Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / IntSumAggregationOperator.cs / 1305376 / IntSumAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // IntSumAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// Inlined aggregations for summing up primitives (int, long, float, double, decimal), as /// well as the nullable versions of each (int?, long?, float?, double?, decimal?). /// internal sealed class IntSumAggregationOperator : InlinedAggregationOperator{ //---------------------------------------------------------------------------------------- // Constructs a new instance of a sum associative operator. // internal IntSumAggregationOperator(IEnumerable child) : base(child) { } //--------------------------------------------------------------------------------------- // Executes the entire query tree, and aggregates the intermediate results into the // final result based on the binary operators and final reduction. // // Return Value: // The single result of aggregation. // protected override int InternalAggregate(ref Exception singularExceptionToThrow) { // Because the final reduction is typically much cheaper than the intermediate // reductions over the individual partitions, and because each parallel partition // will do a lot of work to produce a single output element, we prefer to turn off // pipelining, and process the final reductions serially. using (IEnumerator enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, true)) { // We just reduce the elements in each output partition. int sum = 0; while (enumerator.MoveNext()) { checked { sum += enumerator.Current; } } return sum; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new IntSumAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class IntSumAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal IntSumAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the sum of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref int currentElement) { int element = default(int); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref element, ref keyUnused)) { // We just scroll through the enumerator and accumulate the sum. int tempSum = 0; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); checked { tempSum += element; } } while (source.MoveNext(ref element, ref keyUnused)); // The sum has been calculated. Now just return. currentElement = tempSum; return true; } return false; } //---------------------------------------------------------------------------------------- // Dispose of resources associated with the underlying enumerator. // protected override void Dispose(bool disposing) { Contract.Assert(m_source != null); m_source.Dispose(); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- ApplicationDirectoryMembershipCondition.cs
- ProvidePropertyAttribute.cs
- Label.cs
- ByteKeyFrameCollection.cs
- RowToFieldTransformer.cs
- ToolStripItemRenderEventArgs.cs
- DeferredTextReference.cs
- ProxyWebPart.cs
- SolidColorBrush.cs
- GridViewItemAutomationPeer.cs
- EdmTypeAttribute.cs
- CodeTypeMember.cs
- ConsumerConnectionPoint.cs
- RectConverter.cs
- Latin1Encoding.cs
- SelectionChangedEventArgs.cs
- BitArray.cs
- DateTimeFormatInfoScanner.cs
- X509Utils.cs
- ControlPropertyNameConverter.cs
- TrackingDataItemValue.cs
- MultipleViewProviderWrapper.cs
- EnumerationRangeValidationUtil.cs
- IndentedWriter.cs
- ContainerControl.cs
- RegexCaptureCollection.cs
- DoubleLinkList.cs
- Util.cs
- SizeFConverter.cs
- Decimal.cs
- XsltContext.cs
- SemaphoreSecurity.cs
- NumericUpDownAccelerationCollection.cs
- DataChangedEventManager.cs
- PlatformNotSupportedException.cs
- BuildProvidersCompiler.cs
- AsyncOperationManager.cs
- IpcServerChannel.cs
- WindowsListViewSubItem.cs
- GiveFeedbackEvent.cs
- FileDialog_Vista_Interop.cs
- SqlParameter.cs
- ClientClassGenerator.cs
- BindingCompleteEventArgs.cs
- FontDifferentiator.cs
- ExpressionVisitor.cs
- SerializationAttributes.cs
- DispatcherProcessingDisabled.cs
- RequestQueryProcessor.cs
- BoolLiteral.cs
- PropertyItemInternal.cs
- RealizationDrawingContextWalker.cs
- AssemblyResourceLoader.cs
- WebPartConnectionsCancelVerb.cs
- SqlClientWrapperSmiStreamChars.cs
- StrokeNodeOperations2.cs
- StrongNamePublicKeyBlob.cs
- LinearQuaternionKeyFrame.cs
- SafeNativeMethods.cs
- HatchBrush.cs
- XmlSchemaObjectCollection.cs
- EditingScopeUndoUnit.cs
- TextServicesManager.cs
- EnvelopedSignatureTransform.cs
- DefaultTextStoreTextComposition.cs
- X509RawDataKeyIdentifierClause.cs
- ToolStripProgressBar.cs
- FlagsAttribute.cs
- DbException.cs
- AxisAngleRotation3D.cs
- ObjectDataSourceChooseMethodsPanel.cs
- SessionPageStatePersister.cs
- JobInputBins.cs
- IconConverter.cs
- CommandDevice.cs
- AttachedPropertyBrowsableForTypeAttribute.cs
- BuildProvider.cs
- AttachedAnnotationChangedEventArgs.cs
- WebFormDesignerActionService.cs
- ListViewGroupItemCollection.cs
- TreeViewItemAutomationPeer.cs
- QEncodedStream.cs
- Int32EqualityComparer.cs
- DataGridViewTextBoxColumn.cs
- ErrorFormatterPage.cs
- CompositionTarget.cs
- XmlConvert.cs
- UnsafeNativeMethodsPenimc.cs
- ObjectTag.cs
- TextServicesProperty.cs
- IisTraceWebEventProvider.cs
- TextProperties.cs
- PersonalizationStateQuery.cs
- NamespaceCollection.cs
- ValidatorCollection.cs
- FlowchartDesigner.xaml.cs
- TextSimpleMarkerProperties.cs
- FileDialog_Vista_Interop.cs
- HttpWriter.cs
- SoapIgnoreAttribute.cs