1290001Sglebius/*
2290001Sglebius * Copyright (C) 2004, 2007  Internet Systems Consortium, Inc. ("ISC")
3290001Sglebius * Copyright (C) 2000, 2001  Internet Software Consortium.
4290001Sglebius *
5290001Sglebius * Permission to use, copy, modify, and/or distribute this software for any
6290001Sglebius * purpose with or without fee is hereby granted, provided that the above
7290001Sglebius * copyright notice and this permission notice appear in all copies.
8290001Sglebius *
9290001Sglebius * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10290001Sglebius * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11290001Sglebius * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12290001Sglebius * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13290001Sglebius * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14290001Sglebius * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15290001Sglebius * PERFORMANCE OF THIS SOFTWARE.
16290001Sglebius */
17290001Sglebius
18290001Sglebius/* $Id: offset.h,v 1.6 2007/06/19 23:47:20 tbox Exp $ */
19290001Sglebius
20290001Sglebius#ifndef ISC_OFFSET_H
21290001Sglebius#define ISC_OFFSET_H 1
22290001Sglebius
23290001Sglebius/*
24290001Sglebius * File offsets are operating-system dependent.
25290001Sglebius */
26290001Sglebius#include <limits.h>             /* Required for CHAR_BIT. */
27290001Sglebius#include <sys/types.h>
28290001Sglebius
29290001Sglebiustypedef _off_t isc_offset_t;
30290001Sglebius
31290001Sglebius/*
32290001Sglebius * POSIX says "Additionally, blkcnt_t and off_t are extended signed integral
33290001Sglebius * types", so the maximum value is all 1s except for the high bit.
34290001Sglebius * This definition is more complex than it really needs to be because it was
35290001Sglebius * crafted to keep both the SunOS 5.6 and the HP/UX 11 compilers quiet about
36290001Sglebius * integer overflow.  For example, though this is equivalent to just left
37290001Sglebius * shifting 1 to the high bit and then inverting the bits, the SunOS compiler
38290001Sglebius * is unhappy about shifting a positive "1" to negative in a signed integer.
39290001Sglebius */
40290001Sglebius#define ISC_OFFSET_MAXIMUM \
41290001Sglebius	(~(((off_t)-1 >> (sizeof(off_t) * CHAR_BIT - 1)) \
42290001Sglebius		      << (sizeof(off_t) * CHAR_BIT - 1)))
43290001Sglebius
44290001Sglebius#endif /* ISC_OFFSET_H */
45