/// <summary>
/// Dumps an <see cref="FST{T}"/> to a GraphViz's <c>dot</c> language description
/// for visualization. Example of use:
///
/// <code>
/// using (TextWriter sw = new StreamWriter("out.dot"))
/// {
/// Util.ToDot(fst, sw, true, true);
/// }
/// </code>
///
/// and then, from command line:
///
/// <code>
/// dot -Tpng -o out.png out.dot
/// </code>
///
/// <para/>
/// Note: larger FSTs (a few thousand nodes) won't even
/// render, don't bother. If the FST is > 2.1 GB in size
/// then this method will throw strange exceptions.
/// <para/>
/// See also <a href="http://www.graphviz.org/">http://www.graphviz.org/</a>.
/// </summary>
/// <param name="sameRank">
/// If <c>true</c>, the resulting <c>dot</c> file will try
/// to order states in layers of breadth-first traversal. This may
/// mess up arcs, but makes the output FST's structure a bit clearer.
/// </param>
/// <param name="labelStates">
/// If <c>true</c> states will have labels equal to their offsets in their
/// binary format. Expands the graph considerably.
/// </param>
public static void ToDot <T>(FST <T> fst, TextWriter @out, bool sameRank, bool labelStates)
{
const string expandedNodeColor = "blue";
// this is the start arc in the automaton (from the epsilon state to the first state
// with outgoing transitions.
FST.Arc <T> startArc = fst.GetFirstArc(new FST.Arc <T>());
// A queue of transitions to consider for the next level.
IList <FST.Arc <T> > thisLevelQueue = new List <FST.Arc <T> >();
// A queue of transitions to consider when processing the next level.
IList <FST.Arc <T> > nextLevelQueue = new List <FST.Arc <T> >();
nextLevelQueue.Add(startArc);
//System.out.println("toDot: startArc: " + startArc);
// A list of states on the same level (for ranking).
IList <int?> sameLevelStates = new List <int?>();
// A bitset of already seen states (target offset).
BitArray seen = new BitArray(32);
seen.SafeSet((int)startArc.Target, true);
// Shape for states.
const string stateShape = "circle";
const string finalStateShape = "doublecircle";
// Emit DOT prologue.
@out.Write("digraph FST {\n");
@out.Write(" rankdir = LR; splines=true; concentrate=true; ordering=out; ranksep=2.5; \n");
if (!labelStates)
{
@out.Write(" node [shape=circle, width=.2, height=.2, style=filled]\n");
}
EmitDotState(@out, "initial", "point", "white", "");
T NO_OUTPUT = fst.Outputs.NoOutput;
var r = fst.GetBytesReader();
// final FST.Arc<T> scratchArc = new FST.Arc<>();
{
string stateColor;
if (fst.IsExpandedTarget(startArc, r))
{
stateColor = expandedNodeColor;
}
else
{
stateColor = null;
}
bool isFinal;
T finalOutput;
if (startArc.IsFinal)
{
isFinal = true;
finalOutput = startArc.NextFinalOutput.Equals(NO_OUTPUT) ? default(T) : startArc.NextFinalOutput;
}
else
{
isFinal = false;
finalOutput = default(T);
}
EmitDotState(@out, Convert.ToString(startArc.Target), isFinal ? finalStateShape : stateShape, stateColor, finalOutput == null ? "" : fst.Outputs.OutputToString(finalOutput));
}
@out.Write(" initial -> " + startArc.Target + "\n");
int level = 0;
while (nextLevelQueue.Count > 0)
{
// we could double buffer here, but it doesn't matter probably.
//System.out.println("next level=" + level);
thisLevelQueue.AddRange(nextLevelQueue);
nextLevelQueue.Clear();
level++;
@out.Write("\n // Transitions and states at level: " + level + "\n");
while (thisLevelQueue.Count > 0)
{
FST.Arc <T> arc = thisLevelQueue[thisLevelQueue.Count - 1];
thisLevelQueue.RemoveAt(thisLevelQueue.Count - 1);
//System.out.println(" pop: " + arc);
if (FST <T> .TargetHasArcs(arc))
{
// scan all target arcs
//System.out.println(" readFirstTarget...");
long node = arc.Target;
fst.ReadFirstRealTargetArc(arc.Target, arc, r);
//System.out.println(" firstTarget: " + arc);
while (true)
{
//System.out.println(" cycle arc=" + arc);
// Emit the unseen state and add it to the queue for the next level.
if (arc.Target >= 0 && !seen.SafeGet((int)arc.Target))
{
/*
* boolean isFinal = false;
* T finalOutput = null;
* fst.readFirstTargetArc(arc, scratchArc);
* if (scratchArc.isFinal() && fst.targetHasArcs(scratchArc)) {
* // target is final
* isFinal = true;
* finalOutput = scratchArc.output == NO_OUTPUT ? null : scratchArc.output;
* System.out.println("dot hit final label=" + (char) scratchArc.label);
* }
*/
string stateColor;
if (fst.IsExpandedTarget(arc, r))
{
stateColor = expandedNodeColor;
}
else
{
stateColor = null;
}
string finalOutput;
if (arc.NextFinalOutput != null && !arc.NextFinalOutput.Equals(NO_OUTPUT))
{
finalOutput = fst.Outputs.OutputToString(arc.NextFinalOutput);
}
else
{
finalOutput = "";
}
EmitDotState(@out, Convert.ToString(arc.Target), stateShape, stateColor, finalOutput);
// To see the node address, use this instead:
//emitDotState(out, Integer.toString(arc.target), stateShape, stateColor, String.valueOf(arc.target));
seen.SafeSet((int)arc.Target, true);
nextLevelQueue.Add((new FST.Arc <T>()).CopyFrom(arc));
sameLevelStates.Add((int)arc.Target);
}
string outs;
if (!arc.Output.Equals(NO_OUTPUT))
{
outs = "/" + fst.Outputs.OutputToString(arc.Output);
}
else
{
outs = "";
}
if (!FST <T> .TargetHasArcs(arc) && arc.IsFinal && !arc.NextFinalOutput.Equals(NO_OUTPUT))
{
// Tricky special case: sometimes, due to
// pruning, the builder can [sillily] produce
// an FST with an arc into the final end state
// (-1) but also with a next final output; in
// this case we pull that output up onto this
// arc
outs = outs + "/[" + fst.Outputs.OutputToString(arc.NextFinalOutput) + "]";
}
string arcColor;
if (arc.Flag(FST.BIT_TARGET_NEXT))
{
arcColor = "red";
}
else
{
arcColor = "black";
}
Debug.Assert(arc.Label != FST.END_LABEL);
@out.Write(" " + node + " -> " + arc.Target + " [label=\"" + PrintableLabel(arc.Label) + outs + "\"" + (arc.IsFinal ? " style=\"bold\"" : "") + " color=\"" + arcColor + "\"]\n");
// Break the loop if we're on the last arc of this state.
if (arc.IsLast)
{
//System.out.println(" break");
break;
}
fst.ReadNextRealArc(arc, r);
}
}
}
// Emit state ranking information.
if (sameRank && sameLevelStates.Count > 1)
{
@out.Write(" {rank=same; ");
foreach (int state in sameLevelStates)
{
@out.Write(state + "; ");
}
@out.Write(" }\n");
}
sameLevelStates.Clear();
}
// Emit terminating state (always there anyway).
@out.Write(" -1 [style=filled, color=black, shape=doublecircle, label=\"\"]\n\n");
@out.Write(" {rank=sink; -1 }\n");
@out.Write("}\n");
@out.Flush();
}