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 U_SHOW_CPLUSPLUS_API
  20
  21 #if !UCONFIG_NO_FORMATTING
  22
  23 #include "unicode/timezone.h"
  24 #include "unicode/tzrule.h"
  25 #include "unicode/tztrans.h"
  26
  27 U_NAMESPACE_BEGIN
  28
  29 // forward declarations
  30 class UVector;
  31
  32 /**
  33  * <code>BasicTimeZone</code> is an abstract class extending <code>TimeZone</code>.
  34  * This class provides some additional methods to access time zone transitions and rules.
  35  * All ICU <code>TimeZone</code> concrete subclasses extend this class.
  36  * @stable ICU 3.8
  37  */
  38 class U_I18N_API BasicTimeZone: public TimeZone {
  39 public:
  40     /**
  41      * Destructor.
  42      * @stable ICU 3.8
  43      */
  44     virtual ~BasicTimeZone();
  45
  46     /**
  47      * Clones this object polymorphically.
  48      * The caller owns the result and should delete it when done.
  49      * @return clone, or nullptr if an error occurred
  50      * @stable ICU 3.8
  51      */
  52     virtual BasicTimeZone* clone() const = 0;
  53
  54     /**
  55      * Gets the first time zone transition after the base time.
  56      * @param base      The base time.
  57      * @param inclusive Whether the base time is inclusive or not.
  58      * @param result    Receives the first transition after the base time.
  59      * @return  TRUE if the transition is found.
  60      * @stable ICU 3.8
  61      */
  62     virtual UBool getNextTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  63
  64     /**
  65      * Gets the most recent time zone transition before the base time.
  66      * @param base      The base time.
  67      * @param inclusive Whether the base time is inclusive or not.
  68      * @param result    Receives the most recent transition before the base time.
  69      * @return  TRUE if the transition is found.
  70      * @stable ICU 3.8
  71      */
  72     virtual UBool getPreviousTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const = 0;
  73
  74     /**
  75      * Checks if the time zone has equivalent transitions in the time range.
  76      * This method returns true when all of transition times, from/to standard
  77      * offsets and DST savings used by this time zone match the other in the
  78      * time range.
  79      * @param tz    The <code>BasicTimeZone</code> object to be compared with.
  80      * @param start The start time of the evaluated time range (inclusive)
  81      * @param end   The end time of the evaluated time range (inclusive)
  82      * @param ignoreDstAmount
  83      *              When true, any transitions with only daylight saving amount
  84      *              changes will be ignored, except either of them is zero.
  85      *              For example, a transition from rawoffset 3:00/dstsavings 1:00
  86      *              to rawoffset 2:00/dstsavings 2:00 is excluded from the comparison,
  87      *              but a transtion from rawoffset 2:00/dstsavings 1:00 to
  88      *              rawoffset 3:00/dstsavings 0:00 is included.
  89      * @param ec    Output param to filled in with a success or an error.
  90      * @return      true if the other time zone has the equivalent transitions in the
  91      *              time range.
  92      * @stable ICU 3.8
  93      */
  94     virtual UBool hasEquivalentTransitions(const BasicTimeZone& tz, UDate start, UDate end,
  95         UBool ignoreDstAmount, UErrorCode& ec) const;
  96
  97     /**
  98      * Returns the number of <code>TimeZoneRule</code>s which represents time transitions,
  99      * for this time zone, that is, all <code>TimeZoneRule</code>s for this time zone except
 100      * <code>InitialTimeZoneRule</code>.  The return value range is 0 or any positive value.
 101      * @param status    Receives error status code.
 102      * @return The number of <code>TimeZoneRule</code>s representing time transitions.
 103      * @stable ICU 3.8
 104      */
 105     virtual int32_t countTransitionRules(UErrorCode& status) const = 0;
 106
 107     /**
 108      * Gets the <code>InitialTimeZoneRule</code> and the set of <code>TimeZoneRule</code>
 109      * which represent time transitions for this time zone.  On successful return,
 110      * the argument initial points to non-NULL <code>InitialTimeZoneRule</code> and
 111      * the array trsrules is filled with 0 or multiple <code>TimeZoneRule</code>
 112      * instances up to the size specified by trscount.  The results are referencing the
 113      * rule instance held by this time zone instance.  Therefore, after this time zone
 114      * is destructed, they are no longer available.
 115      * @param initial       Receives the initial timezone rule
 116      * @param trsrules      Receives the timezone transition rules
 117      * @param trscount      On input, specify the size of the array 'transitions' receiving
 118      *                      the timezone transition rules.  On output, actual number of
 119      *                      rules filled in the array will be set.
 120      * @param status        Receives error status code.
 121      * @stable ICU 3.8
 122      */
 123     virtual void getTimeZoneRules(const InitialTimeZoneRule*& initial,
 124         const TimeZoneRule* trsrules[], int32_t& trscount, UErrorCode& status) const = 0;
 125
 126     /**
 127      * Gets the set of time zone rules valid at the specified time.  Some known external time zone
 128      * implementations are not capable to handle historic time zone rule changes.  Also some
 129      * implementations can only handle certain type of rule definitions.
 130      * If this time zone does not use any daylight saving time within about 1 year from the specified
 131      * time, only the <code>InitialTimeZone</code> is returned.  Otherwise, the rule for standard
 132      * time and daylight saving time transitions are returned in addition to the
 133      * <code>InitialTimeZoneRule</code>.  The standard and daylight saving time transition rules are
 134      * represented by <code>AnnualTimeZoneRule</code> with <code>DateTimeRule::DOW</code> for its date
 135      * rule and <code>DateTimeRule::WALL_TIME</code> for its time rule.  Because daylight saving time
 136      * rule is changing time to time in many time zones and also mapping a transition time rule to
 137      * different type is lossy transformation, the set of rules returned by this method may be valid
 138      * for short period of time.
 139      * The time zone rule objects returned by this method is owned by the caller, so the caller is
 140      * responsible for deleting them after use.
 141      * @param date      The date used for extracting time zone rules.
 142      * @param initial   Receives the <code>InitialTimeZone</code>, always not NULL.
 143      * @param std       Receives the <code>AnnualTimeZoneRule</code> for standard time transitions.
 144      *                  When this time time zone does not observe daylight saving times around the
 145      *                  specified date, NULL is set.
 146      * @param dst       Receives the <code>AnnualTimeZoneRule</code> for daylight saving time
 147      *                  transitions.  When this time zone does not observer daylight saving times
 148      *                  around the specified date, NULL is set.
 149      * @param status    Receives error status code.
 150      * @stable ICU 3.8
 151      */
 152     virtual void getSimpleRulesNear(UDate date, InitialTimeZoneRule*& initial,
 153         AnnualTimeZoneRule*& std, AnnualTimeZoneRule*& dst, UErrorCode& status) const;
 154
 155
 156 #ifndef U_HIDE_INTERNAL_API
 157     /**
 158      * The time type option bit flags used by getOffsetFromLocal
 159      * @internal
 160      */
 161     enum {
 162         kStandard = 0x01,
 163         kDaylight = 0x03,
 164         kFormer = 0x04,
 165         kLatter = 0x0C
 166     };
 167 #endif  /* U_HIDE_INTERNAL_API */
 168
 169     /**
 170      * Get time zone offsets from local wall time.
 171      * @internal
 172      */
 173     virtual void getOffsetFromLocal(UDate date, int32_t nonExistingTimeOpt, int32_t duplicatedTimeOpt,
 174         int32_t& rawOffset, int32_t& dstOffset, UErrorCode& status) const;
 175
 176 protected:
 177
 178 #ifndef U_HIDE_INTERNAL_API
 179     /**
 180      * The time type option bit masks used by getOffsetFromLocal
 181      * @internal
 182      */
 183     enum {
 184         kStdDstMask = kDaylight,
 185         kFormerLatterMask = kLatter
 186     };
 187 #endif  /* U_HIDE_INTERNAL_API */
 188
 189     /**
 190      * Default constructor.
 191      * @stable ICU 3.8
 192      */
 193     BasicTimeZone();
 194
 195     /**
 196      * Construct a timezone with a given ID.
 197      * @param id a system time zone ID
 198      * @stable ICU 3.8
 199      */
 200     BasicTimeZone(const UnicodeString &id);
 201
 202     /**
 203      * Copy constructor.
 204      * @param source the object to be copied.
 205      * @stable ICU 3.8
 206      */
 207     BasicTimeZone(const BasicTimeZone& source);
 208
 209     /**
 210      * Gets the set of TimeZoneRule instances applicable to the specified time and after.
 211      * @param start     The start date used for extracting time zone rules
 212      * @param initial   Receives the InitialTimeZone, always not NULL
 213      * @param transitionRules   Receives the transition rules, could be NULL
 214      * @param status    Receives error status code
 215      */
 216     void getTimeZoneRulesAfter(UDate start, InitialTimeZoneRule*& initial, UVector*& transitionRules,
 217         UErrorCode& status) const;
 218 };
 219
 220 U_NAMESPACE_END
 221
 222 #endif /* #if !UCONFIG_NO_FORMATTING */
 223
 224 #endif /* U_SHOW_CPLUSPLUS_API */
 225
 226 #endif // BASICTZ_H
 227
 228 //eof