Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / whidbey / netfxsp / 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
- HandlerBase.cs
- HttpRequest.cs
- RTLAwareMessageBox.cs
- TextRangeEdit.cs
- SchemaTypeEmitter.cs
- ListItemParagraph.cs
- EditorBrowsableAttribute.cs
- ScrollChrome.cs
- DateTimePicker.cs
- SymbolMethod.cs
- FileDialogCustomPlace.cs
- ActivityExecutionFilter.cs
- __TransparentProxy.cs
- basecomparevalidator.cs
- FilteredAttributeCollection.cs
- SymbolTable.cs
- XsltArgumentList.cs
- RtType.cs
- URI.cs
- TriggerCollection.cs
- ComEventsMethod.cs
- JsonSerializer.cs
- OrderedEnumerableRowCollection.cs
- UInt16Storage.cs
- SqlFlattener.cs
- Span.cs
- InstanceOwnerQueryResult.cs
- XmlILModule.cs
- DesignTimeData.cs
- AQNBuilder.cs
- DirectoryObjectSecurity.cs
- SelectionHighlightInfo.cs
- DragEvent.cs
- TemplateApplicationHelper.cs
- AdornerLayer.cs
- AspNetHostingPermission.cs
- RelatedView.cs
- StringAnimationBase.cs
- BuildManagerHost.cs
- WaitHandle.cs
- BitmapEffectGroup.cs
- DateTimeFormat.cs
- ButtonField.cs
- SubqueryRules.cs
- ExpressionVisitor.cs
- AlgoModule.cs
- TraceUtility.cs
- ResXFileRef.cs
- DesignTimeSiteMapProvider.cs
- InvalidCastException.cs
- Convert.cs
- DragEventArgs.cs
- StrokeCollectionConverter.cs
- CannotUnloadAppDomainException.cs
- ThreadStaticAttribute.cs
- ProgramPublisher.cs
- DiagnosticStrings.cs
- DataGridViewColumnTypePicker.cs
- BitmapCodecInfo.cs
- Oid.cs
- CaseCqlBlock.cs
- DependencyPropertyDescriptor.cs
- ProfilePropertyNameValidator.cs
- GeometryHitTestParameters.cs
- StylusPoint.cs
- CustomAttributeFormatException.cs
- FormsAuthenticationUserCollection.cs
- TextStore.cs
- ThicknessAnimation.cs
- KeyConverter.cs
- XmlIlTypeHelper.cs
- Token.cs
- NumericExpr.cs
- Imaging.cs
- GatewayIPAddressInformationCollection.cs
- RoleGroupCollection.cs
- CompositeActivityTypeDescriptor.cs
- BrushValueSerializer.cs
- Enumerable.cs
- MyContact.cs
- SaveFileDialog.cs
- UxThemeWrapper.cs
- ChangeBlockUndoRecord.cs
- SerializationAttributes.cs
- DictionaryEntry.cs
- AppDomainFactory.cs
- InstanceContextMode.cs
- StatusBar.cs
- SemaphoreSecurity.cs
- XmlComplianceUtil.cs
- EventLogger.cs
- ColorConvertedBitmap.cs
- DataTableMapping.cs
- XPathSelfQuery.cs
- Tuple.cs
- RequestQueryParser.cs
- CqlParser.cs
- TemplatePartAttribute.cs
- Int16.cs
- StreamReader.cs