104 lines
3.5 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UniversalEditor.Accessors;
using UniversalEditor.IO;
namespace UniversalEditor.Compression.Modules.LZRW1
{
public class LZRW1CompressionModule : CompressionModule
{
/// <summary>
/// Number of bytes used by copy flag
/// </summary>
private const byte FLAG_BYTES = 0x04;
private const byte FLAG_COMPRESS = 0x00;
private const byte FLAG_COPY = 0x01;
public override string Name
{
get { return "LZRW1"; }
}
protected override void CompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream)
{
throw new NotImplementedException();
}
protected override void DecompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream, int inputLength, int outputLength)
{
StreamAccessor sao = new StreamAccessor(outputStream);
StreamAccessor sai = new StreamAccessor(inputStream);
Reader br = new Reader(sai);
Writer bw = new Writer(sao);
/*
byte *p_src = p_src_first + 4,
*p_dst = p_dst_first,
*p_dst_end = p_dst_first + dst_len;
byte *p_src_post = p_src_first + src_len;
byte *p_src_max16 = p_src_first + src_len - (16 * 2);
*/
uint control = 1;
uint flag = br.ReadUInt32();
if (flag == FLAG_COPY)
{
// entire stream is uncompressed, so read it all
byte[] data = br.ReadToEnd();
bw.WriteBytes(data);
}
while (!br.EndOfStream)
{
uint unroll;
if (control == 1)
{
control = (uint)(0x10000 | br.ReadByte());
control |= (uint)(br.ReadByte() << 8);
}
unroll = (uint)((br.Accessor.Position <= (br.Accessor.Length - 32)) ? 16 : 1);
while (unroll-- != 0)
{
if ((control & 1) != 0)
{
byte offsetCalcByte1 = br.ReadByte();
byte offsetCalcByte2 = br.ReadByte();
ushort offset = (ushort)(((offsetCalcByte1 & 0xF0) << 4) | offsetCalcByte2);
ushort len = (ushort)(offsetCalcByte1 & 0xF);
long oldpos = sao.Position;
sao.Position = sao.Length - offset;
IO.Reader bro = new Reader(sao);
byte value = bro.ReadByte();
sao.Position = oldpos;
// if((p_dst + offset) > p_dst_end) return(-1);
for (int i = 0; i < len + 3; i++)
{
bw.WriteByte(value);
}
System.IO.File.WriteAllBytes(@"C:\Temp\Test.dat", outputStream.ToByteArray());
}
else
{
if (br.EndOfStream) return;
bw.WriteByte(br.ReadByte());
System.IO.File.WriteAllBytes(@"C:\Temp\Test.dat", outputStream.ToByteArray());
}
control >>= 1;
}
}
}
}
}