/*-

 * Copyright (c) 1990, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Chris Torek.

 *

 * 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.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.

 * * Portions Copyright (c) 2005-2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved. 

 */

#if defined(LIBC_SCCS) && !defined(lint)

static char sccsid[] = "@(#)ungetc.c	8.2 (Berkeley) 11/3/93";

#endif /* LIBC_SCCS and not lint */

#include <sys/cdefs.h>

#ifndef __SYMBIAN32__

__FBSDID("$FreeBSD: src/lib/libc/stdio/ungetc.c,v 1.16 2004/03/10 12:41:11 tjr Exp $");

#endif

#include "namespace.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "un-namespace.h"

#include "local.h"

#include "libc_private.h"

#include "sysreent.h"

#if (defined(__SYMBIAN32__) && (defined(__WINSCW__) || defined(__WINS__)))

#include "libc_wsd_defs.h"

#endif

#ifdef EMULATOR

int *GET_WSD_VAR_NAME(__sdidinit, g)();

#define __sdidinit (*GET_WSD_VAR_NAME(__sdidinit, g)())

#endif //EMULATOR

static int __submore(FILE *);

/*

 * Expand the ungetc buffer `in place'.  That is, adjust fp->_p when

 * the buffer moves, so that it points the same distance from the end,

 * and move the bytes in the buffer around as necessary so that they

 * are all at the end (stack-style).

 */

static int

__submore(FILE *fp)

{

	int i;

	unsigned char *p;

	#ifdef __SYMBIAN32__

	int flags=fp->_flags; /*for checking presence of user supplied buffer*/

	#endif

	if (fp->_ub._base == fp->_ubuf) {

		/*

		 * Get a new buffer (rather than expanding the old one).

		 */

		 #ifdef __SYMBIAN32__

		if ((p = BackendAlloc((size_t)BUFSIZ)) == NULL)

			return (EOF);

		#else

		if ((p = malloc((size_t)BUFSIZ)) == NULL)

			return (EOF);

		#endif

		fp->_ub._base = p;

		fp->_ub._size = BUFSIZ;

		p += BUFSIZ - sizeof(fp->_ubuf);

		for (i = sizeof(fp->_ubuf); --i >= 0;)

			p[i] = fp->_ubuf[i];

		fp->_p = p;

		return (0);

	}

	i = fp->_ub._size;

	#ifdef __SYMBIAN32__

	if (flags &  __SMBF)

	p = BackendReAlloc(fp->_ub._base, (size_t)(i << 1)); /* backend allocated buffer*/

	else

	p = realloc(fp->_ub._base, (size_t)(i << 1)); /*user supplied buffer*/

	#else

	p = realloc(fp->_ub._base, (size_t)(i << 1));

	#endif

	if (p == NULL)

		return (EOF);

	/* no overlap (hence can use memcpy) because we doubled the size */

	(void)memcpy((void *)(p + i), (void *)p, (size_t)i);

	fp->_p = p + i;

	fp->_ub._base = p;

	fp->_ub._size = i << 1;

	return (0);

}

/*

 * MT-safe version

 */

EXPORT_C int

ungetc(int c, FILE *fp)

{

	int ret;

	if (!__sdidinit)

		__sinit();

	FLOCKFILE(fp);

	ORIENT(fp, -1);

	ret = __ungetc(c, fp);

	FUNLOCKFILE(fp);

	return (ret);

}

/*

 * Non-MT-safe version

 */

int

__ungetc(int c, FILE *fp)

{

	if (c == EOF)

		return (EOF);

	if ((fp->_flags & __SRD) == 0) {

		/*

		 * Not already reading: no good unless reading-and-writing.

		 * Otherwise, flush any current write stuff.

		 */

		if ((fp->_flags & __SRW) == 0)

			return (EOF);

		if (fp->_flags & __SWR) {

			if (__sflush(fp))

				return (EOF);

			fp->_flags &= ~__SWR;

			fp->_w = 0;

			fp->_lbfsize = 0;

		}

		fp->_flags |= __SRD;

	}

	c = (unsigned char)c;

	/*

	 * If we are in the middle of ungetc'ing, just continue.

	 * This may require expanding the current ungetc buffer.

	 */

	if (HASUB(fp)) {

		if (fp->_r >= fp->_ub._size && __submore(fp))

			return (EOF);

		*--fp->_p = c;

		fp->_r++;

		return (c);

	}

	fp->_flags &= ~__SEOF;

	/*

	 * If we can handle this by simply backing up, do so,

	 * but never replace the original character.

	 * (This makes sscanf() work when scanning `const' data.)

	 */

	if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&

	    fp->_p[-1] == c) {

		fp->_p--;

		fp->_r++;

		return (c);

	}

	/*

	 * Create an ungetc buffer.

	 * Initially, we will use the `reserve' buffer.

	 */

	fp->_ur = fp->_r;

	fp->_extra->_up = fp->_p;

	fp->_ub._base = fp->_ubuf;

	fp->_ub._size = sizeof(fp->_ubuf);

	fp->_ubuf[sizeof(fp->_ubuf) - 1] = c;

	fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];

	fp->_r = 1;

	return (c);

}