sortix-mirror/libc/ungetc.cpp

/*******************************************************************************

    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.

    This file is part of the Sortix C Library.

    The Sortix C Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or (at your
    option) any later version.

    The Sortix C Library is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.

    ungetc.cpp
    Inserts data in front of the current read queue, allowing applications to
    peek the incoming data and pretend they didn't.

*******************************************************************************/

#include <stdio.h>
#include <errno.h>

extern "C" int ungetc(int c, FILE* fp)
{
	if ( fp->numpushedback == _FILE_MAX_PUSHBACK ) { errno = ERANGE; return EOF; }
	unsigned char uc = c;
	fp->pushedback[fp->numpushedback++] = uc;
	return uc;
}