/// <summary>
/// Code up the min/max result operators. We run the loop out, and then
/// we return the result whatever it is. We only work when the type is
/// something simple we can deal with!
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
/// <returns></returns>
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
///
/// Some argument checking
///
if (cc == null)
throw new ArgumentNullException("cc");
if (gc == null)
throw new ArgumentNullException("gc");
if (gc.Depth == 1)
throw new ArgumentException("The Max/Min operators can't be used as result operators for a query - they can only be used in a sub-query");
///
/// Is it min or max?
///
var minOperator = resultOperator as MinResultOperator;
var maxOperator = resultOperator as MaxResultOperator;
if (minOperator == null && maxOperator == null)
throw new InvalidOperationException("Should always have min or max operator!");
bool doMax = maxOperator != null;
bool returnDefaultValue = false;
if (doMax)
returnDefaultValue = maxOperator.ReturnDefaultWhenEmpty;
else
returnDefaultValue = minOperator.ReturnDefaultWhenEmpty;
///
/// Next, look at the type of the current result that is running.
///
var valueExpr = queryModel.SelectClause.Selector;
if (!TimeCanBeCompared(valueExpr.Type))
throw new ArgumentException(string.Format("I don't know how to fix the min or max of a sequence of '{0}'s", cc.LoopVariable.Type.Name));
///
/// Now, declare two variables, one bool which gets set when we get the first value,
/// and the other to hold the min/max value! Note that we initalize the variable to
/// the proper type. We don't declare minmax holder - as it may end up be used
/// externally.
///
var vIsFilled = DeclarableParameter.CreateDeclarableParameterExpression(typeof(bool));
vIsFilled.InitialValue = new ValSimple("false", typeof(bool), null);
var vMaxMin = DeclarableParameter.CreateDeclarableParameterExpression(valueExpr.Type);
vMaxMin.InitialValue = new ValSimple("0", typeof(int), null);
gc.AddOutsideLoop(vIsFilled);
///
/// The expression we want to mimize or maximize
///
var exprToMinOrMaximize = ExpressionToCPP.GetExpression(valueExpr, gc, cc, container);
///
/// Now, we just have to put the x-checks in there.
///
var ifStatement = new Statements.StatementMinMaxTest(vIsFilled, vMaxMin, exprToMinOrMaximize, doMax);
gc.Add(ifStatement);
return vMaxMin;
}
/// <summary>
/// Code up the min/max result operators. We run the loop out, and then
/// we return the result whatever it is. We only work when the type is
/// something simple we can deal with!
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
/// <returns></returns>
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
///
/// Some argument checking
///
if (cc == null)
{
throw new ArgumentNullException("cc");
}
if (gc == null)
{
throw new ArgumentNullException("gc");
}
if (gc.Depth == 1)
{
throw new ArgumentException("The Max/Min operators can't be used as result operators for a query - they can only be used in a sub-query");
}
///
/// Is it min or max?
///
var minOperator = resultOperator as MinResultOperator;
var maxOperator = resultOperator as MaxResultOperator;
if (minOperator == null && maxOperator == null)
{
throw new InvalidOperationException("Should always have min or max operator!");
}
bool doMax = maxOperator != null;
bool returnDefaultValue = false;
if (doMax)
{
returnDefaultValue = maxOperator.ReturnDefaultWhenEmpty;
}
else
{
returnDefaultValue = minOperator.ReturnDefaultWhenEmpty;
}
///
/// Next, look at the type of the current result that is running.
///
var valueExpr = queryModel.SelectClause.Selector;
if (!TimeCanBeCompared(valueExpr.Type))
{
throw new ArgumentException(string.Format("I don't know how to fix the min or max of a sequence of '{0}'s", cc.LoopVariable.Type.Name));
}
///
/// Now, declare two variables, one bool which gets set when we get the first value,
/// and the other to hold the min/max value! Note that we initalize the variable to
/// the proper type. We don't declare minmax holder - as it may end up be used
/// externally.
///
var vIsFilled = DeclarableParameter.CreateDeclarableParameterExpression(typeof(bool));
vIsFilled.InitialValue = new ValSimple("false", typeof(bool), null);
var vMaxMin = DeclarableParameter.CreateDeclarableParameterExpression(valueExpr.Type);
vMaxMin.InitialValue = new ValSimple("0", typeof(int), null);
gc.AddOutsideLoop(vIsFilled);
///
/// The expression we want to mimize or maximize
///
var exprToMinOrMaximize = ExpressionToCPP.GetExpression(valueExpr, gc, cc, container);
///
/// Now, we just have to put the x-checks in there.
///
var ifStatement = new Statements.StatementMinMaxTest(vIsFilled, vMaxMin, exprToMinOrMaximize, doMax);
gc.Add(ifStatement);
return(vMaxMin);
}