/// <summary>
/// Worst: O(4 log n)
/// </summary>
public long Alloc(long length)
{
if (length <= 0)
{
throw new ArgumentOutOfRangeException(nameof(length));
}
if (m_avail.Count > 0)
{
// search for an available memory segment of at least length bytes, returning the smallest result that is >= length
var res = m_avail.BinarySearch_GreaterOrEqualTo(new MemorySegment(0, length), CompareMemorySegmentsSizeOnly);
if (res.Diff <= 0) // if available_memory_segment >= length
{
var x = res.Node.Key;
var bsr = m_availAddresses.BinarySearch(x.Address);
if (bsr.Index < 0)
{
bsr = bsr.BitwiseNot();
}
m_avail.Remove(res.Node);
var address = x.Address;
x = new MemorySegment(address + length, x.Length - length);
res.Node.UpdateKey(x);
this.TotalFree -= length;
if (x.Length > 0)
{
bsr.Update(x.Address, x.Length);
m_avail.Add(x);
}
else
{
m_availAddresses.Remove(bsr);
}
return(address);
}
}
// if theres not enough consecutive memory, then add at the end
var end = this.Capacity;
this.Capacity = end + length;
return(end);
}