public void TestPermutationNetwork()
{
byte[] permutation = new byte[64];
// Identity permutation
for (byte i = 0; i < 64; i++)
{
Identity[i] = i;
}
for (int i1 = 0; i1 < 62; i1++)
{
for (int i2 = i1 + 1; i2 < 64; i2++)
{
TestTwoCycle(i1, i2, permutation);
}
}
Array.Copy(Identity, permutation, 64);
PermutationNetwork pnwk = new PermutationNetwork(permutation);
Assert.AreEqual(56ul, pnwk.Permute(56));
// Swap unit and two's bits
permutation[0] = 1;
permutation[1] = 0;
pnwk = new PermutationNetwork(permutation);
Assert.AreEqual(1ul, pnwk.Permute(2));
Assert.AreEqual(2ul, pnwk.Permute(1));
Assert.AreEqual(3ul, pnwk.Permute(3));
Assert.AreEqual(5ul, pnwk.Permute(6));
Assert.AreEqual(6ul, pnwk.Permute(5));
// Cycle the bottom four bits
permutation[0] = 1;
permutation[1] = 2;
permutation[2] = 3;
permutation[3] = 0;
pnwk = new PermutationNetwork(permutation);
Assert.AreEqual(2ul, pnwk.Permute(1));
Assert.AreEqual(4ul, pnwk.Permute(2));
Assert.AreEqual(8ul, pnwk.Permute(4));
Assert.AreEqual(1ul, pnwk.Permute(8));
Assert.AreEqual(3ul, pnwk.Permute(9));
// Random permutation
Random rnd = new Random(0);
for (int i = 0; i < 63; i++)
{
int swapIndex = rnd.Next(64);
byte b = permutation[i];
permutation[i] = permutation[swapIndex];
permutation[swapIndex] = b;
}
pnwk = new PermutationNetwork(permutation);
ulong testVal = ((ulong)rnd.Next() << 32) | (uint)rnd.Next();
ulong resultVal = pnwk.Permute(testVal);
TestPerm(permutation, testVal, resultVal);
}
private static void TestTwoCycle(int i1, int i2, byte[] permutation)
{
Array.Copy(Identity, permutation, 64);
permutation[i1] = (byte)i2;
permutation[i2] = (byte)i1;
PermutationNetwork pnwk = new PermutationNetwork(permutation);
Assert.AreEqual(1UL << i2, pnwk.Permute(1UL << i1));
Assert.AreEqual(1UL << i1, pnwk.Permute(1UL << i2));
}