icuSources/i18n/unicode/basictz.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 *******************************************************************************
   5 * Copyright (C) 2007-2013, International Business Machines Corporation and
   6 * others. All Rights Reserved.
   7 *******************************************************************************
   8 */
   9 #ifndef BASICTZ_H
  10 #define BASICTZ_H
  11
  12 /**
  13  * \file
  14  * \brief C++ API: ICU TimeZone base class
  15  */
  16
  17 #include "unicode/utypes.h"
  18
  19 #if !UCONFIG_NO_FORMATTING
  20
  21 #include "unicode/timezone.h"
  22 #include "unicode/tzrule.h"
  23 #include "unicode/tztrans.h"
  24
  25 #if U_SHOW_CPLUSPLUS_API
  26 U_NAMESPACE_BEGIN
  27
  28 // forward declarations
  29 class UVector;
  30
  31 /**
  32  * <code>BasicTimeZone</code> is an abstract class extending <code>TimeZone</code>.
  33  * This class provides some additional methods to access time zone transitions and rules.
  34  * All ICU <code>TimeZone</code> concrete subclasses extend this class.
  35  * @stable ICU 3.8
  36  */
  37 class U_I18N_API BasicTimeZone: public TimeZone {
  38 public:
  39     /**
  40      * Destructor.
  41      * @stable ICU 3.8
  42      */
  43     virtual ~BasicTimeZone();
  44
  45     /**
  46      * Gets the first time zone transition after the base time.
  47      * @param base      The base time.
  48      * @param inclusive Whether the base time is inclusive or not.
  49      * @param result    Receives the first transition after the base time.
  50      * @return  TRUE if the transition is found.
  51      * @stable ICU 3.8
  52      */
  53     virtual UBool getNextTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  54
  55     /**
  56      * Gets the most recent time zone transition before the base time.
  57      * @param base      The base time.
  58      * @param inclusive Whether the base time is inclusive or not.
  59      * @param result    Receives the most recent transition before the base time.
  60      * @return  TRUE if the transition is found.
  61      * @stable ICU 3.8
  62      */
  63     virtual UBool getPreviousTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  64
  65     /**
  66      * Checks if the time zone has equivalent transitions in the time range.
  67      * This method returns true when all of transition times, from/to standard
  68      * offsets and DST savings used by this time zone match the other in the
  69      * time range.
  70      * @param tz    The <code>BasicTimeZone</code> object to be compared with.
  71      * @param start The start time of the evaluated time range (inclusive)
  72      * @param end   The end time of the evaluated time range (inclusive)
  73      * @param ignoreDstAmount
  74      *              When true, any transitions with only daylight saving amount
  75      *              changes will be ignored, except either of them is zero.
  76      *              For example, a transition from rawoffset 3:00/dstsavings 1:00
  77      *              to rawoffset 2:00/dstsavings 2:00 is excluded from the comparison,
  78      *              but a transtion from rawoffset 2:00/dstsavings 1:00 to
  79      *              rawoffset 3:00/dstsavings 0:00 is included.
  80      * @param ec    Output param to filled in with a success or an error.
  81      * @return      true if the other time zone has the equivalent transitions in the
  82      *              time range.
  83      * @stable ICU 3.8
  84      */
  85     virtual UBool hasEquivalentTransitions(const BasicTimeZone& tz, UDate start, UDate end,
  86         UBool ignoreDstAmount, UErrorCode& ec) const;
  87
  88     /**
  89      * Returns the number of <code>TimeZoneRule</code>s which represents time transitions,
  90      * for this time zone, that is, all <code>TimeZoneRule</code>s for this time zone except
  91      * <code>InitialTimeZoneRule</code>.  The return value range is 0 or any positive value.
  92      * @param status    Receives error status code.
  93      * @return The number of <code>TimeZoneRule</code>s representing time transitions.
  94      * @stable ICU 3.8
  95      */
  96     virtual int32_t countTransitionRules(UErrorCode& status) const = 0;
  97
  98     /**
  99      * Gets the <code>InitialTimeZoneRule</code> and the set of <code>TimeZoneRule</code>
 100      * which represent time transitions for this time zone.  On successful return,
 101      * the argument initial points to non-NULL <code>InitialTimeZoneRule</code> and
 102      * the array trsrules is filled with 0 or multiple <code>TimeZoneRule</code>
 103      * instances up to the size specified by trscount.  The results are referencing the
 104      * rule instance held by this time zone instance.  Therefore, after this time zone
 105      * is destructed, they are no longer available.
 106      * @param initial       Receives the initial timezone rule
 107      * @param trsrules      Receives the timezone transition rules
 108      * @param trscount      On input, specify the size of the array 'transitions' receiving
 109      *                      the timezone transition rules.  On output, actual number of
 110      *                      rules filled in the array will be set.
 111      * @param status        Receives error status code.
 112      * @stable ICU 3.8
 113      */
 114     virtual void getTimeZoneRules(const InitialTimeZoneRule*& initial,
 115         const TimeZoneRule* trsrules[], int32_t& trscount, UErrorCode& status) const = 0;
 116
 117     /**
 118      * Gets the set of time zone rules valid at the specified time.  Some known external time zone
 119      * implementations are not capable to handle historic time zone rule changes.  Also some
 120      * implementations can only handle certain type of rule definitions.
 121      * If this time zone does not use any daylight saving time within about 1 year from the specified
 122      * time, only the <code>InitialTimeZone</code> is returned.  Otherwise, the rule for standard
 123      * time and daylight saving time transitions are returned in addition to the
 124      * <code>InitialTimeZoneRule</code>.  The standard and daylight saving time transition rules are
 125      * represented by <code>AnnualTimeZoneRule</code> with <code>DateTimeRule::DOW</code> for its date
 126      * rule and <code>DateTimeRule::WALL_TIME</code> for its time rule.  Because daylight saving time
 127      * rule is changing time to time in many time zones and also mapping a transition time rule to
 128      * different type is lossy transformation, the set of rules returned by this method may be valid
 129      * for short period of time.
 130      * The time zone rule objects returned by this method is owned by the caller, so the caller is
 131      * responsible for deleting them after use.
 132      * @param date      The date used for extracting time zone rules.
 133      * @param initial   Receives the <code>InitialTimeZone</code>, always not NULL.
 134      * @param std       Receives the <code>AnnualTimeZoneRule</code> for standard time transitions.
 135      *                  When this time time zone does not observe daylight saving times around the
 136      *                  specified date, NULL is set.
 137      * @param dst       Receives the <code>AnnualTimeZoneRule</code> for daylight saving time
 138      *                  transitions.  When this time zone does not observer daylight saving times
 139      *                  around the specified date, NULL is set.
 140      * @param status    Receives error status code.
 141      * @stable ICU 3.8
 142      */
 143     virtual void getSimpleRulesNear(UDate date, InitialTimeZoneRule*& initial,
 144         AnnualTimeZoneRule*& std, AnnualTimeZoneRule*& dst, UErrorCode& status) const;
 145
 146
 147 #ifndef U_HIDE_INTERNAL_API
 148     /**
 149      * The time type option bit flags used by getOffsetFromLocal
 150      * @internal
 151      */
 152     enum {
 153         kStandard = 0x01,
 154         kDaylight = 0x03,
 155         kFormer = 0x04,
 156         kLatter = 0x0C
 157     };
 158 #endif  /* U_HIDE_INTERNAL_API */
 159
 160     /**
 161      * Get time zone offsets from local wall time.
 162      * @internal
 163      */
 164     virtual void getOffsetFromLocal(UDate date, int32_t nonExistingTimeOpt, int32_t duplicatedTimeOpt,
 165         int32_t& rawOffset, int32_t& dstOffset, UErrorCode& status) const;
 166
 167 protected:
 168
 169 #ifndef U_HIDE_INTERNAL_API
 170     /**
 171      * The time type option bit masks used by getOffsetFromLocal
 172      * @internal
 173      */
 174     enum {
 175         kStdDstMask = kDaylight,
 176         kFormerLatterMask = kLatter
 177     };
 178 #endif  /* U_HIDE_INTERNAL_API */
 179
 180     /**
 181      * Default constructor.
 182      * @stable ICU 3.8
 183      */
 184     BasicTimeZone();
 185
 186     /**
 187      * Construct a timezone with a given ID.
 188      * @param id a system time zone ID
 189      * @stable ICU 3.8
 190      */
 191     BasicTimeZone(const UnicodeString &id);
 192
 193     /**
 194      * Copy constructor.
 195      * @param source the object to be copied.
 196      * @stable ICU 3.8
 197      */
 198     BasicTimeZone(const BasicTimeZone& source);
 199
 200     /**
 201      * Gets the set of TimeZoneRule instances applicable to the specified time and after.
 202      * @param start     The start date used for extracting time zone rules
 203      * @param initial   Receives the InitialTimeZone, always not NULL
 204      * @param transitionRules   Receives the transition rules, could be NULL
 205      * @param status    Receives error status code
 206      */
 207     void getTimeZoneRulesAfter(UDate start, InitialTimeZoneRule*& initial, UVector*& transitionRules,
 208         UErrorCode& status) const;
 209 };
 210
 211 U_NAMESPACE_END
 212 #endif // U_SHOW_CPLUSPLUS_API
 213
 214 #endif /* #if !UCONFIG_NO_FORMATTING */
 215
 216 #endif // BASICTZ_H
 217
 218 //eof