newlib-cygwin/newlib/libc/stdio/fgetwc.c

194 lines
5.2 KiB
C

/*-
* Copyright (c) 2002-2004 Tim J. Robbins.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
FUNCTION
<<fgetwc>>, <<getwc>>, <<fgetwc_unlocked>>, <<getwc_unlocked>>---get a wide character from a file or stream
INDEX
fgetwc
INDEX
fgetwc_unlocked
INDEX
_fgetwc_r
INDEX
_fgetwc_unlocked_r
INDEX
getwc
INDEX
getwc_unlocked
INDEX
_getwc_r
INDEX
_getwc_unlocked_r
SYNOPSIS
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc(FILE *<[fp]>);
#define _GNU_SOURCE
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc_unlocked(FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t _fgetwc_r(struct _reent *<[ptr]>, FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t _fgetwc_unlocked_r(struct _reent *<[ptr]>, FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t getwc(FILE *<[fp]>);
#define _GNU_SOURCE
#include <stdio.h>
#include <wchar.h>
wint_t getwc_unlocked(FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t _getwc_r(struct _reent *<[ptr]>, FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t _getwc_unlocked_r(struct _reent *<[ptr]>, FILE *<[fp]>);
DESCRIPTION
Use <<fgetwc>> to get the next wide character from the file or stream
identified by <[fp]>. As a side effect, <<fgetwc>> advances the file's
current position indicator.
<<fgetwc_unlocked>> is a non-thread-safe version of <<fgetwc>>.
<<fgetwc_unlocked>> may only safely be used within a scope
protected by flockfile() (or ftrylockfile()) and funlockfile(). This
function may safely be used in a multi-threaded program if and only
if they are called while the invoking thread owns the (FILE *)
object, as is the case after a successful call to the flockfile() or
ftrylockfile() functions. If threads are disabled, then
<<fgetwc_unlocked>> is equivalent to <<fgetwc>>.
The <<getwc>> and <<getwc_unlocked>> functions or macros functions identically
to <<fgetwc>> and <<fgetwc_unlocked>>. It may be implemented as a macro, and
may evaluate its argument more than once. There is no reason ever to use it.
<<_fgetwc_r>>, <<_getwc_r>>, <<_fgetwc_unlocked_r>>, and <<_getwc_unlocked_r>>
are simply reentrant versions of the above functions that are passed the
additional reentrant structure pointer argument: <[ptr]>.
RETURNS
The next wide character cast to <<wint_t>>, unless there is no more data,
or the host system reports a read error; in either of these situations,
<<fgetwc>> and <<getwc>> return <<WEOF>>.
You can distinguish the two situations that cause an <<EOF>> result by
using the <<ferror>> and <<feof>> functions.
PORTABILITY
<<fgetwc>> and <<getwc>> are required by C99 and POSIX.1-2001.
<<fgetwc_unlocked>> and <<getwc_unlocked>> are GNU extensions.
*/
#include <_ansi.h>
#include <reent.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include "local.h"
wint_t
__fgetwc (struct _reent *ptr,
register FILE *fp)
{
wchar_t wc;
size_t nconv;
if (fp->_r <= 0 && __srefill_r (ptr, fp))
return (WEOF);
if (MB_CUR_MAX == 1)
{
/* Fast path for single-byte encodings. */
wc = *fp->_p++;
fp->_r--;
return (wc);
}
do
{
nconv = _mbrtowc_r (ptr, &wc, (char *) fp->_p, fp->_r, &fp->_mbstate);
if (nconv == (size_t)-1)
break;
else if (nconv == (size_t)-2)
continue;
else if (nconv == 0)
{
/*
* Assume that the only valid representation of
* the null wide character is a single null byte.
*/
fp->_p++;
fp->_r--;
return (L'\0');
}
else
{
fp->_p += nconv;
fp->_r -= nconv;
return (wc);
}
}
while (__srefill_r(ptr, fp) == 0);
fp->_flags |= __SERR;
errno = EILSEQ;
return (WEOF);
}
wint_t
_fgetwc_r (struct _reent *ptr,
register FILE *fp)
{
wint_t r;
_newlib_flockfile_start (fp);
ORIENT(fp, 1);
r = __fgetwc (ptr, fp);
_newlib_flockfile_end (fp);
return r;
}
wint_t
fgetwc (FILE *fp)
{
struct _reent *reent = _REENT;
CHECK_INIT(reent, fp);
return _fgetwc_r (reent, fp);
}