Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / DecimalMinMaxAggregationOperator.cs / 1305376 / DecimalMinMaxAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // DecimalMinMaxAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined min/max aggregation and its enumerator, for decimals. /// internal sealed class DecimalMinMaxAggregationOperator : InlinedAggregationOperator{ private readonly int m_sign; // The sign (-1 for min, 1 for max). //---------------------------------------------------------------------------------------- // Constructs a new instance of a min/max associative operator. // internal DecimalMinMaxAggregationOperator(IEnumerable child, int sign) : base(child) { Contract.Assert(sign == -1 || sign == 1, "invalid sign"); m_sign = sign; } //--------------------------------------------------------------------------------------- // 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 decimal 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)) { // Throw an error for empty results. if (!enumerator.MoveNext()) { singularExceptionToThrow = new InvalidOperationException(SR.GetString(SR.NoElements)); return default(decimal); } decimal best = enumerator.Current; // Based on the sign, do either a min or max reduction. if (m_sign == -1) { while (enumerator.MoveNext()) { decimal current = enumerator.Current; if (current < best) { best = current; } } } else { while (enumerator.MoveNext()) { decimal current = enumerator.Current; if (current > best) { best = current; } } } return best; } } //--------------------------------------------------------------------------------------- // 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 DecimalMinMaxAggregationOperatorEnumerator (source, index, m_sign, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class DecimalMinMaxAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private QueryOperatorEnumerator m_source; // The source data. private int m_sign; // The sign for comparisons (-1 means min, 1 means max). //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal DecimalMinMaxAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, int sign, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; m_sign = sign; } //--------------------------------------------------------------------------------------- // Tallies up the min/max of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref decimal currentElement) { // Based on the sign, do either a min or max reduction. QueryOperatorEnumerator source = m_source; TKey keyUnused = default(TKey); if (source.MoveNext(ref currentElement, ref keyUnused)) { int i = 0; // We just scroll through the enumerator and find the min or max. if (m_sign == -1) { decimal elem = default(decimal); while (source.MoveNext(ref elem, ref keyUnused)) { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); if (elem < currentElement) { currentElement = elem; } } } else { decimal elem = default(decimal); while (source.MoveNext(ref elem, ref keyUnused)) { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); if (elem > currentElement) { currentElement = elem; } } } 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
- DesignerHelpers.cs
- WebBrowserContainer.cs
- InputLanguage.cs
- ChangePasswordDesigner.cs
- Point3D.cs
- XmlNodeComparer.cs
- BindingWorker.cs
- DefinitionUpdate.cs
- MouseEventArgs.cs
- RequestUriProcessor.cs
- HtmlControlPersistable.cs
- ContextCorrelationInitializer.cs
- UserControlFileEditor.cs
- Symbol.cs
- SecurityException.cs
- glyphs.cs
- HScrollProperties.cs
- ListViewItem.cs
- _NetRes.cs
- RTLAwareMessageBox.cs
- TreeViewCancelEvent.cs
- AccessibleObject.cs
- StrongNameMembershipCondition.cs
- ContractHandle.cs
- UnauthorizedWebPart.cs
- TemplatePagerField.cs
- ClientTargetCollection.cs
- HtmlTernaryTree.cs
- EntityDataSourceValidationException.cs
- DetailsViewCommandEventArgs.cs
- ViewBase.cs
- FramingEncoders.cs
- XmlSchemaParticle.cs
- BaseHashHelper.cs
- ScriptResourceInfo.cs
- ProgressBar.cs
- DynamicUpdateCommand.cs
- GPPOINTF.cs
- ProtectedConfiguration.cs
- XmlSerializationReader.cs
- QilIterator.cs
- NullableFloatSumAggregationOperator.cs
- TreeNodeBindingDepthConverter.cs
- BufferedGraphicsContext.cs
- MarginsConverter.cs
- RegionInfo.cs
- MenuItem.cs
- TrimSurroundingWhitespaceAttribute.cs
- ClearCollection.cs
- XNameTypeConverter.cs
- KeyBinding.cs
- OpCodes.cs
- CodeTypeParameterCollection.cs
- SoapSchemaMember.cs
- StartUpEventArgs.cs
- ShaderRenderModeValidation.cs
- AnnotationElement.cs
- ColorAnimation.cs
- TreeViewImageGenerator.cs
- OracleRowUpdatedEventArgs.cs
- PreProcessor.cs
- ProgramPublisher.cs
- Interlocked.cs
- FilteredDataSetHelper.cs
- ScriptControlManager.cs
- WebBrowserUriTypeConverter.cs
- ExpandCollapseProviderWrapper.cs
- CodeTypeParameterCollection.cs
- WorkflowInstanceExtensionManager.cs
- EntityContainerEntitySet.cs
- WeakKeyDictionary.cs
- ModuleConfigurationInfo.cs
- ActivityDesigner.cs
- DesignerRegion.cs
- FilteredAttributeCollection.cs
- StringValueSerializer.cs
- DelegateBodyWriter.cs
- UnitySerializationHolder.cs
- ConfigXmlText.cs
- CompositeDataBoundControl.cs
- SoapMessage.cs
- InternalBufferOverflowException.cs
- FixedSOMGroup.cs
- MulticastOption.cs
- ConvertTextFrag.cs
- ProtocolsConfigurationHandler.cs
- EventWaitHandle.cs
- UpdateCompiler.cs
- PassportAuthenticationEventArgs.cs
- SmtpLoginAuthenticationModule.cs
- XmlSchemaObjectTable.cs
- FilteredAttributeCollection.cs
- EventHandlersStore.cs
- PerformanceCounterPermissionEntry.cs
- SqlNotificationRequest.cs
- SQLSingleStorage.cs
- WrappedOptions.cs
- AnnotationResource.cs
- WinInet.cs
- ProfileEventArgs.cs