wbuf.c revision 1.12 1 /* $NetBSD: wbuf.c,v 1.12 2003/01/18 11:30:00 thorpej 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. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 #if 0
42 static char sccsid[] = "@(#)wbuf.c 8.1 (Berkeley) 6/4/93";
43 #else
44 __RCSID("$NetBSD: wbuf.c,v 1.12 2003/01/18 11:30:00 thorpej Exp $");
45 #endif
46 #endif /* LIBC_SCCS and not lint */
47
48 #include <assert.h>
49 #include <errno.h>
50 #include <stdio.h>
51 #include "reentrant.h"
52 #include "local.h"
53
54 /*
55 * Write the given character into the (probably full) buffer for
56 * the given file. Flush the buffer out if it is or becomes full,
57 * or if c=='\n' and the file is line buffered.
58 */
59 int
60 __swbuf(c, fp)
61 int c;
62 FILE *fp;
63 {
64 int n;
65
66 _DIAGASSERT(fp != NULL);
67
68 _SET_ORIENTATION(fp, -1);
69
70 /*
71 * In case we cannot write, or longjmp takes us out early,
72 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
73 * (if line buffered) so that we will get called again.
74 * If we did not do this, a sufficient number of putc()
75 * calls might wrap _w from negative to positive.
76 */
77 fp->_w = fp->_lbfsize;
78 if (cantwrite(fp)) {
79 errno = EBADF;
80 return (EOF);
81 }
82 c = (unsigned char)c;
83
84 /*
85 * If it is completely full, flush it out. Then, in any case,
86 * stuff c into the buffer. If this causes the buffer to fill
87 * completely, or if c is '\n' and the file is line buffered,
88 * flush it (perhaps a second time). The second flush will always
89 * happen on unbuffered streams, where _bf._size==1; fflush()
90 * guarantees that putc() will always call wbuf() by setting _w
91 * to 0, so we need not do anything else.
92 */
93 n = fp->_p - fp->_bf._base;
94 if (n >= fp->_bf._size) {
95 if (fflush(fp))
96 return (EOF);
97 n = 0;
98 }
99 fp->_w--;
100 *fp->_p++ = c;
101 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
102 if (fflush(fp))
103 return (EOF);
104 return (c);
105 }
106