/// <summary>
/// Default constructor
/// </summary>
public VM_PageReplacment()
{
InputString = string.Empty;
FramesCount = 0;
AlgorithmType = VMAlgorithmType.FIFO;
}
/// <summary>
/// Parameterized constructor with input string and frames count to work-on
/// </summary>
/// <param name="inputString">The input string</param>
/// <param name="framesCount">The frames count</param>
public VM_PageReplacment(string inputString, int framesCount, VMAlgorithmType type)
{
InputString = inputString;
FramesCount = framesCount;
AlgorithmType = type;
}
private int ObjectToRemoveIndex(List <OSASVMObject> objects, OSASVMObject vmObj, int current, string input, VMAlgorithmType type)
{
int ObjToRemoveIndex = -1;
if (type == VMAlgorithmType.FIFO)
{
var lastFObjects = objects.Where(a => a.Index < current && !a.Hit).ToList();
var objToRemoveValue = lastFObjects[lastFObjects.Count - FramesCount].InputObject;
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(objToRemoveValue)));
}
else if (type == VMAlgorithmType.LRU)
{
var lastFObjects = objects.AsEnumerable().Reverse().Distinct().ToList();
var objToRemoveValue = lastFObjects[FramesCount - 1].InputObject;
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(objToRemoveValue)));
}
else if (type == VMAlgorithmType.Optimal)
{
var rightString = input.Substring(current, input.Length - current);
var rightUsed = rightString.Where(a => vmObj.Frames.Exists(b => b.Equals(a))).ToList();
if (rightUsed.Count == 0)
{
return(ObjToRemoveIndex = 0);
}
var grouped = rightUsed.GroupBy(a => a).ToList();
if (grouped.Count < vmObj.Frames.Count)
{
var notExists = vmObj.Frames.Where(a => !grouped.Exists(b => a.Equals(b.Key))).ToList();
var objToRemoveValue = notExists.FirstOrDefault();
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(objToRemoveValue)));
}
grouped = grouped.OrderByDescending(a => a.Count()).ToList();
var objToRemoveValuee = grouped.LastOrDefault().Key;
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(objToRemoveValuee)));
}
else if (type == VMAlgorithmType.MFU)
{
var groupedObjects = vmObj.Frames.Select(a => new
{
obj = a,
count = input.Substring(0, current).Where(b => b.Equals(a.Value)).Count()
});
var max = groupedObjects.Max(a => a.count);
// Now get the objects with this max count value
var maxCountObjects = groupedObjects.Where(a => a.count == max);
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(maxCountObjects.FirstOrDefault().obj.Value)));
}
else if (type == VMAlgorithmType.SecondChance)
{
//var orderedObjects = objects.SelectMany(a => a.Frames).
// Where(e=>vmObj.Frames.Exists(f=>f.Equals(e))).
// GroupBy(b => b).
// OrderByDescending(c => c.Count());
var orderedObjects = GetValuesCounts(objects, vmObj).OrderBy(a => a.Value);
point:
foreach (var obj in orderedObjects.Reverse())
{
var frameObj = vmObj.Frames.Find(a => a.Equals(obj.Key));
if (frameObj == null)
{
continue;
}
if (frameObj.SecondChance)
{
frameObj.SecondChance = false;
continue;
}
else
{
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(obj.Key)));
}
}
goto point;
}
else if (type == VMAlgorithmType.LFU)
{
var groupedObjects = vmObj.Frames.Select(a => new
{
obj = a,
count = input.Substring(0, current).Where(b => b.Equals(a.Value)).Count(),
stringIndex = input.Substring(0, current).IndexOf((char)a.Value),
});
var min = groupedObjects.Min(a => a.count);
// Now get the objects with this min count value ordered by input string index
var minCountObjects = groupedObjects.Where(a => a.count == min).OrderBy(a => a.stringIndex);
return(ObjToRemoveIndex = vmObj.Frames.FindIndex(a => a.Equals(minCountObjects.FirstOrDefault().obj.Value)));
}
return(ObjToRemoveIndex);
}
