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win32gettimeofday.c
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1/*
2 * win32gettimeofday.c
3 * Win32 gettimeofday() replacement
4 *
5 * src/port/win32gettimeofday.c
6 *
7 * Copyright (c) 2003 SRA, Inc.
8 * Copyright (c) 2003 SKC, Inc.
9 *
10 * Permission to use, copy, modify, and distribute this software and
11 * its documentation for any purpose, without fee, and without a
12 * written agreement is hereby granted, provided that the above
13 * copyright notice and this paragraph and the following two
14 * paragraphs appear in all copies.
15 *
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
17 * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
18 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
19 * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
20 * OF THE POSSIBILITY OF SUCH DAMAGE.
21 *
22 * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
25 * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
26 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
27 */
28
29#include "c.h"
30
31#include <sysinfoapi.h>
32
33#include <sys/time.h>
34
35/* FILETIME of Jan 1 1970 00:00:00, the PostgreSQL epoch */
36static const unsigned __int64 epoch = UINT64CONST(116444736000000000);
37
38/*
39 * FILETIME represents the number of 100-nanosecond intervals since
40 * January 1, 1601 (UTC).
41 */
42#define FILETIME_UNITS_PER_SEC 10000000L
43#define FILETIME_UNITS_PER_USEC 10
44
45
46/*
47 * timezone information is stored outside the kernel so tzp isn't used anymore.
48 *
49 * Note: this function is not for Win32 high precision timing purposes. See
50 * elapsed_time().
51 */
52int
53gettimeofday(struct timeval *tp, void *tzp)
54{
55 FILETIME file_time;
56 ULARGE_INTEGER ularge;
57
58 /*
59 * POSIX declines to define what tzp points to, saying "If tzp is not a
60 * null pointer, the behavior is unspecified". Let's take this
61 * opportunity to verify that noplace in Postgres tries to use any
62 * unportable behavior.
63 */
64 Assert(tzp == NULL);
65
66 GetSystemTimePreciseAsFileTime(&file_time);
67 ularge.LowPart = file_time.dwLowDateTime;
68 ularge.HighPart = file_time.dwHighDateTime;
69
70 tp->tv_sec = (long) ((ularge.QuadPart - epoch) / FILETIME_UNITS_PER_SEC);
71 tp->tv_usec = (long) (((ularge.QuadPart - epoch) % FILETIME_UNITS_PER_SEC)
73
74 return 0;
75}
#define Assert(condition)
Definition: c.h:812
#define UINT64CONST(x)
Definition: c.h:500
#define FILETIME_UNITS_PER_USEC
#define FILETIME_UNITS_PER_SEC
static const unsigned __int64 epoch
int gettimeofday(struct timeval *tp, void *tzp)