stdio.c revision 1573 
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)
38static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <fcntl.h>
42#include <unistd.h>
43#include <stdio.h>
44#include "local.h"
45
46/*
47 * Small standard I/O/seek/close functions.
48 * These maintain the `known seek offset' for seek optimisation.
49 */
50__sread(cookie, buf, n)
51	void *cookie;
52	char *buf;
53	int n;
54{
55	register FILE *fp = cookie;
56	register int ret;
57
58	ret = read(fp->_file, buf, n);
59	/* if the read succeeded, update the current offset */
60	if (ret >= 0)
61		fp->_offset += ret;
62	else
63		fp->_flags &= ~__SOFF;	/* paranoia */
64	return (ret);
65}
66
67__swrite(cookie, buf, n)
68	void *cookie;
69	char const *buf;
70	int n;
71{
72	register FILE *fp = cookie;
73
74	if (fp->_flags & __SAPP)
75		(void) lseek(fp->_file, (off_t)0, SEEK_END);
76	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
77	return (write(fp->_file, buf, n));
78}
79
80fpos_t
81__sseek(cookie, offset, whence)
82	void *cookie;
83	fpos_t offset;
84	int whence;
85{
86	register FILE *fp = cookie;
87	register off_t ret;
88
89	ret = lseek(fp->_file, (off_t)offset, whence);
90	if (ret == -1L)
91		fp->_flags &= ~__SOFF;
92	else {
93		fp->_flags |= __SOFF;
94		fp->_offset = ret;
95	}
96	return (ret);
97}
98
99__sclose(cookie)
100	void *cookie;
101{
102
103	return (close(((FILE *)cookie)->_file));
104}
105