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//
// IntervalAssumeFalseVisitor.cs
//
// Authors:
// Alexander Chebaturkin (chebaturkin@gmail.com)
//
// Copyright (C) 2012 Alexander Chebaturkin
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
namespace Mono.CodeContracts.Static.Analysis.Numerical {
class IntervalAssumeFalseVisitor<TVar, TExpr, TInterval, TNumeric> :
AssumeFalseVisitor<IntervalEnvironmentBase<TVar, TExpr, TInterval, TNumeric>, TVar, TExpr>
where TInterval : IntervalBase<TInterval, TNumeric>
where TVar : IEquatable<TVar> {
public IntervalAssumeFalseVisitor (IExpressionDecoder<TVar, TExpr> decoder)
: base (decoder)
{
}
public override IntervalEnvironmentBase<TVar, TExpr, TInterval, TNumeric> Visit (TExpr expr,
IntervalEnvironmentBase
<TVar, TExpr,
TInterval,
TNumeric> data)
{
var res = base.Visit (expr, data);
if (!Decoder.IsBinaryExpression (expr))
return res;
var left = Decoder.LeftExpressionFor (expr);
var right = Decoder.RightExpressionFor (expr);
var intv = data.Eval (right);
if (intv.IsBottom)
return data.Bottom;
if (!intv.IsSinglePoint)
return res;
switch (Decoder.OperatorFor (expr)) {
case ExpressionOperator.LessThan: {
var leftVar = Decoder.UnderlyingVariable (left);
return res.Assumer.AssumeLessEqualThan (intv, leftVar, res);
}
case ExpressionOperator.LessEqualThan: {
var leftVar = Decoder.UnderlyingVariable (left);
return res.Assumer.AssumeLessThan (intv, leftVar, res);
}
}
return data;
}
protected override IntervalEnvironmentBase<TVar, TExpr, TInterval, TNumeric> DispatchCompare (
CompareVisitor cmp, TExpr left, TExpr right, TExpr original,
IntervalEnvironmentBase<TVar, TExpr, TInterval, TNumeric> data)
{
data = cmp (left, right, original, data);
return base.DispatchCompare (cmp, left, right, original, data);
}
}
}
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