xref: /titanic_41/usr/src/lib/libbc/libc/stdio/common/setvbuf.c (revision 986fd29a0dc13f7608ef7f508f6e700bd7bc2720)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*      Copyright (c) 1984 AT&T */
28 /*        All Rights Reserved   */
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.2 */
31 
32 /*LINTLIBRARY*/
33 #include <stdio.h>
34 
35 extern void free();
36 extern unsigned char (*_smbuf)[_SBFSIZ];
37 extern char *malloc();
38 extern void _getsmbuf();
39 
40 int
41 setvbuf(iop, buf, type, size)
42 register FILE *iop;
43 register char	*buf;
44 register int type;
45 register int size;
46 {
47 	register int fno = fileno(iop);  /* file number */
48 
49 	if(iop->_base != NULL && iop->_flag & _IOMYBUF)
50 		free((char*)iop->_base);
51 	iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
52 	switch (type)  {
53 	    /*note that the flags are the same as the possible values for type*/
54 	    case _IONBF:
55 		/* file is unbuffered except in fastio */
56 		iop->_flag |= _IONBF;
57 		/* use small buffers reserved for this */
58 		iop->_base = _smbuf[fno];
59 		iop->_bufsiz = _SBFSIZ;
60 		break;
61 	    case _IOLBF:
62 	    case _IOFBF:
63 		if (size < 0)
64 			return -1;
65 		iop->_flag |= type;
66 		size = (size == 0) ? BUFSIZ : size;
67 		/*
68 		* need eight characters beyond bufend for stdio slop
69 		*/
70 		if (size <= 8) {
71 		    size = BUFSIZ;
72 		    buf = NULL;
73 		}
74 		if (buf == NULL) {
75 			size += 8;
76 			buf = malloc((unsigned)size);
77 			iop->_flag |= _IOMYBUF;
78 		}
79 		iop->_base = (unsigned char *)buf;
80 		iop->_bufsiz = size - 8;
81 		break;
82 	    default:
83 		return -1;
84 	}
85 	iop->_ptr = iop->_base;
86 	iop->_cnt = 0;
87 	return 0;
88 }
89