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 <ios>
   8 #include <limits>
   9 #include <ostream>
  10 #include <sstream>
  11
  12 #include "base/float_util.h"
  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 int64 TimeDelta::SaturatedAdd(int64 value) const {
 101   CheckedNumeric<int64> rv(delta_);
 102   rv += value;
 103   return FromCheckedNumeric(rv);
 104 }
 105
 106 int64 TimeDelta::SaturatedSub(int64 value) const {
 107   CheckedNumeric<int64> rv(delta_);
 108   rv -= value;
 109   return FromCheckedNumeric(rv);
 110 }
 111
 112 // static
 113 int64 TimeDelta::FromCheckedNumeric(const CheckedNumeric<int64> value) {
 114   if (value.IsValid())
 115     return value.ValueUnsafe();
 116
 117   // We could return max/min but we don't really expose what the maximum delta
 118   // is. Instead, return max/(-max), which is something that clients can reason
 119   // about.
 120   // TODO(rvargas) crbug.com/332611: don't use internal values.
 121   int64 limit = std::numeric_limits<int64>::max();
 122   if (value.validity() == internal::RANGE_UNDERFLOW)
 123     limit = -limit;
 124   return value.ValueOrDefault(limit);
 125 }
 126
 127 std::ostream& operator<<(std::ostream& os, TimeDelta time_delta) {
 128   return os << time_delta.InSecondsF() << "s";
 129 }
 130
 131 // Time -----------------------------------------------------------------------
 132
 133 // static
 134 Time Time::Max() {
 135   return Time(std::numeric_limits<int64>::max());
 136 }
 137
 138 // static
 139 Time Time::FromTimeT(time_t tt) {
 140   if (tt == 0)
 141     return Time();  // Preserve 0 so we can tell it doesn't exist.
 142   if (tt == std::numeric_limits<time_t>::max())
 143     return Max();
 144   return Time((tt * kMicrosecondsPerSecond) + kTimeTToMicrosecondsOffset);
 145 }
 146
 147 time_t Time::ToTimeT() const {
 148   if (is_null())
 149     return 0;  // Preserve 0 so we can tell it doesn't exist.
 150   if (is_max()) {
 151     // Preserve max without offset to prevent overflow.
 152     return std::numeric_limits<time_t>::max();
 153   }
 154   if (std::numeric_limits<int64>::max() - kTimeTToMicrosecondsOffset <= us_) {
 155     DLOG(WARNING) << "Overflow when converting base::Time with internal " <<
 156                      "value " << us_ << " to time_t.";
 157     return std::numeric_limits<time_t>::max();
 158   }
 159   return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;
 160 }
 161
 162 // static
 163 Time Time::FromDoubleT(double dt) {
 164   if (dt == 0 || IsNaN(dt))
 165     return Time();  // Preserve 0 so we can tell it doesn't exist.
 166   if (dt == std::numeric_limits<double>::infinity())
 167     return Max();
 168   return Time(static_cast<int64>((dt *
 169                                   static_cast<double>(kMicrosecondsPerSecond)) +
 170                                  kTimeTToMicrosecondsOffset));
 171 }
 172
 173 double Time::ToDoubleT() const {
 174   if (is_null())
 175     return 0;  // Preserve 0 so we can tell it doesn't exist.
 176   if (is_max()) {
 177     // Preserve max without offset to prevent overflow.
 178     return std::numeric_limits<double>::infinity();
 179   }
 180   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 181           static_cast<double>(kMicrosecondsPerSecond));
 182 }
 183
 184 #if defined(OS_POSIX)
 185 // static
 186 Time Time::FromTimeSpec(const timespec& ts) {
 187   return FromDoubleT(ts.tv_sec +
 188                      static_cast<double>(ts.tv_nsec) /
 189                          base::Time::kNanosecondsPerSecond);
 190 }
 191 #endif
 192
 193 // static
 194 Time Time::FromJsTime(double ms_since_epoch) {
 195   // The epoch is a valid time, so this constructor doesn't interpret
 196   // 0 as the null time.
 197   if (ms_since_epoch == std::numeric_limits<double>::infinity())
 198     return Max();
 199   return Time(static_cast<int64>(ms_since_epoch * kMicrosecondsPerMillisecond) +
 200               kTimeTToMicrosecondsOffset);
 201 }
 202
 203 double Time::ToJsTime() const {
 204   if (is_null()) {
 205     // Preserve 0 so the invalid result doesn't depend on the platform.
 206     return 0;
 207   }
 208   if (is_max()) {
 209     // Preserve max without offset to prevent overflow.
 210     return std::numeric_limits<double>::infinity();
 211   }
 212   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 213           kMicrosecondsPerMillisecond);
 214 }
 215
 216 int64 Time::ToJavaTime() const {
 217   if (is_null()) {
 218     // Preserve 0 so the invalid result doesn't depend on the platform.
 219     return 0;
 220   }
 221   if (is_max()) {
 222     // Preserve max without offset to prevent overflow.
 223     return std::numeric_limits<int64>::max();
 224   }
 225   return ((us_ - kTimeTToMicrosecondsOffset) /
 226           kMicrosecondsPerMillisecond);
 227 }
 228
 229 // static
 230 Time Time::UnixEpoch() {
 231   Time time;
 232   time.us_ = kTimeTToMicrosecondsOffset;
 233   return time;
 234 }
 235
 236 Time Time::LocalMidnight() const {
 237   Exploded exploded;
 238   LocalExplode(&exploded);
 239   exploded.hour = 0;
 240   exploded.minute = 0;
 241   exploded.second = 0;
 242   exploded.millisecond = 0;
 243   return FromLocalExploded(exploded);
 244 }
 245
 246 // static
 247 bool Time::FromStringInternal(const char* time_string,
 248                               bool is_local,
 249                               Time* parsed_time) {
 250   DCHECK((time_string != NULL) && (parsed_time != NULL));
 251
 252   if (time_string[0] == '\0')
 253     return false;
 254
 255   PRTime result_time = 0;
 256   PRStatus result = PR_ParseTimeString(time_string,
 257                                        is_local ? PR_FALSE : PR_TRUE,
 258                                        &result_time);
 259   if (PR_SUCCESS != result)
 260     return false;
 261
 262   result_time += kTimeTToMicrosecondsOffset;
 263   *parsed_time = Time(result_time);
 264   return true;
 265 }
 266
 267 std::ostream& operator<<(std::ostream& os, Time time) {
 268   Time::Exploded exploded;
 269   time.UTCExplode(&exploded);
 270   // Use StringPrintf because iostreams formatting is painful.
 271   return os << StringPrintf("%04d-%02d-%02d %02d:%02d:%02d.%03d UTC",
 272                             exploded.year,
 273                             exploded.month,
 274                             exploded.day_of_month,
 275                             exploded.hour,
 276                             exploded.minute,
 277                             exploded.second,
 278                             exploded.millisecond);
 279 }
 280
 281 // Local helper class to hold the conversion from Time to TickTime at the
 282 // time of the Unix epoch.
 283 class UnixEpochSingleton {
 284  public:
 285   UnixEpochSingleton()
 286       : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}
 287
 288   TimeTicks unix_epoch() const { return unix_epoch_; }
 289
 290  private:
 291   const TimeTicks unix_epoch_;
 292
 293   DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);
 294 };
 295
 296 static LazyInstance<UnixEpochSingleton>::Leaky
 297     leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;
 298
 299 // Static
 300 TimeTicks TimeTicks::UnixEpoch() {
 301   return leaky_unix_epoch_singleton_instance.Get().unix_epoch();
 302 }
 303
 304 TimeTicks TimeTicks::SnappedToNextTick(TimeTicks tick_phase,
 305                                        TimeDelta tick_interval) const {
 306   // |interval_offset| is the offset from |this| to the next multiple of
 307   // |tick_interval| after |tick_phase|, possibly negative if in the past.
 308   TimeDelta interval_offset = TimeDelta::FromInternalValue(
 309       (tick_phase - *this).ToInternalValue() % tick_interval.ToInternalValue());
 310   // If |this| is exactly on the interval (i.e. offset==0), don't adjust.
 311   // Otherwise, if |tick_phase| was in the past, adjust forward to the next
 312   // tick after |this|.
 313   if (interval_offset.ToInternalValue() != 0 && tick_phase < *this) {
 314     interval_offset += tick_interval;
 315   }
 316
 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 // Time::Exploded -------------------------------------------------------------
 331
 332 inline bool is_in_range(int value, int lo, int hi) {
 333   return lo <= value && value <= hi;
 334 }
 335
 336 bool Time::Exploded::HasValidValues() const {
 337   return is_in_range(month, 1, 12) &&
 338          is_in_range(day_of_week, 0, 6) &&
 339          is_in_range(day_of_month, 1, 31) &&
 340          is_in_range(hour, 0, 23) &&
 341          is_in_range(minute, 0, 59) &&
 342          is_in_range(second, 0, 60) &&
 343          is_in_range(millisecond, 0, 999);
 344 }
 345
 346 }  // namespace base