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ea99f21ce6
By default, Newlib uses a huge object of type struct _reent to store thread-specific data. This object is returned by __getreent() if the __DYNAMIC_REENT__ Newlib configuration option is defined. The reentrancy structure contains for example errno and the standard input, output, and error file streams. This means that if an application only uses errno it has a dependency on the file stream support even if it does not use it. This is an issue for lower end targets and applications which need to qualify the software according to safety standards (for example ECSS-E-ST-40C, ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333). If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct _reent is replaced by dedicated thread-local objects for each struct _reent member. The thread-local objects are defined in translation units which use the corresponding object.
93 lines
2.3 KiB
C
93 lines
2.3 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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#ifdef _REENT_THREAD_LOCAL
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_Thread_local _mbstate_t _tls_mbtowc_state;
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#endif
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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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