/// <summary>
/// Generate the sequence of cell locations to hash the given key to.
/// </summary>
/// <param name="configuration">The configuration</param>
/// <param name="data">The invertible Bloom filter data</param>
/// <param name="value">The hash value</param>
/// <returns>A sequence of positions to hash the data to (length equals the number of hash functions configured).</returns>
internal static IEnumerable <long> Probe <TId, TCount>(
this IBloomFilterConfiguration <TId, int> configuration,
IInvertibleBloomFilterData <TId, int, TCount> data,
int value)
where TCount : struct
where TId : struct
{
return(configuration
.Probe(data.BlockSize, data.HashFunctionCount, value));
}
/// <summary>
/// Generate the sequence of cell locations to hash the given key to.
/// </summary>
/// <param name="configuration">The configuration</param>
/// <param name="data">The invertible Bloom filter data</param>
/// <param name="value">The hash value</param>
/// <returns>A sequence of positions to hash the data to (length equals the number of hash functions configured).</returns>
internal static IEnumerable <long> Probe <TId>(
this IBloomFilterConfiguration <TId, int> configuration,
long blockSize,
uint hashFunctionCount,
int value)
where TId : struct
{
return(configuration
.Hashes(value, hashFunctionCount)
.Select(p => Math.Abs(p % blockSize)));
}
/// <summary>
/// Compress the estimator data.
/// </summary>
/// <param name="estimator"></param>
/// <param name="configuration"></param>
/// <returns></returns>
internal static IBitMinwiseHashEstimatorFullData Compress <TId, TCount>(
this IBitMinwiseHashEstimatorFullData estimator,
IBloomFilterConfiguration <TId, int> configuration)
where TId : struct
where TCount : struct
{
if (configuration?.FoldingStrategy == null || estimator == null)
{
return(null);
}
var fold = configuration.FoldingStrategy.FindCompressionFactor(configuration, estimator.Capacity, estimator.Capacity, estimator.ItemCount);
return(fold.HasValue ? estimator.Fold(fold.Value) : null);
}
