public void CeilingToPowerOfTwoReturnsZeroForNegativeNumbers64()
{
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo((long)-1), "-1");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo((long)-2), "-2");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo((long)-3), "-3");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo((long)-4), "-4");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo(Int64.MinValue), "Int64.MinValue");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo(Int64.MinValue + 1), "Int64.MinValue+1");
}
public void CeilingToPowerOfTwoThrowsWhenResultWouldOverflow64()
{
Assert.Throws(
typeof(ArgumentOutOfRangeException),
() => IntegerTheory.CeilingToPowerOfTwo(Int64.MaxValue));
const long maxPowerOfTwo = 0x4000000000000000;
Assert.Throws(
typeof(ArgumentOutOfRangeException),
() => IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo + 1));
Assert.DoesNotThrow(
() => IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo - 1));
}
public void CeilingToPowerOfHandlesPositiveIntegersCorrectly64()
{
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo((long)0), "0");
Assert.AreEqual(1, IntegerTheory.CeilingToPowerOfTwo((long)1), "1");
Assert.AreEqual(2, IntegerTheory.CeilingToPowerOfTwo((long)2), "2");
Assert.AreEqual(4, IntegerTheory.CeilingToPowerOfTwo((long)3), "3");
Assert.AreEqual(4, IntegerTheory.CeilingToPowerOfTwo((long)4), "4");
for (int i = 2; i < 63; i++)
{
long x = ((long)1) << i;
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo(x), x.ToString());
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo(x - 1), x + "-1");
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo((x >> 1) + 1), x + "/2+1");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo(-x), "-" + x);
}
const long maxPowerOfTwo = 0x4000000000000000;
Assert.AreEqual(maxPowerOfTwo, IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo), "max");
Assert.AreEqual(maxPowerOfTwo, IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo - 1), "max");
}
public void CeilingToPowerOfHandlesPositiveIntegersCorrectly32()
{
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo(0), "0");
Assert.AreEqual(1, IntegerTheory.CeilingToPowerOfTwo(1), "1");
Assert.AreEqual(2, IntegerTheory.CeilingToPowerOfTwo(2), "2");
Assert.AreEqual(4, IntegerTheory.CeilingToPowerOfTwo(3), "3");
Assert.AreEqual(4, IntegerTheory.CeilingToPowerOfTwo(4), "4");
for (int i = 2; i < 31; i++)
{
int x = 1 << i;
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo(x), x.ToString());
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo(x - 1), x + "-1");
Assert.AreEqual(x, IntegerTheory.CeilingToPowerOfTwo((x >> 1) + 1), x + "/2+1");
Assert.AreEqual(0, IntegerTheory.CeilingToPowerOfTwo(-x), "-" + x);
}
const int maxPowerOfTwo = 0x40000000;
Assert.AreEqual(maxPowerOfTwo, IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo), "max");
Assert.AreEqual(maxPowerOfTwo, IntegerTheory.CeilingToPowerOfTwo(maxPowerOfTwo - 1), "max");
}