static bool PatchArm9(System.IO.FileStream nds, uint pos, uint len)
{
nds.Position = pos;
byte[] data = new byte[len];
nds.Read(data, 0, (int)len);
// decompress size info: http://www.crackerscrap.com/docs/dsromstructure.html
// TODO: Is there a better way to figure out if an ARM9 is compressed?
nds.Position = nds.Position - 8;
uint compressedSize = nds.ReadUInt24();
byte headerLength = (byte)nds.ReadByte();
uint additionalCompressedSize = nds.ReadUInt32();
uint decompressedSize = additionalCompressedSize + len;
bool compressed = false;
byte[] decData = data;
#if DEBUG
Console.WriteLine("ARM9 old dec size: 0x" + decompressedSize.ToString("X6"));
Console.WriteLine("ARM9 old cmp size: 0x" + compressedSize.ToString("X6"));
Console.WriteLine("ARM9 old filesize: 0x" + len.ToString("X6"));
Console.WriteLine("ARM9 old diff: 0x" + additionalCompressedSize.ToString("X6"));
System.IO.File.WriteAllBytes("arm9-raw.bin", data);
#endif
blz blz = new blz();
// if one of these isn't true then it can't be blz-compressed so don't even try
bool headerLengthValid = (headerLength >= 8 && headerLength <= 11);
bool compressedSizeValid = (data.Length >= compressedSize + 0x4000 && data.Length <= compressedSize + 0x400B);
if (headerLengthValid && compressedSizeValid)
{
try {
blz.arm9 = 1;
byte[] maybeDecData = blz.BLZ_Decode(data);
if (maybeDecData.Length == decompressedSize)
{
compressed = true;
decData = maybeDecData;
#if DEBUG
System.IO.File.WriteAllBytes("arm9-dec.bin", decData);
#endif
}
} catch (blzDecodingException) {
compressed = false;
}
}
byte[] decDataUnmodified = (byte[])decData.Clone();
if (ReplaceInData(decData, 0x00, true))
{
if (compressed)
{
Console.WriteLine("Replacing and recompressing ARM9...");
data = blz.BLZ_Encode(decData, 0);
uint newCompressedSize = (uint)data.Length;
if (newCompressedSize > len)
{
// new ARM is actually bigger, redo without the additional nullterm replacement
decData = decDataUnmodified;
ReplaceInData(decData, 0x00, false);
data = blz.BLZ_Encode(decData, 0, supressWarnings: true);
newCompressedSize = (uint)data.Length;
int arm9diff = (int)len - (int)newCompressedSize;
if (arm9diff < 0)
{
// still too big, remove debug strings
if (!RemoveStringsInKnownGames(GetGamecode(nds), decData))
{
RemoveDebugStrings(decData);
}
#if DEBUG
System.IO.File.WriteAllBytes("arm9-dec-without-debug.bin", decData);
#endif
data = blz.BLZ_Encode(decData, 0, supressWarnings: true);
newCompressedSize = (uint)data.Length;
arm9diff = (int)len - (int)newCompressedSize;
if (arm9diff < 0)
{
Console.WriteLine("WARNING: Recompressed ARM9 is " + -arm9diff + " bytes bigger than original!");
Console.WriteLine(" Patched game may be corrupted!");
#if DEBUG
System.IO.File.WriteAllBytes("arm9-too-big-recomp.bin", data);
#endif
}
}
}
if (newCompressedSize != len)
{
// new ARM is (still) different, attempt to find the metadata in the ARM9 secure area and replace that
bool foundSize = false;
for (int i = 0; i < 0x4000; i += 4)
{
uint maybeSize = BitConverter.ToUInt32(data, i);
if (maybeSize == len + 0x02000000u || maybeSize == len + 0x02004000u)
{
foundSize = true;
byte[] newCmpSizeBytes;
if (maybeSize == len + 0x02004000u)
{
newCmpSizeBytes = BitConverter.GetBytes(newCompressedSize + 0x02004000u);
}
else
{
newCmpSizeBytes = BitConverter.GetBytes(newCompressedSize + 0x02000000u);
}
data[i + 0] = newCmpSizeBytes[0];
data[i + 1] = newCmpSizeBytes[1];
data[i + 2] = newCmpSizeBytes[2];
data[i + 3] = newCmpSizeBytes[3];
break;
}
}
if (!foundSize)
{
Console.WriteLine("WARNING: Recompressed ARM9 is different size, and size could not be found in secure area!");
Console.WriteLine(" Patched game will probably not boot!");
}
}
#if DEBUG
uint newDecompressedSize = (uint)decData.Length;
uint newAdditionalCompressedSize = newDecompressedSize - newCompressedSize;
Console.WriteLine("ARM9 new dec size: 0x" + newDecompressedSize.ToString("X6"));
Console.WriteLine("ARM9 new cmp size: 0x" + newCompressedSize.ToString("X6"));
Console.WriteLine("ARM9 new diff: 0x" + newAdditionalCompressedSize.ToString("X6"));
#endif
}
else
{
Console.WriteLine("Replacing ARM9...");
data = decData;
}
#if DEBUG
System.IO.File.WriteAllBytes("arm9-new.bin", data);
#endif
nds.Position = pos;
nds.Write(data, 0, data.Length);
int newSize = data.Length;
int diff = (int)len - newSize;
// copy back footer
if (diff > 0)
{
List <byte> footer = new List <byte>();
nds.Position = pos + len;
if (nds.PeekUInt32() == 0xDEC00621)
{
for (int j = 0; j < 12; ++j)
{
footer.Add((byte)nds.ReadByte());
}
nds.Position = pos + newSize;
nds.Write(footer.ToArray(), 0, footer.Count);
}
// padding
for (int j = 0; j < diff; ++j)
{
nds.WriteByte(0xFF);
}
}
// write new size
byte[] newSizeBytes = BitConverter.GetBytes(newSize);
nds.Position = 0x2C;
nds.Write(newSizeBytes, 0, 4);
// recalculate checksums
nds.Position = pos;
ushort secureChecksum = new Crc16().ComputeChecksum(nds, 0x4000, 0xFFFF);
nds.Position = 0x6C;
nds.Write(BitConverter.GetBytes(secureChecksum), 0, 2);
nds.Position = 0;
ushort headerChecksum = new Crc16().ComputeChecksum(nds, 0x15E, 0xFFFF);
nds.Write(BitConverter.GetBytes(headerChecksum), 0, 2);
return(true);
}
return(false);
}
