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
- ListViewEditEventArgs.cs
- GradientStop.cs
- TypeViewSchema.cs
- EmptyEnumerable.cs
- DateTimeConstantAttribute.cs
- ProvidePropertyAttribute.cs
- TileModeValidation.cs
- XmlQualifiedNameTest.cs
- invalidudtexception.cs
- NonBatchDirectoryCompiler.cs
- DataRowView.cs
- ClientEventManager.cs
- ReadOnlyHierarchicalDataSourceView.cs
- ZipQueryOperator.cs
- CreateUserWizardStep.cs
- HtmlToClrEventProxy.cs
- XmlEntity.cs
- InputBinder.cs
- SignedXml.cs
- Assert.cs
- x509utils.cs
- MarginsConverter.cs
- ValidationSummary.cs
- HtmlMeta.cs
- GeneralTransform2DTo3DTo2D.cs
- connectionpool.cs
- TreeViewImageIndexConverter.cs
- RecordConverter.cs
- ExpandedWrapper.cs
- assertwrapper.cs
- DataGridViewCellValueEventArgs.cs
- CompatibleComparer.cs
- CompatibleComparer.cs
- TabletDeviceInfo.cs
- CodeMemberField.cs
- Soap12ProtocolImporter.cs
- TraceContextEventArgs.cs
- _ListenerResponseStream.cs
- SystemResourceHost.cs
- ConfigXmlElement.cs
- ValueTable.cs
- DbMetaDataColumnNames.cs
- InstanceContext.cs
- DrawingContextDrawingContextWalker.cs
- ProcessProtocolHandler.cs
- ObjectListCommandsPage.cs
- MapPathBasedVirtualPathProvider.cs
- TrustLevelCollection.cs
- ZipIOFileItemStream.cs
- SpellerStatusTable.cs
- EntityExpressionVisitor.cs
- XpsS0ValidatingLoader.cs
- StylusPointPropertyInfoDefaults.cs
- Timeline.cs
- xsdvalidator.cs
- PageParser.cs
- AutomationProperties.cs
- DesignerSerializerAttribute.cs
- AttributeAction.cs
- UIHelper.cs
- OdbcError.cs
- MessageQueuePermissionEntryCollection.cs
- XmlWrappingReader.cs
- InfoCardTraceRecord.cs
- ScriptingSectionGroup.cs
- DefaultValueTypeConverter.cs
- DbUpdateCommandTree.cs
- ZoneLinkButton.cs
- StringHandle.cs
- ThemeableAttribute.cs
- ImportContext.cs
- FixedMaxHeap.cs
- DataPager.cs
- CodeDOMProvider.cs
- QuerySubExprEliminator.cs
- MappingSource.cs
- HostedAspNetEnvironment.cs
- StrokeCollection.cs
- columnmapkeybuilder.cs
- XXXInfos.cs
- CellLabel.cs
- BaseParser.cs
- SmtpSpecifiedPickupDirectoryElement.cs
- FieldNameLookup.cs
- Padding.cs
- HttpListenerException.cs
- SHA256.cs
- EntityObject.cs
- TextBox.cs
- PageSetupDialog.cs
- CompressionTransform.cs
- JsonUriDataContract.cs
- ThreadSafeList.cs
- OperandQuery.cs
- Latin1Encoding.cs
- Reference.cs
- RtfControlWordInfo.cs
- UserPrincipalNameElement.cs
- OleDbDataReader.cs
- RoutedPropertyChangedEventArgs.cs