public void NextInsideBoxTest()
{
Assert.Equal(27UL, ZCurve.NextInsideBox(0, 27, 102));
Assert.Equal(74UL, ZCurve.NextInsideBox(58, 27, 102));
Assert.Equal(74UL, ZCurve.NextInsideBox(67, 27, 102));
Assert.Equal(96UL, ZCurve.NextInsideBox(79, 27, 102));
Assert.Equal(74UL, ZCurve.NextInsideBox(61, 27, 102));
// What if z is within box(qlo,qhi)? Drill down, cutting
// off parts of the box, until a single cell remains.
Assert.Equal(6UL, ZCurve.NextInsideBox(3, 3, 49));
Assert.Equal(11UL, ZCurve.NextInsideBox(9, 3, 49));
Assert.Equal(14UL, ZCurve.NextInsideBox(13, 3, 49));
Assert.Equal(19UL, ZCurve.NextInsideBox(18, 3, 49));
Assert.Equal(49UL, ZCurve.NextInsideBox(48, 3, 49));
Assert.Equal(0UL, ZCurve.NextInsideBox(49, 3, 49));
Assert.Equal(0UL, ZCurve.NextInsideBox(54, 54, 54));
// What if z > qhi? Only keys 000 or 100 or 101 can occur,
// drilling down (possibly cutting off lower parts of the
// query box) until the box is below and z is above the
// dividing line (key 100) and we return the result so far,
// which is zero (result's initial value).
Assert.Equal(0UL, ZCurve.NextInsideBox(50, 3, 49, 5)); // x within, y beyond
Assert.Equal(0UL, ZCurve.NextInsideBox(51, 3, 49, 5)); // x within, y beyond
Assert.Equal(0UL, ZCurve.NextInsideBox(52, 3, 49, 5)); // x beyond, y within
Assert.Equal(0UL, ZCurve.NextInsideBox(53, 3, 49, 5)); // x beyond, y within
Assert.Equal(0UL, ZCurve.NextInsideBox(54, 3, 49, 5)); // both x and y beyond
// Enumerate cells within query box qlo..qhi:
var result = new List <ulong>();
var expected = new ulong[] { 3, 6, 7, 9, 11, 12, 13, 14, 15, 18, 19, 24, 25, 26, 27, 33, 36, 37, 48, 49 };
ulong qlo = ZCurve.Encode(1U, 1U); // 3
ulong qhi = ZCurve.Encode(5U, 4U); // 49
ulong cur = qlo;
while (true)
{
result.Add(cur);
cur += 1;
if (cur > qhi)
{
break;
}
const int starti = 5;
if (!ZCurve.IsInsideBox(cur, qlo, qhi))
{
cur = ZCurve.NextInsideBox(cur, qlo, qhi, starti);
}
}
Assert.Equal(expected, result);
}
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);
}
