1/* 2 * Copyright (C) 2006 Apple Inc. All rights reserved. 3 * Copyright (C) 2008 Google Inc. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: 8 * 9 * * Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * * Redistributions in binary form must reproduce the above 12 * copyright notice, this list of conditions and the following disclaimer 13 * in the documentation and/or other materials provided with the 14 * distribution. 15 * * Neither the name of Google Inc. nor the names of its 16 * contributors may be used to endorse or promote products derived from 17 * this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#ifndef CurrentTime_h 33#define CurrentTime_h 34 35#include <time.h> 36 37namespace WTF { 38 39// Returns the current UTC time in seconds, counted from January 1, 1970. 40// Precision varies depending on platform but is usually as good or better 41// than a millisecond. 42// Use this function only if wall clock time is needed. For elapsed time 43// measurement use monotonicallyIncreasingTime() instead. 44WTF_EXPORT_PRIVATE double currentTime(); 45 46// Same thing, in milliseconds. 47inline double currentTimeMS() 48{ 49 return currentTime() * 1000.0; 50} 51 52// Provides a monotonically increasing time in seconds since an arbitrary point in the past. 53// On unsupported platforms, this function only guarantees the result will be non-decreasing. 54// Result of this function increases monotonically even when clock time goes back due to 55// NTP or manual adjustments, so it is better suited for elapsed time measurement. 56WTF_EXPORT_PRIVATE double monotonicallyIncreasingTime(); 57 58// Returns the current CPU time of the current thread in seconds. 59// Precision varies depending on platform but is usually as good or better 60// than a millisecond. 61WTF_EXPORT_PRIVATE double currentCPUTime(); 62 63// Returns the current CPU time of the current thread in milliseconds. 64WTF_EXPORT_PRIVATE double currentCPUTimeMS(); 65 66} // namespace WTF 67 68using WTF::currentTime; 69using WTF::currentTimeMS; 70using WTF::monotonicallyIncreasingTime; 71using WTF::currentCPUTime; 72 73#endif // CurrentTime_h 74