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