scuffed-code/icu4c/source/i18n/olsontz.h

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/*
**********************************************************************
* Copyright (c) 2003-2007, 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/timezone.h"
struct UResourceBundle;
U_NAMESPACE_BEGIN
class SimpleTimeZone;
/**
* A time zone based on the Olson 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 several formats, which are differentiated
* based on length.
*
* a. Alias (int, length 1). An alias 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. Aliases
* represent Olson links and ICU compatibility IDs.
*
* b. Simple zone (array, length 3). The three subelements are:
*
* i. An intvector of transitions. These are given in epoch
* seconds. This may be an empty invector (length 0). If the
* transtions list is empty, then the zone's behavior is fixed and
* given by the offset list, which will contain exactly one pair.
* Otherwise each transtion indicates a time after which (inclusive)
* the associated offset pair is in effect.
*
* ii. An intvector of offsets. These are in pairs of raw offset /
* DST offset, in units of seconds. There will be at least one pair
* (length >= 2 && length % 2 == 0).
*
* iii. A binary resource. This is of the same length as the
* transitions vector, so length may be zero. Each unsigned byte
* corresponds to one transition, and has a value of 0..n-1, where n
* is the number of pairs in the offset vector. This forms a map
* between transitions and offset pairs.
*
* c. Simple zone with aliases (array, length 4). This is like a
* simple zone, but also contains a fourth element:
*
* iv. An intvector of aliases. This list includes this zone
* itself, and lists all aliases of this zone.
*
* d. Complex zone (array, length 5). This is like a simple zone,
* but contains two more elements:
*
* iv. A string, giving the name of a rule. This is the "final
* rule", which governs the zone's behavior beginning in the "final
* year". The rule ID is given without leading underscore, e.g.,
* "EU".
*
* v. An intvector of length 2, containing the raw offset for the
* final rule (in seconds), and the final year. The final rule
* takes effect for years >= the final year.
*
* e. Complex zone with aliases (array, length 6). This is like a
* complex zone, but also contains a sixth element:
*
* vi. An intvector of aliases. This list includes this zone
* itself, and lists all aliases of this zone.
*
* 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. Countries. These have keys corresponding to the 2-letter ISO
* country codes, with a percent sign prepended, e.g., "%US". Each
* resource is an intvector listing the zones associated with the
* given country. The special entry "%" corresponds to "no country",
* that is, the category of zones assigned to no country in the Olson
* DB.
*
* 4. Metadata. Metadata is stored under the key "_". It is an
* intvector of length three containing the number of zones resources,
* rule resources, and country resources. For the purposes of this
* count, the metadata entry itself is considered a rule resource,
* since its key begins with an underscore.
*/
class OlsonTimeZone: public TimeZone {
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.
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* @param res the resource bundle of the zone to be constructed
* @param ec input-output error code
*/
OlsonTimeZone(const UResourceBundle* top,
const UResourceBundle* res, 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 UBool operator==(const TimeZone& other) const;
/**
* TimeZone API.
*/
virtual TimeZone* clone() const;
/**
* TimeZone API.
*/
U_I18N_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;
/**
* 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;
virtual int32_t getDSTSavings() const;
protected:
/**
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* Default constructor. Creates a time zone with an empty ID and
* a fixed GMT offset of zero.
*/
OlsonTimeZone();
private:
void constructEmpty();
int16_t findTransition(double time, UBool local) const;
int32_t zoneOffset(int16_t index) const;
int32_t rawOffset(int16_t index) const;
int32_t dstOffset(int16_t index) const;
/**
* Number of transitions, 0..~370
*/
int16_t transitionCount;
/**
* Number of types, 1..255
*/
int16_t typeCount;
/**
* Time of each transition in seconds from 1970 epoch.
* Length is transitionCount int32_t's.
*/
const int32_t *transitionTimes; // alias into res; do not delete
/**
* Offset from GMT in seconds for each type.
* Length is typeCount int32_t's.
*/
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 int8_t's.
*/
const uint8_t *typeData; // alias into res; do not delete
/**
* The last year for which the transitions data are to be used
* rather than the finalZone. If there is no finalZone, then this
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* is set to INT32_MAX. NOTE: This corresponds to the year _before_
* the one indicated by finalMillis.
*/
int32_t finalYear;
/**
* The millis for the start of the first year for which finalZone
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* is to be used, or DBL_MAX if finalZone is 0. NOTE: This is
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* 0:00 GMT Jan 1, <finalYear + 1> (not <finalMillis>).
*/
double finalMillis;
/**
* A SimpleTimeZone that governs the behavior for years > finalYear.
* If and only if finalYear == INT32_MAX then finalZone == 0.
*/
SimpleTimeZone *finalZone; // owned, may be NULL
};
inline int32_t
OlsonTimeZone::zoneOffset(int16_t index) const {
index <<= 1;
return typeOffsets[index] + typeOffsets[index+1];
}
inline int32_t
OlsonTimeZone::rawOffset(int16_t index) const {
return typeOffsets[(uint32_t)(index << 1)];
}
inline int32_t
OlsonTimeZone::dstOffset(int16_t index) const {
return typeOffsets[(uint32_t)((index << 1) + 1)];
}
U_NAMESPACE_END
#endif // !UCONFIG_NO_FORMATTING
#endif // OLSONTZ_H
//eof