public void Start(Process process, MemoryBitmapEntry head)
{
var entry = head;
while (entry != null)
{
if (entry.Type is MemoryBitmapEntryType.Hole && entry.Value >= process.Size)
{
if (entry.Value == process.Size) // Exact fit
{
entry.Type = MemoryBitmapEntryType.Process;
entry.Process = process;
}
else
{
MemoryBitmapEntry holeEntry = new(MemoryBitmapEntryType.Hole, entry.Value - process.Size, entry.Next);
entry.Next = holeEntry;
entry.Type = MemoryBitmapEntryType.Process;
entry.Value = process.Size;
entry.Process = process;
}
return;
}
entry = entry.Next;
}
throw new Exception("Can't allocate memory");
}
public static void MergeHoles(MemoryBitmapEntry previous, MemoryBitmapEntry current)
{
if (previous is not null && previous.Type is MemoryBitmapEntryType.Hole)
{
previous.Value += current.Value;
previous.Next = current.Next;
MergeHoles(null, previous);
return;
}
if (current.Next is not null && current.Next.Type is MemoryBitmapEntryType.Hole)
{
MergeHoles(current, current.Next);
return;
}
}
public void Start(Process process, MemoryBitmapEntry head)
{
MemoryBitmapEntry entry = head;
MemoryBitmapEntry min = null;
while (entry != null)
{
if (entry.Type is MemoryBitmapEntryType.Hole && entry.Value >= process.Size)
{
if (min is null)
{
min = entry;
}
if (entry.Value < min.Value)
{
min = entry;
}
if (min.Value == process.Size)
{
break;
}
}
entry = entry.Next;
}
if (min is null)
{
throw new Exception("Can't allocate memory");
}
if (min.Value == process.Size)
{
min.Type = MemoryBitmapEntryType.Process;
min.Process = process;
}
else
{
MemoryBitmapEntry holeEntry = new(MemoryBitmapEntryType.Hole, min.Value - process.Size, min.Next);
min.Next = holeEntry;
min.Type = MemoryBitmapEntryType.Process;
min.Value = process.Size;
min.Process = process;
}
}
private void OnProcessKilled(object sender, ProcessKilledEventArgs eventArgs)
{
MemoryBitmapEntry previous = null, current = Head;
while (current != null)
{
if (current.Type is MemoryBitmapEntryType.Process && current.Process.Pid == eventArgs.Pid)
{
current.Type = MemoryBitmapEntryType.Hole;
current.Process.Killed -= OnProcessKilled;
current.Process = null;
HoleMerger.MergeHoles(previous, current);
}
previous = current;
current = current.Next;
}
}
public static string BuildView(MemoryBitmapEntry head)
{
StringBuilder view = new();
var current = head;
List <MemoryBitmapEntry> entries = new();
while (current != null)
{
entries.Add(current);
current = current.Next;
}
view.AppendJoin("=>", entries.Select(entry =>
{
var symbol = entry.Type is MemoryBitmapEntryType.Hole ? 'H' : 'P';
return($"[{symbol}|{entry.Value}]");
}));
return(view.ToString());
}
public BitmapMemoryManager(long memoryAmount)
{
Head = new MemoryBitmapEntry(MemoryBitmapEntryType.Hole, memoryAmount);
}