81 lines
2.4 KiB
C#
81 lines
2.4 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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using System.IO;
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using UniversalEditor.Compression.Common;
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namespace UniversalEditor.Compression.Modules.LZSS
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{
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public class LZSSCompressionModule : CompressionModule
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{
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public override string Name
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{
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get { return "lzss"; }
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}
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protected override void DecompressInternal(Stream inputStream, Stream outputStream, int inputLength, int outputLength)
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{
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MT19937ar myMT19937ar = new MT19937ar();
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uint act_outputLength = 0u;
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uint nActWindowByte = 4080u;
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byte[] win = new byte[4096];
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ushort flag = 0;
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uint[] init_key = new uint[4];
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byte[] rnd = new byte[1024];
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init_key[0] = ((uint)outputLength | 128u) >> 5;
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init_key[1] = ((uint)outputLength << 9 | 6u);
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init_key[2] = ((uint)outputLength << 6 | 4u);
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init_key[3] = ((uint)outputLength | 72u) >> 3;
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myMT19937ar.init_by_array(init_key, 4);
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for (uint i = 0u; i < 1024u; i += 1u)
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{
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rnd[(int)(i)] = (byte)(myMT19937ar.genrand_int32() >> (int)(i % 7u));
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}
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uint seed = (uint)outputLength / 1000u % 10u + (uint)outputLength / 100u % 10u + (uint)outputLength / 10u % 10u + (uint)outputLength % 10u & 794u;
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win.Initialize();
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byte[] result;
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while (act_outputLength < outputLength)
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{
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flag = (ushort)(flag >> 1);
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if (act_outputLength < 32860u)
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{
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goto IL_EE;
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}
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IL_EE:
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if ((flag & 256) == 0)
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{
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seed = (seed + 1u & 1023u);
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flag = (ushort)((inputStream.ReadByte() ^ rnd[(int)(seed)]) | 65280);
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}
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seed = (seed + 1u & 1023u);
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byte data;
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if ((flag & 1) == 0)
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{
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uint win_offset = (uint)(inputStream.ReadByte() ^ rnd[(int)(seed)]);
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seed = (seed + 1u & 1023u);
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uint copy_bytes = (uint)(inputStream.ReadByte() ^ rnd[(int)(seed)]);
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win_offset |= (copy_bytes & 240u) << 4;
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copy_bytes &= 15u;
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copy_bytes += 3u;
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for (uint i = 0u; i < copy_bytes; i += 1u)
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{
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data = win[(int)((win_offset + i & 4095u))];
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outputStream.WriteByte(data);
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win[(int)((nActWindowByte++))] = data;
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nActWindowByte &= 4095u;
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if (act_outputLength >= outputLength) return;
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}
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continue;
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}
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data = (byte)(inputStream.ReadByte() ^ rnd[(int)(seed)]);
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outputStream.WriteByte(data);
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win[(int)((nActWindowByte++))] = data;
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nActWindowByte &= 4095u;
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}
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}
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protected override void CompressInternal(Stream inputStream, Stream outputStream)
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{
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throw new NotImplementedException();
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}
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}
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}
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