base/time/time.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/time/time.h"
   6
   7 #include <cmath>
   8 #include <ios>
   9 #include <limits>
  10 #include <ostream>
  11 #include <sstream>
  12
  13 #include "base/lazy_instance.h"
  14 #include "base/logging.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/third_party/nspr/prtime.h"
  17
  18 namespace base {
  19
  20 // TimeDelta ------------------------------------------------------------------
  21
  22 // static
  23 TimeDelta TimeDelta::Max() {
  24   return TimeDelta(std::numeric_limits<int64>::max());
  25 }
  26
  27 int TimeDelta::InDays() const {
  28   if (is_max()) {
  29     // Preserve max to prevent overflow.
  30     return std::numeric_limits<int>::max();
  31   }
  32   return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);
  33 }
  34
  35 int TimeDelta::InHours() const {
  36   if (is_max()) {
  37     // Preserve max to prevent overflow.
  38     return std::numeric_limits<int>::max();
  39   }
  40   return static_cast<int>(delta_ / Time::kMicrosecondsPerHour);
  41 }
  42
  43 int TimeDelta::InMinutes() const {
  44   if (is_max()) {
  45     // Preserve max to prevent overflow.
  46     return std::numeric_limits<int>::max();
  47   }
  48   return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute);
  49 }
  50
  51 double TimeDelta::InSecondsF() const {
  52   if (is_max()) {
  53     // Preserve max to prevent overflow.
  54     return std::numeric_limits<double>::infinity();
  55   }
  56   return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond;
  57 }
  58
  59 int64 TimeDelta::InSeconds() const {
  60   if (is_max()) {
  61     // Preserve max to prevent overflow.
  62     return std::numeric_limits<int64>::max();
  63   }
  64   return delta_ / Time::kMicrosecondsPerSecond;
  65 }
  66
  67 double TimeDelta::InMillisecondsF() const {
  68   if (is_max()) {
  69     // Preserve max to prevent overflow.
  70     return std::numeric_limits<double>::infinity();
  71   }
  72   return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond;
  73 }
  74
  75 int64 TimeDelta::InMilliseconds() const {
  76   if (is_max()) {
  77     // Preserve max to prevent overflow.
  78     return std::numeric_limits<int64>::max();
  79   }
  80   return delta_ / Time::kMicrosecondsPerMillisecond;
  81 }
  82
  83 int64 TimeDelta::InMillisecondsRoundedUp() const {
  84   if (is_max()) {
  85     // Preserve max to prevent overflow.
  86     return std::numeric_limits<int64>::max();
  87   }
  88   return (delta_ + Time::kMicrosecondsPerMillisecond - 1) /
  89       Time::kMicrosecondsPerMillisecond;
  90 }
  91
  92 int64 TimeDelta::InMicroseconds() const {
  93   if (is_max()) {
  94     // Preserve max to prevent overflow.
  95     return std::numeric_limits<int64>::max();
  96   }
  97   return delta_;
  98 }
  99
 100 namespace time_internal {
 101
 102 int64 SaturatedAdd(TimeDelta delta, int64 value) {
 103   CheckedNumeric<int64> rv(delta.delta_);
 104   rv += value;
 105   return FromCheckedNumeric(rv);
 106 }
 107
 108 int64 SaturatedSub(TimeDelta delta, int64 value) {
 109   CheckedNumeric<int64> rv(delta.delta_);
 110   rv -= value;
 111   return FromCheckedNumeric(rv);
 112 }
 113
 114 int64 FromCheckedNumeric(const CheckedNumeric<int64> value) {
 115   if (value.IsValid())
 116     return value.ValueUnsafe();
 117
 118   // We could return max/min but we don't really expose what the maximum delta
 119   // is. Instead, return max/(-max), which is something that clients can reason
 120   // about.
 121   // TODO(rvargas) crbug.com/332611: don't use internal values.
 122   int64 limit = std::numeric_limits<int64>::max();
 123   if (value.validity() == internal::RANGE_UNDERFLOW)
 124     limit = -limit;
 125   return value.ValueOrDefault(limit);
 126 }
 127
 128 }  // namespace time_internal
 129
 130 std::ostream& operator<<(std::ostream& os, TimeDelta time_delta) {
 131   return os << time_delta.InSecondsF() << "s";
 132 }
 133
 134 // Time -----------------------------------------------------------------------
 135
 136 // static
 137 Time Time::Max() {
 138   return Time(std::numeric_limits<int64>::max());
 139 }
 140
 141 // static
 142 Time Time::FromTimeT(time_t tt) {
 143   if (tt == 0)
 144     return Time();  // Preserve 0 so we can tell it doesn't exist.
 145   if (tt == std::numeric_limits<time_t>::max())
 146     return Max();
 147   return Time((tt * kMicrosecondsPerSecond) + kTimeTToMicrosecondsOffset);
 148 }
 149
 150 time_t Time::ToTimeT() const {
 151   if (is_null())
 152     return 0;  // Preserve 0 so we can tell it doesn't exist.
 153   if (is_max()) {
 154     // Preserve max without offset to prevent overflow.
 155     return std::numeric_limits<time_t>::max();
 156   }
 157   if (std::numeric_limits<int64>::max() - kTimeTToMicrosecondsOffset <= us_) {
 158     DLOG(WARNING) << "Overflow when converting base::Time with internal " <<
 159                      "value " << us_ << " to time_t.";
 160     return std::numeric_limits<time_t>::max();
 161   }
 162   return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;
 163 }
 164
 165 // static
 166 Time Time::FromDoubleT(double dt) {
 167   if (dt == 0 || std::isnan(dt))
 168     return Time();  // Preserve 0 so we can tell it doesn't exist.
 169   if (dt == std::numeric_limits<double>::infinity())
 170     return Max();
 171   return Time(static_cast<int64>((dt *
 172                                   static_cast<double>(kMicrosecondsPerSecond)) +
 173                                  kTimeTToMicrosecondsOffset));
 174 }
 175
 176 double Time::ToDoubleT() const {
 177   if (is_null())
 178     return 0;  // Preserve 0 so we can tell it doesn't exist.
 179   if (is_max()) {
 180     // Preserve max without offset to prevent overflow.
 181     return std::numeric_limits<double>::infinity();
 182   }
 183   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 184           static_cast<double>(kMicrosecondsPerSecond));
 185 }
 186
 187 #if defined(OS_POSIX)
 188 // static
 189 Time Time::FromTimeSpec(const timespec& ts) {
 190   return FromDoubleT(ts.tv_sec +
 191                      static_cast<double>(ts.tv_nsec) /
 192                          base::Time::kNanosecondsPerSecond);
 193 }
 194 #endif
 195
 196 // static
 197 Time Time::FromJsTime(double ms_since_epoch) {
 198   // The epoch is a valid time, so this constructor doesn't interpret
 199   // 0 as the null time.
 200   if (ms_since_epoch == std::numeric_limits<double>::infinity())
 201     return Max();
 202   return Time(static_cast<int64>(ms_since_epoch * kMicrosecondsPerMillisecond) +
 203               kTimeTToMicrosecondsOffset);
 204 }
 205
 206 double Time::ToJsTime() const {
 207   if (is_null()) {
 208     // Preserve 0 so the invalid result doesn't depend on the platform.
 209     return 0;
 210   }
 211   if (is_max()) {
 212     // Preserve max without offset to prevent overflow.
 213     return std::numeric_limits<double>::infinity();
 214   }
 215   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 216           kMicrosecondsPerMillisecond);
 217 }
 218
 219 int64 Time::ToJavaTime() const {
 220   if (is_null()) {
 221     // Preserve 0 so the invalid result doesn't depend on the platform.
 222     return 0;
 223   }
 224   if (is_max()) {
 225     // Preserve max without offset to prevent overflow.
 226     return std::numeric_limits<int64>::max();
 227   }
 228   return ((us_ - kTimeTToMicrosecondsOffset) /
 229           kMicrosecondsPerMillisecond);
 230 }
 231
 232 // static
 233 Time Time::UnixEpoch() {
 234   Time time;
 235   time.us_ = kTimeTToMicrosecondsOffset;
 236   return time;
 237 }
 238
 239 Time Time::LocalMidnight() const {
 240   Exploded exploded;
 241   LocalExplode(&exploded);
 242   exploded.hour = 0;
 243   exploded.minute = 0;
 244   exploded.second = 0;
 245   exploded.millisecond = 0;
 246   return FromLocalExploded(exploded);
 247 }
 248
 249 // static
 250 bool Time::FromStringInternal(const char* time_string,
 251                               bool is_local,
 252                               Time* parsed_time) {
 253   DCHECK((time_string != NULL) && (parsed_time != NULL));
 254
 255   if (time_string[0] == '\0')
 256     return false;
 257
 258   PRTime result_time = 0;
 259   PRStatus result = PR_ParseTimeString(time_string,
 260                                        is_local ? PR_FALSE : PR_TRUE,
 261                                        &result_time);
 262   if (PR_SUCCESS != result)
 263     return false;
 264
 265   result_time += kTimeTToMicrosecondsOffset;
 266   *parsed_time = Time(result_time);
 267   return true;
 268 }
 269
 270 std::ostream& operator<<(std::ostream& os, Time time) {
 271   Time::Exploded exploded;
 272   time.UTCExplode(&exploded);
 273   // Use StringPrintf because iostreams formatting is painful.
 274   return os << StringPrintf("%04d-%02d-%02d %02d:%02d:%02d.%03d UTC",
 275                             exploded.year,
 276                             exploded.month,
 277                             exploded.day_of_month,
 278                             exploded.hour,
 279                             exploded.minute,
 280                             exploded.second,
 281                             exploded.millisecond);
 282 }
 283
 284 // Local helper class to hold the conversion from Time to TickTime at the
 285 // time of the Unix epoch.
 286 class UnixEpochSingleton {
 287  public:
 288   UnixEpochSingleton()
 289       : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}
 290
 291   TimeTicks unix_epoch() const { return unix_epoch_; }
 292
 293  private:
 294   const TimeTicks unix_epoch_;
 295
 296   DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);
 297 };
 298
 299 static LazyInstance<UnixEpochSingleton>::Leaky
 300     leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;
 301
 302 // Static
 303 TimeTicks TimeTicks::UnixEpoch() {
 304   return leaky_unix_epoch_singleton_instance.Get().unix_epoch();
 305 }
 306
 307 TimeTicks TimeTicks::SnappedToNextTick(TimeTicks tick_phase,
 308                                        TimeDelta tick_interval) const {
 309   // |interval_offset| is the offset from |this| to the next multiple of
 310   // |tick_interval| after |tick_phase|, possibly negative if in the past.
 311   TimeDelta interval_offset = (tick_phase - *this) % tick_interval;
 312   // If |this| is exactly on the interval (i.e. offset==0), don't adjust.
 313   // Otherwise, if |tick_phase| was in the past, adjust forward to the next
 314   // tick after |this|.
 315   if (!interval_offset.is_zero() && tick_phase < *this)
 316     interval_offset += tick_interval;
 317   return *this + interval_offset;
 318 }
 319
 320 std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks) {
 321   // This function formats a TimeTicks object as "bogo-microseconds".
 322   // The origin and granularity of the count are platform-specific, and may very
 323   // from run to run. Although bogo-microseconds usually roughly correspond to
 324   // real microseconds, the only real guarantee is that the number never goes
 325   // down during a single run.
 326   const TimeDelta as_time_delta = time_ticks - TimeTicks();
 327   return os << as_time_delta.InMicroseconds() << " bogo-microseconds";
 328 }
 329
 330 std::ostream& operator<<(std::ostream& os, ThreadTicks thread_ticks) {
 331   const TimeDelta as_time_delta = thread_ticks - ThreadTicks();
 332   return os << as_time_delta.InMicroseconds() << " bogo-thread-microseconds";
 333 }
 334
 335 std::ostream& operator<<(std::ostream& os, TraceTicks trace_ticks) {
 336   const TimeDelta as_time_delta = trace_ticks - TraceTicks();
 337   return os << as_time_delta.InMicroseconds() << " bogo-trace-microseconds";
 338 }
 339
 340 // Time::Exploded -------------------------------------------------------------
 341
 342 inline bool is_in_range(int value, int lo, int hi) {
 343   return lo <= value && value <= hi;
 344 }
 345
 346 bool Time::Exploded::HasValidValues() const {
 347   return is_in_range(month, 1, 12) &&
 348          is_in_range(day_of_week, 0, 6) &&
 349          is_in_range(day_of_month, 1, 31) &&
 350          is_in_range(hour, 0, 23) &&
 351          is_in_range(minute, 0, 59) &&
 352          is_in_range(second, 0, 60) &&
 353          is_in_range(millisecond, 0, 999);
 354 }
 355
 356 }  // namespace base