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(kTimeTToMicrosecondsOffset) + TimeDelta::FromSeconds(tt);
 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   return Time(kTimeTToMicrosecondsOffset) + TimeDelta::FromSecondsD(dt);
 170 }
 171
 172 double Time::ToDoubleT() const {
 173   if (is_null())
 174     return 0;  // Preserve 0 so we can tell it doesn't exist.
 175   if (is_max()) {
 176     // Preserve max without offset to prevent overflow.
 177     return std::numeric_limits<double>::infinity();
 178   }
 179   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 180           static_cast<double>(kMicrosecondsPerSecond));
 181 }
 182
 183 #if defined(OS_POSIX)
 184 // static
 185 Time Time::FromTimeSpec(const timespec& ts) {
 186   return FromDoubleT(ts.tv_sec +
 187                      static_cast<double>(ts.tv_nsec) /
 188                          base::Time::kNanosecondsPerSecond);
 189 }
 190 #endif
 191
 192 // static
 193 Time Time::FromJsTime(double ms_since_epoch) {
 194   // The epoch is a valid time, so this constructor doesn't interpret
 195   // 0 as the null time.
 196   return Time(kTimeTToMicrosecondsOffset) +
 197          TimeDelta::FromMillisecondsD(ms_since_epoch);
 198 }
 199
 200 double Time::ToJsTime() const {
 201   if (is_null()) {
 202     // Preserve 0 so the invalid result doesn't depend on the platform.
 203     return 0;
 204   }
 205   if (is_max()) {
 206     // Preserve max without offset to prevent overflow.
 207     return std::numeric_limits<double>::infinity();
 208   }
 209   return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
 210           kMicrosecondsPerMillisecond);
 211 }
 212
 213 int64 Time::ToJavaTime() const {
 214   if (is_null()) {
 215     // Preserve 0 so the invalid result doesn't depend on the platform.
 216     return 0;
 217   }
 218   if (is_max()) {
 219     // Preserve max without offset to prevent overflow.
 220     return std::numeric_limits<int64>::max();
 221   }
 222   return ((us_ - kTimeTToMicrosecondsOffset) /
 223           kMicrosecondsPerMillisecond);
 224 }
 225
 226 // static
 227 Time Time::UnixEpoch() {
 228   Time time;
 229   time.us_ = kTimeTToMicrosecondsOffset;
 230   return time;
 231 }
 232
 233 Time Time::LocalMidnight() const {
 234   Exploded exploded;
 235   LocalExplode(&exploded);
 236   exploded.hour = 0;
 237   exploded.minute = 0;
 238   exploded.second = 0;
 239   exploded.millisecond = 0;
 240   return FromLocalExploded(exploded);
 241 }
 242
 243 // static
 244 bool Time::FromStringInternal(const char* time_string,
 245                               bool is_local,
 246                               Time* parsed_time) {
 247   DCHECK((time_string != NULL) && (parsed_time != NULL));
 248
 249   if (time_string[0] == '\0')
 250     return false;
 251
 252   PRTime result_time = 0;
 253   PRStatus result = PR_ParseTimeString(time_string,
 254                                        is_local ? PR_FALSE : PR_TRUE,
 255                                        &result_time);
 256   if (PR_SUCCESS != result)
 257     return false;
 258
 259   result_time += kTimeTToMicrosecondsOffset;
 260   *parsed_time = Time(result_time);
 261   return true;
 262 }
 263
 264 std::ostream& operator<<(std::ostream& os, Time time) {
 265   Time::Exploded exploded;
 266   time.UTCExplode(&exploded);
 267   // Use StringPrintf because iostreams formatting is painful.
 268   return os << StringPrintf("%04d-%02d-%02d %02d:%02d:%02d.%03d UTC",
 269                             exploded.year,
 270                             exploded.month,
 271                             exploded.day_of_month,
 272                             exploded.hour,
 273                             exploded.minute,
 274                             exploded.second,
 275                             exploded.millisecond);
 276 }
 277
 278 // Local helper class to hold the conversion from Time to TickTime at the
 279 // time of the Unix epoch.
 280 class UnixEpochSingleton {
 281  public:
 282   UnixEpochSingleton()
 283       : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}
 284
 285   TimeTicks unix_epoch() const { return unix_epoch_; }
 286
 287  private:
 288   const TimeTicks unix_epoch_;
 289
 290   DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);
 291 };
 292
 293 static LazyInstance<UnixEpochSingleton>::Leaky
 294     leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;
 295
 296 // Static
 297 TimeTicks TimeTicks::UnixEpoch() {
 298   return leaky_unix_epoch_singleton_instance.Get().unix_epoch();
 299 }
 300
 301 TimeTicks TimeTicks::SnappedToNextTick(TimeTicks tick_phase,
 302                                        TimeDelta tick_interval) const {
 303   // |interval_offset| is the offset from |this| to the next multiple of
 304   // |tick_interval| after |tick_phase|, possibly negative if in the past.
 305   TimeDelta interval_offset = (tick_phase - *this) % tick_interval;
 306   // If |this| is exactly on the interval (i.e. offset==0), don't adjust.
 307   // Otherwise, if |tick_phase| was in the past, adjust forward to the next
 308   // tick after |this|.
 309   if (!interval_offset.is_zero() && tick_phase < *this)
 310     interval_offset += tick_interval;
 311   return *this + interval_offset;
 312 }
 313
 314 std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks) {
 315   // This function formats a TimeTicks object as "bogo-microseconds".
 316   // The origin and granularity of the count are platform-specific, and may very
 317   // from run to run. Although bogo-microseconds usually roughly correspond to
 318   // real microseconds, the only real guarantee is that the number never goes
 319   // down during a single run.
 320   const TimeDelta as_time_delta = time_ticks - TimeTicks();
 321   return os << as_time_delta.InMicroseconds() << " bogo-microseconds";
 322 }
 323
 324 std::ostream& operator<<(std::ostream& os, ThreadTicks thread_ticks) {
 325   const TimeDelta as_time_delta = thread_ticks - ThreadTicks();
 326   return os << as_time_delta.InMicroseconds() << " bogo-thread-microseconds";
 327 }
 328
 329 std::ostream& operator<<(std::ostream& os, TraceTicks trace_ticks) {
 330   const TimeDelta as_time_delta = trace_ticks - TraceTicks();
 331   return os << as_time_delta.InMicroseconds() << " bogo-trace-microseconds";
 332 }
 333
 334 // Time::Exploded -------------------------------------------------------------
 335
 336 inline bool is_in_range(int value, int lo, int hi) {
 337   return lo <= value && value <= hi;
 338 }
 339
 340 bool Time::Exploded::HasValidValues() const {
 341   return is_in_range(month, 1, 12) &&
 342          is_in_range(day_of_week, 0, 6) &&
 343          is_in_range(day_of_month, 1, 31) &&
 344          is_in_range(hour, 0, 23) &&
 345          is_in_range(minute, 0, 59) &&
 346          is_in_range(second, 0, 60) &&
 347          is_in_range(millisecond, 0, 999);
 348 }
 349
 350 }  // namespace base