/* Compress */
public override MemoryStream Compress(ref Stream data, string filename)
{
try
{
uint DecompressedSize = (uint)data.Length;
MemoryStream CompressedData = new MemoryStream();
byte[] DecompressedData = data.ToByteArray();
uint SourcePointer = 0x0;
uint DestPointer = 0x10;
// Test if the file is too large to be compressed
if (data.Length > 0xFFFFFFFF)
throw new Exception("Input file is too large to compress.");
// Set up the Lz Compression Dictionary
LzBufferDictionary LzDictionary = new LzBufferDictionary();
LzDictionary.SetBufferSize(0x1000);
LzDictionary.SetBufferStart(0xFEE);
LzDictionary.SetMaxMatchAmount(0xF + 3);
// Start compression
CompressedData.Write("LZ01");
CompressedData.Write((uint)0); // Will be filled in later
CompressedData.Write(DecompressedSize);
CompressedData.Seek(4, SeekOrigin.Current); // Advance 4 bytes
while (SourcePointer < DecompressedSize)
{
byte Flag = 0x0;
uint FlagPosition = DestPointer;
CompressedData.WriteByte(Flag); // It will be filled in later
DestPointer++;
for (int i = 0; i < 8; i++)
{
int[] LzSearchMatch = LzDictionary.Search(DecompressedData, SourcePointer, DecompressedSize);
if (LzSearchMatch[1] > 0) // There is a compression match
{
Flag |= (byte)(0 << i);
CompressedData.WriteByte((byte)(LzSearchMatch[0] & 0xFF));
CompressedData.WriteByte((byte)(((LzSearchMatch[0] & 0xF00) >> 4) | ((LzSearchMatch[1] - 3) & 0xF)));
LzDictionary.AddEntryRange(DecompressedData, (int)SourcePointer, LzSearchMatch[1]);
SourcePointer += (uint)LzSearchMatch[1];
DestPointer += 2;
}
else // There wasn't a match
{
Flag |= (byte)(1 << i);
CompressedData.WriteByte(DecompressedData[SourcePointer]);
LzDictionary.AddEntry(DecompressedData, (int)SourcePointer);
SourcePointer++;
DestPointer++;
}
// Check for out of bounds
if (SourcePointer >= DecompressedSize)
break;
}
// Write the flag.
// Note that the original position gets reset after writing.
CompressedData.Seek(FlagPosition, SeekOrigin.Begin);
CompressedData.WriteByte(Flag);
CompressedData.Seek(DestPointer, SeekOrigin.Begin);
}
CompressedData.Seek(0x4, SeekOrigin.Begin);
CompressedData.Write((uint)CompressedData.Length);
CompressedData.Seek(0, SeekOrigin.End);
return CompressedData;
}
catch
{
return null; // An error occured while compressing
}
}
/* Compress */
public override MemoryStream Compress(ref Stream data, string filename)
{
try
{
uint DecompressedSize = (uint)data.Length;
MemoryStream CompressedData = new MemoryStream();
byte[] DecompressedData = data.ToByteArray();
uint SourcePointer = 0x0;
uint DestPointer = 0x40;
uint MagicValue = (uint)(DateTime.Now - new DateTime(1970, 1, 1)).TotalSeconds;
// Test if the file is too large to be compressed
if (data.Length > 0xFFFFFFFF)
throw new Exception("Input file is too large to compress.");
// Set up the Lz Compression Dictionary
LzBufferDictionary LzDictionary = new LzBufferDictionary();
LzDictionary.SetBufferSize(0x1000);
LzDictionary.SetBufferStart(0xFEE);
LzDictionary.SetMaxMatchAmount(0xF + 3);
// Start compression
CompressedData.Write("LZ00");
CompressedData.Write(0u); // Will be filled in later
CompressedData.Seek(8, SeekOrigin.Current); // Advance 8 bytes
// If the file extension is MRZ or TEZ, we probably want to change it
if (Path.GetExtension(filename).ToLower() == ".mrz")
filename = Path.GetFileNameWithoutExtension(filename) + ".mrg";
else if (Path.GetExtension(filename).ToLower() == ".tez")
filename = Path.GetFileNameWithoutExtension(filename) + ".tex";
CompressedData.Write(filename, 31, 32, Encoding.GetEncoding("Shift_JIS"));
CompressedData.Write(DecompressedSize);
CompressedData.Write(MagicValue);
CompressedData.Seek(8, SeekOrigin.Current); // Advance 8 bytes
while (SourcePointer < DecompressedSize)
{
MagicValue = GetNewMagicValue(MagicValue);
byte Flag = 0x0;
uint FlagPosition = DestPointer;
uint FlagMagicValue = MagicValue; // Since it won't be filled in now
CompressedData.WriteByte(Flag); // It will be filled in later
DestPointer++;
for (int i = 0; i < 8; i++)
{
int[] LzSearchMatch = LzDictionary.Search(DecompressedData, SourcePointer, DecompressedSize);
if (LzSearchMatch[1] > 0) // There is a compression match
{
Flag |= (byte)(0 << i);
MagicValue = GetNewMagicValue(MagicValue);
CompressedData.WriteByte(EncryptByte((byte)(LzSearchMatch[0] & 0xFF), MagicValue));
MagicValue = GetNewMagicValue(MagicValue);
CompressedData.WriteByte(EncryptByte((byte)(((LzSearchMatch[0] & 0xF00) >> 4) | ((LzSearchMatch[1] - 3) & 0xF)), MagicValue));
LzDictionary.AddEntryRange(DecompressedData, (int)SourcePointer, LzSearchMatch[1]);
SourcePointer += (uint)LzSearchMatch[1];
DestPointer += 2;
}
else // There wasn't a match
{
Flag |= (byte)(1 << i);
MagicValue = GetNewMagicValue(MagicValue);
CompressedData.WriteByte(EncryptByte(DecompressedData[SourcePointer], MagicValue));
LzDictionary.AddEntry(DecompressedData, (int)SourcePointer);
SourcePointer++;
DestPointer++;
}
// Check for out of bounds
if (SourcePointer >= DecompressedSize)
break;
}
// Write the flag.
// Note that the original position gets reset after writing.
CompressedData.Seek(FlagPosition, SeekOrigin.Begin);
CompressedData.WriteByte(EncryptByte(Flag, FlagMagicValue));
CompressedData.Seek(DestPointer, SeekOrigin.Begin);
}
CompressedData.Seek(0x4, SeekOrigin.Begin);
CompressedData.Write((uint)CompressedData.Length);
CompressedData.Seek(0, SeekOrigin.End);
return CompressedData;
}
catch
{
return null; // An error occured while compressing
}
}