* Copyright (c) 1990 The Regents of the University of California.
* This code is derived from software contributed to Berkeley by
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)ungetc.c 5.6 (Berkeley) 5/4/91";
#endif /* LIBC_SCCS and not lint */
* 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).
register unsigned char *p
;
if (fp
->_ub
._base
== fp
->_ubuf
) {
* Get a new buffer (rather than expanding the old one).
if ((p
= malloc((size_t)BUFSIZ
)) == NULL
)
p
+= BUFSIZ
- sizeof(fp
->_ubuf
);
for (i
= sizeof(fp
->_ubuf
); --i
>= 0;)
p
= realloc(fp
->_ub
._base
, i
<< 1);
(void) bcopy((void *)p
, (void *)(p
+ i
), (size_t)i
);
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)
if (fp
->_flags
& __SWR
) {
* If we are in the middle of ungetc'ing, just continue.
* This may require expanding the current ungetc buffer.
if (fp
->_r
>= fp
->_ub
._size
&& __submore(fp
))
* 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
&&
* Create an ungetc buffer.
* Initially, we will use the `reserve' buffer.
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];