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/*
Copyright (c) 1990 Regents of the University of California.
All rights reserved.
*/
/*
FUNCTION
<<mblen>>---minimal multibyte length function
INDEX
mblen
SYNOPSIS
#include <stdlib.h>
int mblen(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>> 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>
#include <wchar.h>
#include "local.h"
int
mblen(const char *s, size_t n)
{
#ifdef __MB_CAPABLE
int retval = 0;
static _mbstate_t _mblen_state;
retval = __MBTOWC(NULL, s, n, &_mblen_state);
if (retval < 0) {
_mblen_state.__count = 0;
return -1;
} else
return retval;
#else /* not __MB_CAPABLE */
if (s == NULL || *s == '\0')
return 0;
if (n == 0)
return -1;
return 1;
#endif /* not __MB_CAPABLE */
}
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