Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / whidbey / NetFXspW7 / 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
- ColorInterpolationModeValidation.cs
- TransformedBitmap.cs
- OleDbMetaDataFactory.cs
- securitycriticaldataformultiplegetandset.cs
- UnmanagedMemoryStream.cs
- TextBounds.cs
- GridViewPageEventArgs.cs
- CodeArrayCreateExpression.cs
- BitmapFrameDecode.cs
- SQLBinaryStorage.cs
- BamlRecords.cs
- ToolStripItem.cs
- SqlDataSourceCache.cs
- HtmlInputRadioButton.cs
- DirectoryGroupQuery.cs
- HttpProfileGroupBase.cs
- DataGridLinkButton.cs
- RuntimeArgumentHandle.cs
- HtmlContainerControl.cs
- FormViewDesigner.cs
- SystemColorTracker.cs
- ComponentConverter.cs
- Int32.cs
- SyndicationSerializer.cs
- IList.cs
- StoreAnnotationsMap.cs
- TextTreeUndoUnit.cs
- ListViewUpdateEventArgs.cs
- DivideByZeroException.cs
- GrowingArray.cs
- CursorConverter.cs
- ZoomComboBox.cs
- DataGridViewCellEventArgs.cs
- ConsumerConnectionPoint.cs
- ServiceMemoryGates.cs
- LabelEditEvent.cs
- SearchForVirtualItemEventArgs.cs
- Vertex.cs
- ListViewDeleteEventArgs.cs
- XmlSerializerAssemblyAttribute.cs
- DLinqAssociationProvider.cs
- _FtpControlStream.cs
- OleDbConnectionInternal.cs
- ModulesEntry.cs
- InputBuffer.cs
- EdmFunctions.cs
- JsonUriDataContract.cs
- CapabilitiesAssignment.cs
- ModuleBuilderData.cs
- DefaultValidator.cs
- NavigationWindowAutomationPeer.cs
- XPathNodePointer.cs
- DiagnosticEventProvider.cs
- ContextDataSourceView.cs
- ObjectStateEntryOriginalDbUpdatableDataRecord.cs
- MultiBinding.cs
- SimpleMailWebEventProvider.cs
- AnnotationMap.cs
- HostingEnvironmentException.cs
- FaultBookmark.cs
- Processor.cs
- EntityDataSourceColumn.cs
- ObjectDataSourceSelectingEventArgs.cs
- EntityType.cs
- Renderer.cs
- DbInsertCommandTree.cs
- XmlReader.cs
- GiveFeedbackEventArgs.cs
- XPathSelectionIterator.cs
- PageRequestManager.cs
- HandlerWithFactory.cs
- InvokeProviderWrapper.cs
- RayMeshGeometry3DHitTestResult.cs
- Panel.cs
- EdmItemError.cs
- BitmapEffectInput.cs
- CustomAttributeBuilder.cs
- WindowManager.cs
- TargetPerspective.cs
- RegexCode.cs
- ReaderOutput.cs
- CommonXSendMessage.cs
- SQLDecimalStorage.cs
- WebSysDescriptionAttribute.cs
- InternalTypeHelper.cs
- ZipIOLocalFileDataDescriptor.cs
- DispatcherOperation.cs
- XPathAxisIterator.cs
- ObjectManager.cs
- FrameworkTemplate.cs
- ObjectList.cs
- ReferencedAssembly.cs
- EraserBehavior.cs
- ScaleTransform.cs
- PasswordRecovery.cs
- TypeNameConverter.cs
- Component.cs
- FacetChecker.cs
- DiscreteKeyFrames.cs
- TimersDescriptionAttribute.cs