public IEnumerable <Element> Values(float x1, float y1, float x2, float y2)
{
RegionLock.EnterReadLock();
try
{
// get the starting row,col and ending row,col
GetRegion(x1, y1, out int r1, out int c1, validate: false);
GetRegion(x2, y2, out int r2, out int c2, validate: false);
// assuming we start to 0,0 in the upper left and corner and increase right and down
// ensure r1,c1 if the upper left and corner
if (r2 < r1)
{
// swap
var tmp = r1;
r1 = r2;
r2 = tmp;
}
if (c2 < c1)
{
var tmp = c1;
c1 = c2;
c2 = tmp;
}
// expand the region
r1 -= 1; c1 -= 1;
r2 += 1; c2 += 1;
// hold the lock for the duration of this call
for (int r = (r1 >= 0 ? r1 : 0); r <= r2 && r < Regions.Length; r++)
{
for (int c = (c1 >= 0 ? c1 : 0); c <= c2 && c < Regions[r].Length; c++)
{
if (Regions[r][c].Count == 0)
{
continue;
}
foreach (var elem in Regions[r][c].Values)
{
yield return(elem);
}
}
}
// always return the oversized items
foreach (var elem in Oversized.Values)
{
yield return(elem);
}
}
finally
{
RegionLock.ExitReadLock();
}
}
public Region GetRegion(Element elem)
{
if (elem == null)
{
throw new Exception("Invalid element to get region");
}
RegionLock.EnterReadLock();
try
{
if (IsOversized(elem))
{
return(new Region(-1, -1));
}
GetRegion(elem.X, elem.Y, out int row, out int column);
return(new Region(row, column));
}
finally
{
RegionLock.ExitReadLock();
}
}