gettimeofday.c

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/*
 * Copied from vcpkg under the MIT license
 * https://github.com/microsoft/vcpkg/blob/master/ports/gettimeofday/gettimeofday.c
 */
 
/*
 * Copied from PostgreSQL source:
 *  http://doxygen.postgresql.org/gettimeofday_8c_source.html
 *
 */
 
/*
 * gettimeofday.c
 *        Win32 gettimeofday() replacement
 *
 * src/port/gettimeofday.c
 *
 * Copyright (c) 2003 SRA, Inc.
 * Copyright (c) 2003 SKC, Inc.
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose, without fee, and without a
 * written agreement is hereby granted, provided that the above
 * copyright notice and this paragraph and the following two
 * paragraphs appear in all copies.
 *
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
 * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
 * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
 * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */
 
#ifdef _MSC_VER
 
#include <winsock2.h>
 
/* FILETIME of Jan 1 1970 00:00:00. */
static const unsigned __int64 epoch = 116444736000000000Ui64;
 
/*
 * timezone information is stored outside the kernel so tzp isn't used anymore.
 *
 * Note: this function is not for Win32 high precision timing purpose. See
 * elapsed_time().
 */
int gettimeofday(struct timeval *tp, struct timezone *tzp)
{
    FILETIME file_time;
    SYSTEMTIME system_time;
    ULARGE_INTEGER ularge;
 
    GetSystemTime(&system_time);
    SystemTimeToFileTime(&system_time, &file_time);
    ularge.LowPart = file_time.dwLowDateTime;
    ularge.HighPart = file_time.dwHighDateTime;
 
    tp->tv_sec = (long)((ularge.QuadPart - epoch) / 10000000L);
    tp->tv_usec = (long)(system_time.wMilliseconds * 1000);
 
    return 0;
}
 
#endif /* _MSC_VER */