1290001Sglebius/*
2290001Sglebius * Copyright (C) 2004, 2005, 2007, 2008  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 1.17 2008/12/01 23:47:45 tbox Exp $ */
19290001Sglebius
20290001Sglebius#ifndef ISC_OFFSET_H
21290001Sglebius#define ISC_OFFSET_H 1
22290001Sglebius
23290001Sglebius/*! \file
24290001Sglebius * \brief
25290001Sglebius * File offsets are operating-system dependent.
26290001Sglebius */
27290001Sglebius#include <limits.h>             /* Required for CHAR_BIT. */
28290001Sglebius#include <sys/types.h>
29290001Sglebius#include <stddef.h>		/* For Linux Standard Base. */
30290001Sglebius
31290001Sglebiustypedef off_t isc_offset_t;
32290001Sglebius
33290001Sglebius/*%
34290001Sglebius * POSIX says "Additionally, blkcnt_t and off_t are extended signed integral
35290001Sglebius * types", so the maximum value is all 1s except for the high bit.
36290001Sglebius * This definition is more complex than it really needs to be because it was
37290001Sglebius * crafted to keep both the SunOS 5.6 and the HP/UX 11 compilers quiet about
38290001Sglebius * integer overflow.  For example, though this is equivalent to just left
39290001Sglebius * shifting 1 to the high bit and then inverting the bits, the SunOS compiler
40290001Sglebius * is unhappy about shifting a positive "1" to negative in a signed integer.
41290001Sglebius */
42290001Sglebius#define ISC_OFFSET_MAXIMUM \
43290001Sglebius	(~(((off_t)-1 >> (sizeof(off_t) * CHAR_BIT - 1)) \
44290001Sglebius		      << (sizeof(off_t) * CHAR_BIT - 1)))
45290001Sglebius
46290001Sglebius#endif /* ISC_OFFSET_H */
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