mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.Analysis.Numerical/DisIntervalAssumer.cs

   1 //
   2 // DisIntervalAssumer.cs
   3 //
   4 // Authors:
   5 //      Alexander Chebaturkin (chebaturkin@gmail.com)
   6 //
   7 // Copyright (C) 2012 Alexander Chebaturkin
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30
  31 namespace Mono.CodeContracts.Static.Analysis.Numerical {
  32         class DisIntervalAssumer<Var, Expr> : IntervalRationalAssumerBase<Var, Expr, DisInterval>
  33                 where Var : IEquatable<Var> {
  34                 public override IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> AssumeNotEqualToZero
  35                         (Var var, IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> env)
  36                 {
  37                         return AssumeEqualToDisInterval (var, DisInterval.NotZero, env);
  38                 }
  39
  40                 static IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> AssumeEqualToDisInterval
  41                         (Var var, DisInterval intv, IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> env)
  42                 {
  43                         return env.RefineVariable (var, intv);
  44                 }
  45
  46                 public override IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> AssumeNotEqual
  47                         (Expr left, Expr right, IntervalEnvironmentBase<Var, Expr, DisInterval, Rational> env)
  48                 {
  49                         var result = env;
  50
  51                         var rightIntv = env.Eval (right);
  52                         if (rightIntv.IsSinglePoint) {
  53                                 var everythingExcept = DisInterval.EverythingExcept (rightIntv);
  54                                 result = result.RefineVariable (env.Decoder.UnderlyingVariable (left), everythingExcept);
  55                         }
  56
  57                         IntervalInference.InferenceResult<Var, DisInterval> resultLeft;
  58                         IntervalInference.InferenceResult<Var, DisInterval> resultRight;
  59                         IntervalInference.ConstraintsFor.NotEqual (left, right, env.Decoder, result, out resultLeft,
  60                                                                    out resultRight);
  61
  62                         var join = resultLeft.Join (resultRight);
  63                         if (join.IsBottom)
  64                                 return env.Bottom as IntervalEnvironmentBase<Var, Expr, DisInterval, Rational>;
  65
  66                         return AssumeConstraints (join.Constraints, env);
  67                 }
  68                 }
  69 }