public virtual void AddBitCombinations()
{
//AutoExpand enum into bit combinations
//Note: We do this to make choosing the parameters easier and faster (ie: one time hit)
//In addition we do this inorder to keep track of each combinations coverage
//Must be an Enumerable type
if (this.Type == null || !this.Type.IsEnum)
{
throw new ModelException(this, "BitMask can only be specified on a Enumerable type", null);
}
//Note: A simple (ripple) counter is the easiest solution
// For example, Given 3 bits { A, B, C } the combinations are simply:
// A, B, C Value
// -------------------
// 0, 0, 0, = 0 (invalid, no bits on)
// 0, 0, 1, = 1
// 0, 1, 0, = 2
// 0, 1, 1, = 3
// 1, 0, 0, = 4
// 1, 0, 1, = 5
// 1, 1, 0, = 6
// 1, 1, 1, = 7
ModelValues values = this.Values;
Hashtable hash = new Hashtable(); //Automatic Dup collapsing
int bits = values.Count; //bits
int total = (int)Math.Pow(2, bits); //2^n
for (int i = 1; i < total; i++)
{
int value = 0;
//Calculate which bits are on
for (int bit = 0; bit < bits; bit++)
{
int mask = 0x00000001 << bit;
if ((i & mask) != 0)
{
value |= (int)values[bit].Value;
}
}
//Note: We have to covert it back to the enum, inorder to call the method
hash[value] = Enum.ToObject(this.Type, value); //Since 0 is skipped
}
//Update our list of values
values.Clear();
foreach (object value in hash.Values)
{
values.Add(new ModelValue(value));
}
}
///<summary>Finds all the model values except those that match the operator specified</summary>
public virtual ModelValues FindOperator(ModelValueOperator op, bool include)
{
ModelValues found = new ModelValues();
foreach (ModelValue item in _list)
{
if ((item.Operator == op) == include)
{
found.Add(item);
}
}
return(found);
}
public ModelRequirement(ModelAction action, ModelRequirementAttribute attr, ModelVariable variable, ModelValue value)
: base(action != null ? action.Model : null, attr)
{
//Action
_action = action;
//Variable
if (variable != null)
{
_variable = variable;
if (variable.BitMask)
{
this.BitMask = true;
}
}
//if(_variable == null)
// throw new ModelException(this, "An empty variable is not a valid requirement", null);
//Only override the attr, if values are really specified
if (value != null)
{
_values = new ModelValues(value);
}
//BitMask
//TODO: Better place to expand this, (incase values added later).
if (this.BitMask)
{
this.AddBitCombinations();
}
//Infer dynamic variable(s)
this.InferDynamicVariables();
//Requirements assoicated with actions, are not global. They are tied to that particular
//instance of the model, and it's instance of state variables. However if not assoicated
//with actions, the default behavior is that their global, they apply to all models
//that contain that state variable, unless explicitly indicated otherwise.
_global = (action == null);
}
protected ModelValue DetermineParameterValue(ModelParameter parameter)
{
ModelValues values = new ModelValues();
values.Add(parameter.Values);
//Parameter values, can be specified in numerous ways:
// 1. Value list - simply choose one of them
// 2. Expression - generate value that meets the criteria (ie: <, >, !=, etc)
// 3. Variable - simply obtain the value by calling a method/field
//#3. Variable - simply obtain the value by calling a method/field
if (parameter.Variable != null)
{
object current = parameter.Variable.CachedValue;
if (current is IEnumerable && !typeof(IEnumerable).IsAssignableFrom(parameter.Type))
{
foreach (object v in (IEnumerable)current)
{
values.Add(new ModelValue(v));
}
}
else
{
values.Add(new ModelValue(current));
}
}
//First ensure we have a set of values/requirements to choose from
if (values.Count <= 0)
{
throw new ModelException(parameter, "No values specified to choose from");
}
//Note: Since we allow the operator on the individual values, this is a little more complex.
//Note: We allow multiple operators, not just one, (ie: x > 5, < 10, and != 7).
//This gives you great power and flexibility in expressions, but means we have to work a
//little hard in determing a value that meets the requirements
//#1. Value list - simply choose one of them
//Note: Bitmask is already exploded into combinations
ModelValues equalvalues = values.FindOperator(ModelValueOperator.Equal);
//#2. Expression - generate value that meets the criteria (ie: <, >, !=, etc)
//Note: Since we allow the operator on the individual values, this is a little more complex.
//Note: We allow multiple operators, not just one, (ie: x > 5, < 10, and != 7).
//This gives you great power and flexibility in expressions, but means we have to work a
//little hard in determing a value that meets the requirements.
int min = Int32.MinValue;
int max = Int32.MaxValue;
//Adjust our parameter, simplier to loop over all of them
foreach (ModelValue value in values.FindOperator(ModelValueOperator.Equal, false).FindOperator(ModelValueOperator.NotEqual, false))
{
//To keep this simple, we just support integers (for now).
if (!(value.Value is int || value.Value is Nullable <int>))
{
throw new ModelException(parameter, "Generated value range must be specified in terms of integers, not '" + value.Type + "'");
}
//Simplify our life
int v = (int)value.Value;
//Adjust Max (if there is one)
switch (value.Operator)
{
case ModelValueOperator.LessThanOrEqual:
if (v < max)
{
max = v;
}
break;
case ModelValueOperator.GreaterThanOrEqual:
if (v > min)
{
min = v;
}
break;
case ModelValueOperator.LessThan:
if (v - 1 < max && v > Int32.MinValue /*prevent underflow*/)
{
max = v - 1;
}
break;
case ModelValueOperator.GreaterThan:
if (v + 1 > min && v < Int32.MaxValue /*prevent overflow*/)
{
min = v + 1;
}
break;
}
;
}
//Choose a new value, within the specified range
//Note: We retry in case it equals one of the existing invalid values (ie: !=)
while (true)
{
ModelValue choice = null;
if (equalvalues.Count > 0)
{
//Simple: Choose one of the specified values
choice = new ModelValue(equalvalues.Choose(this).Value);
}
else
{
//Otherwise: Choose a value within in the range
//Note: Random.Next = min <= x < max (so we have to add one)
int index = _options.Random.Next(min, max < Int32.MaxValue ? max + 1 : max); //Prevent overflow
choice = new ModelValue(index);
}
//As soon as we find a value, within the range, (and not in the invalid list), were done
bool valid = true;
foreach (ModelValue invalid in values.FindOperator(ModelValueOperator.NotEqual))
{
if (invalid.Evaluate(choice.Value, ModelValueOperator.Equal))
{
valid = false;
}
}
if (valid)
{
return(choice);
}
}
}
