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//------------------------------------------------------------------------------
// <copyright file="ByteStorage.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="false" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
namespace System.Data.Common {
using System;
using System.Xml;
using System.Data.SqlTypes;
using System.Collections;
internal sealed class ByteStorage : DataStorage {
private const Byte defaultValue = 0;
private Byte[] values;
internal ByteStorage(DataColumn column)
: base(column, typeof(Byte), defaultValue, StorageType.Byte) {
}
override public Object Aggregate(int[] records, AggregateType kind) {
bool hasData = false;
try {
switch (kind) {
case AggregateType.Sum:
UInt64 sum = defaultValue;
foreach (int record in records) {
if (IsNull(record))
continue;
checked { sum += values[record];}
hasData = true;
}
if (hasData) {
return sum;
}
return NullValue;
case AggregateType.Mean:
Int64 meanSum = (Int64)defaultValue;
int meanCount = 0;
foreach (int record in records) {
if (IsNull(record))
continue;
checked { meanSum += (Int64)values[record];}
meanCount++;
hasData = true;
}
if (hasData) {
Byte mean;
checked {mean = (Byte)(meanSum / meanCount);}
return mean;
}
return NullValue;
case AggregateType.Var:
case AggregateType.StDev:
int count = 0;
double var = (double)defaultValue;
double prec = (double)defaultValue;
double dsum = (double)defaultValue;
double sqrsum = (double)defaultValue;
foreach (int record in records) {
if (IsNull(record))
continue;
dsum += (double)values[record];
sqrsum += (double)values[record]*(double)values[record];
count++;
}
if (count > 1) {
var = ((double)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 = var / (count * (count -1));
if (kind == AggregateType.StDev) {
return Math.Sqrt(var);
}
return var;
}
return NullValue;
case AggregateType.Min:
Byte min = Byte.MaxValue;
for (int i = 0; i < records.Length; i++) {
int record = records[i];
if (IsNull(record))
continue;
min=Math.Min(values[record], min);
hasData = true;
}
if (hasData) {
return min;
}
return NullValue;
case AggregateType.Max:
Byte max = Byte.MinValue;
for (int i = 0; i < records.Length; i++) {
int record = records[i];
if (IsNull(record))
continue;
max=Math.Max(values[record], max);
hasData = true;
}
if (hasData) {
return max;
}
return NullValue;
case AggregateType.First:
if (records.Length > 0) {
return values[records[0]];
}
return null;
case AggregateType.Count:
return base.Aggregate(records, kind);
}
}
catch (OverflowException) {
throw ExprException.Overflow(typeof(Byte));
}
throw ExceptionBuilder.AggregateException(kind, DataType);
}
override public int Compare(int recordNo1, int recordNo2) {
Byte valueNo1 = values[recordNo1];
Byte 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 Byte.CompareTo(Byte)
}
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) {
if (IsNull(recordNo)) {
return 0;
}
return 1;
}
Byte valueNo1 = values[recordNo];
if ((defaultValue == valueNo1) && IsNull(recordNo)) {
return -1;
}
return valueNo1.CompareTo((Byte)value);
//return(valueNo1 - valueNo2); // copied from Byte.CompareTo(Byte)
}
public override object ConvertValue(object value) {
if (NullValue != value) {
if (null != value) {
value = ((IConvertible)value).ToByte(FormatProvider);
}
else {
value = NullValue;
}
}
return value;
}
override public void Copy(int recordNo1, int recordNo2) {
CopyBits(recordNo1, recordNo2);
values[recordNo2] = values[recordNo1];
}
override public Object Get(int record) {
Byte value = values[record];
if (value != defaultValue) {
return value;
}
return GetBits(record);
}
override public 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).ToByte(FormatProvider);
SetNullBit(record, false);
}
}
override public void SetCapacity(int capacity) {
Byte[] newValues = new Byte[capacity];
if (null != values) {
Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
}
values = newValues;
base.SetCapacity(capacity);
}
override public object ConvertXmlToObject(string s) {
return XmlConvert.ToByte(s);
}
override public string ConvertObjectToXml(object value) {
return XmlConvert.ToString((Byte) value);
}
override protected object GetEmptyStorage(int recordCount) {
return new Byte[recordCount];
}
override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
Byte[] typedStore = (Byte[]) store;
typedStore[storeIndex] = values[record];
nullbits.Set(storeIndex, IsNull(record));
}
override protected void SetStorage(object store, BitArray nullbits) {
values = (Byte[]) store;
SetNullStorage(nullbits);
}
}
}
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