118 lines
3.4 KiB
C
118 lines
3.4 KiB
C
/*-
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* Copyright (c) 2002-2004 Tim J. Robbins.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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FUNCTION
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<<ungetwc>>---push wide character data back into a stream
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INDEX
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ungetwc
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INDEX
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_ungetwc_r
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ANSI_SYNOPSIS
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#include <stdio.h>
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#include <wchar.h>
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wint_t ungetwc(wint_t <[wc]>, FILE *<[stream]>);
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wint_t _ungetwc_r(struct _reent *<[reent]>, wint_t <[wc]>, FILE *<[stream]>);
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DESCRIPTION
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<<ungetwc>> is used to return wide characters back to <[stream]> to be
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read again. If <[wc]> is WEOF, the stream is unchanged. Otherwise, the
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wide character <[wc]> is put back on the stream, and subsequent reads will see
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the wide chars pushed back in reverse order. Pushed wide chars are lost if the
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stream is repositioned, such as by <<fseek>>, <<fsetpos>>, or
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<<rewind>>.
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The underlying file is not changed, but it is possible to push back
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something different than what was originally read. Ungetting a
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character will clear the end-of-stream marker, and decrement the file
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position indicator. Pushing back beyond the beginning of a file gives
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unspecified behavior.
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The alternate function <<_ungetwc_r>> is a reentrant version. The
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extra argument <[reent]> is a pointer to a reentrancy structure.
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RETURNS
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The wide character pushed back, or <<WEOF>> on error.
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PORTABILITY
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C99
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*/
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#include <_ansi.h>
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#include <reent.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.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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wint_t
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_DEFUN(_ungetwc_r, (ptr, wc, fp),
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struct _reent *ptr _AND
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wint_t wc _AND
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register FILE *fp)
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{
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char buf[MB_LEN_MAX];
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size_t len;
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_newlib_flockfile_start (fp);
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ORIENT (fp, 1);
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if (wc == WEOF)
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wc = WEOF;
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else if ((len = _wcrtomb_r(ptr, buf, wc, &fp->_mbstate)) == (size_t)-1)
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{
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fp->_flags |= __SERR;
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wc = WEOF;
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}
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else
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while (len-- != 0)
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if (_ungetc_r(ptr, (unsigned char)buf[len], fp) == EOF)
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{
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wc = WEOF;
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break;
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}
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_newlib_flockfile_end (fp);
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return wc;
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}
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/*
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* MT-safe version.
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*/
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wint_t
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_DEFUN(ungetwc, (wint_t wc, FILE *fp),
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wint_t wc _AND
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FILE *fp)
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{
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struct _reent *reent = _REENT;
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CHECK_INIT (reent, fp);
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return _ungetwc_r (reent, wc, fp);
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}
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