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 / 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
- FlowNode.cs
- XPathNodeList.cs
- SiteIdentityPermission.cs
- WebPartDescription.cs
- UnsafeNativeMethods.cs
- ToolStripLabel.cs
- TableCell.cs
- ContextStack.cs
- Double.cs
- CachedCompositeFamily.cs
- FastPropertyAccessor.cs
- SqlBulkCopyColumnMapping.cs
- WebResourceUtil.cs
- PasswordBox.cs
- GAC.cs
- WebPart.cs
- GeometryGroup.cs
- Attributes.cs
- VisualStyleRenderer.cs
- CompatibleComparer.cs
- MemberPath.cs
- FormsAuthenticationTicket.cs
- Literal.cs
- WebUtility.cs
- HostedTcpTransportManager.cs
- DataGridViewCellEventArgs.cs
- _Events.cs
- CapabilitiesUse.cs
- WebException.cs
- HotSpot.cs
- ProcessHostServerConfig.cs
- BuildProviderCollection.cs
- DataGridViewCellPaintingEventArgs.cs
- RawContentTypeMapper.cs
- MatcherBuilder.cs
- RefreshPropertiesAttribute.cs
- SelectionUIService.cs
- MediaPlayerState.cs
- InputReportEventArgs.cs
- ILGenerator.cs
- PermissionSetTriple.cs
- CommonRemoteMemoryBlock.cs
- ToolBarButton.cs
- Base64Encoder.cs
- EntityDataSourceViewSchema.cs
- InputEventArgs.cs
- SafeFindHandle.cs
- TPLETWProvider.cs
- ActivityStateQuery.cs
- QuaternionRotation3D.cs
- CreatingCookieEventArgs.cs
- ConstantSlot.cs
- WebPartRestoreVerb.cs
- MenuItemStyleCollection.cs
- IMembershipProvider.cs
- DbParameterCollectionHelper.cs
- HtmlTextViewAdapter.cs
- IgnoreFileBuildProvider.cs
- SectionInformation.cs
- ToolStripRenderEventArgs.cs
- MULTI_QI.cs
- MSG.cs
- EffectiveValueEntry.cs
- PerformanceCounterScope.cs
- SecurityException.cs
- EntityDataSourceUtil.cs
- Point3DKeyFrameCollection.cs
- CorePropertiesFilter.cs
- InputProcessorProfilesLoader.cs
- ExecutionEngineException.cs
- DbProviderSpecificTypePropertyAttribute.cs
- WebPartEditorCancelVerb.cs
- SerializeAbsoluteContext.cs
- OrderingExpression.cs
- PrivilegeNotHeldException.cs
- EventSetterHandlerConverter.cs
- BaseCodePageEncoding.cs
- AsyncOperation.cs
- XmlDictionaryReaderQuotas.cs
- EntitySqlQueryCacheKey.cs
- ViewPort3D.cs
- Image.cs
- XmlAttributeCollection.cs
- SiteMapProvider.cs
- VisualProxy.cs
- UnicodeEncoding.cs
- X509CertificateCollection.cs
- EqualityComparer.cs
- PageEventArgs.cs
- StateDesignerConnector.cs
- ApplicationManager.cs
- DigestComparer.cs
- CharAnimationUsingKeyFrames.cs
- FixedDocumentPaginator.cs
- TransactionManager.cs
- _IPv4Address.cs
- NativeMethods.cs
- DesignRelationCollection.cs
- DataMisalignedException.cs
- BitFlagsGenerator.cs