public IEnumerable <T> GetValuesAndReturnArray <T>(DataColumnStatistics statistics, IEqualityComparer <T> equalityComparer, IComparer <T> comparer)
{
AssertNotConsumed();
T[] typed = (T[])_array;
if (statistics == null)
{
for (int i = 0; i < Count; i++)
{
yield return(typed[i]);
}
ReturnArray();
yield break;
}
// there's a big win here if you can use the ctor from NET Standard 2.1 that has a capacity, which avoids GC overhead of resize
#if NETSTANDARD2_1
HashSet <T> hashSet = new HashSet <T>(Count, equalityComparer);
#else
HashSet <T> hashSet = new HashSet <T>(equalityComparer);
#endif
T min = default;
T max = default;
for (int i = 0; i < Count; i++)
{
T current = typed[i];
yield return(current);
hashSet.Add(current);
if (i == 0)
{
min = current;
max = current;
}
else
{
int cmin = comparer.Compare(min, current);
int cmax = comparer.Compare(max, current);
if (cmin > 0)
{
min = current;
}
if (cmax < 0)
{
max = current;
}
}
}
statistics.MinValue = min;
statistics.MaxValue = max;
statistics.DistinctCount = hashSet.Count;
ReturnArray();
_consumed = true;
}
public void Write(Thrift.SchemaElement tse, BinaryWriter writer, ArrayView values, DataColumnStatistics statistics)
{
throw new NotSupportedException();
}
public virtual void Write(Thrift.SchemaElement tse, BinaryWriter writer, ArrayView values, DataColumnStatistics statistics)
{
foreach (TSystemType one in values.GetValuesAndReturnArray(statistics, this, this))
{
WriteOne(writer, one);
}
}
public virtual void Write(Thrift.SchemaElement tse, BinaryWriter writer, IList values, DataColumnStatistics statistics)
{
// casing to an array of TSystemType means we avoid Array.GetValue calls, which are slow
var typedArray = (TSystemType[])values;
foreach (TSystemType one in typedArray)
{
WriteOne(writer, one);
}
// calculate statistics if required
if (statistics != null)
{
//number of distinct values
statistics.DistinctCount = ((TSystemType[])values).Distinct(this).Count();
TSystemType min = default;
TSystemType max = default;
for (int i = 0; i < typedArray.Length; i++)
{
if (i == 0)
{
min = typedArray[0];
max = typedArray[0];
}
else
{
TSystemType current = typedArray[i];
int cmin = Compare(min, current);
int cmax = Compare(max, current);
if (cmin > 0)
{
min = current;
}
if (cmax < 0)
{
max = current;
}
}
}
statistics.MinValue = min;
statistics.MaxValue = max;
}
}
