funopen.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[] = "@(#)funopen.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <stdio.h>
42#include <errno.h>
43#include "local.h"
44
45FILE *
46funopen(cookie, readfn, writefn, seekfn, closefn)
47	const void *cookie;
48	int (*readfn)(), (*writefn)();
49#if __STDC__
50	fpos_t (*seekfn)(void *cookie, fpos_t off, int whence);
51#else
52	fpos_t (*seekfn)();
53#endif
54	int (*closefn)();
55{
56	register FILE *fp;
57	int flags;
58
59	if (readfn == NULL) {
60		if (writefn == NULL) {		/* illegal */
61			errno = EINVAL;
62			return (NULL);
63		} else
64			flags = __SWR;		/* write only */
65	} else {
66		if (writefn == NULL)
67			flags = __SRD;		/* read only */
68		else
69			flags = __SRW;		/* read-write */
70	}
71	if ((fp = __sfp()) == NULL)
72		return (NULL);
73	fp->_flags = flags;
74	fp->_file = -1;
75	fp->_cookie = (void *)cookie;
76	fp->_read = readfn;
77	fp->_write = writefn;
78	fp->_seek = seekfn;
79	fp->_close = closefn;
80	return (fp);
81}
82