xref: /minix3/lib/libc/stdio/wbuf.c (revision f14fb602092e015ff630df58e17c2a9cd57d29b3)
1*f14fb602SLionel Sambuc /*	$NetBSD: wbuf.c,v 1.15 2012/03/15 18:22:31 christos Exp $	*/
22fe8fb19SBen Gras 
32fe8fb19SBen Gras /*-
42fe8fb19SBen Gras  * Copyright (c) 1990, 1993
52fe8fb19SBen Gras  *	The Regents of the University of California.  All rights reserved.
62fe8fb19SBen Gras  *
72fe8fb19SBen Gras  * This code is derived from software contributed to Berkeley by
82fe8fb19SBen Gras  * Chris Torek.
92fe8fb19SBen Gras  *
102fe8fb19SBen Gras  * Redistribution and use in source and binary forms, with or without
112fe8fb19SBen Gras  * modification, are permitted provided that the following conditions
122fe8fb19SBen Gras  * are met:
132fe8fb19SBen Gras  * 1. Redistributions of source code must retain the above copyright
142fe8fb19SBen Gras  *    notice, this list of conditions and the following disclaimer.
152fe8fb19SBen Gras  * 2. Redistributions in binary form must reproduce the above copyright
162fe8fb19SBen Gras  *    notice, this list of conditions and the following disclaimer in the
172fe8fb19SBen Gras  *    documentation and/or other materials provided with the distribution.
182fe8fb19SBen Gras  * 3. Neither the name of the University nor the names of its contributors
192fe8fb19SBen Gras  *    may be used to endorse or promote products derived from this software
202fe8fb19SBen Gras  *    without specific prior written permission.
212fe8fb19SBen Gras  *
222fe8fb19SBen Gras  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
232fe8fb19SBen Gras  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
242fe8fb19SBen Gras  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
252fe8fb19SBen Gras  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
262fe8fb19SBen Gras  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
272fe8fb19SBen Gras  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
282fe8fb19SBen Gras  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
292fe8fb19SBen Gras  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
302fe8fb19SBen Gras  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
312fe8fb19SBen Gras  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
322fe8fb19SBen Gras  * SUCH DAMAGE.
332fe8fb19SBen Gras  */
342fe8fb19SBen Gras 
352fe8fb19SBen Gras #include <sys/cdefs.h>
362fe8fb19SBen Gras #if defined(LIBC_SCCS) && !defined(lint)
372fe8fb19SBen Gras #if 0
382fe8fb19SBen Gras static char sccsid[] = "@(#)wbuf.c	8.1 (Berkeley) 6/4/93";
392fe8fb19SBen Gras #else
40*f14fb602SLionel Sambuc __RCSID("$NetBSD: wbuf.c,v 1.15 2012/03/15 18:22:31 christos Exp $");
412fe8fb19SBen Gras #endif
422fe8fb19SBen Gras #endif /* LIBC_SCCS and not lint */
432fe8fb19SBen Gras 
442fe8fb19SBen Gras #include <assert.h>
452fe8fb19SBen Gras #include <errno.h>
462fe8fb19SBen Gras #include <stdio.h>
472fe8fb19SBen Gras #include "reentrant.h"
482fe8fb19SBen Gras #include "local.h"
492fe8fb19SBen Gras 
502fe8fb19SBen Gras /*
512fe8fb19SBen Gras  * Write the given character into the (probably full) buffer for
522fe8fb19SBen Gras  * the given file.  Flush the buffer out if it is or becomes full,
532fe8fb19SBen Gras  * or if c=='\n' and the file is line buffered.
542fe8fb19SBen Gras  */
552fe8fb19SBen Gras int
__swbuf(int c,FILE * fp)56*f14fb602SLionel Sambuc __swbuf(int c, FILE *fp)
572fe8fb19SBen Gras {
582fe8fb19SBen Gras 	int n;
592fe8fb19SBen Gras 
602fe8fb19SBen Gras 	_DIAGASSERT(fp != NULL);
612fe8fb19SBen Gras 
622fe8fb19SBen Gras 	_SET_ORIENTATION(fp, -1);
632fe8fb19SBen Gras 
642fe8fb19SBen Gras 	/*
652fe8fb19SBen Gras 	 * In case we cannot write, or longjmp takes us out early,
662fe8fb19SBen Gras 	 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
672fe8fb19SBen Gras 	 * (if line buffered) so that we will get called again.
682fe8fb19SBen Gras 	 * If we did not do this, a sufficient number of putc()
692fe8fb19SBen Gras 	 * calls might wrap _w from negative to positive.
702fe8fb19SBen Gras 	 */
712fe8fb19SBen Gras 	fp->_w = fp->_lbfsize;
722fe8fb19SBen Gras 	if (cantwrite(fp)) {
732fe8fb19SBen Gras 		errno = EBADF;
74*f14fb602SLionel Sambuc 		return EOF;
752fe8fb19SBen Gras 	}
762fe8fb19SBen Gras 	c = (unsigned char)c;
772fe8fb19SBen Gras 
782fe8fb19SBen Gras 	/*
792fe8fb19SBen Gras 	 * If it is completely full, flush it out.  Then, in any case,
802fe8fb19SBen Gras 	 * stuff c into the buffer.  If this causes the buffer to fill
812fe8fb19SBen Gras 	 * completely, or if c is '\n' and the file is line buffered,
822fe8fb19SBen Gras 	 * flush it (perhaps a second time).  The second flush will always
832fe8fb19SBen Gras 	 * happen on unbuffered streams, where _bf._size==1; fflush()
842fe8fb19SBen Gras 	 * guarantees that putc() will always call wbuf() by setting _w
852fe8fb19SBen Gras 	 * to 0, so we need not do anything else.
862fe8fb19SBen Gras 	 */
87*f14fb602SLionel Sambuc 	_DIAGASSERT(__type_fit(int, fp->_p - fp->_bf._base));
88*f14fb602SLionel Sambuc 	n = (int)(fp->_p - fp->_bf._base);
892fe8fb19SBen Gras 	if (n >= fp->_bf._size) {
902fe8fb19SBen Gras 		if (fflush(fp))
91*f14fb602SLionel Sambuc 			return EOF;
922fe8fb19SBen Gras 		n = 0;
932fe8fb19SBen Gras 	}
942fe8fb19SBen Gras 	fp->_w--;
952fe8fb19SBen Gras 	*fp->_p++ = c;
962fe8fb19SBen Gras 	if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
972fe8fb19SBen Gras 		if (fflush(fp))
98*f14fb602SLionel Sambuc 			return EOF;
99*f14fb602SLionel Sambuc 	return c;
1002fe8fb19SBen Gras }
101