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15637ed4 RG |
1 | /*- |
2 | * Copyright (c) 1990 The Regents of the University of California. | |
3 | * 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) | |
e7b54832 | 38 | static char sccsid[] = "@(#)setvbuf.c 5.5 (Berkeley) 5/6/93"; |
15637ed4 RG |
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 | setvbuf(fp, buf, mode, size) | |
50 | register FILE *fp; | |
51 | char *buf; | |
52 | register int mode; | |
53 | register size_t size; | |
54 | { | |
e7b54832 NW |
55 | register int ret, flags; |
56 | size_t iosize; | |
57 | int ttyflag; | |
15637ed4 RG |
58 | |
59 | /* | |
60 | * Verify arguments. The `int' limit on `size' is due to this | |
e7b54832 NW |
61 | * particular implementation. Note, buf and size are ignored |
62 | * when setting _IONBF. | |
15637ed4 | 63 | */ |
e7b54832 NW |
64 | if (mode != _IONBF) |
65 | if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) | |
66 | return (EOF); | |
15637ed4 RG |
67 | |
68 | /* | |
e7b54832 NW |
69 | * Write current buffer, if any. Discard unread input, cancel |
70 | * line buffering, and free old buffer if malloc()ed. | |
15637ed4 | 71 | */ |
e7b54832 NW |
72 | ret = 0; |
73 | (void)__sflush(fp); | |
74 | fp->_r = fp->_lbfsize = 0; | |
75 | flags = fp->_flags; | |
76 | if (flags & __SMBF) | |
15637ed4 | 77 | free((void *)fp->_bf._base); |
e7b54832 NW |
78 | flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT); |
79 | ||
80 | /* If setting unbuffered mode, skip all the hard work. */ | |
81 | if (mode == _IONBF) | |
82 | goto nbf; | |
15637ed4 RG |
83 | |
84 | /* | |
e7b54832 NW |
85 | * Find optimal I/O size for seek optimization. This also returns |
86 | * a `tty flag' to suggest that we check isatty(fd), but we do not | |
87 | * care since our caller told us how to buffer. | |
15637ed4 | 88 | */ |
e7b54832 NW |
89 | flags |= __swhatbuf(fp, &iosize, &ttyflag); |
90 | if (size == 0) { | |
91 | buf = NULL; /* force local allocation */ | |
92 | size = iosize; | |
93 | } | |
15637ed4 | 94 | |
e7b54832 NW |
95 | /* Allocate buffer if needed. */ |
96 | if (buf == NULL) { | |
97 | if ((buf = malloc(size)) == NULL) { | |
98 | /* | |
99 | * Unable to honor user's request. We will return | |
100 | * failure, but try again with file system size. | |
101 | */ | |
102 | ret = EOF; | |
103 | if (size != iosize) { | |
104 | size = iosize; | |
105 | buf = malloc(size); | |
106 | } | |
107 | } | |
108 | if (buf == NULL) { | |
109 | /* No luck; switch to unbuffered I/O. */ | |
110 | nbf: | |
111 | fp->_flags = flags | __SNBF; | |
112 | fp->_w = 0; | |
113 | fp->_bf._base = fp->_p = fp->_nbuf; | |
114 | fp->_bf._size = 1; | |
115 | return (ret); | |
116 | } | |
117 | flags |= __SMBF; | |
15637ed4 RG |
118 | } |
119 | ||
120 | /* | |
e7b54832 NW |
121 | * Kill any seek optimization if the buffer is not the |
122 | * right size. | |
123 | * | |
124 | * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? | |
15637ed4 | 125 | */ |
e7b54832 NW |
126 | if (size != iosize) |
127 | flags |= __SNPT; | |
128 | ||
129 | /* | |
130 | * Fix up the FILE fields, and set __cleanup for output flush on | |
131 | * exit (since we are buffered in some way). If in r/w mode, go | |
132 | * to the intermediate state, so that everyone has to call | |
133 | * __srefill or __swsetup on the first operation -- it is more | |
134 | * trouble than it is worth to set things up correctly here. | |
135 | */ | |
136 | if (mode == _IOLBF) | |
137 | flags |= __SLBF; | |
138 | if (flags & __SRW) | |
139 | flags &= ~(__SRD | __SWR); | |
140 | fp->_w = 0; | |
141 | fp->_flags = flags; | |
142 | fp->_bf._base = fp->_p = (unsigned char *)buf; | |
143 | fp->_bf._size = size; | |
144 | fp->_lbfsize = 0; | |
145 | __cleanup = _cleanup; | |
15637ed4 | 146 | |
e7b54832 | 147 | return (ret); |
15637ed4 | 148 | } |