/// <summary>
/// Decrypts the given buffer. The buffer must be 64 bytes long.
/// </summary>
/// <param name="buffer"></param>
public void Decrypt64(RandomAccess buffer)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (buffer.Length != 64)
{
throw new ArgumentException($"The given buffer was not 64 bytes ({buffer.Length}).", nameof(buffer));
}
for (int i = 0x0F; i >= 0; i--)
{
int positionA = i;
int keyA = GetWord(positionA);
int positionB = keyA & 0x0F;
int data1 = buffer.JumpAbsolute(positionA * 4).LongLE();
data1 -= keyA;
int data2 = buffer.JumpAbsolute(positionB * 4).LongLE();
data2 -= keyA;
int opAnd1 = data1 & keyA;
int opNotA = ~keyA;
int opAnd2 = data2 & opNotA;
int opOr1 = opAnd1 | opAnd2;
buffer.JumpAbsolute(positionA * 4).WriteLongLE(opOr1);
int opAnd3 = data2 & keyA;
int opAnd4 = data1 & opNotA;
int opOr2 = opAnd3 | opAnd4;
buffer.JumpAbsolute(positionB * 4).WriteLongLE(opOr2);
}
}
public void LEReadWriteTest()
{
var ra = new RandomAccess(new byte[] { 1, 2, 3, 4 });
int value = ra.LongLE();
ra.JumpAbsolute(0);
ra.WriteLongLE(value);
ra.JumpAbsolute(0);
int value2 = ra.LongLE();
Assert.AreEqual(value, value2);
}
public void ShouldSkipPartiallyOverwrittenBlock()
{
var rx = new RandomAccess(new byte[4 * 256]);
rx.WriteLongLE(0);
rx.WriteLongLE(0x300);
rx.JumpAbsolute(0x100); // Inside the previous block!
rx.WriteLongLE(0x100);
rx.WriteLongLE(0x200);
rx.JumpAbsolute(0);
var block = new TpsBlock(rx, 0, 0x300, false);
Assert.AreEqual(1, block.Pages.Count);
Assert.AreEqual(0x100, block.Pages[0].Address);
Assert.AreEqual(0x200, block.Pages[0].Size);
}
public void ShouldReadTwoBlocksWithGap()
{
var rx = new RandomAccess(new byte[4 * 256]);
rx.WriteLongLE(0);
rx.WriteLongLE(0x100);
rx.JumpAbsolute(0x200);
rx.WriteLongLE(0x200);
rx.WriteLongLE(0x100);
rx.JumpAbsolute(0);
var block = new TpsBlock(rx, 0, 0x300, false);
Assert.AreEqual(2, block.Pages.Count);
Assert.AreEqual(0x100, block.Pages[0].Size);
Assert.AreEqual(0x100, block.Pages[1].Size);
}
/// <summary>
/// Encrypts the given buffer. The buffer must be 64 bytes long.
/// </summary>
/// <param name="buffer">The buffer to encrypt.</param>
public void Encrypt64(RandomAccess buffer)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (buffer.Length != 64)
{
throw new ArgumentException($"The given buffer was not 64 bytes ({buffer.Length}).", nameof(buffer));
}
for (int i = 0; i < 0x10; i++)
{
int positionA = i;
int keyA = GetWord(i);
int positionB = keyA & 0x0F;
int data2 = buffer.JumpAbsolute(positionA * 4).LongLE();
int data1 = buffer.JumpAbsolute(positionB * 4).LongLE();
int opAnd1 = keyA & data2;
int opNotA = ~keyA;
int opAnd2 = opNotA & data1;
int opOr1 = opAnd1 | opAnd2;
int sum1 = keyA + opOr1;
buffer.JumpAbsolute(positionA * 4).WriteLongLE(sum1);
int opAnd3 = keyA & data1;
int opAnd4 = opNotA & data2;
int opOr2 = opAnd3 | opAnd4;
int sum2 = opOr2 + keyA;
buffer.JumpAbsolute(positionB * 4).WriteLongLE(sum2);
}
}
public TpsBlock(RandomAccess rx, int start, int end, bool ignorePageErrors)
{
Data = rx ?? throw new ArgumentNullException(nameof(rx));
Start = start;
End = end;
_pages = new List <TpsPage>();
Data.PushPosition();
Data.JumpAbsolute(Start);
try
{
// Some blocks are 0 in length and should be skipped
while (Data.Position < End)
{
if (IsCompletePage())
{
try
{
var page = new TpsPage(Data);
_pages.Add(page);
}
catch (RunLengthEncodingException ex)
{
if (ignorePageErrors)
{
Debug.WriteLine($"Ignored RLE error: {ex.ToString()}");
}
else
{
throw;
}
}
}
else
{
Data.JumpRelative(0x100);
}
NavigateToNextPage();
}
}
finally
{
Data.PopPosition();
}
}
