89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/*
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FUNCTION
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<<mbtowc>>---minimal multibyte to wide char converter
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INDEX
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mbtowc
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SYNOPSIS
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#include <stdlib.h>
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int mbtowc(wchar_t *restrict <[pwc]>, const char *restrict <[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 <<mbtowc>>. In this case,
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only ``multi-byte character sequences'' recognized are single bytes,
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and they are ``converted'' to themselves.
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Each call to <<mbtowc>> copies one character from <<*<[s]>>> to
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<<*<[pwc]>>>, unless <[s]> is a null pointer. The argument n
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is ignored.
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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 <<mbtowc>> returns <<0>> if
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<[s]> is <<NULL>> or is the empty string;
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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 n is <<0>> or the multi-byte character is invalid;
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otherwise it returns the number of bytes in the multibyte character.
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If the return value is -1, no changes are made to the <<pwc>>
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output string. If the input is the empty string, a wchar_t nul
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is placed in the output string and 0 is returned. If the input
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has a length of 0, no changes are made to the <<pwc>> output string.
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PORTABILITY
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<<mbtowc>> is required in the ANSI C standard. However, the precise
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effects vary with the locale.
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<<mbtowc>> 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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int
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mbtowc (wchar_t *__restrict pwc,
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const char *__restrict 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 *ps;
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_REENT_CHECK_MISC(reent);
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ps = &(_REENT_MBTOWC_STATE(reent));
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retval = __MBTOWC (reent, pwc, s, n, ps);
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if (retval < 0)
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{
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ps->__count = 0;
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return -1;
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}
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return retval;
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#else /* not _MB_CAPABLE */
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if (s == NULL)
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return 0;
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if (n == 0)
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return -1;
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if (pwc)
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*pwc = (wchar_t) *s;
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return (*s != '\0');
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#endif /* not _MB_CAPABLE */
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}
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#endif /* !_REENT_ONLY */
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