public void T02_TestBitCounts()
{
// test methods to count leading and trailing zeros
foreach (uint seed in new uint[] { 0xFFFFFFFF, 0x8a23b439, 0x80000001, 0xA3829f27 }) // each seed has the high and low bit set
{
uint f = seed, b = seed;
for (int i = 0; i <= 32; f >>= 1, b <<= 1, i++)
{
Assert.AreEqual(32 - i, BinaryUtility.BitsNeeded(f));
Assert.AreEqual(32 - i, BinaryUtility.BitsNeeded((ulong)f));
if (f == 0)
{
TestHelpers.TestException <ArgumentOutOfRangeException>(() => BinaryUtility.Log2(f));
}
else
{
Assert.AreEqual(31 - i, BinaryUtility.Log2(f));
}
if (f == 0)
{
TestHelpers.TestException <ArgumentOutOfRangeException>(() => BinaryUtility.Log2((ulong)f));
}
else
{
Assert.AreEqual(31 - i, BinaryUtility.Log2((ulong)f));
}
Assert.AreEqual(i, BinaryUtility.CountLeadingZeros(f));
Assert.AreEqual(i + 32, BinaryUtility.CountLeadingZeros((ulong)f));
Assert.AreEqual(i, BinaryUtility.CountTrailingZeros(b));
Assert.AreEqual(b == 0 ? i + 32 : i, BinaryUtility.CountTrailingZeros((ulong)b));
Assert.AreEqual(CountBits(f), BinaryUtility.CountBits(f));
Assert.AreEqual(CountBits(f), BinaryUtility.CountBits((ulong)f));
Assert.AreEqual(CountBits(b), BinaryUtility.CountBits(b));
Assert.AreEqual(CountBits(b), BinaryUtility.CountBits((ulong)b));
Assert.AreEqual(CountBits(f) + CountBits(b), BinaryUtility.CountBits(((ulong)f << 32) | b));
}
}
foreach (ulong seed in new ulong[] { 0xFFFFFFFFFFFFFFFF, 0x8a23A3829f27b439, 0x8000000000000001, 0xA3828a23b4399f27 }) // each seed has the high and low bit set
{
ulong f = seed, b = seed;
for (int i = 0; i <= 64; f >>= 1, b <<= 1, i++)
{
Assert.AreEqual(64 - i, BinaryUtility.BitsNeeded(f));
if (f == 0)
{
TestHelpers.TestException <ArgumentOutOfRangeException>(() => BinaryUtility.Log2(f));
}
else
{
Assert.AreEqual(63 - i, BinaryUtility.Log2(f));
}
Assert.AreEqual(i, BinaryUtility.CountLeadingZeros(f));
Assert.AreEqual(i, BinaryUtility.CountTrailingZeros(b));
Assert.AreEqual(CountBits(f), BinaryUtility.CountBits(f));
Assert.AreEqual(CountBits(b), BinaryUtility.CountBits(b));
}
}
}