scuffed-code/icu4c/source/i18n/timezone.cpp
2000-05-18 22:08:39 +00:00

623 lines
21 KiB
C++

/*
*******************************************************************************
* Copyright (C) 1997-1999, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*
* File TIMEZONE.CPP
*
* Modification History:
*
* Date Name Description
* 12/05/96 clhuang Creation.
* 04/21/97 aliu General clean-up and bug fixing.
* 05/08/97 aliu Fixed Hashtable code per code review.
* 07/09/97 helena Changed createInstance to createDefault.
* 07/29/97 aliu Updated with all-new list of 96 UNIX-derived
* TimeZones. Changed mechanism to load from static
* array rather than resource bundle.
* 07/07/1998 srl Bugfixes from the Java side: UTC GMT CAT NST
* Added getDisplayName API
* going to add custom parsing.
*
* ISSUES:
* - should getDisplayName cache something?
* - should custom time zones be cached? [probably]
* 08/10/98 stephen Brought getDisplayName() API in-line w/ conventions
* 08/19/98 stephen Changed createTimeZone() to never return 0
* 09/02/98 stephen Added getOffset(monthLen) and hasSameRules()
* 09/15/98 stephen Added getStaticClassID()
* 02/22/99 stephen Removed character literals for EBCDIC safety
* 05/04/99 stephen Changed initDefault() for Mutex issues
* 07/12/99 helena HPUX 11 CC Port.
* 12/03/99 aliu Moved data out of static table into icudata.dll.
* Substantial rewrite of zone lookup, default zone, and
* available IDs code. Misc. cleanup.
*********************************************************************************/
#include "unicode/simpletz.h"
#include "unicode/smpdtfmt.h"
#include "unicode/calendar.h"
#include "mutex.h"
#include "unicode/udata.h"
#include "tzdat.h"
#include "cstring.h"
#ifdef _DEBUG
#include "unistrm.h"
#endif
// static initialization
char TimeZone::fgClassID = 0; // Value is irrelevant
TimeZone* TimeZone::fgDefaultZone = NULL;
const UnicodeString TimeZone::GMT_ID = UNICODE_STRING("GMT", 3);
const int32_t TimeZone::GMT_ID_LENGTH = 3;
const UnicodeString TimeZone::CUSTOM_ID = UNICODE_STRING("Custom", 6);
const TimeZone* TimeZone::GMT = new SimpleTimeZone(0, GMT_ID);
// See header file for documentation of the following
const TZHeader * TimeZone::DATA = 0;
const uint32_t* TimeZone::INDEX_BY_ID = 0;
const OffsetIndex* TimeZone::INDEX_BY_OFFSET = 0;
UnicodeString* TimeZone::ZONE_IDS = 0;
UBool TimeZone::DATA_LOADED = FALSE;
UMTX TimeZone::LOCK;
/**
* Attempt to load the system zone data from icudata.dll (or its
* equivalent). After this call returns DATA_LOADED will be true.
* DATA itself will be non-null if the load succeeded; otherwise it
* will be null. This call does nothing if the load has already
* happened or or if it happens in another thread concurrently before
* we can get there.
*
* After this call, we are guaranteed that DATA_LOADED is true. We
* are _not_ guaranteed that DATA will be nonzero. If it is nonzero,
* we are guaranteed that all associated data structures are
* initialized.
*/
void TimeZone::loadZoneData() {
if (!DATA_LOADED) {
Mutex lock(&LOCK);
if (!DATA_LOADED) {
UErrorCode status = U_ZERO_ERROR;
UDataMemory *data = udata_openChoice(0, TZ_DATA_TYPE, TZ_DATA_NAME,
isDataAcceptable, 0, &status);
if (U_SUCCESS(status)) {
DATA = (TZHeader*)udata_getMemory(data);
// Result guaranteed to be nonzero if data is nonzero
// We require that standard zones occur before DST
// zones. Do a quick check for this here, and if the
// check fails, don't use this zone data.
// (Alternatively, we could handle either ordering,
// with a little extra logic.) See
// createSystemTimeZone().
if (DATA->standardDelta > DATA->dstDelta) {
DATA = 0;
} else {
INDEX_BY_ID =
(const uint32_t*)((int8_t*)DATA + DATA->nameIndexDelta);
INDEX_BY_OFFSET =
(const OffsetIndex*)((int8_t*)DATA + DATA->offsetIndexDelta);
// Construct the available IDs array. The ordering
// of this array conforms to the ordering of the
// index by name table.
ZONE_IDS = new UnicodeString[DATA->count];
// Find start of name table, and walk through it
// linearly. If you're wondering why we don't use
// the INDEX_BY_ID, it's because that indexes the
// zone objects, not the name table. The name
// table is unindexed.
const char* name = (const char*)DATA + DATA->nameTableDelta;
for (uint32_t i=0; i<DATA->count; ++i) {
ZONE_IDS[i] = UnicodeString(name, ""); // invariant converter
name += uprv_strlen(name) + 1;
}
}
}
// Whether we succeed or fail, stop future attempts
DATA_LOADED = TRUE;
}
}
}
/**
* udata callback to verify the zone data.
*/
UBool U_CALLCONV
TimeZone::isDataAcceptable(void *context,
const char *type, const char *name,
const UDataInfo *pInfo) {
return
pInfo->size >= sizeof(UDataInfo) &&
pInfo->isBigEndian == U_IS_BIG_ENDIAN &&
pInfo->charsetFamily == U_CHARSET_FAMILY &&
pInfo->dataFormat[0] == 0x7a && // see TZ_SIG, must be numeric literals to be portable
pInfo->dataFormat[1] == 0x6f && // (this is not a string, it just looks like one for debugging)
pInfo->dataFormat[2] == 0x6e &&
pInfo->dataFormat[3] == 0x65 &&
pInfo->formatVersion[0] == TZ_FORMAT_VERSION;
}
// *****************************************************************************
// class TimeZone
// *****************************************************************************
TimeZone::TimeZone()
{
}
// -------------------------------------
TimeZone::~TimeZone()
{
}
// -------------------------------------
TimeZone::TimeZone(const TimeZone &source)
: fID(source.fID)
{
}
// -------------------------------------
TimeZone &
TimeZone::operator=(const TimeZone &right)
{
if (this != &right) fID = right.fID;
return *this;
}
// -------------------------------------
UBool
TimeZone::operator==(const TimeZone& that) const
{
return getDynamicClassID() == that.getDynamicClassID() &&
fID == that.fID;
}
// -------------------------------------
TimeZone*
TimeZone::createTimeZone(const UnicodeString& ID)
{
/* We first try to lookup the zone ID in our system list. If this
* fails, we try to parse it as a custom string GMT[+-]hh:mm. If
* all else fails, we return GMT, which is probably not what the
* user wants, but at least is a functioning TimeZone object.
*/
TimeZone* result = 0;
if (!DATA_LOADED) {
loadZoneData();
}
if (DATA != 0) {
result = createSystemTimeZone(ID);
}
if (result == 0) {
result = createCustomTimeZone(ID);
}
if (result == 0) {
result = GMT->clone();
}
return result;
}
/**
* Lookup the given name in our system zone table. If found,
* instantiate a new zone of that name and return it. If not
* found, return 0.
*/
TimeZone*
TimeZone::createSystemTimeZone(const UnicodeString& name) {
if (0 == DATA) {
return 0;
}
// Perform a binary search. Possible optimization: Unroll the
// search. Not worth it given the small number of zones (416 in
// 1999j).
uint32_t low = 0;
uint32_t high = DATA->count;
while (high > low) {
// Invariant: match, if present, must be in the range [low,
// high).
uint32_t i = (low + high) / 2;
int8_t c = name.compare(ZONE_IDS[i]);
if (c == 0) {
const int8_t* z = (int8_t*)DATA + INDEX_BY_ID[i];
// NOTE: standard zones must be before DST zones. We test
// for this when loading up the data; see loadZoneData().
return INDEX_BY_ID[i] < DATA->dstDelta ?
new SimpleTimeZone(*(const StandardZone*)z, name) :
new SimpleTimeZone(*(const DSTZone*)z, name);
} else if (c < 0) {
high = i;
} else {
low = i + 1;
}
}
return 0;
}
// -------------------------------------
void
TimeZone::initDefault()
{
if (!DATA_LOADED) {
loadZoneData();
}
// This function is called by createDefault() to initialize
// fgDefaultZone from the system default time zone. If
// fgDefaultZone is already filled in, we obviously don't have to
// do anything.
if (fgDefaultZone == 0) {
Mutex lock(&LOCK);
if (fgDefaultZone == 0) {
// We access system timezone data through TPlatformUtilities,
// including tzset(), timezone, and tzname[].
int32_t rawOffset = 0;
const char *hostID;
// First, try to create a system timezone, based
// on the string ID in tzname[0].
{
// NOTE: Global mutex here; TimeZone mutex above
Mutex lock; // mutexed to avoid threading issues in the platform fcns.
uprv_tzset(); // Initialize tz... system data
// get the timezone ID from the host.
hostID = uprv_tzname(0);
// Invert sign because UNIX semantics are backwards
rawOffset = uprv_timezone() * -U_MILLIS_PER_SECOND;
}
// Try to create a system zone with the given ID. This
// _always fails on Windows_ because Windows returns a
// non-standard localized zone name, e.g., "Pacific
// Standard Time" on U.S. systems set to PST. One way to
// fix this is to add a Windows-specific mapping table,
// but that means we'd have to do so for every locale. A
// better way is to use the offset and find a
// corresponding zone, which is what we do below.
fgDefaultZone = createSystemTimeZone(hostID);
// If we couldn't get the time zone ID from the host, use
// the default host timezone offset. Further refinements
// to this include querying the host to determine if DST
// is in use or not and possibly using the host locale to
// select from multiple zones at a the same offset. We
// don't do any of this now, but we could easily add this.
if (fgDefaultZone == 0 && DATA != 0) {
// Use the designated default in the time zone list that has the
// appropriate GMT offset, if there is one.
const OffsetIndex* index = INDEX_BY_OFFSET;
for (;;) {
if (index->gmtOffset > rawOffset) {
// Went past our desired offset; no match found
break;
}
if (index->gmtOffset == rawOffset) {
// Found our desired offset
fgDefaultZone = createTimeZone(ZONE_IDS[index->defaultZone]);
break;
}
// Compute the position of the next entry. If the delta value
// in this entry is zero, then there is no next entry.
uint16_t delta = index->nextEntryDelta;
if (delta == 0) {
break;
}
index = (const OffsetIndex*)((int8_t*)index + delta);
}
}
// If we _still_ don't have a time zone, use GMT. This
// can only happen if the raw offset returned by
// uprv_timezone() does not correspond to any system zone.
if (fgDefaultZone == 0) {
fgDefaultZone = GMT->clone();
}
}
}
}
// -------------------------------------
TimeZone*
TimeZone::createDefault()
{
initDefault(); // After this call fgDefaultZone is not NULL
Mutex lock(&LOCK); // In case adoptDefault is called
return fgDefaultZone->clone();
}
// -------------------------------------
void
TimeZone::adoptDefault(TimeZone* zone)
{
if (zone != NULL)
{
Mutex mutex(&LOCK);
if (fgDefaultZone != NULL) {
delete fgDefaultZone;
}
fgDefaultZone = zone;
}
}
// -------------------------------------
void
TimeZone::setDefault(const TimeZone& zone)
{
adoptDefault(zone.clone());
}
// -------------------------------------
const UnicodeString** const
TimeZone::createAvailableIDs(int32_t rawOffset, int32_t& numIDs)
{
// We are creating a new array to existing UnicodeString pointers.
// The caller will delete the array when done, but not the pointers
// in the array.
if (!DATA_LOADED) {
loadZoneData();
}
if (0 == DATA) {
numIDs = 0;
return 0;
}
/* The offset index table is a table of variable-sized objects.
* Each entry has an offset to the next entry; the last entry has
* a next entry offset of zero.
*
* The entries are sorted in ascending numerical order of GMT
* offset. Each entry lists all the system zones at that offset,
* in lexicographic order of ID. Note that this ordering is
* somewhat significant in that the _first_ zone in each list is
* what will be chosen as the default under certain fallback
* conditions. We currently just let that be the
* lexicographically first zone, but we could also adjust the list
* to pick which zone was first for this situation -- probably not
* worth the trouble, except for the fact that this fallback is
* _always_ used to determine the default zone on Windows.
*
* The list of zones is actually just a list of integers, from
* 0..n-1, where n is the total number of system zones. The
* numbering corresponds exactly to the ordering of ZONE_IDS.
*/
const OffsetIndex* index = INDEX_BY_OFFSET;
for (;;) {
if (index->gmtOffset > rawOffset) {
// Went past our desired offset; no match found
break;
}
if (index->gmtOffset == rawOffset) {
// Found our desired offset
const UnicodeString** const result =
(const UnicodeString** const) new UnicodeString*[index->count];
const uint16_t* zoneNumberArray = &(index->zoneNumber);
for (uint16_t i=0; i<index->count; ++i) {
// Pointer assignment - use existing UnicodeString object!
// Don't create a new UnicodeString on the heap here!
result[i] = &ZONE_IDS[zoneNumberArray[i]];
}
numIDs = index->count;
return result;
}
// Compute the position of the next entry. If the delta value
// in this entry is zero, then there is no next entry.
uint16_t delta = index->nextEntryDelta;
if (delta == 0) {
break;
}
index = (const OffsetIndex*)((int8_t*)index + delta);
}
numIDs = 0;
return 0;
}
// -------------------------------------
const UnicodeString** const
TimeZone::createAvailableIDs(int32_t& numIDs)
{
// We are creating a new array to existing UnicodeString pointers.
// The caller will delete the array when done, but not the pointers
// in the array.
//
// This is really unnecessary, given the fact that we have an
// array of the IDs already constructed, and we could just return
// that. However, that would be a breaking API change, and some
// callers familiar with the original API might try to delete it.
if (!DATA_LOADED) {
loadZoneData();
}
if (0 == DATA) {
numIDs = 0;
return 0;
}
const UnicodeString** const result =
(const UnicodeString** const) new UnicodeString*[DATA->count];
// Create a list of pointers to each and every zone ID
for (uint32_t i=0; i<DATA->count; ++i) {
// Pointer assignment - use existing UnicodeString object!
// Don't create a new UnicodeString on the heap here!
result[i] = &ZONE_IDS[i];
}
numIDs = DATA->count;
return result;
}
// ---------------------------------------
UnicodeString&
TimeZone::getDisplayName(UnicodeString& result) const
{
return getDisplayName(FALSE,LONG,Locale::getDefault(), result);
}
UnicodeString&
TimeZone::getDisplayName(const Locale& locale, UnicodeString& result) const
{
return getDisplayName(FALSE, LONG, locale, result);
}
UnicodeString&
TimeZone::getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const
{
return getDisplayName(daylight,style, Locale::getDefault(), result);
}
UnicodeString&
TimeZone::getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const
{
// SRL TODO: cache the SDF, just like java.
UErrorCode status = U_ZERO_ERROR;
SimpleDateFormat format(style == LONG ? "zzzz" : "z",locale,status);
if(!U_SUCCESS(status))
{
// *** SRL what do I do here?!!
return result.remove();
}
// Create a new SimpleTimeZone as a stand-in for this zone; the
// stand-in will have no DST, or all DST, but the same ID and offset,
// and hence the same display name.
// We don't cache these because they're small and cheap to create.
UnicodeString tempID;
SimpleTimeZone *tz = daylight ?
// For the pure-DST zone, we use JANUARY and DECEMBER
new SimpleTimeZone(getRawOffset(), getID(tempID),
Calendar::JANUARY , 1, 0, 0,
Calendar::DECEMBER , 31, 0, U_MILLIS_PER_DAY, status) :
new SimpleTimeZone(getRawOffset(), getID(tempID));
format.applyPattern(style == LONG ? "zzzz" : "z");
Calendar *myCalendar = (Calendar*)format.getCalendar();
myCalendar->setTimeZone(*tz); // copy
delete tz;
FieldPosition pos(FieldPosition::DONT_CARE);
return format.format(UDate(196262345678.), result, pos); // Must use a valid date here.
}
/**
* Parse a custom time zone identifier and return a corresponding zone.
* @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
* GMT[+-]hh.
* @return a newly created SimpleTimeZone with the given offset and
* no Daylight Savings Time, or null if the id cannot be parsed.
*/
TimeZone*
TimeZone::createCustomTimeZone(const UnicodeString& id)
{
static const int32_t kParseFailed = -99999;
NumberFormat* numberFormat = 0;
UnicodeString idUppercase = id;
idUppercase.toUpper();
if (id.length() > GMT_ID_LENGTH &&
idUppercase.startsWith(GMT_ID))
{
ParsePosition pos(GMT_ID_LENGTH);
UBool negative = FALSE;
int32_t offset;
if (id[pos.getIndex()] == 0x002D /*'-'*/)
negative = TRUE;
else if (id[pos.getIndex()] != 0x002B /*'+'*/)
return 0;
pos.setIndex(pos.getIndex() + 1);
UErrorCode success = U_ZERO_ERROR;
numberFormat = NumberFormat::createInstance(success);
numberFormat->setParseIntegerOnly(TRUE);
// Look for either hh:mm, hhmm, or hh
int32_t start = pos.getIndex();
Formattable n(kParseFailed);
numberFormat->parse(id, n, pos);
if (pos.getIndex() == start) return 0;
offset = n.getLong();
if (pos.getIndex() < id.length() &&
id[pos.getIndex()] == 0x003A /*':'*/)
{
// hh:mm
offset *= 60;
pos.setIndex(pos.getIndex() + 1);
int32_t oldPos = pos.getIndex();
n.setLong(kParseFailed);
numberFormat->parse(id, n, pos);
if (pos.getIndex() == oldPos) return 0;
offset += n.getLong();
}
else
{
// hhmm or hh
// Be strict about interpreting something as hh; it must be
// an offset < 30, and it must be one or two digits. Thus
// 0010 is interpreted as 00:10, but 10 is interpreted as
// 10:00.
if (offset < 30 && (pos.getIndex() - start) <= 2)
offset *= 60; // hh, from 00 to 29; 30 is 00:30
else
offset = offset % 100 + offset / 100 * 60; // hhmm
}
if(negative)
offset = -offset;
return new SimpleTimeZone(offset * 60000, CUSTOM_ID);
delete numberFormat;
}
return 0;
}
UBool
TimeZone::hasSameRules(const TimeZone& other) const
{
return (getRawOffset() == other.getRawOffset() &&
useDaylightTime() == other.useDaylightTime());
}
//eof