public void Layout(MemoryRegion region)
{
var itemsBySize = region.Items.OrderByDescending(item => item.Size);
SortedSet <MemRgn> freeSet = new SortedSet <MemRgn>();
MemRgn top = new MemRgn(0, long.MaxValue);
freeSet.Add(top);
uint alignment = region.MarshalInfo.Alignment;
bool alignPow2 = region.MarshalInfo.UseStrongPow2Alignment;
ulong requiredSize = 0;
foreach (MemoryMappedStorage item in itemsBySize)
{
MemRgn req = new MemRgn(0, item.Size);
var avail = freeSet.GetViewBetween(req, top);
bool found = false;
foreach (MemRgn rgn in avail)
{
ulong offset = rgn.Offset;
offset = MathExt.Align(offset, alignment);
if (alignPow2)
{
ulong alignedSize = MathExt.CeilPow2(item.Size);
offset = (offset + alignedSize - 1) & ~(alignedSize - 1);
}
if (offset + item.Size <= rgn.Offset + rgn.Size)
{
item.Offset = offset;
freeSet.Remove(rgn);
if (rgn.Offset < offset)
{
MemRgn left = new MemRgn(rgn.Offset, offset - rgn.Offset);
freeSet.Add(left);
}
if (offset + item.Size < rgn.Offset + rgn.Size)
{
MemRgn right = new MemRgn(offset + item.Size, rgn.Offset + rgn.Size - offset - item.Size);
freeSet.Add(right);
}
requiredSize = Math.Max(requiredSize, offset + item.Size);
found = true;
break;
}
}
if (!found)
{
throw new MemoryLayoutFailedException();
}
region.RequiredSize = requiredSize;
}
region.Seal();
}
