Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(572)

Unified Diff: base/time/time.h

Issue 1976703005: Allow constexpr variables of TimeDelta type. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@lkcr
Patch Set: Generalize FromProduct a bit. Created 4 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « no previous file | base/time/time_unittest.cc » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: base/time/time.h
diff --git a/base/time/time.h b/base/time/time.h
index 9fce71b581e4ca27c216e31cb40ab78b867760ea..bcc9031e222e795df3283ff8b616455a0a749c02 100644
--- a/base/time/time.h
+++ b/base/time/time.h
@@ -106,14 +106,14 @@ class BASE_EXPORT TimeDelta {
}
// Converts units of time to TimeDeltas.
- static TimeDelta FromDays(int days);
- static TimeDelta FromHours(int hours);
- static TimeDelta FromMinutes(int minutes);
- static TimeDelta FromSeconds(int64_t secs);
- static TimeDelta FromMilliseconds(int64_t ms);
- static TimeDelta FromSecondsD(double secs);
- static TimeDelta FromMillisecondsD(double ms);
- static TimeDelta FromMicroseconds(int64_t us);
+ static constexpr TimeDelta FromDays(int days);
+ static constexpr TimeDelta FromHours(int hours);
+ static constexpr TimeDelta FromMinutes(int minutes);
+ static constexpr TimeDelta FromSeconds(int64_t secs);
+ static constexpr TimeDelta FromMilliseconds(int64_t ms);
+ static constexpr TimeDelta FromSecondsD(double secs);
+ static constexpr TimeDelta FromMillisecondsD(double ms);
+ static constexpr TimeDelta FromMicroseconds(int64_t us);
#if defined(OS_WIN)
static TimeDelta FromQPCValue(LONGLONG qpc_value);
#endif
@@ -222,22 +222,22 @@ class BASE_EXPORT TimeDelta {
}
// Comparison operators.
- bool operator==(TimeDelta other) const {
+ constexpr bool operator==(TimeDelta other) const {
return delta_ == other.delta_;
}
- bool operator!=(TimeDelta other) const {
+ constexpr bool operator!=(TimeDelta other) const {
return delta_ != other.delta_;
}
- bool operator<(TimeDelta other) const {
+ constexpr bool operator<(TimeDelta other) const {
return delta_ < other.delta_;
}
- bool operator<=(TimeDelta other) const {
+ constexpr bool operator<=(TimeDelta other) const {
return delta_ <= other.delta_;
}
- bool operator>(TimeDelta other) const {
+ constexpr bool operator>(TimeDelta other) const {
return delta_ > other.delta_;
}
- bool operator>=(TimeDelta other) const {
+ constexpr bool operator>=(TimeDelta other) const {
return delta_ >= other.delta_;
}
@@ -248,10 +248,14 @@ class BASE_EXPORT TimeDelta {
// 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) {}
+ constexpr explicit TimeDelta(int64_t delta_us) : delta_(delta_us) {}
// Private method to build a delta from a double.
- static TimeDelta FromDouble(double value);
+ static constexpr TimeDelta FromDouble(double value);
+
+ // Private method to build a delta from the product of a user-provided value
+ // and a known-positive value.
+ static constexpr TimeDelta FromProduct(int64_t value, int64_t positive_value);
// Delta in microseconds.
int64_t delta_;
@@ -578,60 +582,71 @@ class BASE_EXPORT Time : public time_internal::TimeBase<Time> {
// Inline the TimeDelta factory methods, for fast TimeDelta construction.
// static
-inline TimeDelta TimeDelta::FromDays(int days) {
- if (days == std::numeric_limits<int>::max())
- return Max();
- return TimeDelta(days * Time::kMicrosecondsPerDay);
+constexpr inline TimeDelta TimeDelta::FromDays(int days) {
Peter Kasting 2016/05/18 20:53:28 Doesn't constexpr imply the same rules (e.g. for O
+ return days == std::numeric_limits<int>::max()
+ ? Max()
+ : TimeDelta(days * Time::kMicrosecondsPerDay);
}
// static
-inline TimeDelta TimeDelta::FromHours(int hours) {
- if (hours == std::numeric_limits<int>::max())
- return Max();
- return TimeDelta(hours * Time::kMicrosecondsPerHour);
+constexpr inline TimeDelta TimeDelta::FromHours(int hours) {
+ return hours == std::numeric_limits<int>::max()
+ ? Max()
+ : TimeDelta(hours * Time::kMicrosecondsPerHour);
}
// static
-inline TimeDelta TimeDelta::FromMinutes(int minutes) {
- if (minutes == std::numeric_limits<int>::max())
- return Max();
- return TimeDelta(minutes * Time::kMicrosecondsPerMinute);
+constexpr inline TimeDelta TimeDelta::FromMinutes(int minutes) {
+ return minutes == std::numeric_limits<int>::max()
+ ? Max()
+ : TimeDelta(minutes * Time::kMicrosecondsPerMinute);
}
// static
-inline TimeDelta TimeDelta::FromSeconds(int64_t secs) {
- return TimeDelta(secs) * Time::kMicrosecondsPerSecond;
+constexpr inline TimeDelta TimeDelta::FromSeconds(int64_t secs) {
+ return FromProduct(secs, Time::kMicrosecondsPerSecond);
}
// static
-inline TimeDelta TimeDelta::FromMilliseconds(int64_t ms) {
- return TimeDelta(ms) * Time::kMicrosecondsPerMillisecond;
+constexpr inline TimeDelta TimeDelta::FromMilliseconds(int64_t ms) {
+ return FromProduct(ms, Time::kMicrosecondsPerMillisecond);
}
// static
-inline TimeDelta TimeDelta::FromSecondsD(double secs) {
+constexpr inline TimeDelta TimeDelta::FromSecondsD(double secs) {
return FromDouble(secs * Time::kMicrosecondsPerSecond);
}
// static
-inline TimeDelta TimeDelta::FromMillisecondsD(double ms) {
+constexpr inline TimeDelta TimeDelta::FromMillisecondsD(double ms) {
return FromDouble(ms * Time::kMicrosecondsPerMillisecond);
}
// static
-inline TimeDelta TimeDelta::FromMicroseconds(int64_t us) {
+constexpr inline TimeDelta TimeDelta::FromMicroseconds(int64_t us) {
return TimeDelta(us);
}
// static
-inline TimeDelta TimeDelta::FromDouble(double value) {
- double max_magnitude = std::numeric_limits<int64_t>::max();
- TimeDelta delta = TimeDelta(static_cast<int64_t>(value));
- if (value > max_magnitude)
- delta = Max();
- else if (value < -max_magnitude)
- delta = -Max();
- return delta;
+constexpr inline TimeDelta TimeDelta::FromDouble(double value) {
+ // TODO(crbug.com/612601): Use saturated_cast<int64_t>(value) once we sort out
+ // the Min() behavior.
+ return value > std::numeric_limits<int64_t>::max()
+ ? Max()
+ : value < -std::numeric_limits<int64_t>::max()
+ ? -Max()
+ : TimeDelta(static_cast<int64_t>(value));
+}
+
+// static
+constexpr inline TimeDelta TimeDelta::FromProduct(int64_t value,
+ int64_t positive_value) {
+ return (DCHECK(positive_value > 0),
+ value > std::numeric_limits<int64_t>::max() / positive_value
+ ? Max()
+ : value < -std::numeric_limits<int64_t>::max() / positive_value
+ ? -Max()
+ : TimeDelta(value * positive_value));
}
// For logging use only.
« no previous file with comments | « no previous file | base/time/time_unittest.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698