cannam@128: //
cannam@128: // © Copyright Henrik Ravn 2004
cannam@128: //
cannam@128: // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
cannam@128: // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
cannam@128: //
cannam@128: 
cannam@128: using System;
cannam@128: using System.Diagnostics;
cannam@128: using System.Runtime.InteropServices;
cannam@128: 
cannam@128: namespace DotZLib
cannam@128: {
cannam@128: 
cannam@128:     /// <summary>
cannam@128:     /// Implements a data decompressor, using the inflate algorithm in the ZLib dll
cannam@128:     /// </summary>
cannam@128:     public class Inflater : CodecBase
cannam@128: 	{
cannam@128:         #region Dll imports
cannam@128:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl, CharSet=CharSet.Ansi)]
cannam@128:         private static extern int inflateInit_(ref ZStream sz, string vs, int size);
cannam@128: 
cannam@128:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
cannam@128:         private static extern int inflate(ref ZStream sz, int flush);
cannam@128: 
cannam@128:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
cannam@128:         private static extern int inflateReset(ref ZStream sz);
cannam@128: 
cannam@128:         [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
cannam@128:         private static extern int inflateEnd(ref ZStream sz);
cannam@128:         #endregion
cannam@128: 
cannam@128:         /// <summary>
cannam@128:         /// Constructs an new instance of the <c>Inflater</c>
cannam@128:         /// </summary>
cannam@128:         public Inflater() : base()
cannam@128: 		{
cannam@128:             int retval = inflateInit_(ref _ztream, Info.Version, Marshal.SizeOf(_ztream));
cannam@128:             if (retval != 0)
cannam@128:                 throw new ZLibException(retval, "Could not initialize inflater");
cannam@128: 
cannam@128:             resetOutput();
cannam@128:         }
cannam@128: 
cannam@128: 
cannam@128:         /// <summary>
cannam@128:         /// Adds more data to the codec to be processed.
cannam@128:         /// </summary>
cannam@128:         /// <param name="data">Byte array containing the data to be added to the codec</param>
cannam@128:         /// <param name="offset">The index of the first byte to add from <c>data</c></param>
cannam@128:         /// <param name="count">The number of bytes to add</param>
cannam@128:         /// <remarks>Adding data may, or may not, raise the <c>DataAvailable</c> event</remarks>
cannam@128:         public override void Add(byte[] data, int offset, int count)
cannam@128:         {
cannam@128:             if (data == null) throw new ArgumentNullException();
cannam@128:             if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
cannam@128:             if ((offset+count) > data.Length) throw new ArgumentException();
cannam@128: 
cannam@128:             int total = count;
cannam@128:             int inputIndex = offset;
cannam@128:             int err = 0;
cannam@128: 
cannam@128:             while (err >= 0 && inputIndex < total)
cannam@128:             {
cannam@128:                 copyInput(data, inputIndex, Math.Min(total - inputIndex, kBufferSize));
cannam@128:                 err = inflate(ref _ztream, (int)FlushTypes.None);
cannam@128:                 if (err == 0)
cannam@128:                     while (_ztream.avail_out == 0)
cannam@128:                     {
cannam@128:                         OnDataAvailable();
cannam@128:                         err = inflate(ref _ztream, (int)FlushTypes.None);
cannam@128:                     }
cannam@128: 
cannam@128:                 inputIndex += (int)_ztream.total_in;
cannam@128:             }
cannam@128:             setChecksum( _ztream.adler );
cannam@128:         }
cannam@128: 
cannam@128: 
cannam@128:         /// <summary>
cannam@128:         /// Finishes up any pending data that needs to be processed and handled.
cannam@128:         /// </summary>
cannam@128:         public override void Finish()
cannam@128:         {
cannam@128:             int err;
cannam@128:             do
cannam@128:             {
cannam@128:                 err = inflate(ref _ztream, (int)FlushTypes.Finish);
cannam@128:                 OnDataAvailable();
cannam@128:             }
cannam@128:             while (err == 0);
cannam@128:             setChecksum( _ztream.adler );
cannam@128:             inflateReset(ref _ztream);
cannam@128:             resetOutput();
cannam@128:         }
cannam@128: 
cannam@128:         /// <summary>
cannam@128:         /// Closes the internal zlib inflate stream
cannam@128:         /// </summary>
cannam@128:         protected override void CleanUp() { inflateEnd(ref _ztream); }
cannam@128: 
cannam@128: 
cannam@128: 	}
cannam@128: }