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

183 lines
4.4 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>>---get a wide character from a file or stream
INDEX
fgetwc
INDEX
_fgetwc_r
INDEX
getwc
INDEX
_getwc_r
ANSI_SYNOPSIS
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc(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 getwc(FILE *<[fp]>);
#include <stdio.h>
#include <wchar.h>
wint_t _getwc_r(struct _reent *<[ptr]>, FILE *<[fp]>);
TRAD_SYNOPSIS
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc(<[fp]>)
FILE *<[fp]>;
#include <stdio.h>
#include <wchar.h>
wint_t _fgetwc_r(<[ptr]>, <[fp]>)
struct _reent *<[ptr]>;
FILE *<[fp]>;
#include <stdio.h>
#include <wchar.h>
wint_t getwc(<[fp]>)
FILE *<[fp]>;
#include <stdio.h>
#include <wchar.h>
wint_t _getwc_r(<[ptr]>, <[fp]>)
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.
The <<getwc>> function or macro functions identically to <<fgetwc>>. 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>> and <<_getwc_r>> are simply reentrant versions of
<<fgetwc>> and <<getwc>> 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
C99, POSIX.1-2001
*/
#include <_ansi.h>
#include <reent.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include "local.h"
static wint_t
_DEFUN(__fgetwc, (ptr, fp),
struct _reent *ptr _AND
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
_DEFUN(_fgetwc_r, (ptr, fp),
struct _reent *ptr _AND
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
_DEFUN(fgetwc, (fp),
FILE *fp)
{
struct _reent *reent = _REENT;
CHECK_INIT(reent, fp);
return _fgetwc_r (reent, fp);
}