text: /*
   * Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
   * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
   * Copyright (C) 2009 Google Inc. All rights reserved.
   * Copyright (C) 2010 Research In Motion Limited. All rights reserved.
   *
   * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   *
   * The contents of this file are subject to the Mozilla Public License Version
   * 1.1 (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   * http://www.mozilla.org/MPL/
   *
   * Software distributed under the License is distributed on an "AS IS" basis,
   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
   * for the specific language governing rights and limitations under the
   * License.
   *
   * The Original Code is Mozilla Communicator client code, released
   * March 31, 1998.
   *
   * The Initial Developer of the Original Code is
   * Netscape Communications Corporation.
   * Portions created by the Initial Developer are Copyright (C) 1998
   * the Initial Developer. All Rights Reserved.
   *
   * Contributor(s):
   *
   * Alternatively, the contents of this file may be used under the terms of
   * either of the GNU General Public License Version 2 or later (the "GPL"),
   * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
   * in which case the provisions of the GPL or the LGPL are applicable instead
   * of those above. If you wish to allow use of your version of this file only
   * under the terms of either the GPL or the LGPL, and not to allow others to
   * use your version of this file under the terms of the MPL, indicate your
   * decision by deleting the provisions above and replace them with the notice
   * and other provisions required by the GPL or the LGPL. If you do not delete
   * the provisions above, a recipient may use your version of this file under
   * the terms of any one of the MPL, the GPL or the LGPL.
   *
   */
  
  #ifndef DateMath_h
  #define DateMath_h
  
  #include <math.h>
  #include <stdint.h>
  #include <string.h>
  #include <time.h>
  #include <wtf/CurrentTime.h>
  #include <wtf/Noncopyable.h>
  #include <wtf/text/WTFString.h>
  
  namespace WTF {
  
  enum TimeType {
      UTCTime = 0,
      LocalTime
  };
  
  struct LocalTimeOffset {
      LocalTimeOffset()
          : isDST(false)
          , offset(0)
      {
      }
  
      LocalTimeOffset(bool isDST, int offset)
          : isDST(isDST)
          , offset(offset)
      {
      }
  
      bool operator==(const LocalTimeOffset& other)
      {
          return isDST == other.isDST && offset == other.offset;
      }
  
      bool operator!=(const LocalTimeOffset& other)
      {
          return isDST != other.isDST || offset != other.offset;
      }
  
      bool isDST;
      int offset;
  };
  
  void initializeDates();
  int equivalentYearForDST(int year);
  
  // Not really math related, but this is currently the only shared place to put these.
  WTF_EXPORT_PRIVATE double parseES5DateFromNullTerminatedCharacters(const char* dateString);
  WTF_EXPORT_PRIVATE double parseDateFromNullTerminatedCharacters(const char* dateString);
  WTF_EXPORT_PRIVATE double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset);
  WTF_EXPORT_PRIVATE double timeClip(double);
  // dayOfWeek: [0, 6] 0 being Monday, day: [1, 31], month: [0, 11], year: ex: 2011, hours: [0, 23], minutes: [0, 59], seconds: [0, 59], utcOffset: [-720,720]. 
  String makeRFC2822DateString(unsigned dayOfWeek, unsigned day, unsigned month, unsigned year, unsigned hours, unsigned minutes, unsigned seconds, int utcOffset);
  
  inline double jsCurrentTime()
  {
      // JavaScript doesn't recognize fractions of a millisecond.
      return floor(WTF::currentTimeMS());
  }
  
  const char* const weekdayName[7] = { "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun" };
  const char* const monthName[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
  const char* const monthFullName[12] = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };
  
  const double hoursPerDay = 24.0;
  const double minutesPerHour = 60.0;
  const double secondsPerMinute = 60.0;
  const double msPerSecond = 1000.0;
  const double msPerMonth = 2592000000.0;
  const double secondsPerHour = secondsPerMinute * minutesPerHour;
  const double secondsPerDay = secondsPerHour * hoursPerDay;
  const double msPerMinute = msPerSecond * secondsPerMinute;
  const double msPerHour = msPerSecond * secondsPerHour;
  const double msPerDay = msPerSecond * secondsPerDay;
  
  WTF_EXPORT_PRIVATE bool isLeapYear(int year);
  
  // Returns the number of days from 1970-01-01 to the specified date.
  WTF_EXPORT_PRIVATE double dateToDaysFrom1970(int year, int month, int day);
  WTF_EXPORT_PRIVATE int msToYear(double ms);
  WTF_EXPORT_PRIVATE double msToDays(double ms);
  WTF_EXPORT_PRIVATE int msToMinutes(double ms);
  WTF_EXPORT_PRIVATE int msToHours(double ms);
  WTF_EXPORT_PRIVATE int dayInYear(int year, int month, int day);
  WTF_EXPORT_PRIVATE int dayInYear(double ms, int year);
  WTF_EXPORT_PRIVATE int monthFromDayInYear(int dayInYear, bool leapYear);
  WTF_EXPORT_PRIVATE int dayInMonthFromDayInYear(int dayInYear, bool leapYear);
  
  // Returns combined offset in millisecond (UTC + DST).
  WTF_EXPORT_PRIVATE LocalTimeOffset calculateLocalTimeOffset(double utcInMilliseconds, TimeType = UTCTime);
  
  } // namespace WTF
  
  using WTF::isLeapYear;
  using WTF::dateToDaysFrom1970;
  using WTF::dayInMonthFromDayInYear;
  using WTF::dayInYear;
  using WTF::minutesPerHour;
  using WTF::monthFromDayInYear;
  using WTF::msPerDay;
  using WTF::msPerHour;
  using WTF::msPerMinute;
  using WTF::msPerSecond;
  using WTF::msToYear;
  using WTF::msToDays;
  using WTF::msToMinutes;
  using WTF::msToHours;
  using WTF::secondsPerDay;
  using WTF::secondsPerMinute;
  using WTF::parseDateFromNullTerminatedCharacters;
  using WTF::makeRFC2822DateString;
  using WTF::LocalTimeOffset;
  using WTF::calculateLocalTimeOffset;
  
  #endif // DateMath_h
  