int64_t
DSTOffsetCache::getDSTOffsetMilliseconds(int64_t localTimeMilliseconds, JSContext *cx)
{
sanityCheck();
int64_t localTimeSeconds = localTimeMilliseconds / MILLISECONDS_PER_SECOND;
if (localTimeSeconds > MAX_UNIX_TIMET) {
localTimeSeconds = MAX_UNIX_TIMET;
} else if (localTimeSeconds < 0) {
/* Go ahead a day to make localtime work (does not work with 0). */
localTimeSeconds = SECONDS_PER_DAY;
}
/*
* NB: Be aware of the initial range values when making changes to this
* code: the first call to this method, with those initial range
* values, must result in a cache miss.
*/
if (rangeStartSeconds <= localTimeSeconds &&
localTimeSeconds <= rangeEndSeconds) {
return offsetMilliseconds;
}
if (oldRangeStartSeconds <= localTimeSeconds &&
localTimeSeconds <= oldRangeEndSeconds) {
return oldOffsetMilliseconds;
}
oldOffsetMilliseconds = offsetMilliseconds;
oldRangeStartSeconds = rangeStartSeconds;
oldRangeEndSeconds = rangeEndSeconds;
if (rangeStartSeconds <= localTimeSeconds) {
int64_t newEndSeconds = JS_MIN(rangeEndSeconds + RANGE_EXPANSION_AMOUNT, MAX_UNIX_TIMET);
if (newEndSeconds >= localTimeSeconds) {
int64_t endOffsetMilliseconds = computeDSTOffsetMilliseconds(newEndSeconds);
if (endOffsetMilliseconds == offsetMilliseconds) {
rangeEndSeconds = newEndSeconds;
return offsetMilliseconds;
}
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
if (offsetMilliseconds == endOffsetMilliseconds) {
rangeStartSeconds = localTimeSeconds;
rangeEndSeconds = newEndSeconds;
} else {
rangeEndSeconds = localTimeSeconds;
}
return offsetMilliseconds;
}
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
rangeStartSeconds = rangeEndSeconds = localTimeSeconds;
return offsetMilliseconds;
}
int64_t newStartSeconds = JS_MAX(rangeStartSeconds - RANGE_EXPANSION_AMOUNT, 0);
if (newStartSeconds <= localTimeSeconds) {
int64_t startOffsetMilliseconds = computeDSTOffsetMilliseconds(newStartSeconds);
if (startOffsetMilliseconds == offsetMilliseconds) {
rangeStartSeconds = newStartSeconds;
return offsetMilliseconds;
}
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
if (offsetMilliseconds == startOffsetMilliseconds) {
rangeStartSeconds = newStartSeconds;
rangeEndSeconds = localTimeSeconds;
} else {
rangeStartSeconds = localTimeSeconds;
}
return offsetMilliseconds;
}
rangeStartSeconds = rangeEndSeconds = localTimeSeconds;
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
return offsetMilliseconds;
}
JSInt64
DSTOffsetCache::getDSTOffsetMilliseconds(JSInt64 localTimeMilliseconds, JSContext *cx)
{
sanityCheck();
noteOffsetCalculation();
JSInt64 localTimeSeconds = localTimeMilliseconds / MILLISECONDS_PER_SECOND;
if (localTimeSeconds > MAX_UNIX_TIMET) {
localTimeSeconds = MAX_UNIX_TIMET;
} else if (localTimeSeconds < 0) {
/* Go ahead a day to make localtime work (does not work with 0). */
localTimeSeconds = SECONDS_PER_DAY;
}
/*
* NB: Be aware of the initial range values when making changes to this
* code: the first call to this method, with those initial range
* values, must result in a cache miss.
*/
if (rangeStartSeconds <= localTimeSeconds &&
localTimeSeconds <= rangeEndSeconds) {
noteCacheHit();
return offsetMilliseconds;
}
if (oldRangeStartSeconds <= localTimeSeconds &&
localTimeSeconds <= oldRangeEndSeconds) {
noteCacheHit();
return oldOffsetMilliseconds;
}
oldOffsetMilliseconds = offsetMilliseconds;
oldRangeStartSeconds = rangeStartSeconds;
oldRangeEndSeconds = rangeEndSeconds;
if (rangeStartSeconds <= localTimeSeconds) {
JSInt64 newEndSeconds = JS_MIN(rangeEndSeconds + RANGE_EXPANSION_AMOUNT, MAX_UNIX_TIMET);
if (newEndSeconds >= localTimeSeconds) {
JSInt64 endOffsetMilliseconds = computeDSTOffsetMilliseconds(newEndSeconds);
if (endOffsetMilliseconds == offsetMilliseconds) {
noteCacheMissIncrease();
rangeEndSeconds = newEndSeconds;
return offsetMilliseconds;
}
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
if (offsetMilliseconds == endOffsetMilliseconds) {
noteCacheMissIncreasingOffsetChangeUpper();
rangeStartSeconds = localTimeSeconds;
rangeEndSeconds = newEndSeconds;
} else {
noteCacheMissIncreasingOffsetChangeExpand();
rangeEndSeconds = localTimeSeconds;
}
return offsetMilliseconds;
}
noteCacheMissLargeIncrease();
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
rangeStartSeconds = rangeEndSeconds = localTimeSeconds;
return offsetMilliseconds;
}
JSInt64 newStartSeconds = JS_MAX(rangeStartSeconds - RANGE_EXPANSION_AMOUNT, 0);
if (newStartSeconds <= localTimeSeconds) {
JSInt64 startOffsetMilliseconds = computeDSTOffsetMilliseconds(newStartSeconds);
if (startOffsetMilliseconds == offsetMilliseconds) {
noteCacheMissDecrease();
rangeStartSeconds = newStartSeconds;
return offsetMilliseconds;
}
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
if (offsetMilliseconds == startOffsetMilliseconds) {
noteCacheMissDecreasingOffsetChangeLower();
rangeStartSeconds = newStartSeconds;
rangeEndSeconds = localTimeSeconds;
} else {
noteCacheMissDecreasingOffsetChangeExpand();
rangeStartSeconds = localTimeSeconds;
}
return offsetMilliseconds;
}
noteCacheMissLargeDecrease();
rangeStartSeconds = rangeEndSeconds = localTimeSeconds;
offsetMilliseconds = computeDSTOffsetMilliseconds(localTimeSeconds);
return offsetMilliseconds;
}