mirror of
https://github.com/Barubary/dsdecmp.git
synced 2024-11-12 22:05:08 +01:00
252 lines
10 KiB
C#
252 lines
10 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Text;
|
|
using System.IO;
|
|
|
|
namespace DSDecmp.Formats.Nitro
|
|
{
|
|
/// <summary>
|
|
/// Compressor and decompressor for the RLE format used in several of the games for the
|
|
/// newer Nintendo consoles and handhelds.
|
|
/// </summary>
|
|
public class RLE : NitroCFormat
|
|
{
|
|
public RLE() : base(0x30) { }
|
|
|
|
public override void Decompress(Stream instream, long inLength, Stream outstream)
|
|
{
|
|
/*
|
|
Data header (32bit)
|
|
Bit 0-3 Reserved
|
|
Bit 4-7 Compressed type (must be 3 for run-length)
|
|
Bit 8-31 Size of decompressed data
|
|
Repeat below. Each Flag Byte followed by one or more Data Bytes.
|
|
Flag data (8bit)
|
|
Bit 0-6 Expanded Data Length (uncompressed N-1, compressed N-3)
|
|
Bit 7 Flag (0=uncompressed, 1=compressed)
|
|
Data Byte(s) - N uncompressed bytes, or 1 byte repeated N times
|
|
*/
|
|
|
|
long readBytes = 0;
|
|
|
|
byte type = (byte)instream.ReadByte();
|
|
if (type != base.magicByte)
|
|
throw new InvalidDataException("The provided stream is not a valid RLE "
|
|
+ "compressed stream (invalid type 0x" + type.ToString("X") + ")");
|
|
byte[] sizeBytes = new byte[3];
|
|
instream.Read(sizeBytes, 0, 3);
|
|
int decompressedSize = base.Bytes2Size(sizeBytes);
|
|
readBytes += 4;
|
|
if (decompressedSize == 0)
|
|
{
|
|
sizeBytes = new byte[4];
|
|
instream.Read(sizeBytes, 0, 4);
|
|
decompressedSize = base.Bytes2Size(sizeBytes);
|
|
readBytes += 4;
|
|
}
|
|
|
|
|
|
int currentOutSize = 0;
|
|
while (currentOutSize < decompressedSize)
|
|
{
|
|
#region (try to) get the flag byte with the length data and compressed flag
|
|
|
|
if (readBytes >= inLength)
|
|
throw new NotEnoughDataException(currentOutSize, decompressedSize);
|
|
int flag = instream.ReadByte(); readBytes++;
|
|
if (flag < 0)
|
|
throw new StreamTooShortException();
|
|
|
|
bool compressed = (flag & 0x80) > 0;
|
|
int length = flag & 0x7F;
|
|
|
|
if (compressed)
|
|
length += 3;
|
|
else
|
|
length += 1;
|
|
|
|
#endregion
|
|
|
|
if (compressed)
|
|
{
|
|
#region compressed: write the next byte (length) times.
|
|
|
|
if (readBytes >= inLength)
|
|
throw new NotEnoughDataException(currentOutSize, decompressedSize);
|
|
int data = instream.ReadByte(); readBytes++;
|
|
if (data < 0)
|
|
throw new StreamTooShortException();
|
|
|
|
if (currentOutSize + length > decompressedSize)
|
|
throw new InvalidDataException("The given stream is not a valid RLE stream; the "
|
|
+ "output length does not match the provided plaintext length.");
|
|
byte bdata = (byte)data;
|
|
for (int i = 0; i < length; i++)
|
|
{
|
|
// Stream.Write(byte[], offset, len) may also work, but only if it is a circular buffer
|
|
outstream.WriteByte(bdata);
|
|
currentOutSize++;
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
else
|
|
{
|
|
#region uncompressed: copy the next (length) bytes.
|
|
|
|
int tryReadLength = length;
|
|
// limit the amount of bytes read by the indicated number of bytes available
|
|
if (readBytes + length > inLength)
|
|
tryReadLength = (int)(inLength - readBytes);
|
|
|
|
byte[] data = new byte[length];
|
|
int readLength = instream.Read(data, 0, (int)tryReadLength);
|
|
readBytes += readLength;
|
|
outstream.Write(data, 0, readLength);
|
|
currentOutSize += readLength;
|
|
|
|
// if the attempted number of bytes read is less than the desired number, the given input
|
|
// length is too small (or there is not enough data in the stream)
|
|
if (tryReadLength < length)
|
|
throw new NotEnoughDataException(currentOutSize, decompressedSize);
|
|
// if the actual number of read bytes is even less, it means that the end of the stream has
|
|
// bee reached, thus the given input length is larger than the actual length of the input
|
|
if (readLength < length)
|
|
throw new StreamTooShortException();
|
|
|
|
#endregion
|
|
}
|
|
}
|
|
|
|
if (readBytes < inLength)
|
|
throw new TooMuchInputException(readBytes, inLength);
|
|
}
|
|
|
|
public override int Compress(Stream instream, long inLength, Stream outstream)
|
|
{
|
|
|
|
if (inLength > 0xFFFFFF)
|
|
throw new InputTooLargeException();
|
|
|
|
List<byte> compressedData = new List<byte>();
|
|
|
|
// at most 0x7F+3=130 bytes are compressed into a single block.
|
|
// (and at most 0x7F+1=128 in an uncompressed block, however we need to read 2
|
|
// more, since the last byte may be part of a repetition).
|
|
byte[] dataBlock = new byte[130];
|
|
// the length of the valid content in the current data block
|
|
int currentBlockLength = 0;
|
|
|
|
int readLength = 0;
|
|
int nextByte;
|
|
int repCount = 1;
|
|
while (readLength < inLength)
|
|
{
|
|
bool foundRepetition = false;
|
|
|
|
while (currentBlockLength < dataBlock.Length && readLength < inLength)
|
|
{
|
|
nextByte = instream.ReadByte();
|
|
if (nextByte < 0)
|
|
throw new StreamTooShortException();
|
|
readLength++;
|
|
|
|
dataBlock[currentBlockLength++] = (byte)nextByte;
|
|
if (currentBlockLength > 1)
|
|
{
|
|
if (nextByte == dataBlock[currentBlockLength - 2])
|
|
repCount++;
|
|
else
|
|
repCount = 1;
|
|
}
|
|
|
|
foundRepetition = repCount > 2;
|
|
if (foundRepetition)
|
|
break;
|
|
}
|
|
|
|
|
|
int numUncompToCopy = 0;
|
|
if (foundRepetition)
|
|
{
|
|
// if a repetition was found, copy block size - 3 bytes as compressed data
|
|
numUncompToCopy = currentBlockLength - 3;
|
|
}
|
|
else
|
|
{
|
|
// if no repetition was found, copy min(block size, max block size - 2) bytes as uncompressed data.
|
|
numUncompToCopy = Math.Min(currentBlockLength, dataBlock.Length - 2);
|
|
}
|
|
|
|
#region insert uncompressed block
|
|
if (numUncompToCopy > 0)
|
|
{
|
|
byte flag = (byte)(numUncompToCopy - 1);
|
|
compressedData.Add(flag);
|
|
for (int i = 0; i < numUncompToCopy; i++)
|
|
compressedData.Add(dataBlock[i]);
|
|
// shift some possibly remaining bytes to the start
|
|
for (int i = numUncompToCopy; i < currentBlockLength; i++)
|
|
dataBlock[i - numUncompToCopy] = dataBlock[i];
|
|
currentBlockLength -= numUncompToCopy;
|
|
}
|
|
#endregion
|
|
|
|
if (foundRepetition)
|
|
{
|
|
// if a repetition was found, continue until the first different byte
|
|
// (or until the buffer is full)
|
|
while (currentBlockLength < dataBlock.Length && readLength < inLength)
|
|
{
|
|
nextByte = instream.ReadByte();
|
|
if (nextByte < 0)
|
|
throw new StreamTooShortException();
|
|
readLength++;
|
|
|
|
dataBlock[currentBlockLength++] = (byte)nextByte;
|
|
|
|
if (nextByte != dataBlock[0])
|
|
break;
|
|
else
|
|
repCount++;
|
|
}
|
|
|
|
// the next repCount bytes are the same.
|
|
#region insert compressed block
|
|
byte flag = (byte)(0x80 | (repCount - 3));
|
|
compressedData.Add(flag);
|
|
compressedData.Add(dataBlock[0]);
|
|
// make sure to shift the possible extra byte to the start
|
|
if (repCount != currentBlockLength)
|
|
dataBlock[0] = dataBlock[currentBlockLength - 1];
|
|
currentBlockLength -= repCount;
|
|
#endregion
|
|
}
|
|
}
|
|
|
|
// write any reamaining bytes as uncompressed
|
|
if (currentBlockLength > 0)
|
|
{
|
|
byte flag = (byte)(currentBlockLength - 1);
|
|
compressedData.Add(flag);
|
|
for (int i = 0; i < currentBlockLength; i++)
|
|
compressedData.Add(dataBlock[i]);
|
|
currentBlockLength = 0;
|
|
}
|
|
|
|
// write the RLE marker and the decompressed size
|
|
outstream.WriteByte(0x30);
|
|
int compLen = compressedData.Count;
|
|
outstream.WriteByte((byte)(inLength & 0xFF));
|
|
outstream.WriteByte((byte)((inLength >> 8) & 0xFF));
|
|
outstream.WriteByte((byte)((inLength >> 16) & 0xFF));
|
|
|
|
// write the compressed data
|
|
outstream.Write(compressedData.ToArray(), 0, compLen);
|
|
|
|
// the total compressed stream length is the compressed data length + the 4-byte header
|
|
return compLen + 4;
|
|
}
|
|
}
|
|
}
|