Change to const char *s.
*	06-01-93  CFW	Test for bad MB chars.
*       06-02-93  SRW   ignore _INTL if _NTSUBSET_ defined.
*	06-03-93  CFW	Change name to avoid conflict with mbstring function.
*   		     	Change return type to size_t.
*       08-19-93  CFW   Disallow skipping LB:NULL combos.
*       09-15-93  CFW   Use ANSI conformant "__" names.
*	10-22-93  CFW	Test for invalid MB chars using global preset flag.
*	01-14-94  SRW	if _NTSUBSET_ defined call Rtl functions
*       09-06-94  CFW   Remove _INTL switch.
*	12-21-94  CFW	Remove invalid MB chars NT 3.1 hack.
*	02-06-95  CFW	assert -> _ASSERTE.
*       09-26-95  GJF   New locking macro, and scheme, for functions which
*                       reference the locale.
*
*******************************************************************************/

#if defined(_NTSUBSET_) || defined(_POSIX_)
#include <nt.h>
#include <ntrtl.h>
#include <nturtl.h>
#endif
#include <cruntime.h>
#include <internal.h>
#include <stdlib.h>
#include <ctype.h>
#include <mtdll.h>
#include <locale.h>
#include <setlocal.h>
#include <dbgint.h>

/***
*_mbstrlen - Return number of multibyte characters in a multibyte string
*
*Purpose:
*	Return number of multibyte characters in a multibyte string
*	excluding the terminal null.  Locale-dependent.
*
*Entry:
*	char *s = string
*
*Exit:
*	Returns the number of multibyte characters in the string, or
*	(size_t)-1 if the string contains an invalid multibyte character.
*
*Exceptions:
*
*******************************************************************************/

size_t __cdecl _mbstrlen(
	const char *s
	)
{
	int n;
#if     defined(_MT) && !defined(DLL_FOR_WIN32S)
        int local_lock_flag;
#endif

	_ASSERTE (MB_CUR_MAX == 1 || MB_CUR_MAX == 2);

	if ( MB_CUR_MAX == 1 )
		/* handle single byte character sets */
		return (int)strlen(s);

#if !defined(_NTSUBSET_) && !defined(_POSIX_)

	_lock_locale( local_lock_flag )

	/* verify all valid MB chars */
	if ( MultiByteToWideChar(__lc_codepage, MB_PRECOMPOSED|MB_ERR_INVALID_CHARS,
	s, -1, NULL, 0) == 0 )
		/* bad MB char */
		return (size_t)-1;

	/* count MB chars */
	for (n = 0; *s; n++, s++) {
		if ( isleadbyte((unsigned char)*s) ) {
            if (*++s == '\0')
                break;
	    }
	}

	_unlock_locale( local_lock_flag )

#else

        {
        char *s1 = (char *)s;


        while (RtlAnsiCharToUnicodeChar( &s1 ) != UNICODE_NULL)
                ;

        n = s1 - s;
	}

#endif

    return(n);
}