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//------------------------------------------------------------------------------
// <copyright file="SQLSingleStorage.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.Diagnostics;
using System.Globalization;
using System.IO;
using System.Xml.Serialization;
using System.Collections;
internal sealed class SqlSingleStorage : DataStorage {
private SqlSingle[] values;
public SqlSingleStorage(DataColumn column)
: base(column, typeof(SqlSingle), SqlSingle.Null, SqlSingle.Null, StorageType.SqlSingle) {
}
override public Object Aggregate(int[] records, AggregateType kind) {
bool hasData = false;
try {
switch (kind) {
case AggregateType.Sum:
SqlSingle sum = 0.0f;
foreach (int record in records) {
if (IsNull(record))
continue;
checked { sum += values[record];}
hasData = true;
}
if (hasData)
return sum;
return NullValue;
case AggregateType.Mean:
SqlDouble meanSum = (SqlDouble) 0.0f;
int meanCount = 0;
foreach (int record in records) {
if (IsNull(record))
continue;
checked { meanSum += values[record].ToSqlDouble();}
meanCount++;
hasData = true;
}
if (hasData) {
SqlSingle mean = 0;
checked {mean = (meanSum /(SqlDouble) meanCount).ToSqlSingle();}
return mean;
}
return NullValue;
case AggregateType.Var:
case AggregateType.StDev:
int count = 0;
SqlDouble var = (SqlDouble)0;
SqlDouble prec = (SqlDouble)0;
SqlDouble dsum = (SqlDouble)0;
SqlDouble sqrsum = (SqlDouble)0;
foreach (int record in records) {
if (IsNull(record))
continue;
dsum += values[record].ToSqlDouble();
sqrsum += (values[record]).ToSqlDouble() * (values[record]).ToSqlDouble();
count++;
}
if (count > 1) {
var = ((SqlDouble)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.Value);
}
return var;
}
return NullValue;
case AggregateType.Min:
SqlSingle min = SqlSingle.MaxValue;
for (int i = 0; i < records.Length; i++) {
int record = records[i];
if (IsNull(record))
continue;
if ((SqlSingle.LessThan(values[record], min)).IsTrue)
min = values[record];
hasData = true;
}
if (hasData)
return min;
return NullValue;
case AggregateType.Max:
SqlSingle max = SqlSingle.MinValue;
for (int i = 0; i < records.Length; i++) {
int record = records[i];
if (IsNull(record))
continue;
if ((SqlSingle.GreaterThan(values[record], max)).IsTrue)
max = values[record];
hasData = true;
}
if (hasData)
return max;
return NullValue;
case AggregateType.First:
if (records.Length > 0) {
return values[records[0]];
}
return null;
case AggregateType.Count:
count = 0;
for (int i = 0; i < records.Length; i++) {
if (!IsNull(records[i]))
count++;
}
return count;
}
}
catch (OverflowException) {
throw ExprException.Overflow(typeof(SqlSingle));
}
throw ExceptionBuilder.AggregateException(kind, DataType);
}
override public int Compare(int recordNo1, int recordNo2) {
return values[recordNo1].CompareTo(values[recordNo2]);
}
override public int CompareValueTo(int recordNo, Object value) {
return values[recordNo].CompareTo((SqlSingle)value);
}
override public object ConvertValue(object value) {
if (null != value) {
return SqlConvert.ConvertToSqlSingle(value);
}
return NullValue;
}
override public void Copy(int recordNo1, int recordNo2) {
values[recordNo2] = values[recordNo1];
}
override public Object Get(int record) {
return values[record];
}
override public bool IsNull(int record) {
return (values[record].IsNull);
}
override public void Set(int record, Object value) {
values[record] = SqlConvert.ConvertToSqlSingle(value);
}
override public void SetCapacity(int capacity) {
SqlSingle[] newValues = new SqlSingle[capacity];
if (null != values) {
Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
}
values = newValues;
}
override public object ConvertXmlToObject(string s) {
SqlSingle newValue = new SqlSingle();
string tempStr =string.Concat("<col>", s, "</col>"); // this is done since you can give fragmet to reader,
StringReader strReader = new StringReader(tempStr);
IXmlSerializable tmp = newValue;
using (XmlTextReader xmlTextReader = new XmlTextReader(strReader)) {
tmp.ReadXml(xmlTextReader);
}
return ((SqlSingle)tmp);
}
override public string ConvertObjectToXml(object value) {
Debug.Assert(!DataStorage.IsObjectNull(value), "we should have null here");
Debug.Assert((value.GetType() == typeof(SqlSingle)), "wrong input type");
StringWriter strwriter = new StringWriter(FormatProvider);
using (XmlTextWriter xmlTextWriter = new XmlTextWriter (strwriter)) {
((IXmlSerializable)value).WriteXml(xmlTextWriter);
}
return (strwriter.ToString ());
}
override protected object GetEmptyStorage(int recordCount) {
return new SqlSingle[recordCount];
}
override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
SqlSingle[] typedStore = (SqlSingle[]) store;
typedStore[storeIndex] = values[record];
nullbits.Set(storeIndex, IsNull(record));
}
override protected void SetStorage(object store, BitArray nullbits) {
values = (SqlSingle[]) store;
//SetNullStorage(nullbits);
}
}
}
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