// Copyright (c) 2012 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.

#include "base/time/time.h"

#include <cmath>

#include <ios>

#include <limits>

#include <ostream>

#include <sstream>

#include "base/lazy_instance.h"

#include "base/logging.h"

#include "base/macros.h"

#include "base/strings/stringprintf.h"

#include "base/third_party/nspr/prtime.h"

#include "build/build_config.h"

namespace base {

// TimeDelta ------------------------------------------------------------------

int TimeDelta::InDays() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);

}

int TimeDelta::InHours() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerHour);

}

int TimeDelta::InMinutes() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int>::max();

  }

  return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute);

}

double TimeDelta::InSecondsF() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond;

}

int64_t TimeDelta::InSeconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_ / Time::kMicrosecondsPerSecond;

}

double TimeDelta::InMillisecondsF() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMilliseconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_ / Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMillisecondsRoundedUp() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return (delta_ + Time::kMicrosecondsPerMillisecond - 1) /

      Time::kMicrosecondsPerMillisecond;

}

int64_t TimeDelta::InMicroseconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_;

}

int64_t TimeDelta::InNanoseconds() const {

  if (is_max()) {

    // Preserve max to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return delta_ * Time::kNanosecondsPerMicrosecond;

}

namespace time_internal {

int64_t SaturatedAdd(TimeDelta delta, int64_t value) {

  CheckedNumeric<int64_t> rv(delta.delta_);

  rv += value;

  if (rv.IsValid())

    return rv.ValueOrDie();

  // Positive RHS overflows. Negative RHS underflows.

  if (value < 0)

    return std::numeric_limits<int64_t>::min();

  return std::numeric_limits<int64_t>::max();

}

int64_t SaturatedSub(TimeDelta delta, int64_t value) {

  CheckedNumeric<int64_t> rv(delta.delta_);

  rv -= value;

  if (rv.IsValid())

    return rv.ValueOrDie();

  // Negative RHS overflows. Positive RHS underflows.

  if (value < 0)

    return std::numeric_limits<int64_t>::max();

  return std::numeric_limits<int64_t>::min();

}

}  // namespace time_internal

std::ostream& operator<<(std::ostream& os, TimeDelta time_delta) {

  return os << time_delta.InSecondsF() << " s";

}

// Time -----------------------------------------------------------------------

// static

Time Time::FromTimeT(time_t tt) {

  if (tt == 0)

    return Time();  // Preserve 0 so we can tell it doesn't exist.

  if (tt == std::numeric_limits<time_t>::max())

    return Max();

  return Time(kTimeTToMicrosecondsOffset) + TimeDelta::FromSeconds(tt);

}

time_t Time::ToTimeT() const {

  if (is_null())

    return 0;  // Preserve 0 so we can tell it doesn't exist.

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<time_t>::max();

  }

  if (std::numeric_limits<int64_t>::max() - kTimeTToMicrosecondsOffset <= us_) {

    DLOG(WARNING) << "Overflow when converting base::Time with internal " <<

                     "value " << us_ << " to time_t.";

    return std::numeric_limits<time_t>::max();

  }

  return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;

}

// static

Time Time::FromDoubleT(double dt) {

  if (dt == 0 || std::isnan(dt))

    return Time();  // Preserve 0 so we can tell it doesn't exist.

  return Time(kTimeTToMicrosecondsOffset) + TimeDelta::FromSecondsD(dt);

}

double Time::ToDoubleT() const {

  if (is_null())

    return 0;  // Preserve 0 so we can tell it doesn't exist.

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /

          static_cast<double>(kMicrosecondsPerSecond));

}

#if defined(OS_POSIX)

// static

Time Time::FromTimeSpec(const timespec& ts) {

  return FromDoubleT(ts.tv_sec +

                     static_cast<double>(ts.tv_nsec) /

                         base::Time::kNanosecondsPerSecond);

}

#endif

// static

Time Time::FromJsTime(double ms_since_epoch) {

  // The epoch is a valid time, so this constructor doesn't interpret

  // 0 as the null time.

  return Time(kTimeTToMicrosecondsOffset) +

         TimeDelta::FromMillisecondsD(ms_since_epoch);

}

double Time::ToJsTime() const {

  if (is_null()) {

    // Preserve 0 so the invalid result doesn't depend on the platform.

    return 0;

  }

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<double>::infinity();

  }

  return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /

          kMicrosecondsPerMillisecond);

}

Time Time::FromJavaTime(int64_t ms_since_epoch) {

  return base::Time::UnixEpoch() +

         base::TimeDelta::FromMilliseconds(ms_since_epoch);

}

int64_t Time::ToJavaTime() const {

  if (is_null()) {

    // Preserve 0 so the invalid result doesn't depend on the platform.

    return 0;

  }

  if (is_max()) {

    // Preserve max without offset to prevent overflow.

    return std::numeric_limits<int64_t>::max();

  }

  return ((us_ - kTimeTToMicrosecondsOffset) /

          kMicrosecondsPerMillisecond);

}

// static

Time Time::UnixEpoch() {

  Time time;

  time.us_ = kTimeTToMicrosecondsOffset;

  return time;

}

Time Time::LocalMidnight() const {

  Exploded exploded;

  LocalExplode(&exploded);

  exploded.hour = 0;

  exploded.minute = 0;

  exploded.second = 0;

  exploded.millisecond = 0;

  Time out_time;

  if (FromLocalExploded(exploded, &out_time))

    return out_time;

  // This function must not fail.

  NOTREACHED();

  return Time();

}

#if !defined(MOZ_SANDBOX)

// static

bool Time::FromStringInternal(const char* time_string,

                              bool is_local,

                              Time* parsed_time) {

  DCHECK((time_string != NULL) && (parsed_time != NULL));

  if (time_string[0] == '\0')

    return false;

  PRTime result_time = 0;

  PRStatus result = PR_ParseTimeString(time_string,

                                       is_local ? PR_FALSE : PR_TRUE,

                                       &result_time);

  if (PR_SUCCESS != result)

    return false;

  result_time += kTimeTToMicrosecondsOffset;

  *parsed_time = Time(result_time);

  return true;

}

#endif

// static

bool Time::ExplodedMostlyEquals(const Exploded& lhs, const Exploded& rhs) {

  return lhs.year == rhs.year && lhs.month == rhs.month &&

         lhs.day_of_month == rhs.day_of_month && lhs.hour == rhs.hour &&

         lhs.minute == rhs.minute && lhs.second == rhs.second &&

         lhs.millisecond == rhs.millisecond;

}

std::ostream& operator<<(std::ostream& os, Time time) {

  Time::Exploded exploded;

  time.UTCExplode(&exploded);

  // Use StringPrintf because iostreams formatting is painful.

  return os << StringPrintf("%04d-%02d-%02d %02d:%02d:%02d.%03d UTC",

                            exploded.year,

                            exploded.month,

                            exploded.day_of_month,

                            exploded.hour,

                            exploded.minute,

                            exploded.second,

                            exploded.millisecond);

}

// Local helper class to hold the conversion from Time to TickTime at the

// time of the Unix epoch.

class UnixEpochSingleton {

 public:

  UnixEpochSingleton()

      : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}

  TimeTicks unix_epoch() const { return unix_epoch_; }

 private:

  const TimeTicks unix_epoch_;

  DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);

};

static LazyInstance<UnixEpochSingleton>::Leaky

    leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;

// Static

TimeTicks TimeTicks::UnixEpoch() {

  return leaky_unix_epoch_singleton_instance.Get().unix_epoch();

}

TimeTicks TimeTicks::SnappedToNextTick(TimeTicks tick_phase,

                                       TimeDelta tick_interval) const {

  // |interval_offset| is the offset from |this| to the next multiple of

  // |tick_interval| after |tick_phase|, possibly negative if in the past.

  TimeDelta interval_offset = (tick_phase - *this) % tick_interval;

  // If |this| is exactly on the interval (i.e. offset==0), don't adjust.

  // Otherwise, if |tick_phase| was in the past, adjust forward to the next

  // tick after |this|.

  if (!interval_offset.is_zero() && tick_phase < *this)

    interval_offset += tick_interval;

  return *this + interval_offset;

}

std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks) {

  // This function formats a TimeTicks object as "bogo-microseconds".

  // The origin and granularity of the count are platform-specific, and may very

  // from run to run. Although bogo-microseconds usually roughly correspond to

  // real microseconds, the only real guarantee is that the number never goes

  // down during a single run.

  const TimeDelta as_time_delta = time_ticks - TimeTicks();

  return os << as_time_delta.InMicroseconds() << " bogo-microseconds";

}

std::ostream& operator<<(std::ostream& os, ThreadTicks thread_ticks) {

  const TimeDelta as_time_delta = thread_ticks - ThreadTicks();

  return os << as_time_delta.InMicroseconds() << " bogo-thread-microseconds";

}

// Time::Exploded -------------------------------------------------------------

inline bool is_in_range(int value, int lo, int hi) {

  return lo <= value && value <= hi;

}

bool Time::Exploded::HasValidValues() const {

  return is_in_range(month, 1, 12) &&

         is_in_range(day_of_week, 0, 6) &&

         is_in_range(day_of_month, 1, 31) &&

         is_in_range(hour, 0, 23) &&

         is_in_range(minute, 0, 59) &&

         is_in_range(second, 0, 60) &&

         is_in_range(millisecond, 0, 999);

}

}  // namespace base