| public static Decompress ( Stream instream, Stream outstream ) : long | ||
| instream | Stream | |
| outstream | Stream | |
| return | long | |
public static long Decompress(Stream instream, Stream outstream)
{
#region Format definition in NDSTEK style
/* Data header (32bit)
Bit 0-3 Reserved
Bit 4-7 Compressed type (must be 1 for LZ77)
Bit 8-31 Size of decompressed data. if 0, the next 4 bytes are decompressed length
Repeat below. Each Flag Byte followed by eight Blocks.
Flag data (8bit)
Bit 0-7 Type Flags for next 8 Blocks, MSB first
Block Type 0 - Uncompressed - Copy 1 Byte from Source to Dest
Bit 0-7 One data byte to be copied to dest
Block Type 1 - Compressed - Copy LEN Bytes from Dest-Disp-1 to Dest
If Reserved is 0: - Default
Bit 0-3 Disp MSBs
Bit 4-7 LEN - 3
Bit 8-15 Disp LSBs
If Reserved is 1: - Higher compression rates for files with (lots of) long repetitions
Bit 4-7 Indicator
If Indicator > 1:
Bit 0-3 Disp MSBs
Bit 4-7 LEN - 1 (same bits as Indicator)
Bit 8-15 Disp LSBs
If Indicator is 1: A(B CD E)(F GH)
Bit 0-3 (LEN - 0x111) MSBs
Bit 4-7 Indicator; unused
Bit 8-15 (LEN- 0x111) 'middle'-SBs
Bit 16-19 Disp MSBs
Bit 20-23 (LEN - 0x111) LSBs
Bit 24-31 Disp LSBs
If Indicator is 0:
Bit 0-3 (LEN - 0x11) MSBs
Bit 4-7 Indicator; unused
Bit 8-11 Disp MSBs
Bit 12-15 (LEN - 0x11) LSBs
Bit 16-23 Disp LSBs
*/
#endregion
long readBytes = 0;
byte type = (byte)instream.ReadByte();
if (type != 0x11)
throw new InvalidDataException("The provided stream is not a valid LZ-0x11 "
+ "compressed stream (invalid type 0x" + type.ToString("X") + ")");
byte[] sizeBytes = new byte[4];
instream.Read(sizeBytes, 0, 3);
int decompressedSize = BitConverter.ToInt32(sizeBytes, 0);
readBytes += 4;
if (decompressedSize == 0)
{
sizeBytes = new byte[4];
instream.Read(sizeBytes, 0, 4);
decompressedSize = BitConverter.ToInt32(sizeBytes, 0);
readBytes += 4;
}
// the maximum 'DISP-1' is still 0xFFF.
int bufferLength = 0x1000;
byte[] buffer = new byte[bufferLength];
int bufferOffset = 0;
int currentOutSize = 0;
int flags = 0, mask = 1;
while (currentOutSize < decompressedSize)
{
// (throws when requested new flags byte is not available)
#region Update the mask. If all flag bits have been read, get a new set.
// the current mask is the mask used in the previous run. So if it masks the
// last flag bit, get a new flags byte.
if (mask == 1)
{
flags = instream.ReadByte(); readBytes++;
if (flags < 0)
throw new IOException();
mask = 0x80;
}
else
{
mask >>= 1;
}
#endregion
// bit = 1 <=> compressed.
if ((flags & mask) > 0)
{
// (throws when not enough bytes are available)
#region Get length and displacement('disp') values from next 2, 3 or 4 bytes
// read the first byte first, which also signals the size of the compressed block
int byte1 = instream.ReadByte(); readBytes++;
if (byte1 < 0)
throw new IOException();
int length = byte1 >> 4;
int disp = -1;
if (length == 0)
{
#region case 0; 0(B C)(D EF) + (0x11)(0x1) = (LEN)(DISP)
// case 0:
// data = AB CD EF (with A=0)
// LEN = ABC + 0x11 == BC + 0x11
// DISP = DEF + 1
// we need two more bytes available
int byte2 = instream.ReadByte(); readBytes++;
int byte3 = instream.ReadByte(); readBytes++;
if (byte3 < 0)
throw new IOException();
length = (((byte1 & 0x0F) << 4) | (byte2 >> 4)) + 0x11;
disp = (((byte2 & 0x0F) << 8) | byte3) + 0x1;
#endregion
}
else if (length == 1)
{
#region case 1: 1(B CD E)(F GH) + (0x111)(0x1) = (LEN)(DISP)
// case 1:
// data = AB CD EF GH (with A=1)
// LEN = BCDE + 0x111
// DISP = FGH + 1
// we need three more bytes available
int byte2 = instream.ReadByte(); readBytes++;
int byte3 = instream.ReadByte(); readBytes++;
int byte4 = instream.ReadByte(); readBytes++;
if (byte4 < 0)
throw new IOException();
length = (((byte1 & 0x0F) << 12) | (byte2 << 4) | (byte3 >> 4)) + 0x111;
disp = (((byte3 & 0x0F) << 8) | byte4) + 0x1;
#endregion
}
else
{
#region case > 1: (A)(B CD) + (0x1)(0x1) = (LEN)(DISP)
// case other:
// data = AB CD
// LEN = A + 1
// DISP = BCD + 1
// we need only one more byte available
int byte2 = instream.ReadByte(); readBytes++;
if (byte2 < 0)
throw new IOException();
length = ((byte1 & 0xF0) >> 4) + 0x1;
disp = (((byte1 & 0x0F) << 8) | byte2) + 0x1;
#endregion
}
if (disp > currentOutSize)
throw new InvalidDataException("Cannot go back more than already written. "
+ "DISP = " + disp + ", #written bytes = 0x" + currentOutSize.ToString("X")
+ " before 0x" + instream.Position.ToString("X") + " with indicator 0x"
+ (byte1 >> 4).ToString("X"));
#endregion
int bufIdx = bufferOffset + bufferLength - disp;
for (int i = 0; i < length; i++)
{
byte next = buffer[bufIdx % bufferLength];
bufIdx++;
outstream.WriteByte(next);
buffer[bufferOffset] = next;
bufferOffset = (bufferOffset + 1) % bufferLength;
}
currentOutSize += length;
}
else
{
int next = instream.ReadByte(); readBytes++;
if (next < 0)
throw new IOException();
outstream.WriteByte((byte)next); currentOutSize++;
buffer[bufferOffset] = (byte)next;
bufferOffset = (bufferOffset + 1) % bufferLength;
}
}
return decompressedSize;
}
private void openButton_Click(object sender, EventArgs e)
{
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "Binary files (*.bin)|*.bin|All files (*.*)|*.*";
if (openFileDialog.ShowDialog() != DialogResult.OK) return;
long length = (new FileInfo(openFileDialog.FileName)).Length;
if (length > saveLength_EUR)
{
MessageBox.Show("Invalid save file", "Error");
return;
}
// Open a decompressed save file, for testing purpose
if (length == saveLength_EUR)
{
Header = null;
SaveData = File.ReadAllBytes(openFileDialog.FileName);
enableButtons();
return;
}
Header = new byte[headerLength_EUR];
byte[] compressed = new byte[length - headerLength_EUR];
using (FileStream fs = new FileStream(openFileDialog.FileName, FileMode.Open, FileAccess.Read))
{
using (BinaryReader br = new BinaryReader(fs))
{
br.BaseStream.Seek(headerLength_EUR, SeekOrigin.Begin);
byte isLZ11 = br.ReadByte();
if (isLZ11 != 0x11)
{
MessageBox.Show("Invalid save file", "Error");
return;
}
br.BaseStream.Seek(0x00, SeekOrigin.Begin);
br.Read(Header, 0x0, headerLength_EUR);
br.Read(compressed, 0x0, (int)length - headerLength_EUR);
}
}
// Decompress
byte[] decompressed = null;
LZ11 lz11 = new LZ11();
using (MemoryStream inStream = new MemoryStream(compressed))
{
using (MemoryStream outStream = new MemoryStream())
{
lz11.Decompress(inStream, compressed.Length, outStream);
if (outStream != null)
decompressed = outStream.ToArray();
else
{
MessageBox.Show("Invalid save file", "Error");
return;
}
}
}
// Check file validity and save loading
if (decompressed.Length != saveLength_EUR)
{
labelRegion.Text = "USA";
MessageBox.Show("Invalid save file", "Error");
return;
}
SaveData = decompressed;
labelRegion.Text = "EUR";
enableButtons();
}