File indexing completed on 2024-05-05 17:50:04

 /*
    Copyright (C) 2014 Andreas Hartmetz <ahartmetz@gmail.com>
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LGPL.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
 
    Alternatively, this file is available under the Mozilla Public License
    Version 1.1.  You may obtain a copy of the License at
    http://www.mozilla.org/MPL/
 */
 
 #include "platformtime.h"
 
 #ifdef _WIN32
 // GetTickCount64() requires Vista or greater which is NT version 0x0600
 #define _WIN32_WINNT 0x0600
 #define WIN32_LEAN_AND_MEAN
 #include "windows.h"
 #elif defined(__linux__)
 #include <time.h>
 #else
 #include <chrono>
 #endif
 
 namespace PlatformTime
 {
 
 uint64 monotonicMsecs()
 {
 #ifdef _WIN32
     return GetTickCount64();
 #elif defined(__linux__)
     timespec tspec;
     // performance note: at least on Linux AMD64, clock_gettime(CLOCK_MONOTONIC) does not (usually?)
     // make a syscall, so it's surprisingly cheap; presumably it uses some built-in CPU timer feature
     clock_gettime(CLOCK_MONOTONIC, &tspec);
     return uint64(tspec.tv_sec) * 1000 + uint64(tspec.tv_nsec) / 1000000;
 #else
     auto ret = uint64(std::chrono::duration_cast<std::chrono::milliseconds>(
                             std::chrono::steady_clock::now().time_since_epoch()).count());
     return ret;
 #endif
 }
 
 }