Code:
/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / 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 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
- WriteFileContext.cs
- UrlMappingsModule.cs
- ReflectTypeDescriptionProvider.cs
- XamlParser.cs
- OleDbTransaction.cs
- TextDecorationLocationValidation.cs
- ActiveXSite.cs
- Semaphore.cs
- Command.cs
- querybuilder.cs
- Or.cs
- PublisherMembershipCondition.cs
- FileDetails.cs
- SelectionBorderGlyph.cs
- PhysicalAddress.cs
- NamespaceList.cs
- EventRoute.cs
- ProgressBar.cs
- ProgressPage.cs
- EllipseGeometry.cs
- ArgumentOutOfRangeException.cs
- CanonicalFontFamilyReference.cs
- PropertyBuilder.cs
- TypeSource.cs
- ContextMenuAutomationPeer.cs
- SelectiveScrollingGrid.cs
- NullableDecimalAverageAggregationOperator.cs
- _FtpDataStream.cs
- HttpProfileBase.cs
- PlacementWorkspace.cs
- BaseAddressPrefixFilterElement.cs
- ListViewAutomationPeer.cs
- SqlHelper.cs
- SystemFonts.cs
- ProxyGenerator.cs
- TextRunCacheImp.cs
- streamingZipPartStream.cs
- _SSPISessionCache.cs
- TypeToken.cs
- AlternateViewCollection.cs
- AnnotationDocumentPaginator.cs
- mediaeventargs.cs
- WebPartMovingEventArgs.cs
- AutomationFocusChangedEventArgs.cs
- DataAdapter.cs
- smtpconnection.cs
- ChainOfResponsibility.cs
- ImageDrawing.cs
- SHA256Managed.cs
- SafeRegistryHandle.cs
- FontConverter.cs
- CommonObjectSecurity.cs
- DebuggerAttributes.cs
- CheckableControlBaseAdapter.cs
- FixedDocumentSequencePaginator.cs
- Stacktrace.cs
- HtmlTable.cs
- SqlCrossApplyToCrossJoin.cs
- HostAdapter.cs
- CustomCredentialPolicy.cs
- DataGridViewColumnCollectionEditor.cs
- StandardToolWindows.cs
- ISO2022Encoding.cs
- StyleCollection.cs
- SslStream.cs
- PropVariant.cs
- ExpressionReplacer.cs
- AnnouncementEventArgs.cs
- entityreference_tresulttype.cs
- OdbcConnectionFactory.cs
- PolicyException.cs
- ContractCodeDomInfo.cs
- PrintPreviewControl.cs
- ListViewUpdateEventArgs.cs
- httpstaticobjectscollection.cs
- DrawToolTipEventArgs.cs
- JournalEntryStack.cs
- ParserContext.cs
- SessionSwitchEventArgs.cs
- Utils.cs
- GridViewSelectEventArgs.cs
- TrackBarRenderer.cs
- DbProviderManifest.cs
- ProfileGroupSettingsCollection.cs
- Font.cs
- HttpBrowserCapabilitiesWrapper.cs
- TextOutput.cs
- ObjectDataProvider.cs
- ViewService.cs
- OleDbErrorCollection.cs
- TrustManagerPromptUI.cs
- KeyManager.cs
- BitmapImage.cs
- DesignerCategoryAttribute.cs
- RawStylusInputCustomData.cs
- ViewgenGatekeeper.cs
- CommonRemoteMemoryBlock.cs
- RectangleGeometry.cs
- HeaderCollection.cs
- TextEncodedRawTextWriter.cs