/// <summary>
/// Computes the cache entry value for the given year, but without populating the cache.
/// </summary>
private static int ComputeCacheEntry(int year)
{
int days = ElapsedDaysNoCache(year);
// We want the elapsed days for the next year as well. Check the cache if possible.
int nextYear = year + 1;
int nextYearDays;
if (nextYear <= MaxYear)
{
int cacheIndex = YearStartCacheEntry.GetCacheIndex(nextYear);
YearStartCacheEntry cacheEntry = YearCache[cacheIndex];
nextYearDays = cacheEntry.IsValidForYear(nextYear)
? cacheEntry.StartOfYearDays & ElapsedDaysCacheMask
: ElapsedDaysNoCache(nextYear);
}
else
{
nextYearDays = ElapsedDaysNoCache(year + 1);
}
int daysInYear = nextYearDays - days;
bool isHeshvanLong = daysInYear % 10 == 5;
bool isKislevShort = daysInYear % 10 == 3;
return(days
| (isHeshvanLong ? IsHeshvanLongCacheBit : 0)
| (isKislevShort ? IsKislevShortCacheBit : 0));
}
/// <summary>
/// Fetches the start of the year (in days since 1970-01-01 ISO) from the cache, or calculates
/// and caches it.
/// </summary>
/// <param name="year">The year to fetch the days at the start of. This must be within 1 year of the min/max
/// range, but can exceed it to make week-year calculations simple.</param>
internal virtual int GetStartOfYearInDays([Trusted] int year)
{
Preconditions.DebugCheckArgumentRange(nameof(year), year, MinYear - 1, MaxYear + 1);
int cacheIndex = YearStartCacheEntry.GetCacheIndex(year);
YearStartCacheEntry cacheEntry = yearCache[cacheIndex];
if (!cacheEntry.IsValidForYear(year))
{
int days = CalculateStartOfYearDays(year);
cacheEntry = new YearStartCacheEntry(year, days);
yearCache[cacheIndex] = cacheEntry;
}
return(cacheEntry.StartOfYearDays);
}
/// <summary>
/// Fetches the start of the year (in days since 1970-01-01 ISO) from the cache, or calculates
/// and caches it.
/// </summary>
protected int GetStartOfYearInDays(int year)
{
if (year < MinYear || year > MaxYear)
{
return(CalculateStartOfYearDays(year));
}
int cacheIndex = YearStartCacheEntry.GetCacheIndex(year);
YearStartCacheEntry cacheEntry = yearCache[cacheIndex];
if (!cacheEntry.IsValidForYear(year))
{
int days = CalculateStartOfYearDays(year);
cacheEntry = new YearStartCacheEntry(year, days);
yearCache[cacheIndex] = cacheEntry;
}
return(cacheEntry.StartOfYearDays);
}
/// <summary>
/// Returns the cached "elapsed day at start of year / IsHeshvanLong / IsKislevShort" combination,
/// populating the cache if necessary. Bits 0-22 are the "elapsed days start of year"; bit 23 is
/// "is Heshvan long"; bit 24 is "is Kislev short". If the year is out of the range for the cache,
/// the value is populated but not cached.
/// </summary>
/// <param name="year"></param>
private static int GetOrPopulateCache(int year)
{
if (year < MinYear || year > MaxYear)
{
return(ComputeCacheEntry(year));
}
int cacheIndex = YearStartCacheEntry.GetCacheIndex(year);
YearStartCacheEntry cacheEntry = YearCache[cacheIndex];
if (!cacheEntry.IsValidForYear(year))
{
int days = ComputeCacheEntry(year);
cacheEntry = new YearStartCacheEntry(year, days);
YearCache[cacheIndex] = cacheEntry;
}
return(cacheEntry.StartOfYearDays);
}
/// <summary>
/// Fetches the start of the year (in days since 1970-01-01 ISO) from the cache, or calculates
/// and caches it.
/// </summary>
/// <param name="year">The year to fetch the days at the start of. This must be within 1 year of the min/max
/// range, but can exceed it to make week-year calculations simple.</param>
internal virtual int GetStartOfYearInDays([Trusted] int year)
{
Preconditions.DebugCheckArgumentRange(nameof(year), year, MinYear - 1, MaxYear + 1);
// TODO(2.0): Check that it's valid to cache values outside the advertised
// bounds of the calendar (by one year). We used not to cache them, but just
// the check was relatively expensive.
int cacheIndex = YearStartCacheEntry.GetCacheIndex(year);
YearStartCacheEntry cacheEntry = yearCache[cacheIndex];
if (!cacheEntry.IsValidForYear(year))
{
int days = CalculateStartOfYearDays(year);
cacheEntry = new YearStartCacheEntry(year, days);
yearCache[cacheIndex] = cacheEntry;
}
return(cacheEntry.StartOfYearDays);
}
/// <summary>
/// Returns the cached "elapsed day at start of year / IsHeshvanLong / IsKislevShort" combination,
/// populating the cache if necessary. Bits 0-22 are the "elapsed days start of year"; bit 23 is
/// "is Heshvan long"; bit 24 is "is Kislev short". If the year is out of the range for the cache,
/// the value is populated but not cached.
/// </summary>
/// <param name="year"></param>
private static int GetOrPopulateCache(int year)
{
if (year < MinYear || year > MaxYear)
{
return ComputeCacheEntry(year);
}
int cacheIndex = YearStartCacheEntry.GetCacheIndex(year);
YearStartCacheEntry cacheEntry = YearCache[cacheIndex];
if (!cacheEntry.IsValidForYear(year))
{
int days = ComputeCacheEntry(year);
cacheEntry = new YearStartCacheEntry(year, days);
YearCache[cacheIndex] = cacheEntry;
}
return cacheEntry.StartOfYearDays;
}
