1 /* $NetBSD: wbuf.c,v 1.15 2012/03/15 18:22:31 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: wbuf.c,v 1.15 2012/03/15 18:22:31 christos Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #include <assert.h>
45 #include <errno.h>
46 #include <stdio.h>
47 #include "reentrant.h"
48 #include "local.h"
49
50 /*
51 * Write the given character into the (probably full) buffer for
52 * the given file. Flush the buffer out if it is or becomes full,
53 * or if c=='\n' and the file is line buffered.
54 */
55 int
__swbuf(int c,FILE * fp)56 __swbuf(int c, FILE *fp)
57 {
58 int n;
59
60 _DIAGASSERT(fp != NULL);
61
62 _SET_ORIENTATION(fp, -1);
63
64 /*
65 * In case we cannot write, or longjmp takes us out early,
66 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
67 * (if line buffered) so that we will get called again.
68 * If we did not do this, a sufficient number of putc()
69 * calls might wrap _w from negative to positive.
70 */
71 fp->_w = fp->_lbfsize;
72 if (cantwrite(fp)) {
73 errno = EBADF;
74 return EOF;
75 }
76 c = (unsigned char)c;
77
78 /*
79 * If it is completely full, flush it out. Then, in any case,
80 * stuff c into the buffer. If this causes the buffer to fill
81 * completely, or if c is '\n' and the file is line buffered,
82 * flush it (perhaps a second time). The second flush will always
83 * happen on unbuffered streams, where _bf._size==1; fflush()
84 * guarantees that putc() will always call wbuf() by setting _w
85 * to 0, so we need not do anything else.
86 */
87 _DIAGASSERT(__type_fit(int, fp->_p - fp->_bf._base));
88 n = (int)(fp->_p - fp->_bf._base);
89 if (n >= fp->_bf._size) {
90 if (fflush(fp))
91 return EOF;
92 n = 0;
93 }
94 fp->_w--;
95 *fp->_p++ = c;
96 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
97 if (fflush(fp))
98 return EOF;
99 return c;
100 }
101