source: branches/2839_HiveProjectManagement/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Interpreter/InterpreterState.cs @ 16057

Last change on this file since 16057 was 16057, checked in by jkarder, 4 years ago

#2839:

File size: 2.9 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
23
24namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
25  public class InterpreterState {
26    private readonly double[] argumentStack;
27    private int argumentStackPointer;
28    private readonly Instruction[] code;
29
30    public int ProgramCounter { get; set; }
31    public bool InLaggedContext { get; set; }
32
33    public InterpreterState(Instruction[] code, int argumentStackSize) {
34      this.code = code;
35      this.ProgramCounter = 0;
36      this.InLaggedContext = false;
37      if (argumentStackSize > 0) {
38        this.argumentStack = new double[argumentStackSize];
39      }
40      this.argumentStackPointer = 0;
41    }
42
43    public void Reset() {
44      this.ProgramCounter = 0;
45      this.argumentStackPointer = 0;
46      this.InLaggedContext = false;
47    }
48
49    public Instruction NextInstruction() {
50      return code[ProgramCounter++];
51    }
52    // skips a whole branch
53    public void SkipInstructions() {
54      int i = 1;
55      while (i > 0) {
56        i += NextInstruction().nArguments;
57        i--;
58      }
59    }
60
61    private void Push(double val) {
62      argumentStack[argumentStackPointer++] = val;
63    }
64    private double Pop() {
65      return argumentStack[--argumentStackPointer];
66    }
67
68    public void CreateStackFrame(double[] argValues) {
69      // push in reverse order to make indexing easier
70      for (int i = argValues.Length - 1; i >= 0; i--) {
71        argumentStack[argumentStackPointer++] = argValues[i];
72      }
73      Push(argValues.Length);
74    }
75
76    public void RemoveStackFrame() {
77      int size = (int)Pop();
78      argumentStackPointer -= size;
79    }
80
81    public double GetStackFrameValue(ushort index) {
82      // layout of stack:
83      // [0]   <- argumentStackPointer
84      // [StackFrameSize = N + 1]
85      // [Arg0] <- argumentStackPointer - 2 - 0
86      // [Arg1] <- argumentStackPointer - 2 - 1
87      // [...]
88      // [ArgN] <- argumentStackPointer - 2 - N
89      // <Begin of stack frame>
90      return argumentStack[argumentStackPointer - index - 2];
91    }
92  }
93}
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