Mercurial > pub > ImplabNet

comparison Implab/Automaton/DFAutomaton.cs @ 162:0526412bbb26 ref20160224

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
DFA refactoring
author cin
date Wed, 24 Feb 2016 08:39:53 +0300
parents
children
comparison
equal deleted inserted replaced
161:2a8466f0cb8a 162:0526412bbb26
1 using Implab;
2 using System;
3 using System.Collections.Generic;
4 using System.Diagnostics;
5 using System.Linq;
6 using System.Text;
7 using System.Threading.Tasks;
8
9 namespace Implab.Automaton {
10 public abstract class DFAutomaton<T> {
11 protected struct ContextFrame {
12 public DFAStateDescriptior[] states;
13 public int current;
14 public T info;
15 }
16
17 public const int INITIAL_STATE = DFADefinition.INITIAL_STATE;
18 public const int UNREACHEBLE_STATE = DFADefinition.UNREACHEBLE_STATE;
19
20 protected ContextFrame m_context;
21 Stack<ContextFrame> m_contextStack = new Stack<ContextFrame>();
22
23 protected int Level {
24 get { return m_contextStack.Count; }
25 }
26
27 protected DFAutomaton(DFAStateDescriptior[] states, int startState, T info) {
28 Safe.ArgumentNotNull(states, "states");
29 Safe.ArgumentInRange(startState, 0, states.Length - 1, "startState");
30
31 m_context.states = states;
32 m_context.current = startState;
33 m_context.info = info;
34 }
35
36 protected void Switch(DFAStateDescriptior[] states, int current, T info) {
37 Debug.Assert(states != null);
38 Debug.Assert(current >= 0 && current < states.Length);
39 m_contextStack.Push(m_context);
40 m_context.states = states;
41 m_context.current = current;
42 m_context.info = info;
43 }
44
45 protected void Restore() {
46 Debug.Assert(m_contextStack.Count > 0);
47
48 m_context = m_contextStack.Pop();
49 }
50
51 protected void Move(int input) {
52 Debug.Assert(input > 0 && input < m_context.states[m_context.current].transitions.Length);
53 m_context.current = m_context.states[m_context.current].transitions[input];
54 }
55
56 protected bool CanMove(int input) {
57 Debug.Assert(input > 0 && input < m_context.states[m_context.current].transitions.Length);
58 return m_context.states[m_context.current].transitions[input] != UNREACHEBLE_STATE;
59 }
60 }
61 }