private static IComparerExpression <T> Reverse(IComparerExpression <T> comparer)
{
Contract.Requires(comparer != null);
Expression <Comparison <T> > expression = comparer.GetCompareExpr();
Expression <Comparison <T> > template = (left, right) => CallInliner.Call(expression, right, left);
Expression <Comparison <T> > reversedExpression = template.InlineCalls();
return(new ComparerExpression <T>(reversedExpression));
}
public static IComparerExpression <TNewInput> TransformInput <TOldInput, TNewInput>(this IComparerExpression <TOldInput> comparer, Expression <Func <TNewInput, TOldInput> > transform)
{
Contract.Requires(comparer != null);
Contract.Requires(transform != null);
var expression = comparer.GetCompareExpr();
Expression <Comparison <TNewInput> > template =
(left, right) => CallInliner.Call(expression, CallInliner.Call(transform, left), CallInliner.Call(transform, right));
var transformedExpression = template.InlineCalls();
return(new ComparerExpression <TNewInput>(transformedExpression));
}
private static IComparerExpression <T> ThenOrderBy(IComparerExpression <T> comparer1, IComparerExpression <T> comparer2)
{
Contract.Requires(comparer1 != null);
Contract.Requires(comparer2 != null);
Expression <Comparison <T> > primary = comparer1.GetCompareExpr();
Expression <Comparison <T> > secondary = comparer2.GetCompareExpr();
Expression <Comparison <T> > template =
(left, right) =>
CallInliner.Call(primary, left, right) == 0
? CallInliner.Call(secondary, left, right)
: CallInliner.Call(primary, left, right);
Expression <Comparison <T> > newExpression = template.InlineCalls();
return(new ComparerExpression <T>(newExpression));
}
public static IAggregate <TInput, NullOutputWrapper <TState>, TResult> OutputDefaultWhenEmpty <TInput, TState, TResult>(
this IAggregate <TInput, TState, TResult> aggregate)
{
Contract.Requires(aggregate != null);
Expression <Func <NullOutputWrapper <TState> > > newInitialState =
() => new NullOutputWrapper <TState>
{
Count = 0,
State = CallInliner.Call(aggregate.InitialState())
};
Expression <Func <NullOutputWrapper <TState>, long, TInput, NullOutputWrapper <TState> > > newAccumulate =
(oldState, timestamp, input) => new NullOutputWrapper <TState>
{
Count = oldState.Count + 1,
State = CallInliner.Call(aggregate.Accumulate(), oldState.State, timestamp, input)
};
Expression <Func <NullOutputWrapper <TState>, long, TInput, NullOutputWrapper <TState> > > newDeaccumulate =
(oldState, timestamp, input) => new NullOutputWrapper <TState>
{
Count = oldState.Count - 1,
State = CallInliner.Call(aggregate.Deaccumulate(), oldState.State, timestamp, input)
};
Expression <Func <NullOutputWrapper <TState>, NullOutputWrapper <TState>, NullOutputWrapper <TState> > > newDifference =
(leftState, rightState) => new NullOutputWrapper <TState>
{
Count = leftState.Count - rightState.Count,
State = CallInliner.Call(aggregate.Difference(), leftState.State, rightState.State)
};
Expression <Func <NullOutputWrapper <TState>, TResult> > newComputeResult =
state => state.Count == 0 ? default : CallInliner.Call(aggregate.ComputeResult(), state.State);
return(GeneratedAggregate.Create(
initialState: newInitialState.InlineCalls(),
accumulate: newAccumulate.InlineCalls(),
deaccumulate: newDeaccumulate.InlineCalls(),
difference: newDifference.InlineCalls(),
computeResult: newComputeResult.InlineCalls()));
}
public static IAggregate <TInput, TState, TResult> ApplyFilter <TInput, TState, TResult>(
this IAggregate <TInput, TState, TResult> aggregate,
Expression <Func <TInput, bool> > filter)
{
Contract.Requires(aggregate != null);
if (filter == null || filter.Body.ExpressionEquals(Expression.Constant(true)))
{
return(aggregate);
}
Expression <Func <TState, long, TInput, TState> > newAccumulate = (oldState, timestamp, input) =>
CallInliner.Call(filter, input) ? CallInliner.Call(aggregate.Accumulate(), oldState, timestamp, input) : oldState;
Expression <Func <TState, long, TInput, TState> > newDeaccumulate = (oldState, timestamp, input) =>
CallInliner.Call(filter, input) ? CallInliner.Call(aggregate.Deaccumulate(), oldState, timestamp, input) : oldState;
return(GeneratedAggregate.Create(
initialState: aggregate.InitialState(),
accumulate: newAccumulate.InlineCalls(),
deaccumulate: newDeaccumulate.InlineCalls(),
difference: aggregate.Difference(),
computeResult: aggregate.ComputeResult()));
}
public static IAggregate <TInput?, TState, TResult> MakeInputNullableAndSkipNulls <TInput, TState, TResult>(
this IAggregate <TInput, TState, TResult> aggregate) where TInput : struct
{
Contract.Requires(aggregate != null);
Expression <Func <TState, long, TInput?, TState> > newAccumulate = (oldState, timestamp, input) =>
input.HasValue ? CallInliner.Call(aggregate.Accumulate(), oldState, timestamp, input.Value) : oldState;
Expression <Func <TState, long, TInput?, TState> > newDeaccumulate = (oldState, timestamp, input) =>
input.HasValue ? CallInliner.Call(aggregate.Deaccumulate(), oldState, timestamp, input.Value) : oldState;
return(GeneratedAggregate.Create(
initialState: aggregate.InitialState(),
accumulate: newAccumulate.InlineCalls(),
deaccumulate: newDeaccumulate.InlineCalls(),
difference: aggregate.Difference(),
computeResult: aggregate.ComputeResult()));
}