Code:
/ FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / clr / src / BCL / System / Runtime / Serialization / ObjectIDGenerator.cs / 1 / ObjectIDGenerator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== /*============================================================ ** ** Class: ObjectIDGenerator ** ** ** Purpose: ObjectIDGenerator is a simple id generator that keeps track of ** objects with a hashtable. ** ** ===========================================================*/ namespace System.Runtime.Serialization { using System; using System.Runtime.CompilerServices; using System.Runtime.Remoting; using System.Runtime.Remoting.Proxies; [Serializable()] [System.Runtime.InteropServices.ComVisible(true)] public class ObjectIDGenerator { private const int numbins = 4; internal int m_currentCount; internal int m_currentSize; internal long []m_ids; internal Object []m_objs; // Table of prime numbers to use as hash table sizes. Each entry is the // smallest prime number larger than twice the previous entry. private static readonly int[] sizes = { 5, 11, 29, 47, 97, 197, 397, 797, 1597, 3203, 6421, 12853, 25717, 51437, 102877, 205759, 411527, 823117, 1646237, 3292489, 6584983}; // Constructs a new ObjectID generator, initalizing all of the necessary variables. public ObjectIDGenerator() { m_currentCount=1; m_currentSize = sizes[0]; m_ids = new long[m_currentSize*numbins]; m_objs = new Object[m_currentSize*numbins]; } // Determines where element obj lives, or should live, // within the table. It calculates the hashcode and searches all of the // bins where the given object could live. If it's not found within the bin, // we rehash and go look for it in another bin. If we find the object, we // set found to true and return it's position. If we can't find the object, // we set found to false and return the position where the object should be inserted. // private int FindElement(Object obj, out bool found) { //This double-hashing algorithm is recomended by CLR, pg 236. //We're hosed if somebody rehashes the table while we're doing the lookup, but that's //generally true for most of these operations. int hashcode = RuntimeHelpers.GetHashCode(obj); int hashIncrement = (1+((hashcode&0x7FFFFFFF)%(m_currentSize-2))); do { int pos = ((hashcode&0x7FFFFFFF)%m_currentSize)*numbins; for (int i=pos; i(m_currentSize*numbins)/2) { Rehash(); } } else { BCLDebug.Trace("SER", "[ObjectIDGenerator.GetID] Found objectid: ", (m_ids[pos]), " with hashcode: ", RuntimeHelpers.GetHashCode(obj), " Type: ", obj); foundID = m_ids[pos]; } firstTime = !found; return foundID; } // Checks to see if obj has already been assigned an id. If it has, // we return that id, otherwise we return 0. // public virtual long HasId(Object obj, out bool firstTime) { bool found; if (obj==null) { throw new ArgumentNullException("obj", Environment.GetResourceString("ArgumentNull_Obj")); } int pos = FindElement(obj, out found); if (found) { firstTime = false; return m_ids[pos]; } firstTime=true; return 0; } // Rehashes the table by finding the next larger size in the list provided, // allocating two new arrays of that size and rehashing all of the elements in // the old arrays into the new ones. Expensive but necessary. // private void Rehash() { int i,pos; long [] newIds; long [] oldIds; Object[] newObjs; Object[] oldObjs; bool found; int currSize; for (i=0, currSize=m_currentSize; i
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- UniqueConstraint.cs
- brushes.cs
- GZipObjectSerializer.cs
- DesignSurfaceManager.cs
- CharAnimationBase.cs
- SQLDouble.cs
- ObjectParameterCollection.cs
- HotCommands.cs
- _NetRes.cs
- ToolStripDropDownItem.cs
- InputScopeManager.cs
- FrameworkElementFactory.cs
- DoubleAnimation.cs
- EditCommandColumn.cs
- SingleResultAttribute.cs
- TextAdaptor.cs
- PrefixHandle.cs
- Run.cs
- NumberFunctions.cs
- BindUriHelper.cs
- EUCJPEncoding.cs
- Brush.cs
- WhitespaceRuleLookup.cs
- MetadataArtifactLoader.cs
- WeakReferenceKey.cs
- DropShadowBitmapEffect.cs
- KeyedCollection.cs
- MediaElement.cs
- SystemIcmpV4Statistics.cs
- InstallerTypeAttribute.cs
- CodeGroup.cs
- LambdaCompiler.Generated.cs
- LocalizableAttribute.cs
- XmlWriter.cs
- ClientBuildManagerCallback.cs
- Tuple.cs
- ToolStripPanelRow.cs
- TransactionChannelFaultConverter.cs
- ContactManager.cs
- LinqDataSourceView.cs
- Color.cs
- TraceSwitch.cs
- ProcessInfo.cs
- RegexMatchCollection.cs
- SeekStoryboard.cs
- AddInControllerImpl.cs
- ExclusiveHandleList.cs
- AppDomainManager.cs
- ProfileInfo.cs
- ProjectionAnalyzer.cs
- HtmlShim.cs
- XmlWriterTraceListener.cs
- DetailsViewInsertedEventArgs.cs
- HttpException.cs
- MsmqInputChannelBase.cs
- TaiwanCalendar.cs
- TextSegment.cs
- X509Extension.cs
- AuthenticationServiceManager.cs
- TextCharacters.cs
- PerformanceCounterPermissionEntry.cs
- ACL.cs
- StyleXamlParser.cs
- DateTimeConverter2.cs
- SelectorItemAutomationPeer.cs
- TextRenderer.cs
- ToolStripScrollButton.cs
- _TransmitFileOverlappedAsyncResult.cs
- XmlSerializableWriter.cs
- RedBlackList.cs
- DelegatingTypeDescriptionProvider.cs
- SspiNegotiationTokenProviderState.cs
- DataGridViewCellConverter.cs
- MarkupObject.cs
- CorePropertiesFilter.cs
- ValueTable.cs
- Inline.cs
- CommandHelpers.cs
- CursorConverter.cs
- BuildProvidersCompiler.cs
- processwaithandle.cs
- TreeNodeCollection.cs
- SRef.cs
- ProcessInfo.cs
- JavaScriptObjectDeserializer.cs
- RealizationDrawingContextWalker.cs
- UInt64Storage.cs
- QueryExpr.cs
- DiscoveryDocumentReference.cs
- DesignerTransaction.cs
- SortDescription.cs
- HyperlinkAutomationPeer.cs
- ReachFixedPageSerializerAsync.cs
- PropertyInfoSet.cs
- BinarySecretKeyIdentifierClause.cs
- HashFinalRequest.cs
- ValuePattern.cs
- CodeGotoStatement.cs
- SymbolMethod.cs
- JavascriptCallbackMessageInspector.cs