Chris@43: //
Chris@43: // © Copyright Henrik Ravn 2004
Chris@43: //
Chris@43: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
Chris@43: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@43: //
Chris@43: 
Chris@43: using System;
Chris@43: using System.Diagnostics;
Chris@43: using System.Runtime.InteropServices;
Chris@43: 
Chris@43: namespace DotZLib
Chris@43: {
Chris@43: 
Chris@43:     /// <summary>
Chris@43:     /// Implements a data compressor, using the deflate algorithm in the ZLib dll
Chris@43:     /// </summary>
Chris@43: 	public sealed class Deflater : CodecBase
Chris@43: 	{
Chris@43:         #region Dll imports
Chris@43:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl, CharSet=CharSet.Ansi)]
Chris@43:         private static extern int deflateInit_(ref ZStream sz, int level, string vs, int size);
Chris@43: 
Chris@43:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
Chris@43:         private static extern int deflate(ref ZStream sz, int flush);
Chris@43: 
Chris@43:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
Chris@43:         private static extern int deflateReset(ref ZStream sz);
Chris@43: 
Chris@43:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
Chris@43:         private static extern int deflateEnd(ref ZStream sz);
Chris@43:         #endregion
Chris@43: 
Chris@43:         /// <summary>
Chris@43:         /// Constructs an new instance of the <c>Deflater</c>
Chris@43:         /// </summary>
Chris@43:         /// <param name="level">The compression level to use for this <c>Deflater</c></param>
Chris@43: 		public Deflater(CompressLevel level) : base()
Chris@43: 		{
Chris@43:             int retval = deflateInit_(ref _ztream, (int)level, Info.Version, Marshal.SizeOf(_ztream));
Chris@43:             if (retval != 0)
Chris@43:                 throw new ZLibException(retval, "Could not initialize deflater");
Chris@43: 
Chris@43:             resetOutput();
Chris@43: 		}
Chris@43: 
Chris@43:         /// <summary>
Chris@43:         /// Adds more data to the codec to be processed.
Chris@43:         /// </summary>
Chris@43:         /// <param name="data">Byte array containing the data to be added to the codec</param>
Chris@43:         /// <param name="offset">The index of the first byte to add from <c>data</c></param>
Chris@43:         /// <param name="count">The number of bytes to add</param>
Chris@43:         /// <remarks>Adding data may, or may not, raise the <c>DataAvailable</c> event</remarks>
Chris@43:         public override void Add(byte[] data, int offset, int count)
Chris@43:         {
Chris@43:             if (data == null) throw new ArgumentNullException();
Chris@43:             if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
Chris@43:             if ((offset+count) > data.Length) throw new ArgumentException();
Chris@43: 
Chris@43:             int total = count;
Chris@43:             int inputIndex = offset;
Chris@43:             int err = 0;
Chris@43: 
Chris@43:             while (err >= 0 && inputIndex < total)
Chris@43:             {
Chris@43:                 copyInput(data, inputIndex, Math.Min(total - inputIndex, kBufferSize));
Chris@43:                 while (err >= 0 && _ztream.avail_in > 0)
Chris@43:                 {
Chris@43:                     err = deflate(ref _ztream, (int)FlushTypes.None);
Chris@43:                     if (err == 0)
Chris@43:                         while (_ztream.avail_out == 0)
Chris@43:                         {
Chris@43:                             OnDataAvailable();
Chris@43:                             err = deflate(ref _ztream, (int)FlushTypes.None);
Chris@43:                         }
Chris@43:                     inputIndex += (int)_ztream.total_in;
Chris@43:                 }
Chris@43:             }
Chris@43:             setChecksum( _ztream.adler );
Chris@43:         }
Chris@43: 
Chris@43: 
Chris@43:         /// <summary>
Chris@43:         /// Finishes up any pending data that needs to be processed and handled.
Chris@43:         /// </summary>
Chris@43:         public override void Finish()
Chris@43:         {
Chris@43:             int err;
Chris@43:             do
Chris@43:             {
Chris@43:                 err = deflate(ref _ztream, (int)FlushTypes.Finish);
Chris@43:                 OnDataAvailable();
Chris@43:             }
Chris@43:             while (err == 0);
Chris@43:             setChecksum( _ztream.adler );
Chris@43:             deflateReset(ref _ztream);
Chris@43:             resetOutput();
Chris@43:         }
Chris@43: 
Chris@43:         /// <summary>
Chris@43:         /// Closes the internal zlib deflate stream
Chris@43:         /// </summary>
Chris@43:         protected override void CleanUp() { deflateEnd(ref _ztream); }
Chris@43: 
Chris@43:     }
Chris@43: }