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package com.google.protobuf.util;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.math.IntMath.checkedAdd;
import static com.google.common.math.IntMath.checkedSubtract;
import static com.google.common.math.LongMath.checkedAdd;
import static com.google.common.math.LongMath.checkedMultiply;
import static com.google.common.math.LongMath.checkedSubtract;
import static com.google.protobuf.util.Timestamps.MICROS_PER_SECOND;
import static com.google.protobuf.util.Timestamps.MILLIS_PER_SECOND;
import static com.google.protobuf.util.Timestamps.NANOS_PER_MICROSECOND;
import static com.google.protobuf.util.Timestamps.NANOS_PER_MILLISECOND;
import static com.google.protobuf.util.Timestamps.NANOS_PER_SECOND;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.protobuf.Duration;
import java.text.ParseException;
import java.util.Comparator;

Utilities to help create/manipulate protobuf/duration.proto. All operations throw an IllegalArgumentException if the input(s) are not valid. /**
 * Utilities to help create/manipulate {@code protobuf/duration.proto}. All operations throw an
 * {@link IllegalArgumentException} if the input(s) are not {@linkplain #isValid(Duration) valid}.
 */
public final class Durations {
  static final long DURATION_SECONDS_MIN = -315576000000L;
  static final long DURATION_SECONDS_MAX = 315576000000L;

  private static final long SECONDS_PER_MINUTE = 60L;
  private static final long SECONDS_PER_HOUR = SECONDS_PER_MINUTE * 60;
  private static final long SECONDS_PER_DAY = SECONDS_PER_HOUR * 24;

  
A constant holding the minimum valid Duration, approximately -10,000 years. /** A constant holding the minimum valid {@link Duration}, approximately {@code -10,000} years. */
  public static final Duration MIN_VALUE =
      Duration.newBuilder().setSeconds(DURATION_SECONDS_MIN).setNanos(-999999999).build();

  
A constant holding the maximum valid Duration, approximately +10,000 years. /** A constant holding the maximum valid {@link Duration}, approximately {@code +10,000} years. */
  public static final Duration MAX_VALUE =
      Duration.newBuilder().setSeconds(DURATION_SECONDS_MAX).setNanos(999999999).build();

  
A constant holding the duration of zero. /** A constant holding the duration of zero. */
  public static final Duration ZERO = Duration.newBuilder().setSeconds(0L).setNanos(0).build();

  private Durations() {}

  private static final Comparator<Duration> COMPARATOR =
      new Comparator<Duration>() {
        @Override
        public int compare(Duration d1, Duration d2) {
          checkValid(d1);
          checkValid(d2);
          int secDiff = Long.compare(d1.getSeconds(), d2.getSeconds());
          return (secDiff != 0) ? secDiff : Integer.compare(d1.getNanos(), d2.getNanos());
        }
      };

  
Returns a Comparator for Durations which sorts in increasing chronological order. Nulls and invalid Durations are not allowed (see isValid). /**
   * Returns a {@link Comparator} for {@link Duration}s which sorts in increasing chronological
   * order. Nulls and invalid {@link Duration}s are not allowed (see {@link #isValid}).
   */
  public static Comparator<Duration> comparator() {
    return COMPARATOR;
  }

  
Compares two durations. The value returned is identical to what would be returned by: 
Durations.comparator().compare(x, y). 
Returns:
the value 0 if x == y; a value less than 0 if x < y; and a value greater than 0 if x > y/**
   * Compares two durations. The value returned is identical to what would be returned by: {@code
   * Durations.comparator().compare(x, y)}.
   *
   * @return the value {@code 0} if {@code x == y}; a value less than {@code 0} if {@code x < y};
   *     and a value greater than {@code 0} if {@code x > y}
   */
  public static int compare(Duration x, Duration y) {
    return COMPARATOR.compare(x, y);
  }

  
Returns true if the given Duration is valid. The seconds value must be in the range [-315,576,000,000, +315,576,000,000]. The nanos value must be in the range [-999,999,999, +999,999,999]. 
Note: Durations less than one second are represented with a 0 seconds field and a positive or negative nanos field. For durations of one second or more, a non-zero value for the nanos field must be of the same sign as the seconds field. /**
   * Returns true if the given {@link Duration} is valid. The {@code seconds} value must be in the
   * range [-315,576,000,000, +315,576,000,000]. The {@code nanos} value must be in the range
   * [-999,999,999, +999,999,999].
   *
   * <p><b>Note:</b> Durations less than one second are represented with a 0 {@code seconds} field
   * and a positive or negative {@code nanos} field. For durations of one second or more, a non-zero
   * value for the {@code nanos} field must be of the same sign as the {@code seconds} field.
   */
  public static boolean isValid(Duration duration) {
    return isValid(duration.getSeconds(), duration.getNanos());
  }

  
Returns true if the given number of seconds and nanos is a valid Duration. The 
seconds value must be in the range [-315,576,000,000, +315,576,000,000]. The nanos value must be in the range [-999,999,999, +999,999,999]. 
Note: Durations less than one second are represented with a 0 seconds field and a positive or negative nanos field. For durations of one second or more, a non-zero value for the nanos field must be of the same sign as the seconds field. /**
   * Returns true if the given number of seconds and nanos is a valid {@link Duration}. The {@code
   * seconds} value must be in the range [-315,576,000,000, +315,576,000,000]. The {@code nanos}
   * value must be in the range [-999,999,999, +999,999,999].
   *
   * <p><b>Note:</b> Durations less than one second are represented with a 0 {@code seconds} field
   * and a positive or negative {@code nanos} field. For durations of one second or more, a non-zero
   * value for the {@code nanos} field must be of the same sign as the {@code seconds} field.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static boolean isValid(long seconds, int nanos) {
    if (seconds < DURATION_SECONDS_MIN || seconds > DURATION_SECONDS_MAX) {
      return false;
    }
    if (nanos < -999999999L || nanos >= NANOS_PER_SECOND) {
      return false;
    }
    if (seconds < 0 || nanos < 0) {
      if (seconds > 0 || nanos > 0) {
        return false;
      }
    }
    return true;
  }

  
Returns whether the given Duration is negative or not. /** Returns whether the given {@link Duration} is negative or not. */
  public static boolean isNegative(Duration duration) {
    checkValid(duration);
    return (duration.getSeconds() == 0) ? duration.getNanos() < 0 : duration.getSeconds() < 0;
  }

  
Ensures that the given Duration is not negative. 
Throws:
IllegalArgumentException – if duration is negative or invalid
NullPointerException – if duration is null/**
   * Ensures that the given {@link Duration} is not negative.
   *
   * @throws IllegalArgumentException if {@code duration} is negative or invalid
   * @throws NullPointerException if {@code duration} is {@code null}
   */
  @CanIgnoreReturnValue
  public static Duration checkNotNegative(Duration duration) {
    checkValid(duration);
    checkArgument(!isNegative(duration), "duration (%s) must not be negative", toString(duration));
    return duration;
  }

  
Ensures that the given Duration is positive. 
Throws:
IllegalArgumentException – if duration is negative, ZERO, or invalid
NullPointerException – if duration is null/**
   * Ensures that the given {@link Duration} is positive.
   *
   * @throws IllegalArgumentException if {@code duration} is negative, {@code ZERO}, or invalid
   * @throws NullPointerException if {@code duration} is {@code null}
   */
  @CanIgnoreReturnValue
  public static Duration checkPositive(Duration duration) {
    checkValid(duration);
    checkArgument(
        !isNegative(duration) && !duration.equals(ZERO),
        "duration (%s) must be positive",
        toString(duration));
    return duration;
  }

  
Throws an IllegalArgumentException if the given Duration is not valid. /** Throws an {@link IllegalArgumentException} if the given {@link Duration} is not valid. */
  @CanIgnoreReturnValue
  public static Duration checkValid(Duration duration) {
    long seconds = duration.getSeconds();
    int nanos = duration.getNanos();
    if (!isValid(seconds, nanos)) {
      throw new IllegalArgumentException(
          String.format(
              "Duration is not valid. See proto definition for valid values. "
                  + "Seconds (%s) must be in range [-315,576,000,000, +315,576,000,000]. "
                  + "Nanos (%s) must be in range [-999,999,999, +999,999,999]. "
                  + "Nanos must have the same sign as seconds",
              seconds, nanos));
    }
    return duration;
  }

  
Builds the given builder and throws an IllegalArgumentException if it is not valid. See checkValid(Duration). 
Returns:
A valid, built Duration./**
   * Builds the given builder and throws an {@link IllegalArgumentException} if it is not valid. See
   * {@link #checkValid(Duration)}.
   *
   * @return A valid, built {@link Duration}.
   */
  public static Duration checkValid(Duration.Builder durationBuilder) {
    return checkValid(durationBuilder.build());
  }

  
Convert Duration to string format. The string format will contains 3, 6, or 9 fractional digits
depending on the precision required to represent the exact Duration value. For example: "1s",
"1.010s", "1.000000100s", "-3.100s" The range that can be represented by Duration is from
-315,576,000,000 to +315,576,000,000 inclusive (in seconds).
Throws:
IllegalArgumentException – if the given duration is not in the valid range.
Returns:
The string representation of the given duration./**
   * Convert Duration to string format. The string format will contains 3, 6, or 9 fractional digits
   * depending on the precision required to represent the exact Duration value. For example: "1s",
   * "1.010s", "1.000000100s", "-3.100s" The range that can be represented by Duration is from
   * -315,576,000,000 to +315,576,000,000 inclusive (in seconds).
   *
   * @return The string representation of the given duration.
   * @throws IllegalArgumentException if the given duration is not in the valid range.
   */
  public static String toString(Duration duration) {
    checkValid(duration);

    long seconds = duration.getSeconds();
    int nanos = duration.getNanos();

    StringBuilder result = new StringBuilder();
    if (seconds < 0 || nanos < 0) {
      result.append("-");
      seconds = -seconds;
      nanos = -nanos;
    }
    result.append(seconds);
    if (nanos != 0) {
      result.append(".");
      result.append(Timestamps.formatNanos(nanos));
    }
    result.append("s");
    return result.toString();
  }

  
Parse from a string to produce a duration.
Throws:
ParseException – if parsing fails.
Returns:
A Duration parsed from the string./**
   * Parse from a string to produce a duration.
   *
   * @return A Duration parsed from the string.
   * @throws ParseException if parsing fails.
   */
  public static Duration parse(String value) throws ParseException {
    // Must ended with "s".
    if (value.isEmpty() || value.charAt(value.length() - 1) != 's') {
      throw new ParseException("Invalid duration string: " + value, 0);
    }
    boolean negative = false;
    if (value.charAt(0) == '-') {
      negative = true;
      value = value.substring(1);
    }
    String secondValue = value.substring(0, value.length() - 1);
    String nanoValue = "";
    int pointPosition = secondValue.indexOf('.');
    if (pointPosition != -1) {
      nanoValue = secondValue.substring(pointPosition + 1);
      secondValue = secondValue.substring(0, pointPosition);
    }
    long seconds = Long.parseLong(secondValue);
    int nanos = nanoValue.isEmpty() ? 0 : Timestamps.parseNanos(nanoValue);
    if (seconds < 0) {
      throw new ParseException("Invalid duration string: " + value, 0);
    }
    if (negative) {
      seconds = -seconds;
      nanos = -nanos;
    }
    try {
      return normalizedDuration(seconds, nanos);
    } catch (IllegalArgumentException e) {
      throw new ParseException("Duration value is out of range.", 0);
    }
  }

  // Static factories

  
Create a Duration from the number of days. /** Create a Duration from the number of days. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromDays(long days) {
    return Duration.newBuilder()
        .setSeconds(checkedMultiply(days, SECONDS_PER_DAY))
        .setNanos(0)
        .build();
  }

  
Create a Duration from the number of hours. /** Create a Duration from the number of hours. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromHours(long hours) {
    return Duration.newBuilder()
        .setSeconds(checkedMultiply(hours, SECONDS_PER_HOUR))
        .setNanos(0)
        .build();
  }

  
Create a Duration from the number of minutes. /** Create a Duration from the number of minutes. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromMinutes(long minutes) {
    return Duration.newBuilder()
        .setSeconds(checkedMultiply(minutes, SECONDS_PER_MINUTE))
        .setNanos(0)
        .build();
  }

  
Create a Duration from the number of seconds. /** Create a Duration from the number of seconds. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromSeconds(long seconds) {
    return normalizedDuration(seconds, 0);
  }

  
Create a Duration from the number of milliseconds. /** Create a Duration from the number of milliseconds. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromMillis(long milliseconds) {
    return normalizedDuration(
        milliseconds / MILLIS_PER_SECOND,
        (int) (milliseconds % MILLIS_PER_SECOND * NANOS_PER_MILLISECOND));
  }

  
Create a Duration from the number of microseconds. /** Create a Duration from the number of microseconds. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromMicros(long microseconds) {
    return normalizedDuration(
        microseconds / MICROS_PER_SECOND,
        (int) (microseconds % MICROS_PER_SECOND * NANOS_PER_MICROSECOND));
  }

  
Create a Duration from the number of nanoseconds. /** Create a Duration from the number of nanoseconds. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static Duration fromNanos(long nanoseconds) {
    return normalizedDuration(
        nanoseconds / NANOS_PER_SECOND, (int) (nanoseconds % NANOS_PER_SECOND));
  }

  // Conversion APIs

  
Convert a Duration to the number of days. The result will be rounded towards 0 to the nearest
day.
/**
   * Convert a Duration to the number of days. The result will be rounded towards 0 to the nearest
   * day.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toDays(Duration duration) {
    return checkValid(duration).getSeconds() / SECONDS_PER_DAY;
  }

  
Convert a Duration to the number of hours. The result will be rounded towards 0 to the nearest
hour.
/**
   * Convert a Duration to the number of hours. The result will be rounded towards 0 to the nearest
   * hour.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toHours(Duration duration) {
    return checkValid(duration).getSeconds() / SECONDS_PER_HOUR;
  }

  
Convert a Duration to the number of minutes. The result will be rounded towards 0 to the
nearest minute.
/**
   * Convert a Duration to the number of minutes. The result will be rounded towards 0 to the
   * nearest minute.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toMinutes(Duration duration) {
    return checkValid(duration).getSeconds() / SECONDS_PER_MINUTE;
  }

  
Convert a Duration to the number of seconds. The result will be rounded towards 0 to the
nearest second. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
/**
   * Convert a Duration to the number of seconds. The result will be rounded towards 0 to the
   * nearest second. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toSeconds(Duration duration) {
    return checkValid(duration).getSeconds();
  }

  
Returns the number of seconds of the given duration as a double. This method should be used to accommodate APIs that only accept durations as double values. 
This conversion may lose precision.
If you need the number of seconds in this duration as a long (not a double), simply use duration.getSeconds() or toSeconds (which includes validation). /**
   * Returns the number of seconds of the given duration as a {@code double}. This method should be
   * used to accommodate APIs that <b>only</b> accept durations as {@code double} values.
   *
   * <p>This conversion may lose precision.
   *
   * <p>If you need the number of seconds in this duration as a {@code long} (not a {@code double}),
   * simply use {@code duration.getSeconds()} or {@link #toSeconds} (which includes validation).
   */
  @SuppressWarnings({
    "DurationSecondsToDouble", // that's the whole point of this method
    "GoodTime" // this is a legacy conversion API
  })
  public static double toSecondsAsDouble(Duration duration) {
    checkValid(duration);
    return duration.getSeconds() + duration.getNanos() / 1e9;
  }

  
Convert a Duration to the number of milliseconds. The result will be rounded towards 0 to the
nearest millisecond. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
/**
   * Convert a Duration to the number of milliseconds. The result will be rounded towards 0 to the
   * nearest millisecond. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toMillis(Duration duration) {
    checkValid(duration);
    return checkedAdd(
        checkedMultiply(duration.getSeconds(), MILLIS_PER_SECOND),
        duration.getNanos() / NANOS_PER_MILLISECOND);
  }

  
Convert a Duration to the number of microseconds. The result will be rounded towards 0 to the
nearest microseconds. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
/**
   * Convert a Duration to the number of microseconds. The result will be rounded towards 0 to the
   * nearest microseconds. E.g., if the duration represents -1 nanosecond, it will be rounded to 0.
   */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toMicros(Duration duration) {
    checkValid(duration);
    return checkedAdd(
        checkedMultiply(duration.getSeconds(), MICROS_PER_SECOND),
        duration.getNanos() / NANOS_PER_MICROSECOND);
  }

  
Convert a Duration to the number of nanoseconds. /** Convert a Duration to the number of nanoseconds. */
  @SuppressWarnings("GoodTime") // this is a legacy conversion API
  public static long toNanos(Duration duration) {
    checkValid(duration);
    return checkedAdd(
        checkedMultiply(duration.getSeconds(), NANOS_PER_SECOND), duration.getNanos());
  }

  // Math operations

  
Add two durations. /** Add two durations. */
  public static Duration add(Duration d1, Duration d2) {
    checkValid(d1);
    checkValid(d2);
    return normalizedDuration(
        checkedAdd(d1.getSeconds(), d2.getSeconds()), checkedAdd(d1.getNanos(), d2.getNanos()));
  }

  
Subtract a duration from another. /** Subtract a duration from another. */
  public static Duration subtract(Duration d1, Duration d2) {
    checkValid(d1);
    checkValid(d2);
    return normalizedDuration(
        checkedSubtract(d1.getSeconds(), d2.getSeconds()),
        checkedSubtract(d1.getNanos(), d2.getNanos()));
  }

  static Duration normalizedDuration(long seconds, int nanos) {
    if (nanos <= -NANOS_PER_SECOND || nanos >= NANOS_PER_SECOND) {
      seconds = checkedAdd(seconds, nanos / NANOS_PER_SECOND);
      nanos %= NANOS_PER_SECOND;
    }
    if (seconds > 0 && nanos < 0) {
      nanos += NANOS_PER_SECOND; // no overflow since nanos is negative (and we're adding)
      seconds--; // no overflow since seconds is positive (and we're decrementing)
    }
    if (seconds < 0 && nanos > 0) {
      nanos -= NANOS_PER_SECOND; // no overflow since nanos is positive (and we're subtracting)
      seconds++; // no overflow since seconds is negative (and we're incrementing)
    }
    Duration duration = Duration.newBuilder().setSeconds(seconds).setNanos(nanos).build();
    return checkValid(duration);
  }
}