text: // © 2016 and later: Unicode, Inc. and others.
  // License & terms of use: http://www.unicode.org/copyright.html
  /*
  *******************************************************************************
  * Copyright (C) 2007-2013, International Business Machines Corporation and
  * others. All Rights Reserved.
  *******************************************************************************
  */
  #ifndef BASICTZ_H
  #define BASICTZ_H
  
  /**
   * \file 
   * \brief C++ API: ICU TimeZone base class
   */
  
  #include "unicode/utypes.h"
  
  #if !UCONFIG_NO_FORMATTING
  
  #include "unicode/timezone.h"
  #include "unicode/tzrule.h"
  #include "unicode/tztrans.h"
  
  U_NAMESPACE_BEGIN
  
  // forward declarations
  class UVector;
  
  /**
   * <code>BasicTimeZone</code> is an abstract class extending <code>TimeZone</code>.
   * This class provides some additional methods to access time zone transitions and rules.
   * All ICU <code>TimeZone</code> concrete subclasses extend this class.
   * @stable ICU 3.8
   */
  class U_I18N_API BasicTimeZone: public TimeZone {
  public:
      /**
       * Destructor.
       * @stable ICU 3.8
       */
      virtual ~BasicTimeZone();
  
      /**
       * Gets the first time zone transition after the base time.
       * @param base      The base time.
       * @param inclusive Whether the base time is inclusive or not.
       * @param result    Receives the first transition after the base time.
       * @return  TRUE if the transition is found.
       * @stable ICU 3.8
       */
      virtual UBool getNextTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  
      /**
       * Gets the most recent time zone transition before the base time.
       * @param base      The base time.
       * @param inclusive Whether the base time is inclusive or not.
       * @param result    Receives the most recent transition before the base time.
       * @return  TRUE if the transition is found.
       * @stable ICU 3.8
       */
      virtual UBool getPreviousTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  
      /**
       * Checks if the time zone has equivalent transitions in the time range.
       * This method returns true when all of transition times, from/to standard
       * offsets and DST savings used by this time zone match the other in the
       * time range.
       * @param tz    The <code>BasicTimeZone</code> object to be compared with.
       * @param start The start time of the evaluated time range (inclusive)
       * @param end   The end time of the evaluated time range (inclusive)
       * @param ignoreDstAmount
       *              When true, any transitions with only daylight saving amount
       *              changes will be ignored, except either of them is zero.
       *              For example, a transition from rawoffset 3:00/dstsavings 1:00
       *              to rawoffset 2:00/dstsavings 2:00 is excluded from the comparison,
       *              but a transtion from rawoffset 2:00/dstsavings 1:00 to
       *              rawoffset 3:00/dstsavings 0:00 is included.
       * @param ec    Output param to filled in with a success or an error.
       * @return      true if the other time zone has the equivalent transitions in the
       *              time range.
       * @stable ICU 3.8
       */
      virtual UBool hasEquivalentTransitions(const BasicTimeZone& tz, UDate start, UDate end,
          UBool ignoreDstAmount, UErrorCode& ec) const;
  
      /**
       * Returns the number of <code>TimeZoneRule</code>s which represents time transitions,
       * for this time zone, that is, all <code>TimeZoneRule</code>s for this time zone except
       * <code>InitialTimeZoneRule</code>.  The return value range is 0 or any positive value.
       * @param status    Receives error status code.
       * @return The number of <code>TimeZoneRule</code>s representing time transitions.
       * @stable ICU 3.8
       */
      virtual int32_t countTransitionRules(UErrorCode& status) const = 0;
  
      /**
       * Gets the <code>InitialTimeZoneRule</code> and the set of <code>TimeZoneRule</code>
       * which represent time transitions for this time zone.  On successful return,
       * the argument initial points to non-NULL <code>InitialTimeZoneRule</code> and
       * the array trsrules is filled with 0 or multiple <code>TimeZoneRule</code>
       * instances up to the size specified by trscount.  The results are referencing the
       * rule instance held by this time zone instance.  Therefore, after this time zone
       * is destructed, they are no longer available.
       * @param initial       Receives the initial timezone rule
       * @param trsrules      Receives the timezone transition rules
       * @param trscount      On input, specify the size of the array 'transitions' receiving
       *                      the timezone transition rules.  On output, actual number of
       *                      rules filled in the array will be set.
       * @param status        Receives error status code.
       * @stable ICU 3.8
       */
      virtual void getTimeZoneRules(const InitialTimeZoneRule*& initial,
          const TimeZoneRule* trsrules[], int32_t& trscount, UErrorCode& status) const = 0;
  
      /**
       * Gets the set of time zone rules valid at the specified time.  Some known external time zone
       * implementations are not capable to handle historic time zone rule changes.  Also some
       * implementations can only handle certain type of rule definitions.
       * If this time zone does not use any daylight saving time within about 1 year from the specified
       * time, only the <code>InitialTimeZone</code> is returned.  Otherwise, the rule for standard
       * time and daylight saving time transitions are returned in addition to the
       * <code>InitialTimeZoneRule</code>.  The standard and daylight saving time transition rules are
       * represented by <code>AnnualTimeZoneRule</code> with <code>DateTimeRule::DOW</code> for its date
       * rule and <code>DateTimeRule::WALL_TIME</code> for its time rule.  Because daylight saving time
       * rule is changing time to time in many time zones and also mapping a transition time rule to
       * different type is lossy transformation, the set of rules returned by this method may be valid
       * for short period of time.
       * The time zone rule objects returned by this method is owned by the caller, so the caller is
       * responsible for deleting them after use.
       * @param date      The date used for extracting time zone rules.
       * @param initial   Receives the <code>InitialTimeZone</code>, always not NULL.
       * @param std       Receives the <code>AnnualTimeZoneRule</code> for standard time transitions.
       *                  When this time time zone does not observe daylight saving times around the
       *                  specified date, NULL is set.
       * @param dst       Receives the <code>AnnualTimeZoneRule</code> for daylight saving time
       *                  transitions.  When this time zone does not observer daylight saving times
       *                  around the specified date, NULL is set.
       * @param status    Receives error status code.
       * @stable ICU 3.8
       */
      virtual void getSimpleRulesNear(UDate date, InitialTimeZoneRule*& initial,
          AnnualTimeZoneRule*& std, AnnualTimeZoneRule*& dst, UErrorCode& status) const;
  
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * The time type option bit flags used by getOffsetFromLocal
       * @internal
       */
      enum {
          kStandard = 0x01,
          kDaylight = 0x03,
          kFormer = 0x04,
          kLatter = 0x0C
      };
  #endif  /* U_HIDE_INTERNAL_API */
  
      /**
       * Get time zone offsets from local wall time.
       * @internal
       */
      virtual void getOffsetFromLocal(UDate date, int32_t nonExistingTimeOpt, int32_t duplicatedTimeOpt,
          int32_t& rawOffset, int32_t& dstOffset, UErrorCode& status) const;
  
  protected:
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * The time type option bit masks used by getOffsetFromLocal
       * @internal
       */
      enum {
          kStdDstMask = kDaylight,
          kFormerLatterMask = kLatter
      };
  #endif  /* U_HIDE_INTERNAL_API */
  
      /**
       * Default constructor.
       * @stable ICU 3.8
       */
      BasicTimeZone();
  
      /**
       * Construct a timezone with a given ID.
       * @param id a system time zone ID
       * @stable ICU 3.8
       */
      BasicTimeZone(const UnicodeString &id);
  
      /**
       * Copy constructor.
       * @param source the object to be copied.
       * @stable ICU 3.8
       */
      BasicTimeZone(const BasicTimeZone& source);
  
      /**
       * Gets the set of TimeZoneRule instances applicable to the specified time and after.
       * @param start     The start date used for extracting time zone rules
       * @param initial   Receives the InitialTimeZone, always not NULL
       * @param transitionRules   Receives the transition rules, could be NULL
       * @param status    Receives error status code
       */
      void getTimeZoneRulesAfter(UDate start, InitialTimeZoneRule*& initial, UVector*& transitionRules,
          UErrorCode& status) const;
  };
  
  U_NAMESPACE_END
  
  #endif /* #if !UCONFIG_NO_FORMATTING */
  
  #endif // BASICTZ_H
  
  //eof
  