root / prex-0.9.0 / usr / lib / libc / stdio / makebuf.c @ 03e9c04a
History | View | Annotate | Download (2.9 KB)
1 | 03e9c04a | Brad Neuman | /*-
|
---|---|---|---|
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. Neither the name of the University nor the names of its contributors
|
||
17 | * may be used to endorse or promote products derived from this software
|
||
18 | * without specific prior written permission.
|
||
19 | *
|
||
20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
30 | * SUCH DAMAGE.
|
||
31 | */
|
||
32 | |||
33 | #include <sys/types.h> |
||
34 | #include <sys/stat.h> |
||
35 | #include <unistd.h> |
||
36 | #include <stdio.h> |
||
37 | #include <stdlib.h> |
||
38 | #include "local.h" |
||
39 | |||
40 | /*
|
||
41 | * Internal routine to determine `proper' buffering for a file.
|
||
42 | */
|
||
43 | static int |
||
44 | __swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
|
||
45 | { |
||
46 | struct stat st;
|
||
47 | |||
48 | *bufsize = BUFSIZ; |
||
49 | *couldbetty = 0;
|
||
50 | if (fp->_file < 0 || fstat(fp->_file, &st) < 0) |
||
51 | return 0; |
||
52 | |||
53 | /* could be a tty iff it is a character device */
|
||
54 | *couldbetty = S_ISCHR(st.st_mode); |
||
55 | return 0; |
||
56 | } |
||
57 | |||
58 | /*
|
||
59 | * Allocate a file buffer, or switch to unbuffered I/O.
|
||
60 | * Per the ANSI C standard, ALL tty devices default to line buffered.
|
||
61 | *
|
||
62 | * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
|
||
63 | * optimisation) right after the fstat() that finds the buffer size.
|
||
64 | */
|
||
65 | void
|
||
66 | __smakebuf(fp) |
||
67 | FILE *fp; |
||
68 | { |
||
69 | void *p;
|
||
70 | int flags;
|
||
71 | size_t size; |
||
72 | int couldbetty;
|
||
73 | |||
74 | if (fp->_flags & __SNBF) {
|
||
75 | fp->_bf._base = fp->_p = fp->_nbuf; |
||
76 | fp->_bf._size = 1;
|
||
77 | return;
|
||
78 | } |
||
79 | flags = __swhatbuf(fp, &size, &couldbetty); |
||
80 | if ((p = malloc(size)) == NULL) { |
||
81 | fp->_flags |= __SNBF; |
||
82 | fp->_bf._base = fp->_p = fp->_nbuf; |
||
83 | fp->_bf._size = 1;
|
||
84 | return;
|
||
85 | } |
||
86 | __cleanup = _cleanup; |
||
87 | flags |= __SMBF; |
||
88 | fp->_bf._base = fp->_p = p; |
||
89 | fp->_bf._size = size; |
||
90 | if (couldbetty && isatty(fp->_file))
|
||
91 | flags |= __SLBF; |
||
92 | |||
93 | fp->_flags |= flags; |
||
94 | } |