1 /* $OpenBSD: wsetup.c,v 1.7 2005/08/08 08:05:36 espie Exp $ */
2 /*-
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include "local.h"
37
38 /*
39 * Various output routines call wsetup to be sure it is safe to write,
40 * because either _flags does not include __SWR, or _buf is NULL.
41 * _wsetup returns 0 if OK to write, nonzero otherwise.
42 */
43 int
__swsetup(FILE * fp)44 __swsetup(FILE *fp)
45 {
46 /* make sure stdio is set up */
47 if (!__sdidinit)
48 __sinit();
49
50 /*
51 * If we are not writing, we had better be reading and writing.
52 */
53 if ((fp->_flags & __SWR) == 0) {
54 if ((fp->_flags & __SRW) == 0)
55 return (EOF);
56 if (fp->_flags & __SRD) {
57 /* clobber any ungetc data */
58 if (HASUB(fp))
59 FREEUB(fp);
60 fp->_flags &= ~(__SRD|__SEOF);
61 fp->_r = 0;
62 fp->_p = fp->_bf._base;
63 }
64 fp->_flags |= __SWR;
65 }
66
67 /*
68 * Make a buffer if necessary, then set _w.
69 */
70 if (fp->_bf._base == NULL) {
71 if ((fp->_flags & (__SSTR | __SALC)) == __SSTR)
72 return (EOF);
73 __smakebuf(fp);
74 }
75 if (fp->_flags & __SLBF) {
76 /*
77 * It is line buffered, so make _lbfsize be -_bufsize
78 * for the putc() macro. We will change _lbfsize back
79 * to 0 whenever we turn off __SWR.
80 */
81 fp->_w = 0;
82 fp->_lbfsize = -fp->_bf._size;
83 } else
84 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
85 return (0);
86 }
87