1/*
2 * Copyright (C) 2004, 2005, 2007, 2008  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2000, 2001  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: offset.h,v 1.17 2008/12/01 23:47:45 tbox Exp $ */
19
20#ifndef ISC_OFFSET_H
21#define ISC_OFFSET_H 1
22
23/*! \file
24 * \brief
25 * File offsets are operating-system dependent.
26 */
27#include <limits.h>             /* Required for CHAR_BIT. */
28#include <sys/types.h>
29#include <stddef.h>		/* For Linux Standard Base. */
30
31typedef off_t isc_offset_t;
32
33/*%
34 * POSIX says "Additionally, blkcnt_t and off_t are extended signed integral
35 * types", so the maximum value is all 1s except for the high bit.
36 * This definition is more complex than it really needs to be because it was
37 * crafted to keep both the SunOS 5.6 and the HP/UX 11 compilers quiet about
38 * integer overflow.  For example, though this is equivalent to just left
39 * shifting 1 to the high bit and then inverting the bits, the SunOS compiler
40 * is unhappy about shifting a positive "1" to negative in a signed integer.
41 */
42#define ISC_OFFSET_MAXIMUM \
43	(~(((off_t)-1 >> (sizeof(off_t) * CHAR_BIT - 1)) \
44		      << (sizeof(off_t) * CHAR_BIT - 1)))
45
46#endif /* ISC_OFFSET_H */
47