[icu-design] API Proposal: C wrappers for for VTimeZone, TimeZoneTransition and TimeZoneRule

[Jason J S. <sp...@us...>]

Dear ICU team & users,

I would like to propose adding C wrappers for the VTimeZone, 
TimeZoneTransition and TimeZoneRule CPP classes.

For details see http://www.icu-project.org/trac/ticket/7524 

Please provide feedback by  Wednesday 2010-May-12
I would like to designate Steven Loomis as reviewer

Thank you.

------
The wrapper for VTimeZone will be VZone and will have methods as follows:
------

struct VZone;
/**
 * A UnicodeSet.  Use the vzone_* API to manipulate.  Create with
 * vzone_open*, and destroy with vzone_close.
 * @draft ICU 4.6
 */
typedef struct VZone VZone;

/**
 * Creates a vzone from the given time zone ID.
 * @param ID The time zone ID, such as America/New_York
 * @param idLength, length of the ID parameter
 * @return A vzone object initialized by the time zone ID,
 * or NULL when the ID is unknown.
 * @draft ICU 4.6
 */
U_DRAFT VZone* U_EXPORT2
vzone_openID(const UChar* ID, int32_t idLength);
 
/**
 * Create a vzone instance by RFC2445 VTIMEZONE data
 * @param vtzdata The string including VTIMEZONE data block
 * @param vtzdataLength, length of the vtzdata
 * @param status Output param to filled in with a success or an error.
 * @return A vzone initialized by the VTIMEZONE data or
 * NULL if failed to load the rule from the VTIMEZONE data.
 * @draft ICU 4.6
 */
U_DRAFT VZone* U_EXPORT2
vzone_openData(const UChar* vtzdata, int32_t vtzdataLength, UErrorCode& 
status);

/**
 * Disposes of the storage used by a VZone object.  This function should
 * be called exactly once for objects returned by vzone_open*.
 * @param set the object to dispose of
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_close(VZone* zone);

/**
 * Returns a copy of this object.
 * @param zone the original vzone
 * @return the newly allocated copy of the vzone
 * @draft ICU 4.6
 */
U_DRAFT VZone* U_EXPORT2
vzone_clone(const VZone *zone);

/**
 * Returns true if zone1 is identical to zone2
 * and vis versa.
 * @param zone1 to be checked for containment
 * @param zone2 to be checked for containment
 * @return true if the test condition is met
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_equals(const VZone* zone1, const VZone* zone2);

/**
 * Gets the RFC2445 TZURL property value.  When a vzone instance was
 * created from VTIMEZONE data, the initial value is set by the TZURL 
 * property value in the data.  Otherwise, the initial value is not set.
 *
 * If the URL receiver variable is null, urlLength will contain the number
 * of bytes necessary to hold the URL and the receiver variable will not
 * be set.
 *
 * @param zone, the vzone to use
 * @param url Receives the RFC2445 TZURL property value.
 * @param urlLength, length of the url
 * @return TRUE if TZURL attribute is available and value is set.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_getTZURL(VZone* zone, UChar* & url, int32_t & urlLength);

/**
 * Sets the RFC2445 TZURL property value.
 * @param zone, the vzone to use
 * @param url The TZURL property value.
 * @param urlLength, length of the url
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_setTZURL(VZone* zone, UChar* url, int32_t urlLength);

/**
 * Gets the RFC2445 LAST-MODIFIED property value.  When a vzone instance
 * was created from VTIMEZONE data, the initial value is set by the 
 * LAST-MODIFIED property value in the data.  Otherwise, the initial value 

 * is not set.
 * @param zone, the vzone to use
 * @param lastModified Receives the last modified date.
 * @return TRUE if lastModified attribute is available and value is set.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_getLastModified(VZone* zone, UDate& lastModified);

/**
 * Sets the RFC2445 LAST-MODIFIED property value.
 * @param zone, the vzone to use
 * @param lastModified The LAST-MODIFIED date.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_setLastModified(VZone* zone, UDate lastModified);

/**
 * Writes RFC2445 VTIMEZONE data for this time zone
 *
 * If the receiver variable is null, the returned length will contain the 
number
 * of bytes necessary to hold the data and the receiver variable will not
 * be set.
 *
 * @param zone, the vzone to use
 * @param result Output param to filled in with the VTIMEZONE data.
 * @param resultLength, length of the result output
 * @param status Output param to filled in with a success or an error.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_write(VZone* zone, UChar* & result, int32_t & resultLength, 
UErrorCode& status);

/**
 * Writes RFC2445 VTIMEZONE data for this time zone applicalbe
 * for dates after the specified start time.
 *
 * If the receiver variable is null, the returned length will contain the 
number
 * of bytes necessary to hold the data and the receiver variable will not
 * be set.
 *
 * @param zone, the vzone to use
 * @param start The start date.
 * @param result Output param to filled in with the VTIMEZONE data.
 * @param resultLength, length of the result output
 * @param status Output param to filled in with a success or an error.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_writeFromStart(VZone* zone, UDate start, UChar* & result, int32_t & 
resultLength, UErrorCode& status);

/**
 * Writes RFC2445 VTIMEZONE data applicalbe for the specified date.
 * Some common iCalendar implementations can only handle a single time
 * zone property or a pair of standard and daylight time properties using
 * BYDAY rule with day of week (such as BYDAY=1SUN).  This method produce
 * the VTIMEZONE data which can be handled these implementations.  The 
rules
 * produced by this method can be used only for calculating time zone 
offset
 * around the specified date.
 *
 * If the receiver variable is null, the returned length will contain the 
number
 * of bytes necessary to hold the data and the receiver variable will not
 * be set.
 *
 * @param zone, the vzone to use
 * @param time The date used for rule extraction.
 * @param result Output param to filled in with the VTIMEZONE data.
 * @param status Output param to filled in with a success or an error.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_writeSimple(VZone* zone, UDate time, UChar* & result, int32_t & 
resultLength, UErrorCode& status);

/**
 * Returns the time zone raw and GMT offset for the given moment
 * in time.  Upon return, local-millis = GMT-millis + rawOffset +
 * dstOffset.  All computations are performed in the proleptic
 * Gregorian calendar.  The default implementation in the TimeZone
 * class delegates to the 8-argument getOffset().
 *
 * @param zone, the vzone to use
 * @param date moment in time for which to return offsets, in
 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
 * time or local wall time, depending on `local'.
 * @param local if true, `date' is local wall time; otherwise it
 * is in GMT time.
 * @param rawOffset output parameter to receive the raw offset, that
 * is, the offset not including DST adjustments
 * @param dstOffset output parameter to receive the DST offset,
 * that is, the offset to be added to `rawOffset' to obtain the
 * total offset between local and GMT time. If DST is not in
 * effect, this value is zero; otherwise it is a positive value,
 * typically one hour.
 * @param ec input-output error code
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_getOffset(VZone* zone, UDate date, UBool local, int32_t& rawOffset,
                int32_t& dstOffset, UErrorCode& ec);

/**
 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to 
add
 * to GMT to get local time, before taking daylight savings time into 
account).
 *
 * @param zone, the vzone to use
 * @param offsetMillis  The new raw GMT offset for this time zone.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
vzone_setRawOffset(VZone* zone, int32_t offsetMillis);

/**
 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds 
to add
 * to GMT to get local time, before taking daylight savings time into 
account).
 *
 * @param zone, the vzone to use
 * @return   The TimeZone's raw GMT offset.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
vzone_getRawOffset(VZone* zone);

/**
 * Queries if this time zone uses daylight savings time.
 * @param zone, the vzone to use
 * @return true if this time zone uses daylight savings time,
 * false, otherwise.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_useDaylightTime(VZone* zone);

/**
 * Returns true if this zone has the same rule and offset as another zone.
 * That is, if this zone differs only in ID, if at all.
 * @param zone, the vzone to use
 * @param other the <code>TimeZone</code> object to be compared with
 * @return true if the given zone is the same as this one,
 * with the possible exception of the ID
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_hasSameRules(VZone* zone, const VZone* other);

/**
 * Gets the first time zone transition after the base time.
 * @param zone, the vzone to use
 * @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.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_getNextTransition(VZone* zone, UDate base, UBool inclusive, ZTrans* 
result);

/**
 * Gets the most recent time zone transition before the base time.
 * @param zone, the vzone to use
 * @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.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
vzone_getPreviousTransition(VZone* zone, UDate base, UBool inclusive, 
ZTrans* result);

/**
 * 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 zone, the vzone to use 
 * @param status    Receives error status code.
 * @return The number of <code>TimeZoneRule</code>s representing time 
transitions.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
vzone_countTransitionRules(VZone* zone, UErrorCode& status);

/**
 * Return the class ID for this class. This is useful only for comparing 
to
 * a return value from getDynamicClassID(). For example:
 * <pre>
 * .   Base* polymorphic_pointer = createPolymorphicObject();
 * .   if (polymorphic_pointer->getDynamicClassID() ==
 * .       erived::getStaticClassID()) ...
 * </pre>
 * @param zone, the vzone to use
 * @return          The class ID for all objects of this class.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
vzone_getStaticClassID(VZone* zone);

/**
 * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. This
 * method is to implement a simple version of RTTI, since not all C++
 * compilers support genuine RTTI. Polymorphic operator==() and clone()
 * methods call this method.
 *
 * @param zone, the vzone to use
 * @return          The class ID for this object. All objects of a
 *                  given class have the same class ID.  Objects of
 *                  other classes have different class IDs.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
vzone_getDynamicClassID(VZone* zone);

------
The wrapper for TimeZoneTransition will be ZTrans and will have methods as 
follows:
------

/**
 * A TimeZoneTransition.  Use the ztrans_* API to manipulate.  Create with
 * ztrans_open*, and destroy with ztrans_close.
 * @draft ICU 4.6
 */
struct ZTrans;
typedef struct ZTrans ZTrans;


/**
 * Constructs a time zone transition with the time and the rules 
before/after
 * the transition.
 * 
 * @param time  The time of transition in milliseconds since the base 
time.
 * @param from  The time zone rule used before the transition.
 * @param to    The time zone rule used after the transition.
 * @draft ICU 4.6
 */
U_DRAFT ZTrans* U_EXPORT2
ztrans_open(UDate time, const void* from, const void* to);

/**
 * Constructs an empty <code>TimeZoneTransition</code>
 * @draft ICU 4.6
 */
U_DRAFT ZTrans* U_EXPORT2
ztrans_openEmpty();

/**
 * Disposes of the storage used by a ZTrans object.  This function should
 * be called exactly once for objects returned by ztrans_open*.
 * @param trans the object to dispose of
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_close(ZTrans *trans);

/**
 * Returns a copy of this object.
 * @param rule the original ZRule
 * @return the newly allocated copy of the ZRule
 * @draft ICU 4.6
 */
U_DRAFT ZTrans* U_EXPORT2
ztrans_clone(ZTrans *trans);

/**
 * Returns true if trans1 is identical to trans2
 * and vis versa.
 * @param trans1 to be checked for containment
 * @param trans2 to be checked for containment
 * @return true if the test condition is met
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
ztrans_equals(const ZTrans* trans1, const ZTrans* trans2);

/**
 * Returns the time of transition in milliseconds.
 * param trans, the transition to use
 * @return the time of the transition in milliseconds since the 1970 Jan 1 
epoch time.
 * @draft ICU 4.6
 */
U_DRAFT UDate U_EXPORT2
ztrans_getTime(ZTrans* trans);

/**
 * Sets the time of transition in milliseconds.
 * param trans, the transition to use
 * @param time the time of the transition in milliseconds since the 1970 
Jan 1 epoch time.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_setTime(ZTrans* trans, UDate time);

/**
 * Returns the rule used before the transition.
 * @param trans, the transition to use
 * @return the time zone rule used after the transition.
 * @draft ICU 4.6
 */
U_DRAFT void* U_EXPORT2
ztrans_getFrom(ZTrans* & trans);

/**
 * Sets the rule used before the transition.  The caller remains
 * responsible for deleting the TimeZoneRule object.
 * @param trans, the transition to use
 * @param from the time zone rule used before the transition.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_setFrom(ZTrans* trans, const void* from);

/**
 * Adopts the rule used before the transition.  The caller must
 * not delete the TimeZoneRule object passed in.
 * @param trans, the transition to use
 * @param from the time zone rule used before the transition.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_adoptFrom(ZTrans* trans, void* from);

/**
 * Returns the rule used after the transition.
 * @param trans, the transition to use
 * @return the time zone rule used after the transition.
 * @draft ICU 4.6
 */
U_DRAFT void* U_EXPORT2
ztrans_getTo(ZTrans* trans);

/**
 * Sets the rule used after the transition.  The caller remains
 * responsible for deleting the TimeZoneRule object.
 * @param trans, the transition to use
 * @param to the time zone rule used after the transition.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_setTo(ZTrans* trans, const void* to);

/**
 * Adopts the rule used after the transition.  The caller must
 * not delete the TimeZoneRule object passed in.
 * @param trans, the transition to use
 * @param to the time zone rule used after the transition.
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
ztrans_adoptTo(ZTrans* trans, void* to);

/**
 * Return the class ID for this class. This is useful only for comparing 
to
 * a return value from getDynamicClassID(). For example:
 * <pre>
 * .   Base* polymorphic_pointer = createPolymorphicObject();
 * .   if (polymorphic_pointer->getDynamicClassID() ==
 * .       erived::getStaticClassID()) ...
 * </pre>
 * @param trans, the transition to use
 * @return the class ID for all objects of this class.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
ztrans_getStaticClassID(ZTrans* trans);

/**
 * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. This
 * method is to implement a simple version of RTTI, since not all C++
 * compilers support genuine RTTI. Polymorphic operator==() and clone()
 * methods call this method.
 *
 * @param trans, the transition to use
 * @return          the class ID for this object. All objects of a
 *                  given class have the same class ID.  Objects of
 *                  other classes have different class IDs.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
ztrans_getDynamicClassID(ZTrans* trans);

------
The wrapper for TimeZoneRule will be ZRule and will have methods as 
follows:
------

/**
 * A TimeZoneRule.  Use the zrule_* API to manipulate.  Create with
 * zrule_open*, and destroy with zrule_close.
 * @draft ICU 4.6
 */
struct ZRule;
typedef struct ZRule ZRule;

/**
 * An InitialTimeZoneRule.  Use the izrule_* API to manipulate.  Create 
with
 * izrule_open*, and destroy with izrule_close.
 * @draft ICU 4.6
 */
struct IZRule;
typedef struct IZRule IZRule;


/*********************************************************************
 * ZRule API
 *********************************************************************/

/**
 * Disposes of the storage used by a ZRule object.  This function should
 * be called exactly once for objects returned by zrule_open*.
 * @param set the object to dispose of
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
zrule_close(ZRule* rule);

/**
 * Returns true if rule1 is identical to rule2
 * and vis versa.
 * @param rule1 to be checked for containment
 * @param rule2 to be checked for containment
 * @return true if the test condition is met
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
zrule_equals(const ZRule* rule1, const ZRule* rule2);

/**
 * Fills in "name" with the name of this time zone.
 *
 * If the receiver variable is null, the returned length will contain the 
number
 * of bytes necessary to hold the data and the receiver variable will not
 * be set.
 *
 * @param rule, the Zrule to use
 * @param name  Receives the name of this time zone.
 * @param nameLength, length of the returned name
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
zrule_getName(ZRule* rule, UChar* name, int32_t nameLength);

/**
 * Gets the standard time offset.
 * @param rule, the Zrule to use
 * @return  The standard time offset from UTC in milliseconds.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
zrule_getRawOffset(ZRule* rule);

/**
 * Gets the amount of daylight saving delta time from the standard time.
 * @param rule, the Zrule to use
 * @return  The amount of daylight saving offset used by this rule
 *          in milliseconds.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
zrule_getDSTSavings(ZRule* rule);

/**
 * Returns if this rule represents the same rule and offsets as another.
 * When two ZRule objects differ only its names, this method
 * returns true.
 * @param rule1 to be checked for containment
 * @param rule2 to be checked for containment
 * @return  true if the other <code>TimeZoneRule</code> is the same as 
this one.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
zrule_isEquivalentTo(ZRule* rule1,  ZRule* rule2);

/*********************************************************************
 * IZRule API
 *********************************************************************/

/**
 * Constructs an IZRule with the name, the GMT offset of its
 * standard time and the amount of daylight saving offset adjustment.
 * @param name          The time zone name.
 * @param nameLength    The length of the time zone name.
 * @param rawOffset     The UTC offset of its standard time in 
milliseconds.
 * @param dstSavings    The amount of daylight saving offset adjustment in 
milliseconds.
 *                      If this ia a rule for standard time, the value of 
this argument is 0.
 * @draft ICU 4.6
 */
U_DRAFT IZRule* U_EXPORT2
izrule_open(const UChar* name, int32_t nameLength, int32_t rawOffset, 
int32_t dstSavings);

/**
 * Disposes of the storage used by a IZRule object.  This function should
 * be called exactly once for objects returned by izrule_open*.
 * @param set the object to dispose of
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
izrule_close(IZRule* rule);

/**
 * Returns a copy of this object.
 * @param rule the original IZRule
 * @return the newly allocated copy of the IZRule
 * @draft ICU 4.6
 */
U_DRAFT IZRule* U_EXPORT2
izrule_clone(IZRule *rule);

/**
 * Returns true if rule1 is identical to rule2
 * and vis versa.
 * @param rule1 to be checked for containment
 * @param rule2 to be checked for containment
 * @return true if the test condition is met
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_equals(const IZRule* rule1, const IZRule* rule2);

/**
 * Fills in "name" with the name of this time zone.
 *
 * If the receiver variable is null, the returned length will contain the 
number
 * of bytes necessary to hold the data and the receiver variable will not
 * be set.
 *
 * @param rule, the IZrule to use
 * @param name  Receives the name of this time zone.
 * @param nameLength, length of the returned name
 * @draft ICU 4.6
 */
U_DRAFT void U_EXPORT2
izrule_getName(IZRule* rule, UChar* & name, int32_t & nameLength);

/**
 * Gets the standard time offset.
 * @param rule, the IZrule to use
 * @return  the standard time offset from UTC in milliseconds.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
izrule_getRawOffset(IZRule* rule);

/**
 * Gets the amount of daylight saving delta time from the standard time.
 * @param rule, the IZrule to use
 * @return  the amount of daylight saving offset used by this rule
 *          in milliseconds.
 * @draft ICU 4.6
 */
U_DRAFT int32_t U_EXPORT2
izrule_getDSTSavings(IZRule* rule);

/**
 * Returns if this rule represents the same rule and offsets as another.
 * When two IZRule objects differ only its names, this method
 * returns true.
 * @param rule1 to be checked for containment
 * @param rule2 to be checked for containment
 * @return true if the other <code>TimeZoneRule</code> is the same as this 
one.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_isEquivalentTo(IZRule* rule1,  IZRule* rule2);

/**
 * Gets the very first time when this rule takes effect.
 * @param rule              The IZrule to use
 * @param prevRawOffset     The standard time offset from UTC before this 
rule
 *                          takes effect in milliseconds.
 * @param prevDSTSavings    The amount of daylight saving offset from the
 *                          standard time.
 * @param result            Receives the very first time when this rule 
takes effect.
 * @return  true if the start time is available.  When false is returned, 
output parameter
 *          "result" is unchanged.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_getFirstStart(IZRule* rule, int32_t prevRawOffset, int32_t 
prevDSTSavings, 
                    UDate& result);

/**
 * Gets the final time when this rule takes effect.
 * @param rule              The IZrule to use 
 * @param prevRawOffset     The standard time offset from UTC before this 
rule
 *                          takes effect in milliseconds.
 * @param prevDSTSavings    The amount of daylight saving offset from the
 *                          standard time.
 * @param result            Receives the final time when this rule takes 
effect.
 * @return  true if the start time is available.  When false is returned, 
output parameter
 *          "result" is unchanged.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_getFinalStart(IZRule* rule, int32_t prevRawOffset, int32_t 
prevDSTSavings, 
                    UDate& result);

/**
 * Gets the first time when this rule takes effect after the specified 
time.
 * @param rule              The IZrule to use
 * @param base              The first start time after this base time will 
be returned.
 * @param prevRawOffset     The standard time offset from UTC before this 
rule
 *                          takes effect in milliseconds.
 * @param prevDSTSavings    The amount of daylight saving offset from the
 *                          standard time.
 * @param inclusive         Whether the base time is inclusive or not.
 * @param result            Receives The first time when this rule takes 
effect after
 *                          the specified base time.
 * @return  true if the start time is available.  When false is returned, 
output parameter
 *          "result" is unchanged.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_getNextStart(IZRule* rule, UDate base, int32_t prevRawOffset, 
                   int32_t prevDSTSavings, UBool inclusive, UDate& 
result);

/**
 * Gets the most recent time when this rule takes effect before the 
specified time.
 * @param rule              The IZrule to use
 * @param base              The most recent time before this base time 
will be returned.
 * @param prevRawOffset     The standard time offset from UTC before this 
rule
 *                          takes effect in milliseconds.
 * @param prevDSTSavings    The amount of daylight saving offset from the
 *                          standard time.
 * @param inclusive         Whether the base time is inclusive or not.
 * @param result            Receives The most recent time when this rule 
takes effect before
 *                          the specified base time.
 * @return  true if the start time is available.  When false is returned, 
output parameter
 *          "result" is unchanged.
 * @draft ICU 4.6
 */
U_DRAFT UBool U_EXPORT2
izrule_getPreviousStart(IZRule* rule, UDate base, int32_t prevRawOffset, 
                       int32_t prevDSTSavings, UBool inclusive, UDate& 
result);


/**
 * Return the class ID for this class. This is useful only for comparing 
to
 * a return value from getDynamicClassID(). For example:
 * <pre>
 * .   Base* polymorphic_pointer = createPolymorphicObject();
 * .   if (polymorphic_pointer->getDynamicClassID() ==
 * .       erived::getStaticClassID()) ...
 * </pre>
 * @param rule              The IZrule to use
 * @return          The class ID for all objects of this class.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
izrule_getStaticClassID(IZRule* rule);

/**
 * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. This
 * method is to implement a simple version of RTTI, since not all C++
 * compilers support genuine RTTI. Polymorphic operator==() and clone()
 * methods call this method.
 *
 * @param rule              The IZrule to use
 * @return          The class ID for this object. All objects of a
 *                  given class have the same class ID.  Objects of
 *                  other classes have different class IDs.
 * @draft ICU 4.6
 */
U_DRAFT UClassID U_EXPORT2
izrule_getDynamicClassID(IZRule* rule);

-- Jason