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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Time represents an absolute point in time, internally represented as
// microseconds (s/1,000,000) since a platform-dependent epoch. Each
// platform's epoch, along with other system-dependent clock interface
// routines, is defined in time_PLATFORM.cc.
//
// TimeDelta represents a duration of time, internally represented in
// microseconds.
//
// TimeTicks represents an abstract time that is always incrementing for use
// in measuring time durations. It is internally represented in microseconds.
// It can not be converted to a human-readable time, but is guaranteed not to
// decrease (if the user changes the computer clock, Time::Now() may actually
// decrease or jump).
//
// These classes are represented as only a 64-bit value, so they can be
// efficiently passed by value.
#ifndef BASE_TIME_H_
#define BASE_TIME_H_
#include <time.h>
#include "base/basictypes.h"
namespace base {
class Time;
class TimeTicks;
// This unit test does a lot of manual time manipulation.
class PageLoadTrackerUnitTest;
// TimeDelta ------------------------------------------------------------------
class TimeDelta {
public:
TimeDelta() : delta_(0) {}
// Converts units of time to TimeDeltas.
static TimeDelta FromDays(int64_t days);
static TimeDelta FromHours(int64_t hours);
static TimeDelta FromMinutes(int64_t minutes);
static TimeDelta FromSeconds(int64_t secs);
static TimeDelta FromMilliseconds(int64_t ms);
static TimeDelta FromMicroseconds(int64_t us);
// Returns the internal numeric value of the TimeDelta object. Please don't
// use this and do arithmetic on it, as it is more error prone than using the
// provided operators.
int64_t ToInternalValue() const { return delta_; }
// Returns the time delta in some unit. The F versions return a floating
// point value, the "regular" versions return a rounded-down value.
int InDays() const;
int InHours() const;
int InMinutes() const;
double InSecondsF() const;
int64_t InSeconds() const;
double InMillisecondsF() const;
int64_t InMilliseconds() const;
int64_t InMicroseconds() const;
TimeDelta& operator=(TimeDelta other) {
delta_ = other.delta_;
return *this;
}
// Computations with other deltas.
TimeDelta operator+(TimeDelta other) const {
return TimeDelta(delta_ + other.delta_);
}
TimeDelta operator-(TimeDelta other) const {
return TimeDelta(delta_ - other.delta_);
}
TimeDelta& operator+=(TimeDelta other) {
delta_ += other.delta_;
return *this;
}
TimeDelta& operator-=(TimeDelta other) {
delta_ -= other.delta_;
return *this;
}
TimeDelta operator-() const { return TimeDelta(-delta_); }
// Computations with ints, note that we only allow multiplicative operations
// with ints, and additive operations with other deltas.
TimeDelta operator*(int64_t a) const { return TimeDelta(delta_ * a); }
TimeDelta operator/(int64_t a) const { return TimeDelta(delta_ / a); }
TimeDelta& operator*=(int64_t a) {
delta_ *= a;
return *this;
}
TimeDelta& operator/=(int64_t a) {
delta_ /= a;
return *this;
}
int64_t operator/(TimeDelta a) const { return delta_ / a.delta_; }
// Defined below because it depends on the definition of the other classes.
Time operator+(Time t) const;
TimeTicks operator+(TimeTicks t) const;
// Comparison operators.
bool operator==(TimeDelta other) const { return delta_ == other.delta_; }
bool operator!=(TimeDelta other) const { return delta_ != other.delta_; }
bool operator<(TimeDelta other) const { return delta_ < other.delta_; }
bool operator<=(TimeDelta other) const { return delta_ <= other.delta_; }
bool operator>(TimeDelta other) const { return delta_ > other.delta_; }
bool operator>=(TimeDelta other) const { return delta_ >= other.delta_; }
private:
friend class Time;
friend class TimeTicks;
friend TimeDelta operator*(int64_t a, TimeDelta td);
// Constructs a delta given the duration in microseconds. This is private
// to avoid confusion by callers with an integer constructor. Use
// FromSeconds, FromMilliseconds, etc. instead.
explicit TimeDelta(int64_t delta_us) : delta_(delta_us) {}
// Delta in microseconds.
int64_t delta_;
};
inline TimeDelta operator*(int64_t a, TimeDelta td) {
return TimeDelta(a * td.delta_);
}
// Time -----------------------------------------------------------------------
// Represents a wall clock time.
class Time {
public:
static const int64_t kMillisecondsPerSecond = 1000;
static const int64_t kMicrosecondsPerMillisecond = 1000;
static const int64_t kMicrosecondsPerSecond =
kMicrosecondsPerMillisecond * kMillisecondsPerSecond;
static const int64_t kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
static const int64_t kMicrosecondsPerHour = kMicrosecondsPerMinute * 60;
static const int64_t kMicrosecondsPerDay = kMicrosecondsPerHour * 24;
static const int64_t kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
static const int64_t kNanosecondsPerMicrosecond = 1000;
static const int64_t kNanosecondsPerSecond =
kNanosecondsPerMicrosecond * kMicrosecondsPerSecond;
// Represents an exploded time that can be formatted nicely. This is kind of
// like the Win32 SYSTEMTIME structure or the Unix "struct tm" with a few
// additions and changes to prevent errors.
struct Exploded {
int year; // Four digit year "2007"
signed char month; // 1-based month (values 1 = January, etc.)
signed char day_of_week; // 0-based day of week (0 = Sunday, etc.)
signed char day_of_month; // 1-based day of month (1-31)
signed char hour; // Hour within the current day (0-23)
signed char minute; // Minute within the current hour (0-59)
signed char second; // Second within the current minute (0-59 plus
// leap seconds which may take it up to 60).
int millisecond; // Milliseconds within the current second (0-999)
};
// Contains the NULL time. Use Time::Now() to get the current time.
explicit Time() : us_(0) {}
// Returns true if the time object has not been initialized.
bool is_null() const { return us_ == 0; }
// Returns the current time. Watch out, the system might adjust its clock
// in which case time will actually go backwards. We don't guarantee that
// times are increasing, or that two calls to Now() won't be the same.
static Time Now();
// Returns the current time. Same as Now() except that this function always
// uses system time so that there are no discrepancies between the returned
// time and system time even on virtual environments including our test bot.
// For timing sensitive unittests, this function should be used.
static Time NowFromSystemTime();
// Converts to/from time_t in UTC and a Time class.
// TODO(brettw) this should be removed once everybody starts using the |Time|
// class.
static Time FromTimeT(time_t tt);
time_t ToTimeT() const;
// Converts time to/from a double which is the number of seconds since epoch
// (Jan 1, 1970). Webkit uses this format to represent time.
static Time FromDoubleT(double dt);
double ToDoubleT() const;
// Converts an exploded structure representing either the local time or UTC
// into a Time class.
static Time FromUTCExploded(const Exploded& exploded) {
return FromExploded(false, exploded);
}
static Time FromLocalExploded(const Exploded& exploded) {
return FromExploded(true, exploded);
}
// Converts an integer value representing Time to a class. This is used
// when deserializing a |Time| structure, using a value known to be
// compatible. It is not provided as a constructor because the integer type
// may be unclear from the perspective of a caller.
static Time FromInternalValue(int64_t us) { return Time(us); }
// Converts a string representation of time to a Time object.
// An example of a time string which is converted is as below:-
// "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
// in the input string, we assume local time.
// TODO(iyengar) Move the FromString/FromTimeT/ToTimeT/FromFileTime to
// a new time converter class.
static bool FromString(const wchar_t* time_string, Time* parsed_time);
// For serializing, use FromInternalValue to reconstitute. Please don't use
// this and do arithmetic on it, as it is more error prone than using the
// provided operators.
int64_t ToInternalValue() const { return us_; }
// Fills the given exploded structure with either the local time or UTC from
// this time structure (containing UTC).
void UTCExplode(Exploded* exploded) const { return Explode(false, exploded); }
void LocalExplode(Exploded* exploded) const {
return Explode(true, exploded);
}
// Rounds this time down to the nearest day in local time. It will represent
// midnight on that day.
Time LocalMidnight() const;
Time& operator=(Time other) {
us_ = other.us_;
return *this;
}
// Compute the difference between two times.
TimeDelta operator-(Time other) const { return TimeDelta(us_ - other.us_); }
// Modify by some time delta.
Time& operator+=(TimeDelta delta) {
us_ += delta.delta_;
return *this;
}
Time& operator-=(TimeDelta delta) {
us_ -= delta.delta_;
return *this;
}
// Return a new time modified by some delta.
Time operator+(TimeDelta delta) const { return Time(us_ + delta.delta_); }
Time operator-(TimeDelta delta) const { return Time(us_ - delta.delta_); }
// Comparison operators
bool operator==(Time other) const { return us_ == other.us_; }
bool operator!=(Time other) const { return us_ != other.us_; }
bool operator<(Time other) const { return us_ < other.us_; }
bool operator<=(Time other) const { return us_ <= other.us_; }
bool operator>(Time other) const { return us_ > other.us_; }
bool operator>=(Time other) const { return us_ >= other.us_; }
private:
friend class TimeDelta;
// Explodes the given time to either local time |is_local = true| or UTC
// |is_local = false|.
void Explode(bool is_local, Exploded* exploded) const;
// Unexplodes a given time assuming the source is either local time
// |is_local = true| or UTC |is_local = false|.
static Time FromExploded(bool is_local, const Exploded& exploded);
explicit Time(int64_t us) : us_(us) {}
// The representation of Jan 1, 1970 UTC in microseconds since the
// platform-dependent epoch.
static const int64_t kTimeTToMicrosecondsOffset;
// Time in microseconds in UTC.
int64_t us_;
};
inline Time TimeDelta::operator+(Time t) const { return Time(t.us_ + delta_); }
// Inline the TimeDelta factory methods, for fast TimeDelta construction.
// static
inline TimeDelta TimeDelta::FromDays(int64_t days) {
return TimeDelta(days * Time::kMicrosecondsPerDay);
}
// static
inline TimeDelta TimeDelta::FromHours(int64_t hours) {
return TimeDelta(hours * Time::kMicrosecondsPerHour);
}
// static
inline TimeDelta TimeDelta::FromMinutes(int64_t minutes) {
return TimeDelta(minutes * Time::kMicrosecondsPerMinute);
}
// static
inline TimeDelta TimeDelta::FromSeconds(int64_t secs) {
return TimeDelta(secs * Time::kMicrosecondsPerSecond);
}
// static
inline TimeDelta TimeDelta::FromMilliseconds(int64_t ms) {
return TimeDelta(ms * Time::kMicrosecondsPerMillisecond);
}
// static
inline TimeDelta TimeDelta::FromMicroseconds(int64_t us) {
return TimeDelta(us);
}
// TimeTicks ------------------------------------------------------------------
class TimeTicks {
public:
TimeTicks() : ticks_(0) {}
TimeTicks(const TimeTicks&) = default;
// Platform-dependent tick count representing "right now."
// The resolution of this clock is ~1-15ms. Resolution varies depending
// on hardware/operating system configuration.
static TimeTicks Now();
// Returns true if this object has not been initialized.
bool is_null() const { return ticks_ == 0; }
// Returns the internal numeric value of the TimeTicks object.
int64_t ToInternalValue() const { return ticks_; }
TimeTicks& operator=(TimeTicks other) {
ticks_ = other.ticks_;
return *this;
}
// Compute the difference between two times.
TimeDelta operator-(TimeTicks other) const {
return TimeDelta(ticks_ - other.ticks_);
}
// Modify by some time delta.
TimeTicks& operator+=(TimeDelta delta) {
ticks_ += delta.delta_;
return *this;
}
TimeTicks& operator-=(TimeDelta delta) {
ticks_ -= delta.delta_;
return *this;
}
// Return a new TimeTicks modified by some delta.
TimeTicks operator+(TimeDelta delta) const {
return TimeTicks(ticks_ + delta.delta_);
}
TimeTicks operator-(TimeDelta delta) const {
return TimeTicks(ticks_ - delta.delta_);
}
// Comparison operators
bool operator==(TimeTicks other) const { return ticks_ == other.ticks_; }
bool operator!=(TimeTicks other) const { return ticks_ != other.ticks_; }
bool operator<(TimeTicks other) const { return ticks_ < other.ticks_; }
bool operator<=(TimeTicks other) const { return ticks_ <= other.ticks_; }
bool operator>(TimeTicks other) const { return ticks_ > other.ticks_; }
bool operator>=(TimeTicks other) const { return ticks_ >= other.ticks_; }
protected:
friend class TimeDelta;
friend class PageLoadTrackerUnitTest;
// Please use Now() to create a new object. This is for internal use
// and testing. Ticks is in microseconds.
explicit TimeTicks(int64_t ticks) : ticks_(ticks) {}
// Tick count in microseconds.
int64_t ticks_;
};
inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
return TimeTicks(t.ticks_ + delta_);
}
} // namespace base
#endif // BASE_TIME_H_