setvbuf.c - vx32 - Local 9vx git repository for patches.
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setvbuf.c (4890B)
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1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.2 1996/08/19 08:33:05 tholo Exp $";
39 #endif /* LIBC_SCCS and not lint */
40
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include "local.h"
44
45 /*
46 * Set one of the three kinds of buffering, optionally including
47 * a buffer.
48 */
49 int
50 setvbuf(fp, buf, mode, size)
51 register FILE *fp;
52 char *buf;
53 register int mode;
54 register size_t size;
55 {
56 register int ret, flags;
57 size_t iosize;
58 int ttyflag;
59
60 /*
61 * Verify arguments. The `int' limit on `size' is due to this
62 * particular implementation. Note, buf and size are ignored
63 * when setting _IONBF.
64 */
65 if (mode != _IONBF)
66 if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0)
67 return (EOF);
68
69 /*
70 * Write current buffer, if any. Discard unread input (including
71 * ungetc data), cancel line buffering, and free old buffer if
72 * malloc()ed. We also clear any eof condition, as if this were
73 * a seek.
74 */
75 ret = 0;
76 (void)__sflush(fp);
77 if (HASUB(fp))
78 FREEUB(fp);
79 fp->_r = fp->_lbfsize = 0;
80 flags = fp->_flags;
81 if (flags & __SMBF)
82 free((void *)fp->_bf._base);
83 flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF);
84
85 /* If setting unbuffered mode, skip all the hard work. */
86 if (mode == _IONBF)
87 goto nbf;
88
89 /*
90 * Find optimal I/O size for seek optimization. This also returns
91 * a `tty flag' to suggest that we check isatty(fd), but we do not
92 * care since our caller told us how to buffer.
93 */
94 flags |= __swhatbuf(fp, &iosize, &ttyflag);
95 if (size == 0) {
96 buf = NULL; /* force local allocation */
97 size = iosize;
98 }
99
100 /* Allocate buffer if needed. */
101 if (buf == NULL) {
102 if ((buf = malloc(size)) == NULL) {
103 /*
104 * Unable to honor user's request. We will return
105 * failure, but try again with file system size.
106 */
107 ret = EOF;
108 if (size != iosize) {
109 size = iosize;
110 buf = malloc(size);
111 }
112 }
113 if (buf == NULL) {
114 /* No luck; switch to unbuffered I/O. */
115 nbf:
116 fp->_flags = flags | __SNBF;
117 fp->_w = 0;
118 fp->_bf._base = fp->_p = fp->_nbuf;
119 fp->_bf._size = 1;
120 return (ret);
121 }
122 flags |= __SMBF;
123 }
124
125 /*
126 * Kill any seek optimization if the buffer is not the
127 * right size.
128 *
129 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
130 */
131 if (size != iosize)
132 flags |= __SNPT;
133
134 /*
135 * Fix up the FILE fields, and set __cleanup for output flush on
136 * exit (since we are buffered in some way).
137 */
138 if (mode == _IOLBF)
139 flags |= __SLBF;
140 fp->_flags = flags;
141 fp->_bf._base = fp->_p = (unsigned char *)buf;
142 fp->_bf._size = size;
143 /* fp->_lbfsize is still 0 */
144 if (flags & __SWR) {
145 /*
146 * Begin or continue writing: see __swsetup(). Note
147 * that __SNBF is impossible (it was handled earlier).
148 */
149 if (flags & __SLBF) {
150 fp->_w = 0;
151 fp->_lbfsize = -fp->_bf._size;
152 } else
153 fp->_w = size;
154 } else {
155 /* begin/continue reading, or stay in intermediate state */
156 fp->_w = 0;
157 }
158 __cleanup = _cleanup;
159
160 return (ret);
161 }