source: NonGTP/Boost/boost/date_time/filetime_functions.hpp @ 857

Revision 857, 2.7 KB checked in by igarcia, 19 years ago (diff)
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[857]1#ifndef DATE_TIME_FILETIME_FUNCTIONS_HPP__
2#define DATE_TIME_FILETIME_FUNCTIONS_HPP__
3
4/* Copyright (c) 2004 CrystalClear Software, Inc.
5 * Use, modification and distribution is subject to the
6 * Boost Software License, Version 1.0. (See accompanying
7 * file LICENSE-1.0 or http://www.boost.org/LICENSE-1.0)
8 * Author: Jeff Garland, Bart Garst
9 * $Date: 2004/08/04 22:06:05 $
10 */
11
12/*! @file filetime_functions.hpp
13 * Function(s) for converting between a FILETIME structure and a
14 * time object. This file is only available on systems that have
15 * BOOST_HAS_FTIME defined.
16 */
17
18#include <boost/date_time/compiler_config.hpp>
19#if defined(BOOST_HAS_FTIME) // skip this file if no FILETIME
20#include <windows.h>
21#include <boost/cstdint.hpp>
22#include <boost/date_time/time.hpp>
23
24
25namespace boost {
26namespace date_time {
27
28
29  //! Create a time object from an initialized FILETIME struct.
30  /*! Create a time object from an initialized FILETIME struct.
31   * A FILETIME struct holds 100-nanosecond units (0.0000001). When
32   * built with microsecond resolution the FILETIME's sub second value
33   * will be truncated. Nanosecond resolution has no truncation. */
34  template<class time_type>
35  inline
36  time_type time_from_ftime(const FILETIME& ft){
37    typedef typename time_type::date_type date_type;
38    typedef typename time_type::date_duration_type date_duration_type;
39    typedef typename time_type::time_duration_type time_duration_type;
40
41    /* OFFSET is difference between 1970-Jan-01 & 1601-Jan-01
42     * in 100-nanosecond intervals */
43    uint64_t c1 = 27111902UL;
44    uint64_t c2 = 3577643008UL; // issues warning without 'UL'
45    const uint64_t OFFSET = (c1 << 32) + c2;
46    const long sec_pr_day = 86400; // seconds per day
47
48    uint64_t filetime = ft.dwHighDateTime;
49    filetime <<= 32;
50    filetime += ft.dwLowDateTime;
51    filetime -= OFFSET; // filetime is now 100-nanos since 1970-Jan-01
52
53    uint64_t sec = filetime / 10000000;
54#if defined(BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG)
55    uint64_t sub_sec = (filetime % 10000000) * 100; // nanoseconds
56#else
57    uint64_t sub_sec = (filetime % 10000000) / 10; // truncate to microseconds
58#endif
59
60    // split sec into usable chunks: days, hours, minutes, & seconds
61    long _d = sec / sec_pr_day;
62    long tmp = sec % sec_pr_day;
63    long _h = tmp / 3600; // sec_pr_hour
64    tmp %= 3600;
65    long _m = tmp / 60; // sec_pr_min
66    tmp %= 60;
67    long _s = tmp; // seconds
68
69    date_duration_type dd(_d);
70    date_type d = date_type(1970, Jan, 01) + dd;
71    return time_type(d, time_duration_type(_h, _m, _s, sub_sec));
72  }
73
74}} // boost::date_time
75
76#endif // BOOST_HAS_FTIME
77
78#endif // DATE_TIME_FILETIME_FUNCTIONS_HPP__
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