Code:
/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / Sys / System / IO / compression / GZipDecoder.cs / 1 / GZipDecoder.cs
namespace System.IO.Compression { using System; using System.Diagnostics; internal enum GZIPHeaderState{ // GZIP header ReadingID1, ReadingID2, ReadingCM, ReadingFLG, ReadingMMTime, // iterates 4 times ReadingXFL, ReadingOS, ReadingXLen1, ReadingXLen2, ReadingXLenData, ReadingFileName, ReadingComment, ReadingCRC16Part1, ReadingCRC16Part2, Done, // done reading GZIP header // GZIP footer ReadingCRC, // iterates 4 times ReadingFileSize // iterates 4 times } // This class decodes GZip header and footer information. // See RFC 1952 for details about the format. internal class GZipDecoder { const int FileText = 1; const int CRCFlag = 2; const int ExtraFieldsFlag = 4; const int FileNameFlag = 8; const int CommentFlag= 16; private InputBuffer input; GZIPHeaderState gzipHeaderSubstate; GZIPHeaderState gzipFooterSubstate; int gzip_header_flag; int gzip_header_xlen; uint gzipCrc32; uint gzipOutputStreamSize; int loopCounter; public GZipDecoder(InputBuffer input) { this.input = input; Reset(); } public void Reset() { gzipHeaderSubstate = GZIPHeaderState.ReadingID1; gzipFooterSubstate = GZIPHeaderState.ReadingCRC; gzipCrc32 = 0; gzipOutputStreamSize = 0; } public uint Crc32 { get { return gzipCrc32; } } public uint StreamSize { get { return gzipOutputStreamSize; } } public bool ReadGzipHeader() { while(true) { int bits; switch (gzipHeaderSubstate) { case GZIPHeaderState.ReadingID1: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x1F) { throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader)); } gzipHeaderSubstate = GZIPHeaderState.ReadingID2; goto case GZIPHeaderState.ReadingID2; case GZIPHeaderState.ReadingID2: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x8b) { throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader)); } gzipHeaderSubstate = GZIPHeaderState.ReadingCM; goto case GZIPHeaderState.ReadingCM; case GZIPHeaderState.ReadingCM: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x8) { // compression mode must be 8 (deflate) throw new InvalidDataException(SR.GetString(SR.UnknownCompressionMode)); } gzipHeaderSubstate = GZIPHeaderState.ReadingFLG;; goto case GZIPHeaderState.ReadingFLG; case GZIPHeaderState.ReadingFLG: bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_flag = bits; gzipHeaderSubstate = GZIPHeaderState.ReadingMMTime; loopCounter = 0; // 4 MMTIME bytes goto case GZIPHeaderState.ReadingMMTime; case GZIPHeaderState.ReadingMMTime: bits = 0; while(loopCounter < 4) { bits = input.GetBits(8); if( bits < 0) { return false; } loopCounter++; } gzipHeaderSubstate = GZIPHeaderState.ReadingXFL; loopCounter = 0; goto case GZIPHeaderState.ReadingXFL; case GZIPHeaderState.ReadingXFL: // ignore XFL bits = input.GetBits(8); if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingOS; goto case GZIPHeaderState.ReadingOS; case GZIPHeaderState.ReadingOS: // ignore OS bits = input.GetBits(8); if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingXLen1; goto case GZIPHeaderState.ReadingXLen1; case GZIPHeaderState.ReadingXLen1: if ((gzip_header_flag & ExtraFieldsFlag) == 0) { goto case GZIPHeaderState.ReadingFileName; } bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_xlen = bits; gzipHeaderSubstate = GZIPHeaderState.ReadingXLen2; goto case GZIPHeaderState.ReadingXLen2; case GZIPHeaderState.ReadingXLen2: bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_xlen |= (bits << 8); gzipHeaderSubstate = GZIPHeaderState.ReadingXLenData; loopCounter = 0; // 0 bytes of XLEN data read so far goto case GZIPHeaderState.ReadingXLenData; case GZIPHeaderState.ReadingXLenData: bits = 0; while(loopCounter < gzip_header_xlen) { bits = input.GetBits(8); if( bits < 0) { return false; } loopCounter++; } gzipHeaderSubstate = GZIPHeaderState.ReadingFileName; loopCounter = 0; goto case GZIPHeaderState.ReadingFileName; case GZIPHeaderState.ReadingFileName: if ((gzip_header_flag & FileNameFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.ReadingComment; goto case GZIPHeaderState.ReadingComment; } do { bits = input.GetBits(8); if( bits < 0) { return false; } if( bits == 0) { // see '\0' in the file name string break; } } while (true); gzipHeaderSubstate = GZIPHeaderState.ReadingComment; goto case GZIPHeaderState.ReadingComment; case GZIPHeaderState.ReadingComment: if ((gzip_header_flag & CommentFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part1; goto case GZIPHeaderState.ReadingCRC16Part1; } do { bits = input.GetBits(8); if( bits < 0) { return false; } if( bits == 0) { // see '\0' in the file name string break; } } while (true); gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part1; goto case GZIPHeaderState.ReadingCRC16Part1; case GZIPHeaderState.ReadingCRC16Part1: if ((gzip_header_flag & CRCFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.Done; goto case GZIPHeaderState.Done; } bits = input.GetBits(8); // ignore crc if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part2; goto case GZIPHeaderState.ReadingCRC16Part2; case GZIPHeaderState.ReadingCRC16Part2: bits = input.GetBits(8); // ignore crc if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.Done; goto case GZIPHeaderState.Done; case GZIPHeaderState.Done: return true; default: Debug.Assert(false, "We should not reach unknown state!"); throw new InvalidDataException(SR.GetString(SR.UnknownState)); } } } public bool ReadGzipFooter() { input.SkipToByteBoundary(); if( gzipFooterSubstate == GZIPHeaderState.ReadingCRC) { while (loopCounter < 4 ) { int bits = input.GetBits(8); if( bits < 0) { return false; } gzipCrc32 |= ((uint)bits << (8*loopCounter)); loopCounter++; } gzipFooterSubstate = GZIPHeaderState.ReadingFileSize; loopCounter = 0; } if (gzipFooterSubstate == GZIPHeaderState.ReadingFileSize) { if (loopCounter == 0) gzipOutputStreamSize = 0; while (loopCounter < 4) { int bits = input.GetBits(8); if( bits < 0) { return false; } gzipOutputStreamSize |= ((uint)bits << (8*loopCounter)); loopCounter++; } } return true; } } } // 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; internal enum GZIPHeaderState{ // GZIP header ReadingID1, ReadingID2, ReadingCM, ReadingFLG, ReadingMMTime, // iterates 4 times ReadingXFL, ReadingOS, ReadingXLen1, ReadingXLen2, ReadingXLenData, ReadingFileName, ReadingComment, ReadingCRC16Part1, ReadingCRC16Part2, Done, // done reading GZIP header // GZIP footer ReadingCRC, // iterates 4 times ReadingFileSize // iterates 4 times } // This class decodes GZip header and footer information. // See RFC 1952 for details about the format. internal class GZipDecoder { const int FileText = 1; const int CRCFlag = 2; const int ExtraFieldsFlag = 4; const int FileNameFlag = 8; const int CommentFlag= 16; private InputBuffer input; GZIPHeaderState gzipHeaderSubstate; GZIPHeaderState gzipFooterSubstate; int gzip_header_flag; int gzip_header_xlen; uint gzipCrc32; uint gzipOutputStreamSize; int loopCounter; public GZipDecoder(InputBuffer input) { this.input = input; Reset(); } public void Reset() { gzipHeaderSubstate = GZIPHeaderState.ReadingID1; gzipFooterSubstate = GZIPHeaderState.ReadingCRC; gzipCrc32 = 0; gzipOutputStreamSize = 0; } public uint Crc32 { get { return gzipCrc32; } } public uint StreamSize { get { return gzipOutputStreamSize; } } public bool ReadGzipHeader() { while(true) { int bits; switch (gzipHeaderSubstate) { case GZIPHeaderState.ReadingID1: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x1F) { throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader)); } gzipHeaderSubstate = GZIPHeaderState.ReadingID2; goto case GZIPHeaderState.ReadingID2; case GZIPHeaderState.ReadingID2: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x8b) { throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader)); } gzipHeaderSubstate = GZIPHeaderState.ReadingCM; goto case GZIPHeaderState.ReadingCM; case GZIPHeaderState.ReadingCM: bits = input.GetBits(8); if( bits < 0) { return false; } if( bits != 0x8) { // compression mode must be 8 (deflate) throw new InvalidDataException(SR.GetString(SR.UnknownCompressionMode)); } gzipHeaderSubstate = GZIPHeaderState.ReadingFLG;; goto case GZIPHeaderState.ReadingFLG; case GZIPHeaderState.ReadingFLG: bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_flag = bits; gzipHeaderSubstate = GZIPHeaderState.ReadingMMTime; loopCounter = 0; // 4 MMTIME bytes goto case GZIPHeaderState.ReadingMMTime; case GZIPHeaderState.ReadingMMTime: bits = 0; while(loopCounter < 4) { bits = input.GetBits(8); if( bits < 0) { return false; } loopCounter++; } gzipHeaderSubstate = GZIPHeaderState.ReadingXFL; loopCounter = 0; goto case GZIPHeaderState.ReadingXFL; case GZIPHeaderState.ReadingXFL: // ignore XFL bits = input.GetBits(8); if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingOS; goto case GZIPHeaderState.ReadingOS; case GZIPHeaderState.ReadingOS: // ignore OS bits = input.GetBits(8); if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingXLen1; goto case GZIPHeaderState.ReadingXLen1; case GZIPHeaderState.ReadingXLen1: if ((gzip_header_flag & ExtraFieldsFlag) == 0) { goto case GZIPHeaderState.ReadingFileName; } bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_xlen = bits; gzipHeaderSubstate = GZIPHeaderState.ReadingXLen2; goto case GZIPHeaderState.ReadingXLen2; case GZIPHeaderState.ReadingXLen2: bits = input.GetBits(8); if( bits < 0) { return false; } gzip_header_xlen |= (bits << 8); gzipHeaderSubstate = GZIPHeaderState.ReadingXLenData; loopCounter = 0; // 0 bytes of XLEN data read so far goto case GZIPHeaderState.ReadingXLenData; case GZIPHeaderState.ReadingXLenData: bits = 0; while(loopCounter < gzip_header_xlen) { bits = input.GetBits(8); if( bits < 0) { return false; } loopCounter++; } gzipHeaderSubstate = GZIPHeaderState.ReadingFileName; loopCounter = 0; goto case GZIPHeaderState.ReadingFileName; case GZIPHeaderState.ReadingFileName: if ((gzip_header_flag & FileNameFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.ReadingComment; goto case GZIPHeaderState.ReadingComment; } do { bits = input.GetBits(8); if( bits < 0) { return false; } if( bits == 0) { // see '\0' in the file name string break; } } while (true); gzipHeaderSubstate = GZIPHeaderState.ReadingComment; goto case GZIPHeaderState.ReadingComment; case GZIPHeaderState.ReadingComment: if ((gzip_header_flag & CommentFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part1; goto case GZIPHeaderState.ReadingCRC16Part1; } do { bits = input.GetBits(8); if( bits < 0) { return false; } if( bits == 0) { // see '\0' in the file name string break; } } while (true); gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part1; goto case GZIPHeaderState.ReadingCRC16Part1; case GZIPHeaderState.ReadingCRC16Part1: if ((gzip_header_flag & CRCFlag) == 0) { gzipHeaderSubstate = GZIPHeaderState.Done; goto case GZIPHeaderState.Done; } bits = input.GetBits(8); // ignore crc if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.ReadingCRC16Part2; goto case GZIPHeaderState.ReadingCRC16Part2; case GZIPHeaderState.ReadingCRC16Part2: bits = input.GetBits(8); // ignore crc if( bits < 0) { return false; } gzipHeaderSubstate = GZIPHeaderState.Done; goto case GZIPHeaderState.Done; case GZIPHeaderState.Done: return true; default: Debug.Assert(false, "We should not reach unknown state!"); throw new InvalidDataException(SR.GetString(SR.UnknownState)); } } } public bool ReadGzipFooter() { input.SkipToByteBoundary(); if( gzipFooterSubstate == GZIPHeaderState.ReadingCRC) { while (loopCounter < 4 ) { int bits = input.GetBits(8); if( bits < 0) { return false; } gzipCrc32 |= ((uint)bits << (8*loopCounter)); loopCounter++; } gzipFooterSubstate = GZIPHeaderState.ReadingFileSize; loopCounter = 0; } if (gzipFooterSubstate == GZIPHeaderState.ReadingFileSize) { if (loopCounter == 0) gzipOutputStreamSize = 0; while (loopCounter < 4) { int bits = input.GetBits(8); if( bits < 0) { return false; } gzipOutputStreamSize |= ((uint)bits << (8*loopCounter)); loopCounter++; } } return true; } } } // 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
- FillErrorEventArgs.cs
- OutputCacheSection.cs
- RouteParser.cs
- DataGridTablesFactory.cs
- EdgeModeValidation.cs
- GridEntryCollection.cs
- CompareInfo.cs
- InitializerFacet.cs
- __TransparentProxy.cs
- ApplicationCommands.cs
- ApplicationActivator.cs
- ITreeGenerator.cs
- CryptoConfig.cs
- RenderDataDrawingContext.cs
- SortableBindingList.cs
- BindableTemplateBuilder.cs
- OleDbStruct.cs
- UnsafeNativeMethodsCLR.cs
- GifBitmapDecoder.cs
- BinaryObjectInfo.cs
- PageAdapter.cs
- ArgIterator.cs
- CFStream.cs
- WebPartZoneCollection.cs
- DoubleAnimationClockResource.cs
- SiteMap.cs
- SyntaxCheck.cs
- GradientBrush.cs
- HttpHandlerActionCollection.cs
- FixedTextView.cs
- ChangesetResponse.cs
- OleDbException.cs
- PagedControl.cs
- OverflowException.cs
- AttachedPropertyBrowsableForTypeAttribute.cs
- DbProviderFactoriesConfigurationHandler.cs
- CompilationUnit.cs
- BitmapEffectCollection.cs
- WindowsUserNameSecurityTokenAuthenticator.cs
- XmlEntityReference.cs
- ModuleBuilder.cs
- MessageOperationFormatter.cs
- JournalEntryStack.cs
- WinCategoryAttribute.cs
- SurrogateSelector.cs
- GenericTextProperties.cs
- MsmqIntegrationMessagePool.cs
- SettingsPropertyNotFoundException.cs
- CodeArrayIndexerExpression.cs
- CompilerGlobalScopeAttribute.cs
- ConnectionStringsSection.cs
- DES.cs
- XmlBinaryWriterSession.cs
- TraceContextEventArgs.cs
- Tag.cs
- MetadataUtilsSmi.cs
- objectresult_tresulttype.cs
- ViewLoader.cs
- StringPropertyBuilder.cs
- FacetDescription.cs
- KnownTypeAttribute.cs
- PrintDocument.cs
- WorkflowTraceTransfer.cs
- DrawingGroup.cs
- BeginStoryboard.cs
- PolyBezierSegment.cs
- _UriTypeConverter.cs
- BaseComponentEditor.cs
- NeedSkipTokenVisitor.cs
- DecoderBestFitFallback.cs
- SerializationStore.cs
- XmlSchemaNotation.cs
- EventManager.cs
- ApplicationActivator.cs
- TextTreeTextElementNode.cs
- TrackBarRenderer.cs
- OleDbRowUpdatedEvent.cs
- ClockGroup.cs
- WindowsPrincipal.cs
- OutKeywords.cs
- UriScheme.cs
- CodeDOMUtility.cs
- OLEDB_Enum.cs
- QilCloneVisitor.cs
- SharedUtils.cs
- PrintController.cs
- GraphicsState.cs
- TabItemAutomationPeer.cs
- CapabilitiesPattern.cs
- SHA512Managed.cs
- ComboBox.cs
- DynamicMethod.cs
- RenderingEventArgs.cs
- Vector3DKeyFrameCollection.cs
- NullableBoolConverter.cs
- Vector.cs
- DataGridViewRowsRemovedEventArgs.cs
- TextTreeFixupNode.cs
- SafeTimerHandle.cs
- HtmlContainerControl.cs