79 lines
1.8 KiB
C
79 lines
1.8 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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SYNOPSIS
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#include <stdlib.h>
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int mblen(const char *<[s]>, 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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#ifndef _REENT_ONLY
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#include <newlib.h>
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#include <stdlib.h>
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#include <wchar.h>
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#include "local.h"
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#ifdef _REENT_THREAD_LOCAL
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_Thread_local _mbstate_t _tls_mblen_state;
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#endif
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int
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mblen (const char *s,
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size_t n)
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{
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#ifdef _MB_CAPABLE
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int retval = 0;
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struct _reent *reent = _REENT;
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mbstate_t *state;
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_REENT_CHECK_MISC(reent);
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state = &(_REENT_MBLEN_STATE(reent));
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retval = __MBTOWC (reent, NULL, s, n, state);
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if (retval < 0)
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{
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state->__count = 0;
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return -1;
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}
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else
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return retval;
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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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#endif /* !_REENT_ONLY */
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