// © 2016 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

/*

**********************************************************************

* Copyright (c) 2003-2013, International Business Machines

* Corporation and others.  All Rights Reserved.

**********************************************************************

* Author: Alan Liu

* Created: July 21 2003

* Since: ICU 2.8

**********************************************************************

*/

#ifndef OLSONTZ_H

#define OLSONTZ_H

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/basictz.h"

#include "umutex.h"

struct UResourceBundle;

U_NAMESPACE_BEGIN

class SimpleTimeZone;

/**

 * A time zone based on the Olson tz database.  Olson time zones change

 * behavior over time.  The raw offset, rules, presence or absence of

 * daylight savings time, and even the daylight savings amount can all

 * vary.

 *

 * This class uses a resource bundle named "zoneinfo".  Zoneinfo is a

 * table containing different kinds of resources.  In several places,

 * zones are referred to using integers.  A zone's integer is a number

 * from 0..n-1, where n is the number of zones, with the zones sorted

 * in lexicographic order.

 *

 * 1. Zones.  These have keys corresponding to the Olson IDs, e.g.,

 * "Asia/Shanghai".  Each resource describes the behavior of the given

 * zone.  Zones come in two different formats.

 *

 *   a. Zone (table).  A zone is a table resource contains several

 *   type of resources below:

 *  

 *   - typeOffsets:intvector (Required)

 *  

 *   Sets of UTC raw/dst offset pairs in seconds.  Entries at

 *   2n represents raw offset and 2n+1 represents dst offset

 *   paired with the raw offset at 2n.  The very first pair represents

 *   the initial zone offset (before the first transition) always.

 *

 *   - trans:intvector (Optional) 

 *  

 *   List of transition times represented by 32bit seconds from the

 *   epoch (1970-01-01T00:00Z) in ascending order.

 *  

 *   - transPre32/transPost32:intvector (Optional)

 *  

 *   List of transition times before/after 32bit minimum seconds.

 *   Each time is represented by a pair of 32bit integer.

 * 

 *   - typeMap:bin (Optional)

 *  

 *   Array of bytes representing the mapping between each transition

 *   time (transPre32/trans/transPost32) and its corresponding offset

 *   data (typeOffsets).

 *  

 *   - finalRule:string (Optional)

 *  

 *   If a recurrent transition rule is applicable to a zone forever

 *   after the final transition time, finalRule represents the rule

 *   in Rules data.

 *  

 *   - finalRaw:int (Optional)

 *   

 *   When finalRule is available, finalRaw is required and specifies

 *   the raw (base) offset of the rule.

 *   

 *   - finalYear:int (Optional)

 *   

 *   When finalRule is available, finalYear is required and specifies

 *   the start year of the rule.

 *   

 *   - links:intvector (Optional)

 *   

 *   When this zone data is shared with other zones, links specifies

 *   all zones including the zone itself.  Each zone is referenced by

 *   integer index.

 * 

 *  b. Link (int, length 1).  A link zone is an int resource.  The

 *  integer is the zone number of the target zone.  The key of this

 *  resource is an alternate name for the target zone.  This data

 *  is corresponding to Link data in the tz database.

 *

 *

 * 2. Rules.  These have keys corresponding to the Olson rule IDs,

 * with an underscore prepended, e.g., "_EU".  Each resource describes

 * the behavior of the given rule using an intvector, containing the

 * onset list, the cessation list, and the DST savings.  The onset and

 * cessation lists consist of the month, dowim, dow, time, and time

 * mode.  The end result is that the 11 integers describing the rule

 * can be passed directly into the SimpleTimeZone 13-argument

 * constructor (the other two arguments will be the raw offset, taken

 * from the complex zone element 5, and the ID string, which is not

 * used), with the times and the DST savings multiplied by 1000 to

 * scale from seconds to milliseconds.

 *

 * 3. Regions.  An array specifies mapping between zones and regions.

 * Each item is either a 2-letter ISO country code or "001"

 * (UN M.49 - World).  This data is generated from "zone.tab"

 * in the tz database.

 */

class U_I18N_API OlsonTimeZone: public BasicTimeZone {

 public:

    /**

     * Construct from a resource bundle.

     * @param top the top-level zoneinfo resource bundle.  This is used

     * to lookup the rule that `res' may refer to, if there is one.

     * @param res the resource bundle of the zone to be constructed

     * @param tzid the time zone ID

     * @param ec input-output error code

     */

    OlsonTimeZone(const UResourceBundle* top,

                  const UResourceBundle* res,

                  const UnicodeString& tzid,

                  UErrorCode& ec);

    /**

     * Copy constructor

     */

    OlsonTimeZone(const OlsonTimeZone& other);

    /**

     * Destructor

     */

    virtual ~OlsonTimeZone();

    /**

     * Assignment operator

     */

    OlsonTimeZone& operator=(const OlsonTimeZone& other);

    /**

     * Returns true if the two TimeZone objects are equal.

     */

    virtual bool operator==(const TimeZone& other) const;

    /**

     * TimeZone API.

     */

    virtual OlsonTimeZone* clone() const;

    /**

     * TimeZone API.

     */

    static UClassID U_EXPORT2 getStaticClassID();

    /**

     * TimeZone API.

     */

    virtual UClassID getDynamicClassID() const;

    /**

     * TimeZone API.  Do not call this; prefer getOffset(UDate,...).

     */

    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month,

                              int32_t day, uint8_t dayOfWeek,

                              int32_t millis, UErrorCode& ec) const;

    /**

     * TimeZone API.  Do not call this; prefer getOffset(UDate,...).

     */

    virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month,

                              int32_t day, uint8_t dayOfWeek,

                              int32_t millis, int32_t monthLength,

                              UErrorCode& ec) const;

    /**

     * TimeZone API.

     */

    virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,

                   int32_t& dstOffset, UErrorCode& ec) const;

    /**

     * BasicTimeZone API.

     */

    virtual void getOffsetFromLocal(

        UDate date, UTimeZoneLocalOption nonExistingTimeOpt,

        UTimeZoneLocalOption duplicatedTimeOpt,

        int32_t& rawOffset, int32_t& dstOffset, UErrorCode& status) const;

    /**

     * TimeZone API.  This method has no effect since objects of this

     * class are quasi-immutable (the base class allows the ID to be

     * changed).

     */

    virtual void setRawOffset(int32_t offsetMillis);

    /**

     * TimeZone API.  For a historical zone, the raw offset can change

     * over time, so this API is not useful.  In order to approximate

     * expected behavior, this method returns the raw offset for the

     * current moment in time.

     */

    virtual int32_t getRawOffset() const;

    /**

     * TimeZone API.  For a historical zone, whether DST is used or

     * not varies over time.  In order to approximate expected

     * behavior, this method returns true if DST is observed at any

     * point in the current year.

     */

    virtual UBool useDaylightTime() const;

    /**

     * TimeZone API.

     */

    virtual UBool inDaylightTime(UDate date, UErrorCode& ec) const;

    /**

     * TimeZone API.

     */

    virtual int32_t getDSTSavings() const;

    /**

     * TimeZone API.  Also comare historic transitions.

     */

    virtual UBool hasSameRules(const TimeZone& other) const;

    /**

     * BasicTimeZone API.

     * 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.

     */

    virtual UBool getNextTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const;

    /**

     * BasicTimeZone API.

     * 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.

     */

    virtual UBool getPreviousTransition(UDate base, UBool inclusive, TimeZoneTransition& result) const;

    /**

     * BasicTimeZone API.

     * 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.

     */

    virtual int32_t countTransitionRules(UErrorCode& status) const;

    /**

     * 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.

     */

    virtual void getTimeZoneRules(const InitialTimeZoneRule*& initial,

        const TimeZoneRule* trsrules[], int32_t& trscount, UErrorCode& status) const;

    /**

     * Internal API returning the canonical ID of this zone.

     * This ID won't be affected by setID().

     */

    const UChar *getCanonicalID() const;

private:

    /**

     * Default constructor.  Creates a time zone with an empty ID and

     * a fixed GMT offset of zero.

     */

    OlsonTimeZone();

private:

    void constructEmpty();

    void getHistoricalOffset(UDate date, UBool local,

        int32_t NonExistingTimeOpt, int32_t DuplicatedTimeOpt,

        int32_t& rawoff, int32_t& dstoff) const;

    int16_t transitionCount() const;

    int64_t transitionTimeInSeconds(int16_t transIdx) const;

    double transitionTime(int16_t transIdx) const;

    /*

     * Following 3 methods return an offset at the given transition time index.

     * When the index is negative, return the initial offset.

     */

    int32_t zoneOffsetAt(int16_t transIdx) const;

    int32_t rawOffsetAt(int16_t transIdx) const;

    int32_t dstOffsetAt(int16_t transIdx) const;

    /*

     * Following methods return the initial offset.

     */

    int32_t initialRawOffset() const;

    int32_t initialDstOffset() const;

    /**

     * Number of transitions in each time range

     */

    int16_t transitionCountPre32;

    int16_t transitionCount32;

    int16_t transitionCountPost32;

    /**

     * Time of each transition in seconds from 1970 epoch before 32bit second range (<= 1900).

     * Each transition in this range is represented by a pair of int32_t.

     * Length is transitionCount int32_t's.  NULL if no transitions in this range.

     */

    const int32_t *transitionTimesPre32; // alias into res; do not delete

    /**

     * Time of each transition in seconds from 1970 epoch in 32bit second range.

     * Length is transitionCount int32_t's.  NULL if no transitions in this range.

     */

    const int32_t *transitionTimes32; // alias into res; do not delete

    /**

     * Time of each transition in seconds from 1970 epoch after 32bit second range (>= 2038).

     * Each transition in this range is represented by a pair of int32_t.

     * Length is transitionCount int32_t's.  NULL if no transitions in this range.

     */

    const int32_t *transitionTimesPost32; // alias into res; do not delete

    /**

     * Number of types, 1..255

     */

    int16_t typeCount;

    /**

     * Offset from GMT in seconds for each type.

     * Length is typeCount int32_t's.  At least one type (a pair of int32_t)

     * is required.

     */

    const int32_t *typeOffsets; // alias into res; do not delete

    /**

     * Type description data, consisting of transitionCount uint8_t

     * type indices (from 0..typeCount-1).

     * Length is transitionCount int16_t's.  NULL if no transitions.

     */

    const uint8_t *typeMapData; // alias into res; do not delete

    /**

     * A SimpleTimeZone that governs the behavior for date >= finalMillis.

     */

    SimpleTimeZone *finalZone; // owned, may be NULL

    /**

     * For date >= finalMillis, the finalZone will be used.

     */

    double finalStartMillis;

    /**

     * For year >= finalYear, the finalZone will be used.

     */

    int32_t finalStartYear;

    /*

     * Canonical (CLDR) ID of this zone

     */

    const UChar *canonicalID;

    /* BasicTimeZone support */

    void clearTransitionRules(void);

    void deleteTransitionRules(void);

    void checkTransitionRules(UErrorCode& status) const;

  public:    // Internal, for access from plain C code

    void initTransitionRules(UErrorCode& status);

  private:

    InitialTimeZoneRule *initialRule;

    TimeZoneTransition  *firstTZTransition;

    int16_t             firstTZTransitionIdx;

    TimeZoneTransition  *firstFinalTZTransition;

    TimeArrayTimeZoneRule   **historicRules;

    int16_t             historicRuleCount;

    SimpleTimeZone      *finalZoneWithStartYear; // hack

    UInitOnce           transitionRulesInitOnce = U_INITONCE_INITIALIZER;

};

inline int16_t

OlsonTimeZone::transitionCount() const {

    return transitionCountPre32 + transitionCount32 + transitionCountPost32;

}

inline double

OlsonTimeZone::transitionTime(int16_t transIdx) const {

    return (double)transitionTimeInSeconds(transIdx) * U_MILLIS_PER_SECOND;

}

inline int32_t

OlsonTimeZone::zoneOffsetAt(int16_t transIdx) const {

    int16_t typeIdx = (transIdx >= 0 ? typeMapData[transIdx] : 0) << 1;

    return typeOffsets[typeIdx] + typeOffsets[typeIdx + 1];

}

inline int32_t

OlsonTimeZone::rawOffsetAt(int16_t transIdx) const {

    int16_t typeIdx = (transIdx >= 0 ? typeMapData[transIdx] : 0) << 1;

    return typeOffsets[typeIdx];

}

inline int32_t

OlsonTimeZone::dstOffsetAt(int16_t transIdx) const {

    int16_t typeIdx = (transIdx >= 0 ? typeMapData[transIdx] : 0) << 1;

    return typeOffsets[typeIdx + 1];

}

inline int32_t

OlsonTimeZone::initialRawOffset() const {

    return typeOffsets[0];

}

inline int32_t

OlsonTimeZone::initialDstOffset() const {

    return typeOffsets[1];

}

inline const UChar*

OlsonTimeZone::getCanonicalID() const {

    return canonicalID;

}

U_NAMESPACE_END

#endif // !UCONFIG_NO_FORMATTING

#endif // OLSONTZ_H

//eof