comparison src/zlib-1.2.7/contrib/dotzlib/DotZLib/CodecBase.cs @ 4:e13257ea84a4

Add bzip2, zlib, liblo, portaudio sources

+//
+// © 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
+
+    }
+}