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
- InfoCardPolicy.cs
- ColorAnimationUsingKeyFrames.cs
- RayHitTestParameters.cs
- RangeContentEnumerator.cs
- ApplicationInfo.cs
- HebrewNumber.cs
- WindowInteractionStateTracker.cs
- TemplateKey.cs
- ControlValuePropertyAttribute.cs
- LinkAreaEditor.cs
- SqlError.cs
- StatusInfoItem.cs
- UnsafePeerToPeerMethods.cs
- AutoGeneratedFieldProperties.cs
- SqlClientWrapperSmiStream.cs
- JsonStringDataContract.cs
- SqlFunctions.cs
- NetCodeGroup.cs
- RouteValueExpressionBuilder.cs
- CompilerState.cs
- PeerResolver.cs
- RowUpdatingEventArgs.cs
- ListViewUpdateEventArgs.cs
- VisualStyleTypesAndProperties.cs
- DynamicValidator.cs
- CodeDelegateInvokeExpression.cs
- DragStartedEventArgs.cs
- NameScope.cs
- FillBehavior.cs
- TrackBarRenderer.cs
- KoreanLunisolarCalendar.cs
- TextRangeBase.cs
- SqlClientMetaDataCollectionNames.cs
- ProfileManager.cs
- Selection.cs
- BinaryFormatterSinks.cs
- DetailsViewDeletedEventArgs.cs
- ClientEventManager.cs
- Mappings.cs
- BitmapSource.cs
- InputDevice.cs
- ExpressionBinding.cs
- KeyEventArgs.cs
- ReflectPropertyDescriptor.cs
- RelationshipManager.cs
- TaskResultSetter.cs
- CodeArgumentReferenceExpression.cs
- _IPv6Address.cs
- XamlToRtfWriter.cs
- LayoutInformation.cs
- RectAnimation.cs
- NewExpression.cs
- WindowsImpersonationContext.cs
- XmlSchemaSimpleTypeRestriction.cs
- TryCatch.cs
- StatusBarPanel.cs
- ConfigDefinitionUpdates.cs
- ZoomPercentageConverter.cs
- StreamAsIStream.cs
- handlecollector.cs
- ValidationRule.cs
- SHA512Managed.cs
- BitmapMetadata.cs
- ColumnReorderedEventArgs.cs
- MessageQueue.cs
- DataGridTextBoxColumn.cs
- BindUriHelper.cs
- XmlTextEncoder.cs
- Timer.cs
- MessageBodyDescription.cs
- UInt16Converter.cs
- TemplateModeChangedEventArgs.cs
- ReadOnlyDataSource.cs
- ProcessModelInfo.cs
- Point4D.cs
- newitemfactory.cs
- EventToken.cs
- BufferedGraphicsContext.cs
- _TimerThread.cs
- RightsManagementEncryptedStream.cs
- CellConstant.cs
- DesignerDataConnection.cs
- DataSourceSelectArguments.cs
- Keywords.cs
- ECDiffieHellmanCngPublicKey.cs
- Triangle.cs
- BindingMAnagerBase.cs
- AliasedExpr.cs
- TypeDescriptorFilterService.cs
- PageParserFilter.cs
- ListViewItem.cs
- FileVersion.cs
- CompilerCollection.cs
- DynamicQueryableWrapper.cs
- COAUTHINFO.cs
- DataViewManagerListItemTypeDescriptor.cs
- SqlDataRecord.cs
- SamlEvidence.cs
- DataContractJsonSerializer.cs
- EmptyEnumerator.cs