Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / CompMod / System / Collections / Specialized / HybridDictionary.cs / 1305376 / HybridDictionary.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Collections.Specialized { using System.Collections; using System.Globalization; ////// [Serializable] public class HybridDictionary: IDictionary { // These numbers have been carefully tested to be optimal. Please don't change them // without doing thorough performance testing. private const int CutoverPoint = 9; private const int InitialHashtableSize = 13; private const int FixedSizeCutoverPoint = 6; // Instance variables. This keeps the HybridDictionary very light-weight when empty private ListDictionary list; private Hashtable hashtable; private bool caseInsensitive; ////// This data structure implements IDictionary first using a linked list /// (ListDictionary) and then switching over to use Hashtable when large. This is recommended /// for cases where the number of elements in a dictionary is unknown and might be small. /// /// It also has a single boolean parameter to allow case-sensitivity that is not affected by /// ambient culture and has been optimized for looking up case-insensitive symbols /// ////// public HybridDictionary() { } ///[To be supplied.] ////// public HybridDictionary(int initialSize) : this(initialSize, false) { } ///[To be supplied.] ////// public HybridDictionary(bool caseInsensitive) { this.caseInsensitive = caseInsensitive; } ///[To be supplied.] ////// public HybridDictionary(int initialSize, bool caseInsensitive) { this.caseInsensitive = caseInsensitive; if (initialSize >= FixedSizeCutoverPoint) { if (caseInsensitive) { hashtable = new Hashtable(initialSize, StringComparer.OrdinalIgnoreCase); } else { hashtable = new Hashtable(initialSize); } } } ///[To be supplied.] ////// public object this[object key] { get { //[To be supplied.] ///// Hashtable supports multiple read, one writer thread safety. // Although we never made the same guarantee for HybridDictionary, // it is still nice to do the same thing here since we have recommended // HybridDictioary as replacement for Hashtable. // // ListDictionary cachedList = list; if (hashtable != null) { return hashtable[key]; } else if (cachedList != null) { return cachedList[key]; } else { //// cachedList can be null in too cases: // (1) The dictionary is empty, we will return null in this case // (2) There is writer which is doing ChangeOver. However in that case // we should see the change to hashtable as well. // So it should work just fine. // // if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } return null; } } set { if (hashtable != null) { hashtable[key] = value; } else if (list != null) { if (list.Count >= CutoverPoint - 1) { ChangeOver(); hashtable[key] = value; } else { list[key] = value; } } else { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); list[key] = value; } } } private ListDictionary List { get { if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list; } } private void ChangeOver() { IDictionaryEnumerator en = list.GetEnumerator(); Hashtable newTable; if (caseInsensitive) { newTable = new Hashtable(InitialHashtableSize, StringComparer.OrdinalIgnoreCase); } else { newTable = new Hashtable(InitialHashtableSize); } while (en.MoveNext()) { newTable.Add(en.Key, en.Value); } //// Keep the order of writing to hashtable and list. // We assume we will see the change in hashtable if list is set to null in // this method in another reader thread. // hashtable = newTable; list = null; } ////// public int Count { get { ListDictionary cachedList = list; if (hashtable != null) { return hashtable.Count; } else if (cachedList != null) { return cachedList.Count; } else { return 0; } } } ///[To be supplied.] ////// public ICollection Keys { get { if (hashtable != null) { return hashtable.Keys; } else { return List.Keys; } } } ///[To be supplied.] ////// public bool IsReadOnly { get { return false; } } ///[To be supplied.] ////// public bool IsFixedSize { get { return false; } } ///[To be supplied.] ////// public bool IsSynchronized { get { return false; } } ///[To be supplied.] ////// public object SyncRoot { get { return this; } } ///[To be supplied.] ////// public ICollection Values { get { if (hashtable != null) { return hashtable.Values; } else { return List.Values; } } } ///[To be supplied.] ////// public void Add(object key, object value) { if (hashtable != null) { hashtable.Add(key, value); } else { if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); list.Add(key, value); } else { if (list.Count + 1 >= CutoverPoint) { ChangeOver(); hashtable.Add(key, value); } else { list.Add(key, value); } } } } ///[To be supplied.] ////// public void Clear() { if(hashtable != null) { Hashtable cachedHashtable = hashtable; hashtable = null; cachedHashtable.Clear(); } if( list != null) { ListDictionary cachedList = list; list = null; cachedList.Clear(); } } ///[To be supplied.] ////// public bool Contains(object key) { ListDictionary cachedList = list; if (hashtable != null) { return hashtable.Contains(key); } else if (cachedList != null) { return cachedList.Contains(key); } else { if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } return false; } } ///[To be supplied.] ////// public void CopyTo(Array array, int index) { if (hashtable != null) { hashtable.CopyTo(array, index); } else { List.CopyTo(array, index); } } ///[To be supplied.] ////// public IDictionaryEnumerator GetEnumerator() { if (hashtable != null) { return hashtable.GetEnumerator(); } if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list.GetEnumerator(); } ///[To be supplied.] ////// IEnumerator IEnumerable.GetEnumerator() { if (hashtable != null) { return hashtable.GetEnumerator(); } if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list.GetEnumerator(); } ///[To be supplied.] ////// public void Remove(object key) { if (hashtable != null) { hashtable.Remove(key); } else if (list != null){ list.Remove(key); } else { if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.[To be supplied.] ///
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- CounterCreationDataCollection.cs
- IDReferencePropertyAttribute.cs
- ValidationErrorInfo.cs
- WorkflowMarkupSerializationProvider.cs
- ContractValidationHelper.cs
- FaultReasonText.cs
- BuildProviderCollection.cs
- CompiledIdentityConstraint.cs
- HttpModulesSection.cs
- __ComObject.cs
- CRYPTPROTECT_PROMPTSTRUCT.cs
- AnimatedTypeHelpers.cs
- StylusSystemGestureEventArgs.cs
- ListChangedEventArgs.cs
- ComponentDesigner.cs
- XmlWrappingReader.cs
- DesignerCategoryAttribute.cs
- TreeNodeBinding.cs
- SqlDataSourceSelectingEventArgs.cs
- PagedDataSource.cs
- CodeTypeReferenceCollection.cs
- ColorMap.cs
- Brush.cs
- TextViewSelectionProcessor.cs
- AVElementHelper.cs
- Baml2006Reader.cs
- TransportReplyChannelAcceptor.cs
- ChildTable.cs
- RequiredFieldValidator.cs
- DataGridLengthConverter.cs
- StrokeNode.cs
- ReachPageContentSerializer.cs
- XmlDataDocument.cs
- DataFormats.cs
- ActivationServices.cs
- BinaryUtilClasses.cs
- OutKeywords.cs
- DetailsViewRow.cs
- SessionPageStatePersister.cs
- SevenBitStream.cs
- NotifyCollectionChangedEventArgs.cs
- RuntimeHelpers.cs
- XmlHierarchyData.cs
- ChannelFactory.cs
- EventToken.cs
- HtmlEmptyTagControlBuilder.cs
- Context.cs
- XamlWrappingReader.cs
- HtmlTableCell.cs
- FactoryGenerator.cs
- InstallerTypeAttribute.cs
- Contracts.cs
- SelectedDatesCollection.cs
- ToolStripTemplateNode.cs
- DeclarativeConditionsCollection.cs
- WrappedKeySecurityTokenParameters.cs
- ProviderUtil.cs
- ElementHost.cs
- XmlSchemaChoice.cs
- TagPrefixAttribute.cs
- UnsafeNativeMethods.cs
- Pair.cs
- AndMessageFilter.cs
- TableRowGroup.cs
- X509Extension.cs
- LocationReferenceEnvironment.cs
- VectorValueSerializer.cs
- EntityTypeEmitter.cs
- GridItemPatternIdentifiers.cs
- storepermission.cs
- ExcludePathInfo.cs
- ReachDocumentSequenceSerializer.cs
- HttpDebugHandler.cs
- GeneralTransform.cs
- SiteMapNode.cs
- mil_sdk_version.cs
- TypeForwardedFromAttribute.cs
- PriorityQueue.cs
- FirstMatchCodeGroup.cs
- ToolboxComponentsCreatingEventArgs.cs
- ListViewGroupConverter.cs
- XmlSchemaFacet.cs
- RadioButtonRenderer.cs
- TransformProviderWrapper.cs
- NotFiniteNumberException.cs
- DomainLiteralReader.cs
- RecognizedPhrase.cs
- SerializationAttributes.cs
- XXXOnTypeBuilderInstantiation.cs
- ModelTreeEnumerator.cs
- KeyBinding.cs
- XNodeValidator.cs
- OutputScope.cs
- VirtualPathUtility.cs
- SmiRequestExecutor.cs
- DataGridViewColumnCollectionEditor.cs
- ActivityTypeResolver.xaml.cs
- ImageListImageEditor.cs
- QuotedPairReader.cs
- MimeTypePropertyAttribute.cs