64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
/*
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FUNCTION
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<<mblen>>---minimal multibyte length function
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INDEX
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mblen
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ANSI_SYNOPSIS
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#include <stdlib.h>
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int mblen(const char *<[s]>, size_t <[n]>);
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TRAD_SYNOPSIS
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#include <stdlib.h>
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int mblen(<[s]>, <[n]>)
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const char *<[s]>;
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size_t <[n]>;
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DESCRIPTION
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When MB_CAPABLE is not defined, this is a minimal ANSI-conforming
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implementation of <<mblen>>. In this case, the
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only ``multi-byte character sequences'' recognized are single bytes,
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and thus <<1>> is returned unless <[s]> is the null pointer or
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has a length of 0 or is the empty string.
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When MB_CAPABLE is defined, this routine calls <<_mbtowc_r>> to perform
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the conversion, passing a state variable to allow state dependent
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decoding. The result is based on the locale setting which may
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be restricted to a defined set of locales.
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RETURNS
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This implementation of <<mblen>> returns <<0>> if
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<[s]> is <<NULL>> or the empty string; it returns <<1>> if not MB_CAPABLE or
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the character is a single-byte character; it returns <<-1>>
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if the multi-byte character is invalid; otherwise it returns
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the number of bytes in the multibyte character.
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PORTABILITY
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<<mblen>> is required in the ANSI C standard. However, the precise
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effects vary with the locale.
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<<mblen>> requires no supporting OS subroutines.
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*/
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#include <stdlib.h>
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int
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_DEFUN (mblen, (s, n),
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const char *s _AND
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size_t n)
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{
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#ifdef MB_CAPABLE
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static int state;
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return _mbtowc_r (_REENT, NULL, s, n, &state);
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#else /* not MB_CAPABLE */
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if (s == NULL || *s == '\0')
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return 0;
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if (n == 0)
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return -1;
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return 1;
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#endif /* not MB_CAPABLE */
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}
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