public void CellsPerBlockTest()
{
Assert.Equal(1UL, ZCurve.CellsPerBlock(0));
Assert.Equal(4UL, ZCurve.CellsPerBlock(1));
Assert.Equal(16UL, ZCurve.CellsPerBlock(2));
Assert.Equal(64UL, ZCurve.CellsPerBlock(3));
Assert.Equal(256UL, ZCurve.CellsPerBlock(4));
Assert.Equal(1024UL, ZCurve.CellsPerBlock(5));
Assert.Equal(0x0400000000000000UL, ZCurve.CellsPerBlock(29));
Assert.Equal(0x1000000000000000UL, ZCurve.CellsPerBlock(30));
Assert.Equal(0x4000000000000000UL, ZCurve.CellsPerBlock(31));
Assert.Equal(0UL, ZCurve.CellsPerBlock(32)); // wrap around
}
public void BlockPropertyTest(ulong z, int level, ulong first, ulong last)
{
int i = ZCurve.LargestLevel(z);
ulong f = ZCurve.FirstInBlock(z, i);
ulong l = ZCurve.LastInBlock(z, i);
ulong n = ZCurve.CellsPerBlock(i);
Assert.Equal(level, i);
Assert.Equal(first, f);
Assert.Equal(last, l);
_output.WriteLine($"z={z} i={i} first={f:X8} last={l:X8} cells_in_block={n}");
}
public void QueryBlocksTrial()
{
// Expect shortest ordered sequence of blocks covering query box
// Query box:
ulong qlo = ZCurve.Encode(1U, 1U); // 3
ulong qhi = ZCurve.Encode(5U, 4U); // 49
// Expected result: 3 6 7 9 11 (12..15) 18 19 (24..27) 33 36 37 48 49
var starts = new ulong[] { 3, 6, 7, 9, 11, 12, 18, 19, 24, 33, 36, 37, 48, 49 };
var levels = new[] { 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0 };
var expected = starts.Zip(levels, (s, l) => new ZCurve.Block(s, l)).ToList();
var actual = new List <ZCurve.Block>();
ulong first = ZCurve.FirstInBlock(qlo, 0);
ulong last = ZCurve.FirstInBlock(qhi, 0);
for (ulong cursor = first; ;)
{
int level = ZCurve.LargestLevel(cursor, last);
ulong increment = ZCurve.CellsPerBlock(level);
actual.Add(new ZCurve.Block(cursor, level));
cursor += increment;
if (cursor > last)
{
break;
}
if (!ZCurve.IsInsideBox(cursor, first, last))
{
cursor = ZCurve.NextInsideBox(cursor, first, last);
}
}
Assert.Equal(expected, actual);
}