/// <summary>
/// Get the folded value at the given position
/// </summary>
/// <typeparam name="TCount">Type of the item</typeparam>
/// <param name="values">The values</param>
/// <param name="position">The position</param>
/// <param name="blockSize">The block size of the unfolded Bloom filter</param>
/// <param name="foldFactor">Factor to fold by</param>
/// <param name="foldOperator">The operator to apply during folding</param>
/// <returns></returns>
internal static TCount GetFolded <TCount>(
this ICompressedArray <TCount> values,
long position,
long blockSize,
long foldFactor,
Func <TCount, TCount, TCount> foldOperator)
where TCount : struct
{
if (foldFactor <= 1L)
{
return(values[position]);
}
var foldedSize = blockSize / foldFactor;
position = position % foldedSize;
return(LongEnumerable.Range(1L, foldFactor)
.Aggregate(values[position],
(foldedValue, factor) => foldOperator(foldedValue, values[position + factor * foldedSize])));
}
/// <summary>
/// Set the counter provider.
/// </summary>
/// <param name="configuration"></param>
public void SyncCompressionProviders(
ICountingBloomFilterConfiguration <TId, THash, TCount> configuration)
{
if (configuration == null)
{
throw new ArgumentException("Configuration is null", nameof(configuration));
}
if (_hasDirtyProvider)
{
_hasDirtyProvider = false;
_membershipTest = position => IsMember(configuration.CountConfiguration, this, position);
_hashSumProvider = configuration.CompressedArrayFactory.Create <THash>();
_hashSumProvider.Load(_hashSums, BlockSize, _membershipTest);
_hashSums = null;
_idSumProvider = configuration.CompressedArrayFactory.Create <TId>();
_idSumProvider.Load(_idSums, BlockSize, _membershipTest);
_idSums = null;
}
}
