Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / Utils / FixedMaxHeap.cs / 1305376 / FixedMaxHeap.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // FixedMaxHeap.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; namespace System.Linq.Parallel { ////// Very simple heap data structure, of fixed size. /// ///internal class FixedMaxHeap { private TElement[] m_elements; // Element array. private int m_count; // Current count. private IComparer m_comparer; // Element comparison routine. //------------------------------------------------------------------------------------ // Create a new heap with the specified maximum size. // internal FixedMaxHeap(int maximumSize) : this(maximumSize, Util.GetDefaultComparer ()) { } internal FixedMaxHeap(int maximumSize, IComparer comparer) { m_elements = new TElement[maximumSize]; m_comparer = comparer; } //----------------------------------------------------------------------------------- // Retrieve the count (i.e. how many elements are in the heap). // internal int Count { get { return m_count; } } //----------------------------------------------------------------------------------- // Retrieve the size (i.e. the maximum size of the heap). // internal int Size { get { return m_elements.Length; } } //----------------------------------------------------------------------------------- // Get the current maximum value in the max-heap. // // Note: The heap stores the maximumSize smallest elements that were inserted. // So, if the heap is full, the value returned is the maximumSize-th smallest // element that was inserted into the heap. // internal TElement MaxValue { get { if (m_count == 0) { throw new InvalidOperationException(SR.GetString(SR.NoElements)); } // The maximum element is in the 0th position. return m_elements[0]; } } //------------------------------------------------------------------------------------ // Removes all elements from the heap. // internal void Clear() { m_count = 0; } //----------------------------------------------------------------------------------- // Inserts the new element, maintaining the heap property. // // Return Value: // If the element is greater than the current max element, this function returns // false without modifying the heap. Otherwise, it returns true. // internal bool Insert(TElement e) { if (m_count < m_elements.Length) { // There is room. We can add it and then max-heapify. m_elements[m_count] = e; m_count++; HeapifyLastLeaf(); return true; } else { // No more room. The element might not even fit in the heap. The check // is simple: if it's greater than the maximum element, then it can't be // inserted. Otherwise, we replace the head with it and reheapify. if (m_comparer.Compare(e, m_elements[0]) < 0) { m_elements[0] = e; HeapifyRoot(); return true; } return false; } } //------------------------------------------------------------------------------------ // Replaces the maximum value in the heap with the user-provided value, and restores // the heap property. // internal void ReplaceMax(TElement newValue) { Contract.Assert(m_count > 0); m_elements[0] = newValue; HeapifyRoot(); } //------------------------------------------------------------------------------------ // Removes the maximum value from the heap, and restores the heap property. // internal void RemoveMax() { Contract.Assert(m_count > 0); m_count--; if (m_count > 0) { m_elements[0] = m_elements[m_count]; HeapifyRoot(); } } //----------------------------------------------------------------------------------- // Private helpers to swap elements, and to reheapify starting from the root or // from a leaf element, depending on what is needed. // private void Swap(int i, int j) { TElement tmpElement = m_elements[i]; m_elements[i] = m_elements[j]; m_elements[j] = tmpElement; } private void HeapifyRoot() { // We are heapifying from the head of the list. int i = 0; int n = m_count; while (i < n) { // Calculate the current child node indexes. int n0 = ((i + 1) * 2) - 1; int n1 = n0 + 1; if (n0 < n && m_comparer.Compare(m_elements[i], m_elements[n0]) < 0) { // We have to select the bigger of the two subtrees, and float // the current element down. This maintains the max-heap property. if (n1 < n && m_comparer.Compare(m_elements[n0], m_elements[n1]) < 0) { Swap(i, n1); i = n1; } else { Swap(i, n0); i = n0; } } else if (n1 < n && m_comparer.Compare(m_elements[i], m_elements[n1]) < 0) { // Float down the "right" subtree. We needn't compare this subtree // to the "left", because if the element was smaller than that, the // first if statement's predicate would have evaluated to true. Swap(i, n1); i = n1; } else { // Else, the current key is in its final position. Break out // of the current loop and return. break; } } } private void HeapifyLastLeaf() { int i = m_count - 1; while (i > 0) { int j = ((i + 1) / 2) - 1; if (m_comparer.Compare(m_elements[i], m_elements[j]) > 0) { Swap(i, j); i = j; } else { break; } } } } } // 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
- XsdDataContractImporter.cs
- _CookieModule.cs
- AlignmentXValidation.cs
- MimeMapping.cs
- DetailsViewInsertedEventArgs.cs
- ClientFormsAuthenticationCredentials.cs
- FixedSOMElement.cs
- EventEntry.cs
- basevalidator.cs
- SignatureHelper.cs
- Int32Rect.cs
- TypedElement.cs
- ListViewInsertionMark.cs
- EncodingNLS.cs
- MatrixConverter.cs
- WebSysDefaultValueAttribute.cs
- CapabilitiesAssignment.cs
- SecurityResources.cs
- ManipulationStartedEventArgs.cs
- PasswordTextNavigator.cs
- DataGridViewColumnCollection.cs
- MatrixStack.cs
- Grid.cs
- ColorBuilder.cs
- util.cs
- UrlPath.cs
- CustomError.cs
- MessageQueueAccessControlEntry.cs
- DataGridViewLinkColumn.cs
- SettingsSection.cs
- MobileControlsSectionHandler.cs
- PreservationFileWriter.cs
- PkcsMisc.cs
- RemoteWebConfigurationHostServer.cs
- HTMLTagNameToTypeMapper.cs
- MailFileEditor.cs
- UIElement.cs
- DtdParser.cs
- CustomAttributeSerializer.cs
- InfiniteIntConverter.cs
- SoapSchemaExporter.cs
- EncodingDataItem.cs
- __FastResourceComparer.cs
- XmlNodeComparer.cs
- DetailsView.cs
- BindingList.cs
- SessionStateContainer.cs
- Win32Native.cs
- TextSpanModifier.cs
- ReversePositionQuery.cs
- CommonRemoteMemoryBlock.cs
- LifetimeServices.cs
- ping.cs
- GeometryCombineModeValidation.cs
- UnknownExceptionActionHelper.cs
- Rules.cs
- Knowncolors.cs
- OleDbError.cs
- MembershipSection.cs
- TitleStyle.cs
- RuntimeConfig.cs
- LongValidatorAttribute.cs
- BindingNavigator.cs
- WebPartConnectionsDisconnectVerb.cs
- ManagementObjectSearcher.cs
- JavaScriptObjectDeserializer.cs
- SafeArrayTypeMismatchException.cs
- CircleHotSpot.cs
- ExtenderProviderService.cs
- ApplicationProxyInternal.cs
- TextBoxDesigner.cs
- ReadOnlyMetadataCollection.cs
- FlowDocumentView.cs
- MemberPath.cs
- Compilation.cs
- SQLInt16.cs
- UIElement3D.cs
- DataGridViewButtonColumn.cs
- CompositeCollectionView.cs
- AppDomain.cs
- ScopedKnownTypes.cs
- Random.cs
- KernelTypeValidation.cs
- PipelineModuleStepContainer.cs
- SessionStateUtil.cs
- TextServicesCompartmentContext.cs
- NavigatorOutput.cs
- TargetException.cs
- ThreadStateException.cs
- OdbcDataAdapter.cs
- HasCopySemanticsAttribute.cs
- Set.cs
- IncrementalCompileAnalyzer.cs
- AutoResizedEvent.cs
- StructuredType.cs
- InputElement.cs
- System.Data.OracleClient_BID.cs
- HtmlWindowCollection.cs
- WorkBatch.cs
- UnsafeNetInfoNativeMethods.cs