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Rewrite LZ77 decompression as well

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This commit is contained in:
BtbN 2019-06-14 21:25:45 +02:00
parent 499952b7e6
commit 7ca1f8489b
5 changed files with 33 additions and 88 deletions
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4
ClanServer/Data/L44/ClanMusicInfo.cs
View File

@ -27,9 +27,7 @@ namespace ClanServer.Data.L44
stream.CopyTo(ms);
return new ClanMusicInfo(
new KBinXML(
LZ77.Decompress(
ms.ToArray()
).ToArray()
LZ77.Decompress(ms.ToArray())
).Document
);
}

2
ClanServer/Formatters/EamuseXrpcInputFormatter.cs
View File

@ -89,7 +89,7 @@ namespace ClanServer.Formatters
switch (compAlgo.ToLower())
{
case "lz77":
return LZ77.Decompress(data).ToArray();
return LZ77.Decompress(data);
case "none":
return data;
default:

2
ClanServer/Formatters/EamuseXrpcOutputFormatter.cs
View File

@ -39,7 +39,7 @@ namespace ClanServer.Formatters
string algo = "none";
byte[] compressed = LZ77.Compress(resData);
byte[] compressed = LZ77.Compress(resData, 32);
if (compressed.Length < resData.Length)
{
resData = compressed;

111
eAmuseCore/Compression/LZ77.cs
View File

@ -1,103 +1,50 @@
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace eAmuseCore.Compression
{
public class RepeatingRingBuffer
{
private readonly byte[] buf;
private readonly int mod;
private int pos;
public RepeatingRingBuffer(int size)
{
if (size == 0 || (size & (size - 1)) != 0)
throw new ArgumentException("Size is not a power of two.", "size");
buf = new byte[size];
mod = size - 1;
pos = 0;
}
public byte this[int index]
{
get => buf[(pos + index) & mod];
set => buf[(pos + index) & mod] = value;
}
public int Size
{
get => buf.Length;
}
public void Append(byte b)
{
buf[pos++ & mod] = b;
}
public IEnumerable<byte> Slice(int start, int end)
{
for (int i = start; i < end; ++i)
{
if (start < 0 && i >= 0)
yield return this[start + (i % start)];
else
yield return this[i];
}
}
}
public static class LZ77
{
private const int minLength = 3;
public static IEnumerable<byte> Decompress(IEnumerable<byte> data)
public static byte[] Decompress(byte[] data)
{
RepeatingRingBuffer buffer = new RepeatingRingBuffer(0x1000);
List<byte> res = new List<byte>();
int pos = 0;
int state = 0;
using (var iter = data.GetEnumerator())
while (pos < data.Length)
{
while (iter.MoveNext())
state >>= 1;
if (state <= 1)
state = data[pos++] | 0x100;
if ((state & 1) != 0)
{
state >>= 1;
if (state <= 1)
res.Add(data[pos++]);
}
else
{
byte byte1 = data[pos++];
byte byte2 = data[pos++];
int length = (byte2 & 0xf) + minLength;
int distance = (byte1 << 4) | (byte2 >> 4);
if (distance == 0)
break;
int resPos = res.Count;
for (int i = 0; i < length; ++i)
{
state = iter.Current | 0x100;
if (!iter.MoveNext())
yield break;
}
if ((state & 1) != 0)
{
yield return iter.Current;
buffer.Append(iter.Current);
}
else
{
byte byte1 = iter.Current;
if (!iter.MoveNext())
yield break;
byte byte2 = iter.Current;
int length = (byte2 & 0xf) + minLength;
int distance = (byte1 << 4) | (byte2 >> 4);
if (distance == 0)
yield break;
for (int i = 0; i < length; ++i)
{
byte b = buffer[-distance];
yield return b;
buffer.Append(b);
}
int o = resPos - distance + i;
res.Add((o < 0) ? (byte)0 : res[o]);
}
}
}
return res.ToArray();
}
private struct Match

2
eAmuseTest/Program.cs
View File

@ -27,7 +27,7 @@ namespace eAmuseTest
byte[] rawData = data;
if (compress == "lz77")
rawData = LZ77.Decompress(data).ToArray();
rawData = LZ77.Decompress(data);
else if (compress != "none")
throw new ArgumentException("Unsupported compression algorithm");