|
|
using Implab;
|
|
|
using System;
|
|
|
using System.Collections.Generic;
|
|
|
using System.Diagnostics;
|
|
|
using System.Linq;
|
|
|
|
|
|
namespace Implab.Automaton.RegularExpressions {
|
|
|
/// <summary>
|
|
|
/// Используется для построения ДКА по регулярному выражению, сначала обходит
|
|
|
/// регулярное выражение и вычисляет followpos, затем используется метод
|
|
|
/// <see cref="BuildDFA(IDFADefinition)"/> для построения автомата.
|
|
|
/// </summary>
|
|
|
public class RegularExpressionVisitor : IVisitor {
|
|
|
int m_idx;
|
|
|
Token m_root;
|
|
|
HashSet<int> m_firstpos;
|
|
|
HashSet<int> m_lastpos;
|
|
|
|
|
|
readonly Dictionary<int, HashSet<int>> m_followpos = new Dictionary<int, HashSet<int>>();
|
|
|
readonly Dictionary<int, int> m_indexes = new Dictionary<int, int>();
|
|
|
readonly HashSet<int> m_ends = new HashSet<int>();
|
|
|
|
|
|
readonly IDFATableBuilder m_builder;
|
|
|
readonly IAlphabetBuilder<HashSet<int>> m_states = new MapAlphabet<HashSet<int>>(
|
|
|
false,
|
|
|
new CustomEqualityComparer<HashSet<int>>(
|
|
|
(x, y) => x.SetEquals(y),
|
|
|
x => x.Sum(n => n.GetHashCode())
|
|
|
)
|
|
|
);
|
|
|
|
|
|
public RegularExpressionVisitor(IDFATableBuilder builder) {
|
|
|
Safe.ArgumentNotNull(builder, "builder");
|
|
|
|
|
|
m_builder = builder;
|
|
|
}
|
|
|
|
|
|
HashSet<int> Followpos(int pos) {
|
|
|
HashSet<int> set;
|
|
|
return m_followpos.TryGetValue(pos, out set) ? set : m_followpos[pos] = new HashSet<int>();
|
|
|
}
|
|
|
|
|
|
bool Nullable(object n) {
|
|
|
if (n is EmptyToken || n is StarToken)
|
|
|
return true;
|
|
|
var altToken = n as AltToken;
|
|
|
if (altToken != null)
|
|
|
return Nullable(altToken.Left) || Nullable(altToken.Right);
|
|
|
var catToken = n as CatToken;
|
|
|
if (catToken != null)
|
|
|
return Nullable(catToken.Left) && Nullable(catToken.Right);
|
|
|
return false;
|
|
|
}
|
|
|
|
|
|
protected int Index {
|
|
|
get { return m_idx; }
|
|
|
}
|
|
|
|
|
|
public void Visit(AltToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
var firtspos = new HashSet<int>();
|
|
|
var lastpos = new HashSet<int>();
|
|
|
|
|
|
token.Left.Accept(this);
|
|
|
firtspos.UnionWith(m_firstpos);
|
|
|
lastpos.UnionWith(m_lastpos);
|
|
|
|
|
|
token.Right.Accept(this);
|
|
|
firtspos.UnionWith(m_firstpos);
|
|
|
lastpos.UnionWith(m_lastpos);
|
|
|
|
|
|
m_firstpos = firtspos;
|
|
|
m_lastpos = lastpos;
|
|
|
}
|
|
|
|
|
|
public void Visit(StarToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
token.Token.Accept(this);
|
|
|
|
|
|
foreach (var i in m_lastpos)
|
|
|
Followpos(i).UnionWith(m_firstpos);
|
|
|
}
|
|
|
|
|
|
public void Visit(CatToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
|
|
|
var firtspos = new HashSet<int>();
|
|
|
var lastpos = new HashSet<int>();
|
|
|
token.Left.Accept(this);
|
|
|
firtspos.UnionWith(m_firstpos);
|
|
|
var leftLastpos = m_lastpos;
|
|
|
|
|
|
token.Right.Accept(this);
|
|
|
lastpos.UnionWith(m_lastpos);
|
|
|
var rightFirstpos = m_firstpos;
|
|
|
|
|
|
if (Nullable(token.Left))
|
|
|
firtspos.UnionWith(rightFirstpos);
|
|
|
|
|
|
if (Nullable(token.Right))
|
|
|
lastpos.UnionWith(leftLastpos);
|
|
|
|
|
|
m_firstpos = firtspos;
|
|
|
m_lastpos = lastpos;
|
|
|
|
|
|
foreach (var i in leftLastpos)
|
|
|
Followpos(i).UnionWith(rightFirstpos);
|
|
|
|
|
|
}
|
|
|
|
|
|
public void Visit(EmptyToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
}
|
|
|
|
|
|
public void Visit(SymbolToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
m_idx++;
|
|
|
m_indexes[m_idx] = token.Value;
|
|
|
m_firstpos = new HashSet<int>(new[] { m_idx });
|
|
|
m_lastpos = new HashSet<int>(new[] { m_idx });
|
|
|
}
|
|
|
|
|
|
public virtual void Visit(EndToken token) {
|
|
|
if (m_root == null)
|
|
|
m_root = token;
|
|
|
m_idx++;
|
|
|
m_indexes[m_idx] = AutomatonConst.UNCLASSIFIED_INPUT;
|
|
|
m_firstpos = new HashSet<int>(new[] { m_idx });
|
|
|
m_lastpos = new HashSet<int>(new[] { m_idx });
|
|
|
Followpos(m_idx);
|
|
|
m_ends.Add(m_idx);
|
|
|
}
|
|
|
|
|
|
public void BuildDFA() {
|
|
|
AddState(m_firstpos);
|
|
|
SetInitialState(m_firstpos);
|
|
|
|
|
|
if(IsFinal(m_firstpos))
|
|
|
MarkFinalState(m_firstpos);
|
|
|
|
|
|
var inputMax = m_indexes.Values.Max();
|
|
|
var queue = new Queue<HashSet<int>>();
|
|
|
|
|
|
queue.Enqueue(m_firstpos);
|
|
|
|
|
|
while (queue.Count > 0) {
|
|
|
var s1 = queue.Dequeue();
|
|
|
|
|
|
for (int a = 0; a <= inputMax; a++) {
|
|
|
var s2 = new HashSet<int>();
|
|
|
foreach (var p in s1) {
|
|
|
if (m_indexes[p] == a) {
|
|
|
s2.UnionWith(Followpos(p));
|
|
|
}
|
|
|
}
|
|
|
if (s2.Count > 0) {
|
|
|
if (!HasState(s2)) {
|
|
|
AddState(s2);
|
|
|
if (IsFinal(s2))
|
|
|
MarkFinalState(s2);
|
|
|
|
|
|
queue.Enqueue(s2);
|
|
|
}
|
|
|
|
|
|
DefineTransition(s1, s2, a);
|
|
|
}
|
|
|
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
protected bool HasState(HashSet<int> state) {
|
|
|
return m_states.Contains(state);
|
|
|
}
|
|
|
|
|
|
protected void AddState(HashSet<int> state) {
|
|
|
Debug.Assert(!HasState(state));
|
|
|
|
|
|
m_states.DefineSymbol(state);
|
|
|
}
|
|
|
|
|
|
protected int Translate(HashSet<int> state) {
|
|
|
Debug.Assert(HasState(state));
|
|
|
|
|
|
return m_states.Translate(state);
|
|
|
}
|
|
|
|
|
|
protected virtual void SetInitialState(HashSet<int> state) {
|
|
|
m_builder.SetInitialState(Translate(state));
|
|
|
}
|
|
|
|
|
|
protected virtual void MarkFinalState(HashSet<int> state) {
|
|
|
m_builder.MarkFinalState(Translate(state));
|
|
|
}
|
|
|
|
|
|
protected virtual void DefineTransition(HashSet<int> s1, HashSet<int> s2, int ch) {
|
|
|
|
|
|
m_builder.Add(new AutomatonTransition(Translate(s1), Translate(s2), ch));
|
|
|
}
|
|
|
|
|
|
bool IsFinal(IEnumerable<int> state) {
|
|
|
Debug.Assert(state != null);
|
|
|
return state.Any(m_ends.Contains);
|
|
|
}
|
|
|
|
|
|
}
|
|
|
}
|
|
|
|
