third_party/protobuf/3.6.1/java/util/src/main/java/com/google/protobuf/util/Timestamps.java - bazel - Git at Google

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 package com.google.protobuf.util;

 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 com.google.protobuf.Duration;
 import com.google.protobuf.Timestamp;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Comparator;
 import java.util.Date;
 import java.util.GregorianCalendar;
 import java.util.Locale;
 import java.util.TimeZone;

 /**
  * Utilities to help create/manipulate {@code protobuf/timestamp.proto}. All operations throw an
  * {@link IllegalArgumentException} if the input(s) are not {@linkplain #isValid(Timestamp) valid}.
  */
 public final class Timestamps {

   // Timestamp for "0001-01-01T00:00:00Z"
   static final long TIMESTAMP_SECONDS_MIN = -62135596800L;

   // Timestamp for "9999-12-31T23:59:59Z"
   static final long TIMESTAMP_SECONDS_MAX = 253402300799L;

   static final long NANOS_PER_SECOND = 1000000000;
   static final long NANOS_PER_MILLISECOND = 1000000;
   static final long NANOS_PER_MICROSECOND = 1000;
   static final long MILLIS_PER_SECOND = 1000;
   static final long MICROS_PER_SECOND = 1000000;

   /** A constant holding the minimum valid {@link Timestamp}, {@code 0001-01-01T00:00:00Z}. */
   public static final Timestamp MIN_VALUE =
       Timestamp.newBuilder().setSeconds(TIMESTAMP_SECONDS_MIN).setNanos(0).build();

   /**
    * A constant holding the maximum valid {@link Timestamp}, {@code 9999-12-31T23:59:59.999999999Z}.
    */
   public static final Timestamp MAX_VALUE =
       Timestamp.newBuilder().setSeconds(TIMESTAMP_SECONDS_MAX).setNanos(999999999).build();

   /**
    * A constant holding the {@link Timestamp} of epoch time, {@code 1970-01-01T00:00:00.000000000Z}.
    */
   public static final Timestamp EPOCH = Timestamp.newBuilder().setSeconds(0).setNanos(0).build();

   private static final ThreadLocal<SimpleDateFormat> timestampFormat =
       new ThreadLocal<SimpleDateFormat>() {
         @Override
         protected SimpleDateFormat initialValue() {
           return createTimestampFormat();
         }
       };

   private static SimpleDateFormat createTimestampFormat() {
     SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.ENGLISH);
     GregorianCalendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
     // We use Proleptic Gregorian Calendar (i.e., Gregorian calendar extends
     // backwards to year one) for timestamp formating.
     calendar.setGregorianChange(new Date(Long.MIN_VALUE));
     sdf.setCalendar(calendar);
     return sdf;
   }

   private Timestamps() {}

   private static final Comparator<Timestamp> COMPARATOR =
       new Comparator<Timestamp>() {
         @Override
         public int compare(Timestamp t1, Timestamp t2) {
           checkValid(t1);
           checkValid(t2);
           int secDiff = Long.compare(t1.getSeconds(), t2.getSeconds());
           return (secDiff != 0) ? secDiff : Integer.compare(t1.getNanos(), t2.getNanos());
         }
       };

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

   /**
    * Compares two timestamps. The value returned is identical to what would be returned by:
    * {@code Timestamps.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(Timestamp x, Timestamp y) {
     return COMPARATOR.compare(x, y);
   }

   /**
    * Returns true if the given {@link Timestamp} is valid. The {@code seconds} value must be in the
    * range [-62,135,596,800, +253,402,300,799] (i.e., between 0001-01-01T00:00:00Z and
    * 9999-12-31T23:59:59Z). The {@code nanos} value must be in the range [0, +999,999,999].
    *
    * <p><b>Note:</b> Negative second values with fractional seconds must still have non-negative
    * nanos values that count forward in time.
    */
   public static boolean isValid(Timestamp timestamp) {
     return isValid(timestamp.getSeconds(), timestamp.getNanos());
   }

   /**
    * Returns true if the given number of seconds and nanos is a valid {@link Timestamp}. The {@code
    * seconds} value must be in the range [-62,135,596,800, +253,402,300,799] (i.e., between
    * 0001-01-01T00:00:00Z and 9999-12-31T23:59:59Z). The {@code nanos} value must be in the range
    * [0, +999,999,999].
    *
    * <p><b>Note:</b> Negative second values with fractional seconds must still have non-negative
    * nanos values that count forward in time.
    */
   public static boolean isValid(long seconds, int nanos) {
     if (seconds < TIMESTAMP_SECONDS_MIN || seconds > TIMESTAMP_SECONDS_MAX) {
       return false;
     }
     if (nanos < 0 || nanos >= NANOS_PER_SECOND) {
       return false;
     }
     return true;
   }

   /** Throws an {@link IllegalArgumentException} if the given {@link Timestamp} is not valid. */
   public static Timestamp checkValid(Timestamp timestamp) {
     long seconds = timestamp.getSeconds();
     int nanos = timestamp.getNanos();
     if (!isValid(seconds, nanos)) {
         throw new IllegalArgumentException(String.format(
             "Timestamp is not valid. See proto definition for valid values. "
             + "Seconds (%s) must be in range [-62,135,596,800, +253,402,300,799]. "
             + "Nanos (%s) must be in range [0, +999,999,999].", seconds, nanos));
     }
     return timestamp;
   }

   /**
    * Convert Timestamp to RFC 3339 date string format. The output will always be Z-normalized and
    * uses 3, 6 or 9 fractional digits as required to represent the exact value. Note that Timestamp
    * can only represent time from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. See
    * https://www.ietf.org/rfc/rfc3339.txt
    *
    * <p>Example of generated format: "1972-01-01T10:00:20.021Z"
    *
    * @return The string representation of the given timestamp.
    * @throws IllegalArgumentException if the given timestamp is not in the valid range.
    */
   public static String toString(Timestamp timestamp) {
     checkValid(timestamp);

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

     StringBuilder result = new StringBuilder();
     // Format the seconds part.
     Date date = new Date(seconds * MILLIS_PER_SECOND);
     result.append(timestampFormat.get().format(date));
     // Format the nanos part.
     if (nanos != 0) {
       result.append(".");
       result.append(formatNanos(nanos));
     }
     result.append("Z");
     return result.toString();
   }

   /**
    * Parse from RFC 3339 date string to Timestamp. This method accepts all outputs of {@link
    * #toString(Timestamp)} and it also accepts any fractional digits (or none) and any offset as
    * long as they fit into nano-seconds precision.
    *
    * <p>Example of accepted format: "1972-01-01T10:00:20.021-05:00"
    *
    * @return A Timestamp parsed from the string.
    * @throws ParseException if parsing fails.
    */
   public static Timestamp parse(String value) throws ParseException {
     int dayOffset = value.indexOf('T');
     if (dayOffset == -1) {
       throw new ParseException("Failed to parse timestamp: invalid timestamp \"" + value + "\"", 0);
     }
     int timezoneOffsetPosition = value.indexOf('Z', dayOffset);
     if (timezoneOffsetPosition == -1) {
       timezoneOffsetPosition = value.indexOf('+', dayOffset);
     }
     if (timezoneOffsetPosition == -1) {
       timezoneOffsetPosition = value.indexOf('-', dayOffset);
     }
     if (timezoneOffsetPosition == -1) {
       throw new ParseException("Failed to parse timestamp: missing valid timezone offset.", 0);
     }
     // Parse seconds and nanos.
     String timeValue = value.substring(0, timezoneOffsetPosition);
     String secondValue = timeValue;
     String nanoValue = "";
     int pointPosition = timeValue.indexOf('.');
     if (pointPosition != -1) {
       secondValue = timeValue.substring(0, pointPosition);
       nanoValue = timeValue.substring(pointPosition + 1);
     }
     Date date = timestampFormat.get().parse(secondValue);
     long seconds = date.getTime() / MILLIS_PER_SECOND;
     int nanos = nanoValue.isEmpty() ? 0 : parseNanos(nanoValue);
     // Parse timezone offsets.
     if (value.charAt(timezoneOffsetPosition) == 'Z') {
       if (value.length() != timezoneOffsetPosition + 1) {
         throw new ParseException(
             "Failed to parse timestamp: invalid trailing data \""
                 + value.substring(timezoneOffsetPosition)
                 + "\"",
             0);
       }
     } else {
       String offsetValue = value.substring(timezoneOffsetPosition + 1);
       long offset = parseTimezoneOffset(offsetValue);
       if (value.charAt(timezoneOffsetPosition) == '+') {
         seconds -= offset;
       } else {
         seconds += offset;
       }
     }
     try {
       return normalizedTimestamp(seconds, nanos);
     } catch (IllegalArgumentException e) {
       throw new ParseException("Failed to parse timestamp: timestamp is out of range.", 0);
     }
   }

   /** Create a Timestamp from the number of seconds elapsed from the epoch. */
   public static Timestamp fromSeconds(long seconds) {
     return normalizedTimestamp(seconds, 0);
   }

   /**
    * Convert a Timestamp to the number of seconds elapsed from the epoch.
    *
    * <p>The result will be rounded down to the nearest second. E.g., if the timestamp represents
    * "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 second.
    */
   public static long toSeconds(Timestamp timestamp) {
     return checkValid(timestamp).getSeconds();
   }

   /** Create a Timestamp from the number of milliseconds elapsed from the epoch. */
   public static Timestamp fromMillis(long milliseconds) {
     return normalizedTimestamp(
         milliseconds / MILLIS_PER_SECOND,
         (int) (milliseconds % MILLIS_PER_SECOND * NANOS_PER_MILLISECOND));
   }

   /**
    * Convert a Timestamp to the number of milliseconds elapsed from the epoch.
    *
    * <p>The result will be rounded down to the nearest millisecond. E.g., if the timestamp
    * represents "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 millisecond.
    */
   public static long toMillis(Timestamp timestamp) {
     checkValid(timestamp);
     return checkedAdd(
         checkedMultiply(timestamp.getSeconds(), MILLIS_PER_SECOND),
         timestamp.getNanos() / NANOS_PER_MILLISECOND);
   }

   /** Create a Timestamp from the number of microseconds elapsed from the epoch. */
   public static Timestamp fromMicros(long microseconds) {
     return normalizedTimestamp(
         microseconds / MICROS_PER_SECOND,
         (int) (microseconds % MICROS_PER_SECOND * NANOS_PER_MICROSECOND));
   }

   /**
    * Convert a Timestamp to the number of microseconds elapsed from the epoch.
    *
    * <p>The result will be rounded down to the nearest microsecond. E.g., if the timestamp
    * represents "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 microsecond.
    */
   public static long toMicros(Timestamp timestamp) {
     checkValid(timestamp);
     return checkedAdd(
         checkedMultiply(timestamp.getSeconds(), MICROS_PER_SECOND),
         timestamp.getNanos() / NANOS_PER_MICROSECOND);
   }

   /** Create a Timestamp from the number of nanoseconds elapsed from the epoch. */
   public static Timestamp fromNanos(long nanoseconds) {
     return normalizedTimestamp(
         nanoseconds / NANOS_PER_SECOND, (int) (nanoseconds % NANOS_PER_SECOND));
   }

   /** Convert a Timestamp to the number of nanoseconds elapsed from the epoch. */
   public static long toNanos(Timestamp timestamp) {
     checkValid(timestamp);
     return checkedAdd(
         checkedMultiply(timestamp.getSeconds(), NANOS_PER_SECOND), timestamp.getNanos());
   }

   /** Calculate the difference between two timestamps. */
   public static Duration between(Timestamp from, Timestamp to) {
     checkValid(from);
     checkValid(to);
     return Durations.normalizedDuration(
         checkedSubtract(to.getSeconds(), from.getSeconds()),
         checkedSubtract(to.getNanos(), from.getNanos()));
   }

   /** Add a duration to a timestamp. */
   public static Timestamp add(Timestamp start, Duration length) {
     checkValid(start);
     Durations.checkValid(length);
     return normalizedTimestamp(
         checkedAdd(start.getSeconds(), length.getSeconds()),
         checkedAdd(start.getNanos(), length.getNanos()));
   }

   /** Subtract a duration from a timestamp. */
   public static Timestamp subtract(Timestamp start, Duration length) {
     checkValid(start);
     Durations.checkValid(length);
     return normalizedTimestamp(
         checkedSubtract(start.getSeconds(), length.getSeconds()),
         checkedSubtract(start.getNanos(), length.getNanos()));
   }

   static Timestamp normalizedTimestamp(long seconds, int nanos) {
     if (nanos <= -NANOS_PER_SECOND || nanos >= NANOS_PER_SECOND) {
       seconds = checkedAdd(seconds, nanos / NANOS_PER_SECOND);
       nanos = (int) (nanos % NANOS_PER_SECOND);
     }
     if (nanos < 0) {
       nanos =
           (int)
               (nanos + NANOS_PER_SECOND); // no overflow since nanos is negative (and we're adding)
       seconds = checkedSubtract(seconds, 1);
     }
     Timestamp timestamp = Timestamp.newBuilder().setSeconds(seconds).setNanos(nanos).build();
     return checkValid(timestamp);
   }

   private static long parseTimezoneOffset(String value) throws ParseException {
     int pos = value.indexOf(':');
     if (pos == -1) {
       throw new ParseException("Invalid offset value: " + value, 0);
     }
     String hours = value.substring(0, pos);
     String minutes = value.substring(pos + 1);
     return (Long.parseLong(hours) * 60 + Long.parseLong(minutes)) * 60;
   }

   static int parseNanos(String value) throws ParseException {
     int result = 0;
     for (int i = 0; i < 9; ++i) {
       result = result * 10;
       if (i < value.length()) {
         if (value.charAt(i) < '0' || value.charAt(i) > '9') {
           throw new ParseException("Invalid nanoseconds.", 0);
         }
         result += value.charAt(i) - '0';
       }
     }
     return result;
   }

   /** Format the nano part of a timestamp or a duration. */
   static String formatNanos(int nanos) {
     // Determine whether to use 3, 6, or 9 digits for the nano part.
     if (nanos % NANOS_PER_MILLISECOND == 0) {
       return String.format(Locale.ENGLISH, "%1$03d", nanos / NANOS_PER_MILLISECOND);
     } else if (nanos % NANOS_PER_MICROSECOND == 0) {
       return String.format(Locale.ENGLISH, "%1$06d", nanos / NANOS_PER_MICROSECOND);
     } else {
       return String.format(Locale.ENGLISH, "%1$09d", nanos);
     }
   }
 }
	// Protocol Buffers - Google's data interchange format
	// Copyright 2008 Google Inc. All rights reserved.
	// https://developers.google.com/protocol-buffers/
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are
	// met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above
	// copyright notice, this list of conditions and the following disclaimer
	// in the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Google Inc. nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	package com.google.protobuf.util;

	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 com.google.protobuf.Duration;
	import com.google.protobuf.Timestamp;
	import java.text.ParseException;
	import java.text.SimpleDateFormat;
	import java.util.Comparator;
	import java.util.Date;
	import java.util.GregorianCalendar;
	import java.util.Locale;
	import java.util.TimeZone;

	/**
	* Utilities to help create/manipulate {@code protobuf/timestamp.proto}. All operations throw an
	* {@link IllegalArgumentException} if the input(s) are not {@linkplain #isValid(Timestamp) valid}.
	*/
	public final class Timestamps {

	// Timestamp for "0001-01-01T00:00:00Z"
	static final long TIMESTAMP_SECONDS_MIN = -62135596800L;

	// Timestamp for "9999-12-31T23:59:59Z"
	static final long TIMESTAMP_SECONDS_MAX = 253402300799L;

	static final long NANOS_PER_SECOND = 1000000000;
	static final long NANOS_PER_MILLISECOND = 1000000;
	static final long NANOS_PER_MICROSECOND = 1000;
	static final long MILLIS_PER_SECOND = 1000;
	static final long MICROS_PER_SECOND = 1000000;

	/** A constant holding the minimum valid {@link Timestamp}, {@code 0001-01-01T00:00:00Z}. */
	public static final Timestamp MIN_VALUE =
	Timestamp.newBuilder().setSeconds(TIMESTAMP_SECONDS_MIN).setNanos(0).build();

	/**
	* A constant holding the maximum valid {@link Timestamp}, {@code 9999-12-31T23:59:59.999999999Z}.
	*/
	public static final Timestamp MAX_VALUE =
	Timestamp.newBuilder().setSeconds(TIMESTAMP_SECONDS_MAX).setNanos(999999999).build();

	/**
	* A constant holding the {@link Timestamp} of epoch time, {@code 1970-01-01T00:00:00.000000000Z}.
	*/
	public static final Timestamp EPOCH = Timestamp.newBuilder().setSeconds(0).setNanos(0).build();

	private static final ThreadLocal<SimpleDateFormat> timestampFormat =
	new ThreadLocal<SimpleDateFormat>() {
	@Override
	protected SimpleDateFormat initialValue() {
	return createTimestampFormat();
	}
	};

	private static SimpleDateFormat createTimestampFormat() {
	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.ENGLISH);
	GregorianCalendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
	// We use Proleptic Gregorian Calendar (i.e., Gregorian calendar extends
	// backwards to year one) for timestamp formating.
	calendar.setGregorianChange(new Date(Long.MIN_VALUE));
	sdf.setCalendar(calendar);
	return sdf;
	}

	private Timestamps() {}

	private static final Comparator<Timestamp> COMPARATOR =
	new Comparator<Timestamp>() {
	@Override
	public int compare(Timestamp t1, Timestamp t2) {
	checkValid(t1);
	checkValid(t2);
	int secDiff = Long.compare(t1.getSeconds(), t2.getSeconds());
	return (secDiff != 0) ? secDiff : Integer.compare(t1.getNanos(), t2.getNanos());
	}
	};

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

	/**
	* Compares two timestamps. The value returned is identical to what would be returned by:
	* {@code Timestamps.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(Timestamp x, Timestamp y) {
	return COMPARATOR.compare(x, y);
	}

	/**
	* Returns true if the given {@link Timestamp} is valid. The {@code seconds} value must be in the
	* range [-62,135,596,800, +253,402,300,799] (i.e., between 0001-01-01T00:00:00Z and
	* 9999-12-31T23:59:59Z). The {@code nanos} value must be in the range [0, +999,999,999].
	*
	* <p><b>Note:</b> Negative second values with fractional seconds must still have non-negative
	* nanos values that count forward in time.
	*/
	public static boolean isValid(Timestamp timestamp) {
	return isValid(timestamp.getSeconds(), timestamp.getNanos());
	}

	/**
	* Returns true if the given number of seconds and nanos is a valid {@link Timestamp}. The {@code
	* seconds} value must be in the range [-62,135,596,800, +253,402,300,799] (i.e., between
	* 0001-01-01T00:00:00Z and 9999-12-31T23:59:59Z). The {@code nanos} value must be in the range
	* [0, +999,999,999].
	*
	* <p><b>Note:</b> Negative second values with fractional seconds must still have non-negative
	* nanos values that count forward in time.
	*/
	public static boolean isValid(long seconds, int nanos) {
	if (seconds < TIMESTAMP_SECONDS_MIN \|\| seconds > TIMESTAMP_SECONDS_MAX) {
	return false;
	}
	if (nanos < 0 \|\| nanos >= NANOS_PER_SECOND) {
	return false;
	}
	return true;
	}

	/** Throws an {@link IllegalArgumentException} if the given {@link Timestamp} is not valid. */
	public static Timestamp checkValid(Timestamp timestamp) {
	long seconds = timestamp.getSeconds();
	int nanos = timestamp.getNanos();
	if (!isValid(seconds, nanos)) {
	throw new IllegalArgumentException(String.format(
	"Timestamp is not valid. See proto definition for valid values. "
	+ "Seconds (%s) must be in range [-62,135,596,800, +253,402,300,799]. "
	+ "Nanos (%s) must be in range [0, +999,999,999].", seconds, nanos));
	}
	return timestamp;
	}

	/**
	* Convert Timestamp to RFC 3339 date string format. The output will always be Z-normalized and
	* uses 3, 6 or 9 fractional digits as required to represent the exact value. Note that Timestamp
	* can only represent time from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. See
	* https://www.ietf.org/rfc/rfc3339.txt
	*
	* <p>Example of generated format: "1972-01-01T10:00:20.021Z"
	*
	* @return The string representation of the given timestamp.
	* @throws IllegalArgumentException if the given timestamp is not in the valid range.
	*/
	public static String toString(Timestamp timestamp) {
	checkValid(timestamp);

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

	StringBuilder result = new StringBuilder();
	// Format the seconds part.
	Date date = new Date(seconds * MILLIS_PER_SECOND);
	result.append(timestampFormat.get().format(date));
	// Format the nanos part.
	if (nanos != 0) {
	result.append(".");
	result.append(formatNanos(nanos));
	}
	result.append("Z");
	return result.toString();
	}

	/**
	* Parse from RFC 3339 date string to Timestamp. This method accepts all outputs of {@link
	* #toString(Timestamp)} and it also accepts any fractional digits (or none) and any offset as
	* long as they fit into nano-seconds precision.
	*
	* <p>Example of accepted format: "1972-01-01T10:00:20.021-05:00"
	*
	* @return A Timestamp parsed from the string.
	* @throws ParseException if parsing fails.
	*/
	public static Timestamp parse(String value) throws ParseException {
	int dayOffset = value.indexOf('T');
	if (dayOffset == -1) {
	throw new ParseException("Failed to parse timestamp: invalid timestamp \"" + value + "\"", 0);
	}
	int timezoneOffsetPosition = value.indexOf('Z', dayOffset);
	if (timezoneOffsetPosition == -1) {
	timezoneOffsetPosition = value.indexOf('+', dayOffset);
	}
	if (timezoneOffsetPosition == -1) {
	timezoneOffsetPosition = value.indexOf('-', dayOffset);
	}
	if (timezoneOffsetPosition == -1) {
	throw new ParseException("Failed to parse timestamp: missing valid timezone offset.", 0);
	}
	// Parse seconds and nanos.
	String timeValue = value.substring(0, timezoneOffsetPosition);
	String secondValue = timeValue;
	String nanoValue = "";
	int pointPosition = timeValue.indexOf('.');
	if (pointPosition != -1) {
	secondValue = timeValue.substring(0, pointPosition);
	nanoValue = timeValue.substring(pointPosition + 1);
	}
	Date date = timestampFormat.get().parse(secondValue);
	long seconds = date.getTime() / MILLIS_PER_SECOND;
	int nanos = nanoValue.isEmpty() ? 0 : parseNanos(nanoValue);
	// Parse timezone offsets.
	if (value.charAt(timezoneOffsetPosition) == 'Z') {
	if (value.length() != timezoneOffsetPosition + 1) {
	throw new ParseException(
	"Failed to parse timestamp: invalid trailing data \""
	+ value.substring(timezoneOffsetPosition)
	+ "\"",
	0);
	}
	} else {
	String offsetValue = value.substring(timezoneOffsetPosition + 1);
	long offset = parseTimezoneOffset(offsetValue);
	if (value.charAt(timezoneOffsetPosition) == '+') {
	seconds -= offset;
	} else {
	seconds += offset;
	}
	}
	try {
	return normalizedTimestamp(seconds, nanos);
	} catch (IllegalArgumentException e) {
	throw new ParseException("Failed to parse timestamp: timestamp is out of range.", 0);
	}
	}

	/** Create a Timestamp from the number of seconds elapsed from the epoch. */
	public static Timestamp fromSeconds(long seconds) {
	return normalizedTimestamp(seconds, 0);
	}

	/**
	* Convert a Timestamp to the number of seconds elapsed from the epoch.
	*
	* <p>The result will be rounded down to the nearest second. E.g., if the timestamp represents
	* "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 second.
	*/
	public static long toSeconds(Timestamp timestamp) {
	return checkValid(timestamp).getSeconds();
	}

	/** Create a Timestamp from the number of milliseconds elapsed from the epoch. */
	public static Timestamp fromMillis(long milliseconds) {
	return normalizedTimestamp(
	milliseconds / MILLIS_PER_SECOND,
	(int) (milliseconds % MILLIS_PER_SECOND * NANOS_PER_MILLISECOND));
	}

	/**
	* Convert a Timestamp to the number of milliseconds elapsed from the epoch.
	*
	* <p>The result will be rounded down to the nearest millisecond. E.g., if the timestamp
	* represents "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 millisecond.
	*/
	public static long toMillis(Timestamp timestamp) {
	checkValid(timestamp);
	return checkedAdd(
	checkedMultiply(timestamp.getSeconds(), MILLIS_PER_SECOND),
	timestamp.getNanos() / NANOS_PER_MILLISECOND);
	}

	/** Create a Timestamp from the number of microseconds elapsed from the epoch. */
	public static Timestamp fromMicros(long microseconds) {
	return normalizedTimestamp(
	microseconds / MICROS_PER_SECOND,
	(int) (microseconds % MICROS_PER_SECOND * NANOS_PER_MICROSECOND));
	}

	/**
	* Convert a Timestamp to the number of microseconds elapsed from the epoch.
	*
	* <p>The result will be rounded down to the nearest microsecond. E.g., if the timestamp
	* represents "1969-12-31T23:59:59.999999999Z", it will be rounded to -1 microsecond.
	*/
	public static long toMicros(Timestamp timestamp) {
	checkValid(timestamp);
	return checkedAdd(
	checkedMultiply(timestamp.getSeconds(), MICROS_PER_SECOND),
	timestamp.getNanos() / NANOS_PER_MICROSECOND);
	}

	/** Create a Timestamp from the number of nanoseconds elapsed from the epoch. */
	public static Timestamp fromNanos(long nanoseconds) {
	return normalizedTimestamp(
	nanoseconds / NANOS_PER_SECOND, (int) (nanoseconds % NANOS_PER_SECOND));
	}

	/** Convert a Timestamp to the number of nanoseconds elapsed from the epoch. */
	public static long toNanos(Timestamp timestamp) {
	checkValid(timestamp);
	return checkedAdd(
	checkedMultiply(timestamp.getSeconds(), NANOS_PER_SECOND), timestamp.getNanos());
	}

	/** Calculate the difference between two timestamps. */
	public static Duration between(Timestamp from, Timestamp to) {
	checkValid(from);
	checkValid(to);
	return Durations.normalizedDuration(
	checkedSubtract(to.getSeconds(), from.getSeconds()),
	checkedSubtract(to.getNanos(), from.getNanos()));
	}

	/** Add a duration to a timestamp. */
	public static Timestamp add(Timestamp start, Duration length) {
	checkValid(start);
	Durations.checkValid(length);
	return normalizedTimestamp(
	checkedAdd(start.getSeconds(), length.getSeconds()),
	checkedAdd(start.getNanos(), length.getNanos()));
	}

	/** Subtract a duration from a timestamp. */
	public static Timestamp subtract(Timestamp start, Duration length) {
	checkValid(start);
	Durations.checkValid(length);
	return normalizedTimestamp(
	checkedSubtract(start.getSeconds(), length.getSeconds()),
	checkedSubtract(start.getNanos(), length.getNanos()));
	}

	static Timestamp normalizedTimestamp(long seconds, int nanos) {
	if (nanos <= -NANOS_PER_SECOND \|\| nanos >= NANOS_PER_SECOND) {
	seconds = checkedAdd(seconds, nanos / NANOS_PER_SECOND);
	nanos = (int) (nanos % NANOS_PER_SECOND);
	}
	if (nanos < 0) {
	nanos =
	(int)
	(nanos + NANOS_PER_SECOND); // no overflow since nanos is negative (and we're adding)
	seconds = checkedSubtract(seconds, 1);
	}
	Timestamp timestamp = Timestamp.newBuilder().setSeconds(seconds).setNanos(nanos).build();
	return checkValid(timestamp);
	}

	private static long parseTimezoneOffset(String value) throws ParseException {
	int pos = value.indexOf(':');
	if (pos == -1) {
	throw new ParseException("Invalid offset value: " + value, 0);
	}
	String hours = value.substring(0, pos);
	String minutes = value.substring(pos + 1);
	return (Long.parseLong(hours) * 60 + Long.parseLong(minutes)) * 60;
	}

	static int parseNanos(String value) throws ParseException {
	int result = 0;
	for (int i = 0; i < 9; ++i) {
	result = result * 10;
	if (i < value.length()) {
	if (value.charAt(i) < '0' \|\| value.charAt(i) > '9') {
	throw new ParseException("Invalid nanoseconds.", 0);
	}
	result += value.charAt(i) - '0';
	}
	}
	return result;
	}

	/** Format the nano part of a timestamp or a duration. */
	static String formatNanos(int nanos) {
	// Determine whether to use 3, 6, or 9 digits for the nano part.
	if (nanos % NANOS_PER_MILLISECOND == 0) {
	return String.format(Locale.ENGLISH, "%1$03d", nanos / NANOS_PER_MILLISECOND);
	} else if (nanos % NANOS_PER_MICROSECOND == 0) {
	return String.format(Locale.ENGLISH, "%1$06d", nanos / NANOS_PER_MICROSECOND);
	} else {
	return String.format(Locale.ENGLISH, "%1$09d", nanos);
	}
	}
	}