protected bool TryCreateArraySegment(BoxedExpression low, BoxedExpression upp, Variable arrayLen,
AbstractDomain intv,
INumericalAbstractDomain <BoxedVariable <Variable>, BoxedExpression> numDom,
out ArraySegmentation <AbstractDomain, BoxedVariable <Variable>, BoxedExpression> arraySegmentation)
{
#region Contracts
Contract.Requires(low != null);
Contract.Requires(upp != null);
Contract.Requires(intv != null);
Contract.Requires(arrayLen != null);
Contract.Requires(numDom != null);
Contract.Ensures(!Contract.Result <bool>() || Contract.ValueAtReturn(out arraySegmentation) != null);
#endregion
var lowerBounds = new Set <NormalizedExpression <BoxedVariable <Variable> > >();
lowerBounds.AddIfNotNull(low.ToNormalizedExpression <Variable>());
var upperBounds = new Set <NormalizedExpression <BoxedVariable <Variable> > >();
upperBounds.AddIfNotNull(upp.ToNormalizedExpression <Variable>());
upperBounds.AddIfNotNull(upp.ToNormalizedExpression <Variable>(true));
upperBounds.AddIfNotNull(upp.Simplify(this.DecoderForMetaData).ToNormalizedExpression <Variable>());
upperBounds.AddIfNotNull(this.Decoder.Stripped(upp).ToNormalizedExpression <Variable>());
if (lowerBounds.Count == 0 || upperBounds.Count == 0)
{
arraySegmentation = null;
return(false);
}
var segments = new NonNullList <SegmentLimit <BoxedVariable <Variable> > >();
var elements = new NonNullList <AbstractDomain>();
#region Build the prefix
// Check if low is zero
int lowValue;
if (low.IsConstantInt(out lowValue))
{
if (lowValue < 0)
{
arraySegmentation = default(ArraySegmentation <AbstractDomain, BoxedVariable <Variable>, BoxedExpression>);
return(false);
}
// { 0 } Top { lowValue }
if (lowValue > 0)
{
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(NormalizedExpression <BoxedVariable <Variable> > .For(0), false));
elements.Add((AbstractDomain)intv.Top);
}
// .. { lowValue } intv
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(lowerBounds, false));
elements.Add(intv);
}
else if (numDom.CheckIfGreaterEqualThanZero(low).IsTrue())
{
// { 0 } Top { low }?
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(NormalizedExpression <BoxedVariable <Variable> > .For(0), false));
elements.Add((AbstractDomain)intv.Top);
// intv { upp }?
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(lowerBounds, true)); // F: we can improve precision by asking if low != 0
elements.Add(intv);
}
else
{
arraySegmentation = default(ArraySegmentation <AbstractDomain, BoxedVariable <Variable>, BoxedExpression>);
return(false);
}
#endregion
#region Build the suffix
// ... { upperBounds }
if (arrayLen.Equals(upp.UnderlyingVariable) || arrayLen.Equals(this.Decoder.Stripped(upp).UnderlyingVariable))
{
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(upperBounds, false));
}
else // ... { upperBounds } Top { arrayLen }?
{
segments.Add(new SegmentLimit <BoxedVariable <Variable> >(upperBounds, false));
elements.Add((AbstractDomain)intv.Top);
segments.Add(
new SegmentLimit <BoxedVariable <Variable> >(
NormalizedExpression <BoxedVariable <Variable> > .For(new BoxedVariable <Variable>(arrayLen)), true));
}
#endregion
arraySegmentation = new ArraySegmentation <AbstractDomain, BoxedVariable <Variable>, BoxedExpression>(
segments, elements,
(AbstractDomain)intv.Bottom, this.ExpressionManager);
return(true);
}
