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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections;
using System.Diagnostics.CodeAnalysis;
using System.Xml;
namespace System.Data.Common
{
internal sealed class UInt16Storage : DataStorage
{
private const ushort DefaultValue = ushort.MinValue;
private ushort[] _values = default!; // Late-initialized
public UInt16Storage(DataColumn column)
: base(column, typeof(ushort), DefaultValue, StorageType.UInt16)
{
}
public override object Aggregate(int[] records, AggregateType kind)
{
bool hasData = false;
try
{
switch (kind)
{
case AggregateType.Sum:
ulong sum = DefaultValue;
foreach (int record in records)
{
if (HasValue(record))
{
checked { sum += _values[record]; }
hasData = true;
}
}
if (hasData)
{
return sum;
}
return _nullValue;
case AggregateType.Mean:
long meanSum = DefaultValue;
int meanCount = 0;
foreach (int record in records)
{
if (HasValue(record))
{
checked { meanSum += _values[record]; }
meanCount++;
hasData = true;
}
}
if (hasData)
{
ushort mean;
checked { mean = (ushort)(meanSum / meanCount); }
return mean;
}
return _nullValue;
case AggregateType.Var:
case AggregateType.StDev:
int count = 0;
double var = 0.0f;
double prec = 0.0f;
double dsum = 0.0f;
double sqrsum = 0.0f;
foreach (int record in records)
{
if (HasValue(record))
{
dsum += _values[record];
sqrsum += _values[record] * (double)_values[record];
count++;
}
}
if (count > 1)
{
var = count * sqrsum - (dsum * dsum);
prec = var / (dsum * dsum);
// we are dealing with the risk of a cancellation error
// double is guaranteed only for 15 digits so a difference
// with a result less than 1e-15 should be considered as zero
if ((prec < 1e-15) || (var < 0))
var = 0;
else
var /= (count * (count - 1));
if (kind == AggregateType.StDev)
{
return Math.Sqrt(var);
}
return var;
}
return _nullValue;
case AggregateType.Min:
ushort min = ushort.MaxValue;
for (int i = 0; i < records.Length; i++)
{
int record = records[i];
if (HasValue(record))
{
min = Math.Min(_values[record], min);
hasData = true;
}
}
if (hasData)
{
return min;
}
return _nullValue;
case AggregateType.Max:
ushort max = ushort.MinValue;
for (int i = 0; i < records.Length; i++)
{
int record = records[i];
if (HasValue(record))
{
max = Math.Max(_values[record], max);
hasData = true;
}
}
if (hasData)
{
return max;
}
return _nullValue;
case AggregateType.First: // Does not seem to be implemented
if (records.Length > 0)
{
return _values[records[0]];
}
return null!;
case AggregateType.Count:
count = 0;
for (int i = 0; i < records.Length; i++)
{
if (HasValue(records[i]))
{
count++;
}
}
return count;
}
}
catch (OverflowException)
{
throw ExprException.Overflow(typeof(ushort));
}
throw ExceptionBuilder.AggregateException(kind, _dataType);
}
public override int Compare(int recordNo1, int recordNo2)
{
ushort valueNo1 = _values[recordNo1];
ushort valueNo2 = _values[recordNo2];
if (valueNo1 == DefaultValue || valueNo2 == DefaultValue)
{
int bitCheck = CompareBits(recordNo1, recordNo2);
if (0 != bitCheck)
{
return bitCheck;
}
}
//return valueNo1.CompareTo(valueNo2);
return valueNo1 - valueNo2; // copied from UInt16.CompareTo(UInt16)
}
public override int CompareValueTo(int recordNo, object? value)
{
System.Diagnostics.Debug.Assert(0 <= recordNo, "Invalid record");
System.Diagnostics.Debug.Assert(null != value, "null value");
if (_nullValue == value)
{
return (HasValue(recordNo) ? 1 : 0);
}
ushort valueNo1 = _values[recordNo];
if ((DefaultValue == valueNo1) && !HasValue(recordNo))
{
return -1;
}
return valueNo1.CompareTo((ushort)value);
//return ((int)valueNo1 - (int)valueNo2); // copied from UInt16.CompareTo(UInt16)
}
public override object ConvertValue(object? value)
{
if (_nullValue != value)
{
if (null != value)
{
value = ((IConvertible)value).ToUInt16(FormatProvider);
}
else
{
value = _nullValue;
}
}
return value;
}
public override void Copy(int recordNo1, int recordNo2)
{
CopyBits(recordNo1, recordNo2);
_values[recordNo2] = _values[recordNo1];
}
public override object Get(int record)
{
ushort value = _values[record];
if (!value.Equals(DefaultValue))
{
return value;
}
return GetBits(record);
}
public override void Set(int record, object value)
{
System.Diagnostics.Debug.Assert(null != value, "null value");
if (_nullValue == value)
{
_values[record] = DefaultValue;
SetNullBit(record, true);
}
else
{
_values[record] = ((IConvertible)value).ToUInt16(FormatProvider);
SetNullBit(record, false);
}
}
public override void SetCapacity(int capacity)
{
Array.Resize(ref _values, capacity);
base.SetCapacity(capacity);
}
[RequiresUnreferencedCode(DataSet.RequiresUnreferencedCodeMessage)]
public override object ConvertXmlToObject(string s)
{
return XmlConvert.ToUInt16(s);
}
[RequiresUnreferencedCode(DataSet.RequiresUnreferencedCodeMessage)]
public override string ConvertObjectToXml(object value)
{
return XmlConvert.ToString((ushort)value);
}
protected override object GetEmptyStorage(int recordCount)
{
return new ushort[recordCount];
}
protected override void CopyValue(int record, object store, BitArray nullbits, int storeIndex)
{
ushort[] typedStore = (ushort[])store;
typedStore[storeIndex] = _values[record];
nullbits.Set(storeIndex, !HasValue(record));
}
protected override void SetStorage(object store, BitArray nullbits)
{
_values = (ushort[])store;
SetNullStorage(nullbits);
}
}
}
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