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130 lines
5.1 KiB
130 lines
5.1 KiB
// |
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// CompareFloatWithEqualityOperatorIssue.cs |
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// |
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// Author: |
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// Mansheng Yang <lightyang0@gmail.com> |
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// |
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// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com> |
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// |
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// Permission is hereby granted, free of charge, to any person obtaining a copy |
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// of this software and associated documentation files (the "Software"), to deal |
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// in the Software without restriction, including without limitation the rights |
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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// copies of the Software, and to permit persons to whom the Software is |
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// furnished to do so, subject to the following conditions: |
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// |
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// The above copyright notice and this permission notice shall be included in |
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// 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, EXPRESS OR |
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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// THE SOFTWARE. |
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using System.Collections.Generic; |
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using ICSharpCode.NRefactory.TypeSystem; |
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namespace ICSharpCode.NRefactory.CSharp.Refactoring |
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{ |
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[IssueDescription ("Compare floating point numbers with equality operator", |
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Description = "Comparison of floating point numbers with equality operator.", |
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Category = IssueCategories.CodeQualityIssues, |
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Severity = Severity.Warning, |
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IssueMarker = IssueMarker.Underline)] |
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public class CompareFloatWithEqualityOperatorIssue : ICodeIssueProvider |
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{ |
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public IEnumerable<CodeIssue> GetIssues (BaseRefactoringContext context) |
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{ |
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return new GatherVisitor (context).GetIssues (); |
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} |
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class GatherVisitor : GatherVisitorBase |
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{ |
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public GatherVisitor (BaseRefactoringContext ctx) |
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: base(ctx) |
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{ |
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} |
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static bool IsFloatingPointType (IType type) |
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{ |
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var typeDef = type.GetDefinition (); |
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return typeDef != null && |
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(typeDef.KnownTypeCode == KnownTypeCode.Single || typeDef.KnownTypeCode == KnownTypeCode.Double); |
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} |
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bool IsFloatingPoint(AstNode node) |
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{ |
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return IsFloatingPointType (ctx.Resolve (node).Type); |
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} |
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bool IsNaN (AstNode node, out string floatType) |
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{ |
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floatType = ""; |
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var rr = ctx.Resolve (node); |
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if (!rr.IsCompileTimeConstant) |
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return false; |
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if (rr.ConstantValue is double && double.IsNaN ((double)rr.ConstantValue)) { |
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floatType = "double"; |
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return true; |
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} |
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if (rr.ConstantValue is float && float.IsNaN ((float)rr.ConstantValue)) { |
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floatType = "float"; |
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return true; |
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} |
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return false; |
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} |
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void AddIsNaNIssue(BinaryOperatorExpression binaryOperatorExpr, Expression argExpr, string floatType) |
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{ |
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if (ctx.Resolve (argExpr).Type.ReflectionName != "System.Single") |
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floatType = "double"; |
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AddIssue (binaryOperatorExpr, string.Format(ctx.TranslateString ("Use {0}.IsNan()"), floatType), |
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script => { |
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Expression expr = new InvocationExpression (new MemberReferenceExpression ( |
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new TypeReferenceExpression (new PrimitiveType (floatType)), "IsNaN"), argExpr.Clone ()); |
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if (binaryOperatorExpr.Operator == BinaryOperatorType.InEquality) |
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expr = new UnaryOperatorExpression (UnaryOperatorType.Not, expr); |
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script.Replace (binaryOperatorExpr, expr); |
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}); |
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} |
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public override void VisitBinaryOperatorExpression (BinaryOperatorExpression binaryOperatorExpression) |
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{ |
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base.VisitBinaryOperatorExpression (binaryOperatorExpression); |
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if (binaryOperatorExpression.Operator != BinaryOperatorType.Equality && |
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binaryOperatorExpression.Operator != BinaryOperatorType.InEquality) |
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return; |
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string floatType; |
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if (IsNaN(binaryOperatorExpression.Left, out floatType)) { |
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AddIsNaNIssue (binaryOperatorExpression, binaryOperatorExpression.Right, floatType); |
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} else if (IsNaN (binaryOperatorExpression.Right, out floatType)) { |
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AddIsNaNIssue (binaryOperatorExpression, binaryOperatorExpression.Left, floatType); |
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} else if (IsFloatingPoint(binaryOperatorExpression.Left) || IsFloatingPoint(binaryOperatorExpression.Right)) { |
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AddIssue (binaryOperatorExpression, ctx.TranslateString ("Compare a difference with EPSILON"), |
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script => { |
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// Math.Abs(diff) op EPSILON |
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var diff = new BinaryOperatorExpression (binaryOperatorExpression.Left.Clone (), |
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BinaryOperatorType.Subtract, binaryOperatorExpression.Right.Clone ()); |
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var abs = new InvocationExpression ( |
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new MemberReferenceExpression ( |
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new TypeReferenceExpression (new SimpleType ("System.Math")), |
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"Abs"), |
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diff); |
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var op = binaryOperatorExpression.Operator == BinaryOperatorType.Equality ? |
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BinaryOperatorType.LessThan : BinaryOperatorType.GreaterThan; |
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var epsilon = new IdentifierExpression ("EPSILON"); |
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var compare = new BinaryOperatorExpression (abs, op, epsilon); |
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script.Replace (binaryOperatorExpression, compare); |
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script.Link (epsilon); |
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}); |
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} |
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} |
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} |
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} |
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}
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