Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / Common / DoubleStorage.cs / 1 / DoubleStorage.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //[....] //----------------------------------------------------------------------------- namespace System.Data.Common { using System; using System.Xml; using System.Data.SqlTypes; using System.Collections; internal sealed class DoubleStorage : DataStorage { private const Double defaultValue = 0.0d; private Double[] values; internal DoubleStorage(DataColumn column) : base(column, typeof(Double), defaultValue) { } override public Object Aggregate(int[] records, AggregateType kind) { bool hasData = false; try { switch (kind) { case AggregateType.Sum: Double 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: Double meanSum = (Double)defaultValue; int meanCount = 0; foreach (int record in records) { if (IsNull(record)) continue; checked { meanSum += (Double)values[record];} meanCount++; hasData = true; } if (hasData) { Double mean; checked {mean = (Double)(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: Double min = Double.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: Double max = Double.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(Double)); } throw ExceptionBuilder.AggregateException(kind, DataType); } override public int Compare(int recordNo1, int recordNo2) { Double valueNo1 = values[recordNo1]; Double valueNo2 = values[recordNo2]; if (valueNo1 == defaultValue || valueNo2 == defaultValue) { int bitCheck = CompareBits(recordNo1, recordNo2); if (0 != bitCheck) return bitCheck; } return valueNo1.CompareTo(valueNo2); // not simple, checks Nan } 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; } Double valueNo1 = values[recordNo]; if ((defaultValue == valueNo1) && IsNull(recordNo)) { return -1; } return valueNo1.CompareTo((Double)value); } public override object ConvertValue(object value) { if (NullValue != value) { if (null != value) { value = ((IConvertible)value).ToDouble(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) { Double 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).ToDouble(FormatProvider); SetNullBit(record, false); } } override public void SetCapacity(int capacity) { Double[] newValues = new Double[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.ToDouble(s); } override public string ConvertObjectToXml(object value) { return XmlConvert.ToString((Double) value); } override protected object GetEmptyStorage(int recordCount) { return new Double[recordCount]; } override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) { Double[] typedStore = (Double[]) store; typedStore[storeIndex] = values[record]; nullbits.Set(storeIndex, IsNull(record)); } override protected void SetStorage(object store, BitArray nullbits) { values = (Double[]) store; SetNullStorage(nullbits); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XamlClipboardData.cs
- XMLDiffLoader.cs
- SurrogateSelector.cs
- TableRowGroup.cs
- XmlSchemaElement.cs
- ToolStripContentPanelRenderEventArgs.cs
- MsdtcWrapper.cs
- XmlTypeMapping.cs
- TextRunProperties.cs
- Latin1Encoding.cs
- SafeFindHandle.cs
- PersonalizationEntry.cs
- QilGeneratorEnv.cs
- FrameworkElement.cs
- ServiceDescriptionImporter.cs
- WmiInstallComponent.cs
- EntitySetBaseCollection.cs
- Soap.cs
- CollectionViewProxy.cs
- BasicAsyncResult.cs
- DocumentViewer.cs
- DataView.cs
- WSHttpBindingBaseElement.cs
- MouseOverProperty.cs
- InfiniteTimeSpanConverter.cs
- CommandConverter.cs
- MediaEntryAttribute.cs
- CompilerGeneratedAttribute.cs
- DataTableClearEvent.cs
- WorkflowInstance.cs
- TailCallAnalyzer.cs
- CommandLineParser.cs
- ContainerActivationHelper.cs
- ListViewItem.cs
- TextProviderWrapper.cs
- RenamedEventArgs.cs
- MethodBuilderInstantiation.cs
- SqlException.cs
- DoubleLinkList.cs
- SHA256.cs
- MessageSecurityOverMsmq.cs
- Win32Native.cs
- ClientConfigPaths.cs
- DataGridTable.cs
- DataRowExtensions.cs
- DiscoveryVersion.cs
- EventlogProvider.cs
- ColumnHeaderCollectionEditor.cs
- ResourceDescriptionAttribute.cs
- MobileComponentEditorPage.cs
- EventLogWatcher.cs
- Geometry3D.cs
- DocumentAutomationPeer.cs
- DataBindingExpressionBuilder.cs
- RenderDataDrawingContext.cs
- LongValidatorAttribute.cs
- InternalCache.cs
- PreviewPrintController.cs
- VersionPair.cs
- XamlTreeBuilderBamlRecordWriter.cs
- SecurityTimestamp.cs
- Transactions.cs
- EventProxy.cs
- XmlTypeAttribute.cs
- DataTableExtensions.cs
- XPathSingletonIterator.cs
- InlinedLocationReference.cs
- ResourcePermissionBase.cs
- MemberProjectedSlot.cs
- SystemColorTracker.cs
- CellTreeSimplifier.cs
- Root.cs
- Timer.cs
- ControlPropertyNameConverter.cs
- XmlUtil.cs
- MemberAssignmentAnalysis.cs
- HttpHandlerActionCollection.cs
- SecurityTokenValidationException.cs
- TextParagraphProperties.cs
- PtsPage.cs
- Object.cs
- JournalEntryListConverter.cs
- DataGridViewSelectedCellCollection.cs
- PersonalizationProviderHelper.cs
- HotCommands.cs
- VBCodeProvider.cs
- BooleanToVisibilityConverter.cs
- SystemIPInterfaceProperties.cs
- DefaultBindingPropertyAttribute.cs
- SessionEndedEventArgs.cs
- OracleDateTime.cs
- Identity.cs
- HotCommands.cs
- TextDataBindingHandler.cs
- XPathScanner.cs
- AutomationIdentifierGuids.cs
- EndpointIdentityConverter.cs
- COM2PictureConverter.cs
- SqlMethods.cs
- InitializationEventAttribute.cs