/// <summary>
/// Creates a new NonterminalTransition from <i>source</i> to <i>destination</i> under <i>transitionSymbol</i>.
/// The transition still has to be added to the Transitions of <i>source</i> and <i>source</i> should
/// be added to AccessingStates of <i>destination</i>.
/// </summary>
/// <param name="source">The State where the transition originates.</param>
/// <param name="destination">The State to which the transition leads.</param>
/// <param name="transitionSymbol">The transition symbol's code.</param>
/// <param name="nonterminalTransitionNumber">The ordinal number of the nonterminal transition.</param>
public NonterminalTransition(State source, State destination, int transitionSymbol, int nonterminalTransitionNumber)
{
this.source = source;
this.destination = destination;
this.transitionSymbol = transitionSymbol;
this.nonterminalTransitionNumber = nonterminalTransitionNumber;
}
/// <summary>
/// Creates a new TerminalTransition from <i>source</i> to <i>destination</i> under <i>transitionSymbol</i>.
/// The transition still has to be added to the Transitions of <i>source</i> and <i>source</i> should
/// be added to AccessingStates of <i>destination</i>.
/// </summary>
/// <param name="source">The State where the transition originates.</param>
/// <param name="destination">The State to which the transition leads.</param>
/// <param name="transitionSymbol">The transition symbol's code.</param>
public TerminalTransition(State source, State destination, int transitionSymbol)
{
this.source = source;
this.destination = destination;
this.transitionSymbol = transitionSymbol;
}
private void printSymbolExplanations(State state, Item finalItem, BitVectorSet conflictSymbols, TextWriter writer)
{
//Vyrazíme ze všech vrcholů (vrcholy jsou tady neterminální hrany automatu)
//ležících v lookback(state, finalItem), které mají ve follow množině nějaký konfliktní symbol.
//Prohledáváním do hloubkyv grafu relace 'includes' najdeme nejbližší vrcholy, které mají v Read
//množinách dohromady všechny hledané konfliktní symboly. Posléze vyrazíme z těchto nalezených vrcholů,
//tentokrát po hranách relace 'reads' a budeme hledat nejbližší vrcholy, které mají v Direct Read množinách
//dohromady všechny hledané symboly. Z posledně nalezených vrcholů už jsme vždy schopni vystopovat
//cestu zpět přes reads, includes a lookback hrany až k původnímu konfliktnímu itemu.
//pole předků a značky u navštívených vrcholů pro oba grafy
NonterminalTransition[] includesPredecessors = new NonterminalTransition[numNonterminalTransitions];
bool[] includesExplored = new bool[numNonterminalTransitions];
NonterminalTransition[] readsPredecessors = new NonterminalTransition[numNonterminalTransitions];
bool[] readsExplored = new bool[numNonterminalTransitions];
BitVectorSet symbolsLeftToExplain = new BitVectorSet(conflictSymbols);
//BFS fronty pro oba průchody obou grafů
Queue<NonterminalTransition> includesTransitions = new Queue<NonterminalTransition>();
Queue<NonterminalTransition> readsTransitions = new Queue<NonterminalTransition>();
//vrcholy, které mají v DR množinách konfliktní symboly
List<NonterminalTransition> rootTransitions = new List<NonterminalTransition>();
//procházení po lookback hranách
foreach (NonterminalTransition trans in lookback(state, finalItem))
{
if (!follow[getTransNumber(trans)].IsDisjointWith(conflictSymbols))
{
includesTransitions.Enqueue(trans);
includesExplored[getTransNumber(trans)] = true;
}
}
//průchod přes includes hrany
while ((includesTransitions.Count > 0) && (!symbolsLeftToExplain.IsEmpty()))
{
NonterminalTransition trans = includesTransitions.Dequeue();
BitVectorSet readSet = read[getTransNumber(trans)];
if (!readSet.IsDisjointWith(symbolsLeftToExplain))
{
BitVectorSet symbolsJustExplained = readSet.GetIntersectionWith(symbolsLeftToExplain);
symbolsLeftToExplain -= symbolsJustExplained;
readsTransitions.Enqueue(trans);
readsExplored[getTransNumber(trans)] = true;
}
foreach (NonterminalTransition next in includes.GetNeighboursFor(trans))
if (!includesExplored[getTransNumber(next)])
{
includesPredecessors[getTransNumber(next)] = trans;
includesExplored[getTransNumber(next)] = true;
includesTransitions.Enqueue(next);
}
}
//reset hledaných symbolů a průchod přes reads hrany
symbolsLeftToExplain = new BitVectorSet(conflictSymbols);
while ((readsTransitions.Count > 0) && (!symbolsLeftToExplain.IsEmpty()))
{
NonterminalTransition trans = readsTransitions.Dequeue();
BitVectorSet DRSet = initDR(trans);
if (!DRSet.IsDisjointWith(symbolsLeftToExplain))
{
BitVectorSet symbolsJustExplained = DRSet.GetIntersectionWith(symbolsLeftToExplain);
symbolsLeftToExplain -= symbolsJustExplained;
rootTransitions.Add(trans);
}
foreach (NonterminalTransition next in reads.GetNeighboursFor(trans))
if (!readsExplored[getTransNumber(next)])
{
readsPredecessors[getTransNumber(next)] = trans;
readsExplored[getTransNumber(next)] = true;
readsTransitions.Enqueue(next);
}
}
//teď už jen vystopujeme všechny potřebné cesty z neterminální hrany, která obsahovala konfliktní
//symbol ve své DR množině, až k itemu, kde tímto symbolem přispěla a způsobila konflikt
foreach (NonterminalTransition root in rootTransitions)
{
Stack<NonterminalTransition> readsPath = new Stack<NonterminalTransition>();
Stack<NonterminalTransition> includesPath = new Stack<NonterminalTransition>();
NonterminalTransition trans = root;
while (readsPredecessors[getTransNumber(trans)] != null)
{
readsPath.Push(trans);
trans = readsPredecessors[getTransNumber(trans)];
}
while (includesPredecessors[getTransNumber(trans)] != null)
{
includesPath.Push(trans);
trans = includesPredecessors[getTransNumber(trans)];
}
writer.Write("({0}, ", state.StateNumber);
printItemHTML(finalItem, conflictSymbols, writer);
writer.Write(") <b><i>lookback</i></b> (<a href=\"#State{0}\">{0}</a>, {1})", trans.Source.StateNumber,
getSymbolPrintName(trans.TransitionSymbol));
foreach (NonterminalTransition transition in includesPath)
writer.Write(" <b><i>includes</i></b> (<a href=\"#State{0}\">{0}</a>, {1})", transition.Source.StateNumber,
getSymbolPrintName(transition.TransitionSymbol));
foreach (NonterminalTransition transition in readsPath)
writer.Write(" <b><i>reads</i></b> (<a href=\"#State{0}\">{0}</a>, {1})", transition.Source.StateNumber,
getSymbolPrintName(transition.TransitionSymbol));
writer.Write(" and {");
StringBuilder explainedSymbolsString = new StringBuilder();
foreach (int explainedSymbol in initDR(root).GetIntersectionWith(conflictSymbols))
explainedSymbolsString.AppendFormat("<span style=\"color:red\">{0}</span>, ", getSymbolPrintName(explainedSymbol));
explainedSymbolsString.Remove(explainedSymbolsString.Length - 2, 2);
writer.Write(explainedSymbolsString.ToString());
writer.Write("} ⊂ <b>DR</b>(" + root.Source.StateNumber.ToString() + ", " + getSymbolPrintName(root.TransitionSymbol) + ")");
writer.WriteLine("<br>");
}
}
