diff options
Diffstat (limited to 'zlib/contrib/dotzlib/DotZLib/CodecBase.cs')
| -rw-r--r-- | zlib/contrib/dotzlib/DotZLib/CodecBase.cs | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/zlib/contrib/dotzlib/DotZLib/CodecBase.cs b/zlib/contrib/dotzlib/DotZLib/CodecBase.cs new file mode 100644 index 000000000..954db7db0 --- /dev/null +++ b/zlib/contrib/dotzlib/DotZLib/CodecBase.cs @@ -0,0 +1,198 @@ +//
+// © Copyright Henrik Ravn 2004
+//
+// Use, modification and distribution are subject to the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace DotZLib
+{
+ /// <summary>
+ /// Implements the common functionality needed for all <see cref="Codec"/>s
+ /// </summary>
+ public abstract class CodecBase : Codec, IDisposable
+ {
+
+ #region Data members
+
+ /// <summary>
+ /// Instance of the internal zlib buffer structure that is
+ /// passed to all functions in the zlib dll
+ /// </summary>
+ internal ZStream _ztream = new ZStream();
+
+ /// <summary>
+ /// True if the object instance has been disposed, false otherwise
+ /// </summary>
+ protected bool _isDisposed = false;
+
+ /// <summary>
+ /// The size of the internal buffers
+ /// </summary>
+ protected const int kBufferSize = 16384;
+
+ private byte[] _outBuffer = new byte[kBufferSize];
+ private byte[] _inBuffer = new byte[kBufferSize];
+
+ private GCHandle _hInput;
+ private GCHandle _hOutput;
+
+ private uint _checksum = 0;
+
+ #endregion
+
+ /// <summary>
+ /// Initializes a new instance of the <c>CodeBase</c> class.
+ /// </summary>
+ public CodecBase()
+ {
+ try
+ {
+ _hInput = GCHandle.Alloc(_inBuffer, GCHandleType.Pinned);
+ _hOutput = GCHandle.Alloc(_outBuffer, GCHandleType.Pinned);
+ }
+ catch (Exception)
+ {
+ CleanUp(false);
+ throw;
+ }
+ }
+
+
+ #region Codec Members
+
+ /// <summary>
+ /// Occurs when more processed data are available.
+ /// </summary>
+ public event DataAvailableHandler DataAvailable;
+
+ /// <summary>
+ /// Fires the <see cref="DataAvailable"/> event
+ /// </summary>
+ protected void OnDataAvailable()
+ {
+ if (_ztream.total_out > 0)
+ {
+ if (DataAvailable != null)
+ DataAvailable( _outBuffer, 0, (int)_ztream.total_out);
+ resetOutput();
+ }
+ }
+
+ /// <summary>
+ /// Adds more data to the codec to be processed.
+ /// </summary>
+ /// <param name="data">Byte array containing the data to be added to the codec</param>
+ /// <remarks>Adding data may, or may not, raise the <c>DataAvailable</c> event</remarks>
+ public void Add(byte[] data)
+ {
+ Add(data,0,data.Length);
+ }
+
+ /// <summary>
+ /// Adds more data to the codec to be processed.
+ /// </summary>
+ /// <param name="data">Byte array containing the data to be added to the codec</param>
+ /// <param name="offset">The index of the first byte to add from <c>data</c></param>
+ /// <param name="count">The number of bytes to add</param>
+ /// <remarks>Adding data may, or may not, raise the <c>DataAvailable</c> event</remarks>
+ /// <remarks>This must be implemented by a derived class</remarks>
+ public abstract void Add(byte[] data, int offset, int count);
+
+ /// <summary>
+ /// Finishes up any pending data that needs to be processed and handled.
+ /// </summary>
+ /// <remarks>This must be implemented by a derived class</remarks>
+ public abstract void Finish();
+
+ /// <summary>
+ /// Gets the checksum of the data that has been added so far
+ /// </summary>
+ public uint Checksum { get { return _checksum; } }
+
+ #endregion
+
+ #region Destructor & IDisposable stuff
+
+ /// <summary>
+ /// Destroys this instance
+ /// </summary>
+ ~CodecBase()
+ {
+ CleanUp(false);
+ }
+
+ /// <summary>
+ /// Releases any unmanaged resources and calls the <see cref="CleanUp()"/> method of the derived class
+ /// </summary>
+ public void Dispose()
+ {
+ CleanUp(true);
+ }
+
+ /// <summary>
+ /// Performs any codec specific cleanup
+ /// </summary>
+ /// <remarks>This must be implemented by a derived class</remarks>
+ protected abstract void CleanUp();
+
+ // performs the release of the handles and calls the dereived CleanUp()
+ private void CleanUp(bool isDisposing)
+ {
+ if (!_isDisposed)
+ {
+ CleanUp();
+ if (_hInput.IsAllocated)
+ _hInput.Free();
+ if (_hOutput.IsAllocated)
+ _hOutput.Free();
+
+ _isDisposed = true;
+ }
+ }
+
+
+ #endregion
+
+ #region Helper methods
+
+ /// <summary>
+ /// Copies a number of bytes to the internal codec buffer - ready for proccesing
+ /// </summary>
+ /// <param name="data">The byte array that contains the data to copy</param>
+ /// <param name="startIndex">The index of the first byte to copy</param>
+ /// <param name="count">The number of bytes to copy from <c>data</c></param>
+ protected void copyInput(byte[] data, int startIndex, int count)
+ {
+ Array.Copy(data, startIndex, _inBuffer,0, count);
+ _ztream.next_in = _hInput.AddrOfPinnedObject();
+ _ztream.total_in = 0;
+ _ztream.avail_in = (uint)count;
+
+ }
+
+ /// <summary>
+ /// Resets the internal output buffers to a known state - ready for processing
+ /// </summary>
+ protected void resetOutput()
+ {
+ _ztream.total_out = 0;
+ _ztream.avail_out = kBufferSize;
+ _ztream.next_out = _hOutput.AddrOfPinnedObject();
+ }
+
+ /// <summary>
+ /// Updates the running checksum property
+ /// </summary>
+ /// <param name="newSum">The new checksum value</param>
+ protected void setChecksum(uint newSum)
+ {
+ _checksum = newSum;
+ }
+ #endregion
+
+ }
+}
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