Code:
/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / Sys / System / IO / compression / OutputWindow.cs / 1 / OutputWindow.cs
namespace System.IO.Compression { using System; using System.Diagnostics; using System.Globalization; // This class maintains a window for decompressed output. // We need to keep this because the decompressed information can be // a literal or a length/distance pair. For length/distance pair, // we need to look back in the output window and copy bytes from there. // We use a byte array of WindowSize circularly. // internal class OutputWindow { private const int WindowSize = 32768; private const int WindowMask = 32767; private byte[] window = new byte[WindowSize]; //The window is 2^15 bytes private int end; // this is the position to where we should write next byte private int bytesUsed; // The number of bytes in the output window which is not consumed. // Add a byte to output window public void Write(byte b) { Debug.WriteLineIf(CompressionTracingSwitch.Verbose, String.Format(CultureInfo.InvariantCulture, "Literal: {0}", b), "Compression"); Debug.Assert(bytesUsed < WindowSize, "Can't add byte when window is full!"); window[end++] = b; end &= WindowMask; ++bytesUsed; } public void WriteLengthDistance(int length, int distance) { Debug.WriteLineIf(CompressionTracingSwitch.Verbose, String.Format(CultureInfo.InvariantCulture, "Length/Distance: {0}:{1}", length, distance), "Compression"); Debug.Assert((bytesUsed + length) <= WindowSize, "No Enough space"); // move backwards distance bytes in the output stream, // and copy length bytes from this position to the output stream. bytesUsed += length; int copyStart = (end - distance) & WindowMask; // start position for coping. int border = WindowSize - length; if (copyStart <= border && end < border) { if (length <= distance) { System.Array.Copy(window, copyStart, window, end, length); end += length; } else { // The referenced string may overlap the current // position; for example, if the last 2 bytes decoded have values // X and Y, a string reference with// adds X,Y,X,Y,X to the output stream. while (length-- > 0) { window[end++] = window[copyStart++]; } } } else { // copy byte by byte while (length-- > 0) { window[end++] = window[copyStart++]; end &= WindowMask; copyStart &= WindowMask; } } } // Copy up to length of bytes from input directly. // This is used for uncompressed block. public int CopyFrom(InputBuffer input, int length) { length = Math.Min(Math.Min(length, WindowSize - bytesUsed), input.AvailableBytes); int copied; // We might need wrap around to copy all bytes. int tailLen = WindowSize - end; if (length > tailLen) { // copy the first part copied = input.CopyTo(window, end, tailLen); if (copied == tailLen) { // only try to copy the second part if we have enough bytes in input copied += input.CopyTo(window, 0, length - tailLen); } } else { // only one copy is needed if there is no wrap around. copied = input.CopyTo(window, end, length); } end = (end + copied) & WindowMask; bytesUsed += copied; return copied; } // Free space in output window public int FreeBytes { get { return WindowSize - bytesUsed; } } // bytes not consumed in output window public int AvailableBytes { get { return bytesUsed; } } // copy the decompressed bytes to output array. public int CopyTo(byte[] output, int offset, int length) { int copy_end; if (length > bytesUsed) { // we can copy all the decompressed bytes out copy_end = end; length = bytesUsed; } else { copy_end = (end - bytesUsed + length) & WindowMask; // copy length of bytes } int copied = length; int tailLen = length - copy_end; if ( tailLen > 0) { // this means we need to copy two parts seperately // copy tailLen bytes from the end of output window System.Array.Copy(window, WindowSize - tailLen, output, offset, tailLen); offset += tailLen; length = copy_end; } System.Array.Copy(window, copy_end - length, output, offset, length); bytesUsed -= copied; Debug.Assert(bytesUsed >= 0, "check this function and find why we copied more bytes than we have"); return copied; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. namespace System.IO.Compression { using System; using System.Diagnostics; using System.Globalization; // This class maintains a window for decompressed output. // We need to keep this because the decompressed information can be // a literal or a length/distance pair. For length/distance pair, // we need to look back in the output window and copy bytes from there. // We use a byte array of WindowSize circularly. // internal class OutputWindow { private const int WindowSize = 32768; private const int WindowMask = 32767; private byte[] window = new byte[WindowSize]; //The window is 2^15 bytes private int end; // this is the position to where we should write next byte private int bytesUsed; // The number of bytes in the output window which is not consumed. // Add a byte to output window public void Write(byte b) { Debug.WriteLineIf(CompressionTracingSwitch.Verbose, String.Format(CultureInfo.InvariantCulture, "Literal: {0}", b), "Compression"); Debug.Assert(bytesUsed < WindowSize, "Can't add byte when window is full!"); window[end++] = b; end &= WindowMask; ++bytesUsed; } public void WriteLengthDistance(int length, int distance) { Debug.WriteLineIf(CompressionTracingSwitch.Verbose, String.Format(CultureInfo.InvariantCulture, "Length/Distance: {0}:{1}", length, distance), "Compression"); Debug.Assert((bytesUsed + length) <= WindowSize, "No Enough space"); // move backwards distance bytes in the output stream, // and copy length bytes from this position to the output stream. bytesUsed += length; int copyStart = (end - distance) & WindowMask; // start position for coping. int border = WindowSize - length; if (copyStart <= border && end < border) { if (length <= distance) { System.Array.Copy(window, copyStart, window, end, length); end += length; } else { // The referenced string may overlap the current // position; for example, if the last 2 bytes decoded have values // X and Y, a string reference with // adds X,Y,X,Y,X to the output stream. while (length-- > 0) { window[end++] = window[copyStart++]; } } } else { // copy byte by byte while (length-- > 0) { window[end++] = window[copyStart++]; end &= WindowMask; copyStart &= WindowMask; } } } // Copy up to length of bytes from input directly. // This is used for uncompressed block. public int CopyFrom(InputBuffer input, int length) { length = Math.Min(Math.Min(length, WindowSize - bytesUsed), input.AvailableBytes); int copied; // We might need wrap around to copy all bytes. int tailLen = WindowSize - end; if (length > tailLen) { // copy the first part copied = input.CopyTo(window, end, tailLen); if (copied == tailLen) { // only try to copy the second part if we have enough bytes in input copied += input.CopyTo(window, 0, length - tailLen); } } else { // only one copy is needed if there is no wrap around. copied = input.CopyTo(window, end, length); } end = (end + copied) & WindowMask; bytesUsed += copied; return copied; } // Free space in output window public int FreeBytes { get { return WindowSize - bytesUsed; } } // bytes not consumed in output window public int AvailableBytes { get { return bytesUsed; } } // copy the decompressed bytes to output array. public int CopyTo(byte[] output, int offset, int length) { int copy_end; if (length > bytesUsed) { // we can copy all the decompressed bytes out copy_end = end; length = bytesUsed; } else { copy_end = (end - bytesUsed + length) & WindowMask; // copy length of bytes } int copied = length; int tailLen = length - copy_end; if ( tailLen > 0) { // this means we need to copy two parts seperately // copy tailLen bytes from the end of output window System.Array.Copy(window, WindowSize - tailLen, output, offset, tailLen); offset += tailLen; length = copy_end; } System.Array.Copy(window, copy_end - length, output, offset, length); bytesUsed -= copied; Debug.Assert(bytesUsed >= 0, "check this function and find why we copied more bytes than we have"); return copied; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- _LazyAsyncResult.cs
- ProfileGroupSettingsCollection.cs
- Int32Animation.cs
- SynchronizedPool.cs
- BitVector32.cs
- PackWebRequestFactory.cs
- SiteMapNodeCollection.cs
- ButtonDesigner.cs
- OracleSqlParser.cs
- GPRECT.cs
- AppearanceEditorPart.cs
- Pen.cs
- DecoratedNameAttribute.cs
- CursorConverter.cs
- WebBrowserUriTypeConverter.cs
- XmlCountingReader.cs
- LicenseContext.cs
- IconEditor.cs
- DocumentXPathNavigator.cs
- TextEncodedRawTextWriter.cs
- Deflater.cs
- DataSourceHelper.cs
- PersistenceContext.cs
- OdbcConnectionFactory.cs
- WebConfigurationManager.cs
- PropertyTabChangedEvent.cs
- RadioButtonPopupAdapter.cs
- WebPartsPersonalizationAuthorization.cs
- ExpressionBuilder.cs
- RequestTimeoutManager.cs
- CryptoKeySecurity.cs
- RtfNavigator.cs
- DBDataPermissionAttribute.cs
- XPathNavigator.cs
- BufferAllocator.cs
- DataRowView.cs
- BindingContext.cs
- ButtonChrome.cs
- SchemaTableOptionalColumn.cs
- MouseActionConverter.cs
- XmlILModule.cs
- BindableTemplateBuilder.cs
- IncrementalCompileAnalyzer.cs
- Documentation.cs
- HWStack.cs
- AliasExpr.cs
- GenericsInstances.cs
- NativeObjectSecurity.cs
- BitmapEffectGroup.cs
- OutOfMemoryException.cs
- LoginAutoFormat.cs
- DataStreams.cs
- DuplicateWaitObjectException.cs
- Screen.cs
- CodeMethodReturnStatement.cs
- DynamicRendererThreadManager.cs
- OdbcConnectionString.cs
- SID.cs
- CodeVariableDeclarationStatement.cs
- TraceContextEventArgs.cs
- XmlSchemaAnnotation.cs
- NativeMethods.cs
- TextEffectResolver.cs
- BrowserCapabilitiesCompiler.cs
- TypeReference.cs
- NamedObject.cs
- BufferModeSettings.cs
- BitmapEffectGroup.cs
- DecoderExceptionFallback.cs
- TouchEventArgs.cs
- SortKey.cs
- SatelliteContractVersionAttribute.cs
- VisualStateGroup.cs
- EntityContainerEmitter.cs
- FormViewRow.cs
- EdmRelationshipNavigationPropertyAttribute.cs
- ApplicationBuildProvider.cs
- MessageSmuggler.cs
- DataGridViewButtonCell.cs
- CodeMemberEvent.cs
- NativeMethods.cs
- SqlGatherProducedAliases.cs
- ToolboxItemSnapLineBehavior.cs
- PathFigureCollectionConverter.cs
- XPathChildIterator.cs
- OutputCacheProfileCollection.cs
- UiaCoreApi.cs
- DBConcurrencyException.cs
- ProxyWebPart.cs
- SchemaElementDecl.cs
- SpecialFolderEnumConverter.cs
- CodeTypeConstructor.cs
- QilCloneVisitor.cs
- XmlAttribute.cs
- ConstraintStruct.cs
- ConnectionProviderAttribute.cs
- StylusPointProperty.cs
- MouseBinding.cs
- KoreanCalendar.cs
- Accessors.cs