59 lines
2.1 KiB
C
Executable File
59 lines
2.1 KiB
C
Executable File
/* Copyright (c) 2002, Joerg Wunsch
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All rights reserved.
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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 are met:
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* 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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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND 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 COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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/* $Id: ungetc.c,v 1.2 2003/01/07 22:17:24 joerg_wunsch Exp $ */
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#include <stdio.h>
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#include "stdio_private.h"
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int
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ungetc(int c, FILE *stream)
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{
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/*
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* Streams that are not readable, or streams that already had
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* had an ungetc() before will cause an error.
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*
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* ungetc(EOF, ...) causes an error per definitionem.
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*/
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if ((stream->flags & __SRD) == 0 ||
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(stream->flags & __SUNGET) != 0 ||
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c == EOF)
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return EOF;
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stream->unget = c;
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stream->flags |= __SUNGET;
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stream->flags &= ~__SEOF;
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stream->len--;
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return stream->unget;
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}
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