wbuf.c revision 1.10.10.1 1 /* $NetBSD: wbuf.c,v 1.10.10.1 2002/01/28 20:51:15 nathanw 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 1.10.10.1 2002/01/28 20:51:15 nathanw 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 "local.h"
52
53 /*
54 * Write the given character into the (probably full) buffer for
55 * the given file. Flush the buffer out if it is or becomes full,
56 * or if c=='\n' and the file is line buffered.
57 */
58 int
59 __swbuf(c, fp)
60 int c;
61 FILE *fp;
62 {
63 int n;
64
65 _DIAGASSERT(fp != NULL);
66
67 _SET_ORIENTATION(fp, -1);
68
69 /*
70 * In case we cannot write, or longjmp takes us out early,
71 * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
72 * (if line buffered) so that we will get called again.
73 * If we did not do this, a sufficient number of putc()
74 * calls might wrap _w from negative to positive.
75 */
76 fp->_w = fp->_lbfsize;
77 if (cantwrite(fp)) {
78 errno = EBADF;
79 return (EOF);
80 }
81 c = (unsigned char)c;
82
83 /*
84 * If it is completely full, flush it out. Then, in any case,
85 * stuff c into the buffer. If this causes the buffer to fill
86 * completely, or if c is '\n' and the file is line buffered,
87 * flush it (perhaps a second time). The second flush will always
88 * happen on unbuffered streams, where _bf._size==1; fflush()
89 * guarantees that putc() will always call wbuf() by setting _w
90 * to 0, so we need not do anything else.
91 */
92 n = fp->_p - fp->_bf._base;
93 if (n >= fp->_bf._size) {
94 if (fflush(fp))
95 return (EOF);
96 n = 0;
97 }
98 fp->_w--;
99 *fp->_p++ = c;
100 if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
101 if (fflush(fp))
102 return (EOF);
103 return (c);
104 }
105