Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Sys / System / IO / compression / DeflateStream.cs / 1 / DeflateStream.cs
namespace System.IO.Compression { using System.IO; using System.Diagnostics; using System.Threading; using System.Security.Permissions; public class DeflateStream : Stream { private const int bufferSize = 4096; internal delegate void AsyncWriteDelegate(byte[] array, int offset, int count, bool isAsync); private Stream _stream; private CompressionMode _mode; private bool _leaveOpen; private Inflater inflater; private Deflater deflater; private byte[] buffer; private int asyncOperations; private readonly AsyncCallback m_CallBack; private readonly AsyncWriteDelegate m_AsyncWriterDelegate; public DeflateStream(Stream stream, CompressionMode mode) : this( stream, mode, false, false) { } public DeflateStream(Stream stream, CompressionMode mode, bool leaveOpen) : this(stream, mode, leaveOpen, false){ } internal DeflateStream(Stream stream, CompressionMode mode, bool leaveOpen, bool usingGZip){ _stream = stream; _mode = mode; _leaveOpen = leaveOpen; if(_stream == null ) { throw new ArgumentNullException("stream"); } switch (_mode) { case CompressionMode.Decompress: if (!(_stream.CanRead)) { throw new ArgumentException(SR.GetString(SR.NotReadableStream), "stream"); } inflater = new Inflater(usingGZip); m_CallBack = new AsyncCallback(ReadCallback); break; case CompressionMode.Compress: if (!(_stream.CanWrite)) { throw new ArgumentException(SR.GetString(SR.NotWriteableStream), "stream"); } deflater = new Deflater(usingGZip); m_AsyncWriterDelegate = new AsyncWriteDelegate(this.InternalWrite); m_CallBack = new AsyncCallback(WriteCallback); break; default: throw new ArgumentException(SR.GetString(SR.ArgumentOutOfRange_Enum), "mode"); } buffer = new byte[bufferSize]; } public override bool CanRead { get { if( _stream == null) { return false; } return (_mode == CompressionMode.Decompress && _stream.CanRead); } } public override bool CanWrite { get { if( _stream == null) { return false; } return (_mode == CompressionMode.Compress && _stream.CanWrite); } } public override bool CanSeek { get { return false; } } public override long Length { get { throw new NotSupportedException(SR.GetString(SR.NotSupported)); } } public override long Position { get { throw new NotSupportedException(SR.GetString(SR.NotSupported)); } set { throw new NotSupportedException(SR.GetString(SR.NotSupported)); } } public override void Flush() { if( _stream == null) { throw new ObjectDisposedException(null, SR.GetString(SR.ObjectDisposed_StreamClosed)); } return; } public override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException(SR.GetString(SR.NotSupported)); } public override void SetLength(long value) { throw new NotSupportedException(SR.GetString(SR.NotSupported)); } public override int Read(byte[] array, int offset, int count) { EnsureDecompressionMode(); ValidateParameters(array, offset, count); int bytesRead; int currentOffest = offset; int remainingCount = count; while(true) { bytesRead = inflater.Inflate(array, currentOffest, remainingCount); currentOffest += bytesRead; remainingCount -= bytesRead; if( remainingCount == 0) { break; } if (inflater.Finished() ) { // if we finished decompressing, we can't have anything left in the outputwindow. Debug.Assert(inflater.AvailableOutput == 0, "We should have copied all stuff out!"); break; } Debug.Assert(inflater.NeedsInput(), "We can only run into this case if we are short of input"); int bytes = _stream.Read( buffer, 0, buffer.Length); if( bytes == 0) { break; //Do we want to throw an exception here? } inflater.SetInput(buffer, 0 , bytes); } return count - remainingCount; } private void ValidateParameters(byte[] array, int offset, int count) { if (array==null) { throw new ArgumentNullException("array"); } if (offset < 0) { throw new ArgumentOutOfRangeException("offset"); } if (count < 0) { throw new ArgumentOutOfRangeException("count"); } if (array.Length - offset < count) { throw new ArgumentException(SR.GetString(SR.InvalidArgumentOffsetCount)); } if (_stream == null ) { throw new ObjectDisposedException(null, SR.GetString(SR.ObjectDisposed_StreamClosed)); } } private void EnsureDecompressionMode() { if( _mode != CompressionMode.Decompress) { throw new InvalidOperationException(SR.GetString(SR.CannotReadFromDeflateStream)); } } private void EnsureCompressionMode() { if( _mode != CompressionMode.Compress) { throw new InvalidOperationException(SR.GetString(SR.CannotWriteToDeflateStream)); } } [HostProtection(ExternalThreading=true)] public override IAsyncResult BeginRead(byte[] array, int offset, int count, AsyncCallback asyncCallback, object asyncState) { EnsureDecompressionMode(); if (asyncOperations != 0 ) { throw new InvalidOperationException(SR.GetString(SR.InvalidBeginCall)); } Interlocked.Increment(ref asyncOperations); try { ValidateParameters(array, offset, count); DeflateStreamAsyncResult userResult = new DeflateStreamAsyncResult( this, asyncState, asyncCallback, array, offset, count); userResult.isWrite = false; // Try to read decompressed data in output buffer int bytesRead = inflater.Inflate(array, offset, count); if( bytesRead != 0) { // If decompression output buffer is not empty, return immediately. // 'true' means we complete synchronously. userResult.InvokeCallback(true, (object) bytesRead); return userResult; } if (inflater.Finished() ) { // end of compression stream userResult.InvokeCallback(true, (object) 0); return userResult; } // If there is no data on the output buffer and we are not at // the end of the stream, we need to get more data from the base stream _stream.BeginRead(buffer, 0, buffer.Length, m_CallBack, userResult); userResult.m_CompletedSynchronously &= userResult.IsCompleted; return userResult; } catch { Interlocked.Decrement( ref asyncOperations); throw; } } // callback function for asynchrous reading on base stream private void ReadCallback(IAsyncResult baseStreamResult) { DeflateStreamAsyncResult outerResult = (DeflateStreamAsyncResult) baseStreamResult.AsyncState; outerResult.m_CompletedSynchronously &= baseStreamResult.CompletedSynchronously; int bytesRead = 0; try { bytesRead = _stream.EndRead(baseStreamResult); } catch (Exception exc) { // Defer throwing this until EndXxx where we are ensured of user code on the stack. outerResult.InvokeCallback(exc); return; } if (bytesRead <= 0 ) { // This indicates the base stream has received EOF outerResult.InvokeCallback((object) 0); return; } // Feed the data from base stream into decompression engine inflater.SetInput(buffer, 0 , bytesRead); bytesRead = inflater.Inflate(outerResult.buffer, outerResult.offset, outerResult.count); if( bytesRead == 0 && !inflater.Finished()) { // We could have read in head information and didn't get any data. // Read from the base stream again. // Need to solve recusion. _stream.BeginRead(buffer, 0, buffer.Length, m_CallBack, outerResult); } else { outerResult.InvokeCallback((object) bytesRead); } } public override int EndRead(IAsyncResult asyncResult) { EnsureDecompressionMode(); if (asyncOperations != 1) { throw new InvalidOperationException(SR.GetString(SR.InvalidEndCall)); } if (asyncResult == null) { throw new ArgumentNullException("asyncResult"); } if (_stream == null ) { throw new InvalidOperationException(SR.GetString(SR.ObjectDisposed_StreamClosed)); } DeflateStreamAsyncResult myResult = asyncResult as DeflateStreamAsyncResult; if (myResult == null) { throw new ArgumentNullException("asyncResult"); } try { if (!myResult.IsCompleted) { myResult.AsyncWaitHandle.WaitOne(); } } finally { Interlocked.Decrement(ref asyncOperations); // this will just close the wait handle myResult.Close(); } if (myResult.Result is Exception) { throw (Exception)(myResult.Result); } return (int)myResult.Result; } public override void Write(byte[] array, int offset, int count) { EnsureCompressionMode(); ValidateParameters(array, offset, count); InternalWrite(array, offset, count, false); } internal void InternalWrite(byte[] array, int offset, int count, bool isAsync) { int currentOffest = offset; int remainingCount = count; int bytesCompressed; // compressed the bytes we already passed to the deflater while(!deflater.NeedsInput()) { bytesCompressed = deflater.GetDeflateOutput(buffer); if( bytesCompressed != 0) { if (isAsync) { IAsyncResult result = _stream.BeginWrite(buffer, 0, bytesCompressed, null, null); _stream.EndWrite(result); } else _stream.Write(buffer, 0, bytesCompressed); } } deflater.SetInput(array, offset, count); // compressed the new input while(!deflater.NeedsInput()) { bytesCompressed = deflater.GetDeflateOutput(buffer); if( bytesCompressed != 0) { if (isAsync) { IAsyncResult result = _stream.BeginWrite(buffer, 0, bytesCompressed, null, null); _stream.EndWrite(result); } else _stream.Write(buffer, 0, bytesCompressed); } } } protected override void Dispose(bool disposing) { try { // Flush on the underlying stream can throw (ex., low disk space) if (disposing && _stream != null) { Flush(); // Need to do close the output stream in compression mode if( _mode == CompressionMode.Compress && _stream != null) { int bytesCompressed; // compress any bytes left. while(!deflater.NeedsInput()) { bytesCompressed = deflater.GetDeflateOutput(buffer); if( bytesCompressed != 0) { _stream.Write(buffer, 0, bytesCompressed); } } // Write the end of compressed stream data. // We can safely do this since the buffer is large enough. bytesCompressed = deflater.Finish(buffer); if (bytesCompressed > 0) _stream.Write(buffer, 0, bytesCompressed); } } } finally { try { // Attempt to close the stream even if there was an IO error from Flushing. // Note that Stream.Close() can potentially throw here (may or may not be // due to the same Flush error). In this case, we still need to ensure // cleaning up internal resources, hence the finally block. if(disposing && !_leaveOpen && _stream != null) { _stream.Close(); } } finally { _stream = null; base.Dispose(disposing); } } } [HostProtection(ExternalThreading=true)] public override IAsyncResult BeginWrite(byte[] array, int offset, int count, AsyncCallback asyncCallback, object asyncState) { EnsureCompressionMode(); if (asyncOperations != 0 ) { throw new InvalidOperationException(SR.GetString(SR.InvalidBeginCall)); } Interlocked.Increment(ref asyncOperations); try { ValidateParameters(array, offset, count); DeflateStreamAsyncResult userResult = new DeflateStreamAsyncResult( this, asyncState, asyncCallback, array, offset, count); userResult.isWrite = true; m_AsyncWriterDelegate.BeginInvoke(array, offset, count, true, m_CallBack, userResult); userResult.m_CompletedSynchronously &= userResult.IsCompleted; return userResult; } catch { Interlocked.Decrement( ref asyncOperations); throw; } } // callback function for asynchrous reading on base stream private void WriteCallback(IAsyncResult asyncResult) { DeflateStreamAsyncResult outerResult = (DeflateStreamAsyncResult) asyncResult.AsyncState; outerResult.m_CompletedSynchronously &= asyncResult.CompletedSynchronously; try { m_AsyncWriterDelegate.EndInvoke(asyncResult); } catch (Exception exc) { // Defer throwing this until EndXxx where we are ensured of user code on the stack. outerResult.InvokeCallback(exc); return; } outerResult.InvokeCallback(null); } public override void EndWrite(IAsyncResult asyncResult) { EnsureCompressionMode(); if (asyncOperations != 1) { throw new InvalidOperationException(SR.GetString(SR.InvalidEndCall)); } if (asyncResult == null) { throw new ArgumentNullException("asyncResult"); } if (_stream == null ) { throw new InvalidOperationException(SR.GetString(SR.ObjectDisposed_StreamClosed)); } DeflateStreamAsyncResult myResult = asyncResult as DeflateStreamAsyncResult; if (myResult == null) { throw new ArgumentNullException("asyncResult"); } try { if (!myResult.IsCompleted) { myResult.AsyncWaitHandle.WaitOne(); } } finally { Interlocked.Decrement(ref asyncOperations); // this will just close the wait handle myResult.Close(); } if (myResult.Result is Exception) { throw (Exception)(myResult.Result); } } public Stream BaseStream { get { return _stream; } } } internal class DeflateStreamAsyncResult : IAsyncResult { public byte[] buffer; public int offset; public int count; public bool isWrite; private object m_AsyncObject; // Caller's async object. private object m_AsyncState; // Caller's state object. private AsyncCallback m_AsyncCallback; // Caller's callback method. private object m_Result; // Final IO result to be returned byt the End*() method. internal bool m_CompletedSynchronously; // true if the operation completed synchronously. private int m_InvokedCallback; // 0 is callback is not called private int m_Completed; // 0 if not completed >0 otherwise. private object m_Event; // lazy allocated event to be returned in the IAsyncResult for the client to wait on public DeflateStreamAsyncResult(object asyncObject, object asyncState, AsyncCallback asyncCallback, byte[] buffer, int offset, int count) { this.buffer = buffer; this.offset = offset; this.count = count; m_CompletedSynchronously = true; m_AsyncObject = asyncObject; m_AsyncState = asyncState; m_AsyncCallback = asyncCallback; } // Interface method to return the caller's state object. public object AsyncState { get { return m_AsyncState; } } // Interface property to return a WaitHandle that can be waited on for I/O completion. // This property implements lazy event creation. // the event object is only created when this property is accessed, // since we're internally only using callbacks, as long as the user is using // callbacks as well we will not create an event at all. public WaitHandle AsyncWaitHandle { get { // save a copy of the completion status int savedCompleted = m_Completed; if (m_Event == null) { // lazy allocation of the event: // if this property is never accessed this object is never created Interlocked.CompareExchange(ref m_Event, new ManualResetEvent(savedCompleted != 0), null); } ManualResetEvent castedEvent = (ManualResetEvent)m_Event; if (savedCompleted == 0 && m_Completed != 0) { // if, while the event was created in the reset state, // the IO operation completed, set the event here. castedEvent.Set(); } return castedEvent; } } // Interface property, returning synchronous completion status. public bool CompletedSynchronously { get { return m_CompletedSynchronously; } } // Interface property, returning completion status. public bool IsCompleted { get { return m_Completed != 0; } } // Internal property for setting the IO result. internal object Result { get { return m_Result; } } internal void Close() { if (m_Event != null) { ((ManualResetEvent)m_Event).Close(); } } internal void InvokeCallback(bool completedSynchronously, object result) { Complete(completedSynchronously, result); } internal void InvokeCallback(object result) { Complete(result); } // Internal method for setting completion. // As a side effect, we'll signal the WaitHandle event and clean up. private void Complete(bool completedSynchronously, object result) { m_CompletedSynchronously = completedSynchronously; Complete(result); } private void Complete(object result) { m_Result = result; // Set IsCompleted and the event only after the usercallback method. Interlocked.Increment( ref m_Completed ); if (m_Event != null) { ((ManualResetEvent)m_Event).Set(); } if (Interlocked.Increment(ref m_InvokedCallback)==1) { if( m_AsyncCallback != null) { m_AsyncCallback(this); } } } } }
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