1 /* @(#)fcons.c	2.20 10/11/06 Copyright 1986, 1995-2010 J. Schilling */
2 /*
3  *	Copyright (c) 1986, 1995-2010  J. Schilling
4  */
5 /*
6  * The contents of this file are subject to the terms of the
7  * Common Development and Distribution License, Version 1.0 only
8  * (the "License").  You may not use this file except in compliance
9  * with the License.
10  *
11  * See the file CDDL.Schily.txt in this distribution for details.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file CDDL.Schily.txt from this distribution.
15  */
16 
17 #include "schilyio.h"
18 
19 /*
20  * Note that because of a definition in schilyio.h we are using
21  * fseeko()/ftello() instead of fseek()/ftell() if available.
22  */
23 
24 LOCAL	char	*fmtab[] = {
25 			"",	/* 0	FI_NONE				*/
26 			"r",	/* 1	FI_READ				*/
27 			"w",	/* 2	FI_WRITE		**1)	*/
28 			"r+",	/* 3	FI_READ  | FI_WRITE		*/
29 			"b",	/* 4	FI_NONE  | FI_BINARY		*/
30 			"rb",	/* 5	FI_READ  | FI_BINARY		*/
31 			"wb",	/* 6	FI_WRITE | FI_BINARY	**1)	*/
32 			"r+b",	/* 7	FI_READ  | FI_WRITE | FI_BINARY	*/
33 
34 /* + FI_APPEND	*/	"",	/* 0	FI_NONE				*/
35 /* ...		*/	"r",	/* 1	FI_READ				*/
36 			"a",	/* 2	FI_WRITE		**1)	*/
37 			"a+",	/* 3	FI_READ  | FI_WRITE		*/
38 			"b",	/* 4	FI_NONE  | FI_BINARY		*/
39 			"rb",	/* 5	FI_READ  | FI_BINARY		*/
40 			"ab",	/* 6	FI_WRITE | FI_BINARY	**1)	*/
41 			"a+b",	/* 7	FI_READ  | FI_WRITE | FI_BINARY	*/
42 		};
43 /*
44  * NOTES:
45  *	1)	fdopen() guarantees not to create/trunc files in this case
46  *
47  *	"w"	will create/trunc files with fopen()
48  *	"a"	will create files with fopen()
49  */
50 
51 
52 EXPORT FILE *
53 _fcons(fd, f, flag)
54 	register FILE	*fd;
55 		int	f;
56 		int	flag;
57 {
58 	int	my_gflag = _io_glflag;
59 
60 	if (fd == (FILE *)NULL)
61 		fd = fdopen(f,
62 			fmtab[flag&(FI_READ|FI_WRITE|FI_BINARY | FI_APPEND)]);
63 
64 	if (fd != (FILE *)NULL) {
65 		if (flag & FI_APPEND) {
66 			(void) fseek(fd, (off_t)0, SEEK_END);
67 		}
68 		if (flag & FI_UNBUF) {
69 			setbuf(fd, NULL);
70 			my_gflag |= _JS_IOUNBUF;
71 		}
72 		set_my_flag(fd, my_gflag); /* must clear it if fd is reused */
73 		return (fd);
74 	}
75 	if (flag & FI_CLOSE)
76 		close(f);
77 
78 	return ((FILE *)NULL);
79 }
80