Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / LongCountAggregationOperator.cs / 1305376 / LongCountAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // CountAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined count aggregation and its enumerator. /// ///internal sealed class LongCountAggregationOperator : InlinedAggregationOperator { //---------------------------------------------------------------------------------------- // Constructs a new instance of the operator. // internal LongCountAggregationOperator(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 long 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. long count = 0; while (enumerator.MoveNext()) { checked { count += enumerator.Current; } } return count; } } //--------------------------------------------------------------------------------------- // 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 LongCountAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class LongCountAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal LongCountAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Counts the elements in the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref long currentElement) { TSource elementUnused = default(TSource); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref elementUnused, ref keyUnused)) { // We just scroll through the enumerator and keep a running count. long count = 0; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); checked { count++; } } while (source.MoveNext(ref elementUnused, ref keyUnused)); currentElement = count; 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. // ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // CountAggregationOperator.cs // // [....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined count aggregation and its enumerator. /// ///internal sealed class LongCountAggregationOperator : InlinedAggregationOperator { //---------------------------------------------------------------------------------------- // Constructs a new instance of the operator. // internal LongCountAggregationOperator(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 long 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. long count = 0; while (enumerator.MoveNext()) { checked { count += enumerator.Current; } } return count; } } //--------------------------------------------------------------------------------------- // 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 LongCountAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class LongCountAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal LongCountAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Counts the elements in the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref long currentElement) { TSource elementUnused = default(TSource); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref elementUnused, ref keyUnused)) { // We just scroll through the enumerator and keep a running count. long count = 0; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); checked { count++; } } while (source.MoveNext(ref elementUnused, ref keyUnused)); currentElement = count; 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
- StringDictionary.cs
- VirtualizingStackPanel.cs
- XmlDocumentSerializer.cs
- IDictionary.cs
- TypeSystem.cs
- PoisonMessageException.cs
- FileRecordSequenceCompletedAsyncResult.cs
- ProcessHostMapPath.cs
- QilChoice.cs
- BrowserTree.cs
- XmlLanguage.cs
- ResourceSetExpression.cs
- ModulesEntry.cs
- IdentityHolder.cs
- TypefaceMap.cs
- BuildProviderAppliesToAttribute.cs
- ClearTypeHintValidation.cs
- SqlConnectionHelper.cs
- TimeSpanOrInfiniteConverter.cs
- OperationCanceledException.cs
- LinkDesigner.cs
- DataBindingExpressionBuilder.cs
- DetailsViewModeEventArgs.cs
- OracleConnectionFactory.cs
- ConfigXmlDocument.cs
- ListItemCollection.cs
- ControlType.cs
- ColorTransform.cs
- WebSysDescriptionAttribute.cs
- UserUseLicenseDictionaryLoader.cs
- ObjectAnimationUsingKeyFrames.cs
- RayHitTestParameters.cs
- CellCreator.cs
- TextControl.cs
- VideoDrawing.cs
- ImageIndexEditor.cs
- RuleSetReference.cs
- SelectionRangeConverter.cs
- DynamicPropertyHolder.cs
- DataContractJsonSerializer.cs
- Variant.cs
- OperationInfoBase.cs
- DescendantQuery.cs
- BorderGapMaskConverter.cs
- NegatedCellConstant.cs
- PopupRoot.cs
- ToolStripSplitStackLayout.cs
- EventProviderWriter.cs
- Baml2006SchemaContext.cs
- LeaseManager.cs
- ScriptResourceHandler.cs
- EventEntry.cs
- OSEnvironmentHelper.cs
- ListView.cs
- DbConnectionStringBuilder.cs
- ThreadAbortException.cs
- UdpChannelFactory.cs
- Registry.cs
- InsufficientMemoryException.cs
- ActivityInstance.cs
- CryptoStream.cs
- GeometryHitTestParameters.cs
- HtmlDocument.cs
- PaperSize.cs
- MemberPathMap.cs
- DragSelectionMessageFilter.cs
- RootBrowserWindowAutomationPeer.cs
- AssociationSetEnd.cs
- TextSpanModifier.cs
- ProfileModule.cs
- RSAPKCS1SignatureDeformatter.cs
- ObjectReferenceStack.cs
- __ComObject.cs
- PolygonHotSpot.cs
- GeneralTransform3DCollection.cs
- DoubleAnimationBase.cs
- SoapInteropTypes.cs
- DeviceContext2.cs
- SynchronousChannel.cs
- Item.cs
- DiscardableAttribute.cs
- Size.cs
- MenuRenderer.cs
- ExpressionBindingCollection.cs
- RestClientProxyHandler.cs
- X509ScopedServiceCertificateElementCollection.cs
- CookieProtection.cs
- AnonymousIdentificationModule.cs
- DataObjectMethodAttribute.cs
- ColorContextHelper.cs
- CompModSwitches.cs
- GridViewRow.cs
- ThreadNeutralSemaphore.cs
- CachingHintValidation.cs
- SizeIndependentAnimationStorage.cs
- NamedElement.cs
- WorkflowPersistenceService.cs
- Guid.cs
- CryptoHelper.cs
- WebPartUserCapability.cs