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607 lines
22 KiB
607 lines
22 KiB
// ZlibBaseStream.cs |
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// ------------------------------------------------------------------ |
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// |
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// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation. |
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// All rights reserved. |
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// |
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// This code module is part of DotNetZip, a zipfile class library. |
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// |
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// ------------------------------------------------------------------ |
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// |
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// This code is licensed under the Microsoft Public License. |
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// See the file License.txt for the license details. |
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// More info on: http://dotnetzip.codeplex.com |
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// |
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// ------------------------------------------------------------------ |
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// |
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// last saved (in emacs): |
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// Time-stamp: <2011-August-06 21:22:38> |
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// |
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// ------------------------------------------------------------------ |
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// |
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// This module defines the ZlibBaseStream class, which is an intnernal |
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// base class for DeflateStream, ZlibStream and GZipStream. |
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// |
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// ------------------------------------------------------------------ |
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using BestHTTP.PlatformSupport.Memory; |
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using System; |
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using System.IO; |
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namespace BestHTTP.Decompression.Zlib |
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{ |
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internal enum ZlibStreamFlavor { ZLIB = 1950, DEFLATE = 1951, GZIP = 1952 } |
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internal class ZlibBaseStream : System.IO.Stream |
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{ |
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protected internal ZlibCodec _z = null; // deferred init... new ZlibCodec(); |
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protected internal StreamMode _streamMode = StreamMode.Undefined; |
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protected internal FlushType _flushMode; |
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protected internal ZlibStreamFlavor _flavor; |
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protected internal CompressionMode _compressionMode; |
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protected internal CompressionLevel _level; |
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protected internal bool _leaveOpen; |
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protected internal byte[] _workingBuffer; |
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protected internal int _bufferSize = ZlibConstants.WorkingBufferSizeDefault; |
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protected internal int windowBitsMax; |
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protected internal byte[] _buf1 = new byte[1]; |
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protected internal System.IO.Stream _stream; |
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protected internal CompressionStrategy Strategy = CompressionStrategy.Default; |
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// workitem 7159 |
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BestHTTP.Decompression.Crc.CRC32 crc; |
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protected internal string _GzipFileName; |
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protected internal string _GzipComment; |
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protected internal DateTime _GzipMtime; |
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protected internal int _gzipHeaderByteCount; |
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internal int Crc32 { get { if (crc == null) return 0; return crc.Crc32Result; } } |
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public ZlibBaseStream(System.IO.Stream stream, |
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CompressionMode compressionMode, |
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CompressionLevel level, |
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ZlibStreamFlavor flavor, |
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bool leaveOpen) |
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:this(stream, compressionMode, level, flavor,leaveOpen, ZlibConstants.WindowBitsDefault) |
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{ } |
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public ZlibBaseStream(System.IO.Stream stream, |
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CompressionMode compressionMode, |
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CompressionLevel level, |
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ZlibStreamFlavor flavor, |
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bool leaveOpen, |
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int windowBits) |
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: base() |
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{ |
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this._flushMode = FlushType.None; |
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//this._workingBuffer = new byte[WORKING_BUFFER_SIZE_DEFAULT]; |
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this._stream = stream; |
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this._leaveOpen = leaveOpen; |
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this._compressionMode = compressionMode; |
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this._flavor = flavor; |
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this._level = level; |
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this.windowBitsMax = windowBits; |
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// workitem 7159 |
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if (flavor == ZlibStreamFlavor.GZIP) |
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{ |
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this.crc = new BestHTTP.Decompression.Crc.CRC32(); |
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} |
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} |
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protected internal bool _wantCompress |
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{ |
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get |
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{ |
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return (this._compressionMode == CompressionMode.Compress); |
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} |
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} |
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private ZlibCodec z |
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{ |
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get |
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{ |
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if (_z == null) |
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{ |
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bool wantRfc1950Header = (this._flavor == ZlibStreamFlavor.ZLIB); |
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_z = new ZlibCodec(); |
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if (this._compressionMode == CompressionMode.Decompress) |
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{ |
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_z.InitializeInflate(this.windowBitsMax, wantRfc1950Header); |
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} |
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else |
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{ |
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_z.Strategy = Strategy; |
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_z.InitializeDeflate(this._level, this.windowBitsMax, wantRfc1950Header); |
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} |
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} |
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return _z; |
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} |
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} |
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private byte[] workingBuffer |
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{ |
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get |
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{ |
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if (_workingBuffer == null) |
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_workingBuffer = BufferPool.Get(_bufferSize, true); |
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return _workingBuffer; |
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} |
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} |
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public override void Write(System.Byte[] buffer, int offset, int count) |
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{ |
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// workitem 7159 |
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// calculate the CRC on the unccompressed data (before writing) |
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if (crc != null) |
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crc.SlurpBlock(buffer, offset, count); |
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if (_streamMode == StreamMode.Undefined) |
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_streamMode = StreamMode.Writer; |
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else if (_streamMode != StreamMode.Writer) |
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throw new ZlibException("Cannot Write after Reading."); |
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if (count == 0) |
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return; |
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// first reference of z property will initialize the private var _z |
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z.InputBuffer = buffer; |
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_z.NextIn = offset; |
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_z.AvailableBytesIn = count; |
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bool done = false; |
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do |
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{ |
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_z.OutputBuffer = workingBuffer; |
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_z.NextOut = 0; |
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_z.AvailableBytesOut = _workingBuffer.Length; |
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int rc = (_wantCompress) |
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? _z.Deflate(_flushMode) |
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: _z.Inflate(_flushMode); |
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if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END) |
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throw new ZlibException((_wantCompress ? "de" : "in") + "flating: " + _z.Message); |
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//if (_workingBuffer.Length - _z.AvailableBytesOut > 0) |
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_stream.Write(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut); |
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done = _z.AvailableBytesIn == 0 && _z.AvailableBytesOut != 0; |
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// If GZIP and de-compress, we're done when 8 bytes remain. |
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if (_flavor == ZlibStreamFlavor.GZIP && !_wantCompress) |
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done = (_z.AvailableBytesIn == 8 && _z.AvailableBytesOut != 0); |
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} |
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while (!done); |
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} |
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private void finish() |
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{ |
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if (_z == null) return; |
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if (_streamMode == StreamMode.Writer) |
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{ |
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bool done = false; |
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do |
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{ |
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_z.OutputBuffer = workingBuffer; |
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_z.NextOut = 0; |
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_z.AvailableBytesOut = _workingBuffer.Length; |
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int rc = (_wantCompress) |
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? _z.Deflate(FlushType.Finish) |
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: _z.Inflate(FlushType.Finish); |
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if (rc != ZlibConstants.Z_STREAM_END && rc != ZlibConstants.Z_OK) |
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{ |
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string verb = (_wantCompress ? "de" : "in") + "flating"; |
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if (_z.Message == null) |
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throw new ZlibException(String.Format("{0}: (rc = {1})", verb, rc)); |
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else |
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throw new ZlibException(verb + ": " + _z.Message); |
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} |
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if (_workingBuffer.Length - _z.AvailableBytesOut > 0) |
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{ |
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_stream.Write(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut); |
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} |
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done = _z.AvailableBytesIn == 0 && _z.AvailableBytesOut != 0; |
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// If GZIP and de-compress, we're done when 8 bytes remain. |
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if (_flavor == ZlibStreamFlavor.GZIP && !_wantCompress) |
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done = (_z.AvailableBytesIn == 8 && _z.AvailableBytesOut != 0); |
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} |
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while (!done); |
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Flush(); |
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// workitem 7159 |
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if (_flavor == ZlibStreamFlavor.GZIP) |
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{ |
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if (_wantCompress) |
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{ |
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// Emit the GZIP trailer: CRC32 and size mod 2^32 |
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int c1 = crc.Crc32Result; |
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_stream.Write(BitConverter.GetBytes(c1), 0, 4); |
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int c2 = (Int32)(crc.TotalBytesRead & 0x00000000FFFFFFFF); |
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_stream.Write(BitConverter.GetBytes(c2), 0, 4); |
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} |
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else |
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{ |
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throw new ZlibException("Writing with decompression is not supported."); |
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} |
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} |
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} |
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// workitem 7159 |
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else if (_streamMode == StreamMode.Reader) |
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{ |
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if (_flavor == ZlibStreamFlavor.GZIP) |
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{ |
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if (!_wantCompress) |
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{ |
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// workitem 8501: handle edge case (decompress empty stream) |
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if (_z.TotalBytesOut == 0L) |
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return; |
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// Read and potentially verify the GZIP trailer: |
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// CRC32 and size mod 2^32 |
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byte[] trailer = BufferPool.Get(8, true); |
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// workitems 8679 & 12554 |
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if (_z.AvailableBytesIn < 8) |
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{ |
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// Make sure we have read to the end of the stream |
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Array.Copy(_z.InputBuffer, _z.NextIn, trailer, 0, _z.AvailableBytesIn); |
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int bytesNeeded = 8 - _z.AvailableBytesIn; |
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int bytesRead = _stream.Read(trailer, |
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_z.AvailableBytesIn, |
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bytesNeeded); |
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if (bytesNeeded != bytesRead) |
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{ |
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BufferPool.Release(trailer); |
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throw new ZlibException(String.Format("Missing or incomplete GZIP trailer. Expected 8 bytes, got {0}.", |
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_z.AvailableBytesIn + bytesRead)); |
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} |
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} |
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else |
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{ |
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Array.Copy(_z.InputBuffer, _z.NextIn, trailer, 0, 8); |
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} |
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Int32 crc32_expected = BitConverter.ToInt32(trailer, 0); |
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Int32 crc32_actual = crc.Crc32Result; |
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Int32 isize_expected = BitConverter.ToInt32(trailer, 4); |
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Int32 isize_actual = (Int32)(_z.TotalBytesOut & 0x00000000FFFFFFFF); |
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if (crc32_actual != crc32_expected) |
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{ |
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BufferPool.Release(trailer); |
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throw new ZlibException(String.Format("Bad CRC32 in GZIP trailer. (actual({0:X8})!=expected({1:X8}))", crc32_actual, crc32_expected)); |
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} |
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if (isize_actual != isize_expected) |
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{ |
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BufferPool.Release(trailer); |
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throw new ZlibException(String.Format("Bad size in GZIP trailer. (actual({0})!=expected({1}))", isize_actual, isize_expected)); |
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} |
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BufferPool.Release(trailer); |
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} |
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else |
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{ |
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throw new ZlibException("Reading with compression is not supported."); |
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} |
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} |
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} |
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} |
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private void end() |
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{ |
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if (z == null) |
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return; |
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if (_wantCompress) |
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{ |
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_z.EndDeflate(); |
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} |
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else |
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{ |
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_z.EndInflate(); |
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} |
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_z = null; |
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BufferPool.Release(_workingBuffer); |
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_workingBuffer = null; |
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} |
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public |
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#if !NETFX_CORE |
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override |
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#endif |
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void Close() |
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{ |
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if (_stream == null) return; |
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try |
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{ |
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finish(); |
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} |
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finally |
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{ |
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end(); |
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if (!_leaveOpen) _stream.Dispose(); |
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_stream = null; |
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} |
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} |
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public override void Flush() |
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{ |
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_stream.Flush(); |
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} |
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public override System.Int64 Seek(System.Int64 offset, System.IO.SeekOrigin origin) |
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{ |
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throw new NotImplementedException(); |
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//_outStream.Seek(offset, origin); |
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} |
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public override void SetLength(System.Int64 value) |
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{ |
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_stream.SetLength(value); |
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nomoreinput = false; |
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} |
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#if NOT |
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public int Read() |
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{ |
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if (Read(_buf1, 0, 1) == 0) |
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return 0; |
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// calculate CRC after reading |
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if (crc!=null) |
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crc.SlurpBlock(_buf1,0,1); |
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return (_buf1[0] & 0xFF); |
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} |
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#endif |
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private bool nomoreinput = false; |
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private string ReadZeroTerminatedString() |
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{ |
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var list = new System.Collections.Generic.List<byte>(); |
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bool done = false; |
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do |
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{ |
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// workitem 7740 |
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int n = _stream.Read(_buf1, 0, 1); |
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if (n != 1) |
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throw new ZlibException("Unexpected EOF reading GZIP header."); |
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else |
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{ |
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if (_buf1[0] == 0) |
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done = true; |
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else |
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list.Add(_buf1[0]); |
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} |
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} while (!done); |
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byte[] a = list.ToArray(); |
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return GZipStream.iso8859dash1.GetString(a, 0, a.Length); |
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} |
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private int _ReadAndValidateGzipHeader() |
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{ |
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int totalBytesRead = 0; |
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// read the header on the first read |
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byte[] header = BufferPool.Get(10, true); |
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int n = _stream.Read(header, 0, 10); |
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// workitem 8501: handle edge case (decompress empty stream) |
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if (n == 0) |
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{ |
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BufferPool.Release(header); |
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return 0; |
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} |
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if (n != 10) |
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{ |
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BufferPool.Release(header); |
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throw new ZlibException("Not a valid GZIP stream."); |
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} |
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if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8) |
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{ |
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BufferPool.Release(header); |
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throw new ZlibException("Bad GZIP header."); |
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} |
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Int32 timet = BitConverter.ToInt32(header, 4); |
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_GzipMtime = GZipStream._unixEpoch.AddSeconds(timet); |
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totalBytesRead += n; |
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if ((header[3] & 0x04) == 0x04) |
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{ |
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// read and discard extra field |
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n = _stream.Read(header, 0, 2); // 2-byte length field |
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totalBytesRead += n; |
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Int16 extraLength = (Int16)(header[0] + header[1] * 256); |
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byte[] extra = BufferPool.Get(extraLength, true); |
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n = _stream.Read(extra, 0, extraLength); |
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if (n != extraLength) |
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{ |
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BufferPool.Release(extra); |
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BufferPool.Release(header); |
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throw new ZlibException("Unexpected end-of-file reading GZIP header."); |
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} |
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totalBytesRead += n; |
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} |
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if ((header[3] & 0x08) == 0x08) |
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_GzipFileName = ReadZeroTerminatedString(); |
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if ((header[3] & 0x10) == 0x010) |
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_GzipComment = ReadZeroTerminatedString(); |
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if ((header[3] & 0x02) == 0x02) |
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Read(_buf1, 0, 1); // CRC16, ignore |
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BufferPool.Release(header); |
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return totalBytesRead; |
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} |
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public override System.Int32 Read(System.Byte[] buffer, System.Int32 offset, System.Int32 count) |
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{ |
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// According to MS documentation, any implementation of the IO.Stream.Read function must: |
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// (a) throw an exception if offset & count reference an invalid part of the buffer, |
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// or if count < 0, or if buffer is null |
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// (b) return 0 only upon EOF, or if count = 0 |
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// (c) if not EOF, then return at least 1 byte, up to <count> bytes |
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if (_streamMode == StreamMode.Undefined) |
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{ |
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if (!this._stream.CanRead) throw new ZlibException("The stream is not readable."); |
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// for the first read, set up some controls. |
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_streamMode = StreamMode.Reader; |
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// (The first reference to _z goes through the private accessor which |
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// may initialize it.) |
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z.AvailableBytesIn = 0; |
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if (_flavor == ZlibStreamFlavor.GZIP) |
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{ |
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_gzipHeaderByteCount = _ReadAndValidateGzipHeader(); |
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// workitem 8501: handle edge case (decompress empty stream) |
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if (_gzipHeaderByteCount == 0) |
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return 0; |
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} |
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} |
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if (_streamMode != StreamMode.Reader) |
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throw new ZlibException("Cannot Read after Writing."); |
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if (count == 0) return 0; |
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if (nomoreinput && _wantCompress) return 0; // workitem 8557 |
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if (buffer == null) throw new ArgumentNullException("buffer"); |
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if (count < 0) throw new ArgumentOutOfRangeException("count"); |
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if (offset < buffer.GetLowerBound(0)) throw new ArgumentOutOfRangeException("offset"); |
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if ((offset + count) > buffer.GetLength(0)) throw new ArgumentOutOfRangeException("count"); |
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int rc = 0; |
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// set up the output of the deflate/inflate codec: |
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_z.OutputBuffer = buffer; |
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_z.NextOut = offset; |
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_z.AvailableBytesOut = count; |
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// This is necessary in case _workingBuffer has been resized. (new byte[]) |
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// (The first reference to _workingBuffer goes through the private accessor which |
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// may initialize it.) |
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_z.InputBuffer = workingBuffer; |
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do |
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{ |
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// need data in _workingBuffer in order to deflate/inflate. Here, we check if we have any. |
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if ((_z.AvailableBytesIn == 0) && (!nomoreinput)) |
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{ |
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// No data available, so try to Read data from the captive stream. |
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_z.NextIn = 0; |
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_z.AvailableBytesIn = _stream.Read(_workingBuffer, 0, _workingBuffer.Length); |
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if (_z.AvailableBytesIn == 0) |
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nomoreinput = true; |
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} |
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// we have data in InputBuffer; now compress or decompress as appropriate |
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rc = (_wantCompress) |
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? _z.Deflate(_flushMode) |
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: _z.Inflate(_flushMode); |
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if (nomoreinput && (rc == ZlibConstants.Z_BUF_ERROR)) |
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return 0; |
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if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END) |
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throw new ZlibException(String.Format("{0}flating: rc={1} msg={2}", (_wantCompress ? "de" : "in"), rc, _z.Message)); |
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if ((nomoreinput || rc == ZlibConstants.Z_STREAM_END) && (_z.AvailableBytesOut == count)) |
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break; // nothing more to read |
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} |
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//while (_z.AvailableBytesOut == count && rc == ZlibConstants.Z_OK); |
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while (_z.AvailableBytesOut > 0 && !nomoreinput && rc == ZlibConstants.Z_OK); |
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// workitem 8557 |
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// is there more room in output? |
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if (_z.AvailableBytesOut > 0) |
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{ |
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if (rc == ZlibConstants.Z_OK && _z.AvailableBytesIn == 0) |
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{ |
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// deferred |
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} |
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// are we completely done reading? |
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if (nomoreinput) |
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{ |
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// and in compression? |
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if (_wantCompress) |
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{ |
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// no more input data available; therefore we flush to |
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// try to complete the read |
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rc = _z.Deflate(FlushType.Finish); |
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if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END) |
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throw new ZlibException(String.Format("Deflating: rc={0} msg={1}", rc, _z.Message)); |
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} |
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} |
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} |
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rc = (count - _z.AvailableBytesOut); |
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// calculate CRC after reading |
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if (crc != null) |
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crc.SlurpBlock(buffer, offset, rc); |
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return rc; |
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} |
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public override System.Boolean CanRead |
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{ |
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get { return this._stream.CanRead; } |
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} |
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public override System.Boolean CanSeek |
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{ |
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get { return this._stream.CanSeek; } |
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} |
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public override System.Boolean CanWrite |
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{ |
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get { return this._stream.CanWrite; } |
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} |
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public override System.Int64 Length |
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{ |
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get { return _stream.Length; } |
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} |
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public override long Position |
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{ |
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get { throw new NotImplementedException(); } |
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set { throw new NotImplementedException(); } |
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} |
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internal enum StreamMode |
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{ |
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Writer, |
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Reader, |
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Undefined, |
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} |
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} |
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}
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