85 lines
3.7 KiB
C#
85 lines
3.7 KiB
C#
//
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// AssumeFalseVisitor.cs
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//
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// Authors:
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// Alexander Chebaturkin (chebaturkin@gmail.com)
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//
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// Copyright (C) 2012 Alexander Chebaturkin
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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namespace Mono.CodeContracts.Static.Analysis.Numerical {
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abstract class AssumeFalseVisitor<TDomain, TVar, TExpr> :
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GenericExpressionVisitor<TDomain, TDomain, TVar, TExpr>
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where TDomain : IEnvironmentDomain<TDomain, TVar, TExpr> {
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protected AssumeFalseVisitor (IExpressionDecoder<TVar, TExpr> decoder)
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: base (decoder)
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{
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}
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public AssumeTrueVisitor<TDomain, TVar, TExpr> TrueVisitor { get; set; }
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protected override TDomain Default (TDomain data)
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{
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return data;
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}
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public override TDomain VisitConstant (TExpr left, TDomain data)
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{
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bool boolValue;
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if (Decoder.TryValueOf (left, ExpressionType.Bool, out boolValue))
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return boolValue ? data : data.Bottom;
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int intValue;
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if (Decoder.TryValueOf (left, ExpressionType.Int32, out intValue))
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return intValue != 0 ? data : data.Bottom;
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return data;
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}
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public override TDomain VisitNot (TExpr expr, TDomain data)
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{
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return TrueVisitor.Visit (expr, data);
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}
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public override TDomain VisitEqual (TExpr left, TExpr right, TExpr original, TDomain data)
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{
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int value;
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if (Decoder.TryValueOf (right, ExpressionType.Int32, out value) && value == 0)
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// test (left :neq: 0) ==> test (left)
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return TrueVisitor.Visit (left, data);
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return TrueVisitor.VisitNotEqual (left, right, original, data);
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}
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public override TDomain VisitLessThan (TExpr left, TExpr right, TExpr original, TDomain data)
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{
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// !(left < right) ==> right <= left
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return TrueVisitor.VisitLessEqualThan (right, left, original, data);
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}
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public override TDomain VisitLessEqualThan (TExpr left, TExpr right, TExpr original, TDomain data)
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{
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// !(left <= right) ==> right < left
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return TrueVisitor.VisitLessThan (right, left, original, data);
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}
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}
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} |