2 // © Copyright Henrik Ravn 2004
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4 // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
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5 // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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9 using System.Diagnostics;
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10 using System.Runtime.InteropServices;
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16 /// Implements a data compressor, using the deflate algorithm in the ZLib dll
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18 public sealed class Deflater : CodecBase
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21 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl, CharSet=CharSet.Ansi)]
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22 private static extern int deflateInit_(ref ZStream sz, int level, string vs, int size);
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24 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
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25 private static extern int deflate(ref ZStream sz, int flush);
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27 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
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28 private static extern int deflateReset(ref ZStream sz);
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30 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
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31 private static extern int deflateEnd(ref ZStream sz);
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35 /// Constructs an new instance of the <c>Deflater</c>
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37 /// <param name="level">The compression level to use for this <c>Deflater</c></param>
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38 public Deflater(CompressLevel level) : base()
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40 int retval = deflateInit_(ref _ztream, (int)level, Info.Version, Marshal.SizeOf(_ztream));
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42 throw new ZLibException(retval, "Could not initialize deflater");
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48 /// Adds more data to the codec to be processed.
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50 /// <param name="data">Byte array containing the data to be added to the codec</param>
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51 /// <param name="offset">The index of the first byte to add from <c>data</c></param>
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52 /// <param name="count">The number of bytes to add</param>
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53 /// <remarks>Adding data may, or may not, raise the <c>DataAvailable</c> event</remarks>
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54 public override void Add(byte[] data, int offset, int count)
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56 if (data == null) throw new ArgumentNullException();
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57 if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
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58 if ((offset+count) > data.Length) throw new ArgumentException();
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61 int inputIndex = offset;
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64 while (err >= 0 && inputIndex < total)
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66 copyInput(data, inputIndex, Math.Min(total - inputIndex, kBufferSize));
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67 while (err >= 0 && _ztream.avail_in > 0)
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69 err = deflate(ref _ztream, (int)FlushTypes.None);
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71 while (_ztream.avail_out == 0)
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74 err = deflate(ref _ztream, (int)FlushTypes.None);
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76 inputIndex += (int)_ztream.total_in;
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79 setChecksum( _ztream.adler );
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84 /// Finishes up any pending data that needs to be processed and handled.
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86 public override void Finish()
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91 err = deflate(ref _ztream, (int)FlushTypes.Finish);
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95 setChecksum( _ztream.adler );
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96 deflateReset(ref _ztream);
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101 /// Closes the internal zlib deflate stream
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103 protected override void CleanUp() { deflateEnd(ref _ztream); }
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