public void Initialize(int memSize)
{
MemorySize = memSize;
for (int i = 0; i < MemorySize; i++)
{
Memory.Add(new MemoryBlock()
{
ProcessId = 0,
IsAssigned = false,
IsEnd = false,
IsStart = false
});
}
MemoryInitEventArgs arg = new MemoryInitEventArgs
{
MemoryAlgorithmName = "Best Fit",
NumberOfBlocks = MemorySize,
Memory = this.Memory
};
BlockFit firstblock = new BlockFit();
firstblock.start_pos = 0;
firstblock.ID = 0;
firstblock.blockLength = MemorySize;
avail.Add(firstblock);
OnInitialize(arg);
}
public override bool AllocateProcess(Process proc, out ProcessAllocateEventArgs arg)
{
// Best fit algorithm from Bergmann's class
BlockFit b, newSpace;
List <BlockFit> viableSpaces = new List <BlockFit>();
int size = proc.MemoryInKB;
newSpace = new BlockFit();
int start_position = 0;
// adds all possible fitting blocks to list viableSpaces
for (int i = 0; i < avail.Count; i++)
{
b = avail[i];
if (b.blockLength >= size)
{
viableSpaces.Add(b);
}
}
// orders the blocks so index 0 is the best fit
List <BlockFit> ordered = viableSpaces.OrderBy(f => f.blockLength).ToList();
// modifies the allocated and available lists for adding this new memory block
if (viableSpaces.Count != 0)
{
for (int i = 0; i < viableSpaces.Count; i++)
{
BlockFit block_check = viableSpaces[i];
if (block_check.blockLength == ordered[0].blockLength)
{
// creates a new allocation block
newSpace.start_pos = block_check.start_pos;
newSpace.blockLength = size;
newSpace.ID = proc.ID;
allocated.Add(newSpace);
//updates the available block
block_check.start_pos = block_check.start_pos + size - 1;
block_check.blockLength = block_check.blockLength - size;
//updates for the start position for the display
start_position = newSpace.start_pos;
}
}
}
// places into memory location
arg = new ProcessAllocateEventArgs {
ProcessID = proc.ID, ProcessName = proc.Name, BlockLength = size, StartBlock = start_position
};
Processes.Add(proc);
return(true);
}
public override bool DeAllocateProcess(Process proc, out ProcessDeAllocateEventArgs arg)
{
// modifies memory
bool isEnd = false;
int startIndex = 0;
int blockLength = 0;
for (int i = 0; i < MemorySize; i++)
{
if (Memory[i].ProcessId == proc.ID && Memory[i].IsStart == true)
{
startIndex = i;
}
if (Memory[i].ProcessId == proc.ID && Memory[i].IsEnd == true)
{
blockLength = i - startIndex;
isEnd = true;
}
if (Memory[i].ProcessId == proc.ID)
{
Memory[i].IsAssigned = false;
Memory[i].IsEnd = false;
Memory[i].IsStart = false;
Memory[i].ProcessId = 0;
}
if (isEnd)
{
break;
}
}
// finds and removes the target process
for (int i = Processes.Count - 1; i > 0; i--)
{
if (Processes[i].ID == proc.ID)
{
Processes.RemoveAt(i);
}
}
arg = new ProcessDeAllocateEventArgs
{
ProcessID = proc.ID,
ProcessName = proc.Name
};
// converts the allocated data to available data
BlockFit b = null;
for (int i = 0; i < allocated.Count; i++)
{
b = allocated[i];
if (b.ID == proc.ID)
{
arg.StartBlock = b.start_pos;
arg.BlockLength = b.blockLength;
allocated.Remove(allocated[i]);
for (int j = 0; j < avail.Count; j++)
{
// if the newly available blocks are next to already existing available blocks, merge them
BlockFit bl = avail[j];
if (b.start_pos + b.blockLength - 1 == bl.start_pos)
{
b = new BlockFit()
{
ID = bl.ID, blockLength = b.blockLength + bl.blockLength, start_pos = b.start_pos
};
avail.Remove(avail[j]);
}
if (bl.start_pos + bl.blockLength - 1 == b.start_pos)
{
b = new BlockFit()
{
blockLength = b.blockLength + bl.blockLength, start_pos = bl.start_pos
};
avail.Remove(avail[j]);
}
}
avail.Add(b);
break;
}
}
return(true);
}
