xref: /freebsd/lib/libc/stdio/stdio.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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 #if 0
39 static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
40 #endif
41 static const char rcsid[] =
42 		"$Id$";
43 #endif /* LIBC_SCCS and not lint */
44 
45 #include <fcntl.h>
46 #include <unistd.h>
47 #include <stdio.h>
48 #include "local.h"
49 
50 /*
51  * Small standard I/O/seek/close functions.
52  * These maintain the `known seek offset' for seek optimisation.
53  */
54 int
55 __sread(cookie, buf, n)
56 	void *cookie;
57 	char *buf;
58 	int n;
59 {
60 	register FILE *fp = cookie;
61 	register int ret;
62 
63 	ret = read(fp->_file, buf, (size_t)n);
64 	/* if the read succeeded, update the current offset */
65 	if (ret >= 0)
66 		fp->_offset += ret;
67 	else
68 		fp->_flags &= ~__SOFF;	/* paranoia */
69 	return (ret);
70 }
71 
72 int
73 __swrite(cookie, buf, n)
74 	void *cookie;
75 	char const *buf;
76 	int n;
77 {
78 	register FILE *fp = cookie;
79 
80 	if (fp->_flags & __SAPP)
81 		(void) lseek(fp->_file, (off_t)0, SEEK_END);
82 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
83 	return (write(fp->_file, buf, (size_t)n));
84 }
85 
86 fpos_t
87 __sseek(cookie, offset, whence)
88 	void *cookie;
89 	fpos_t offset;
90 	int whence;
91 {
92 	register FILE *fp = cookie;
93 	register off_t ret;
94 
95 	ret = lseek(fp->_file, (off_t)offset, whence);
96 	if (ret == -1)
97 		fp->_flags &= ~__SOFF;
98 	else {
99 		fp->_flags |= __SOFF;
100 		fp->_offset = ret;
101 	}
102 	return (ret);
103 }
104 
105 int
106 __sclose(cookie)
107 	void *cookie;
108 {
109 
110 	return (close(((FILE *)cookie)->_file));
111 }
112