/// <summary>
/// Create an instance of the enumerator for a given node.
/// </summary>
/// <param name="fsa">The automaton to iterate over.</param>
/// <param name="node">The starting node's identifier (can be the <see cref="FSA.GetRootNode()"/>.</param>
public ByteSequenceEnumerator(FSA fsa, int node)
{
this.bufferWrapper = ByteBuffer.Wrap(buffer);
this.fsa = fsa;
if (fsa.GetFirstArc(node) != 0)
{
RestartFrom(node);
}
}
/// <summary>
/// Same as <see cref="Match(byte[], int, int, int)"/>, but allows passing
/// a reusable <see cref="MatchResult"/> object so that no intermediate garbage is
/// produced.
/// </summary>
/// <param name="reuse">The <see cref="MatchResult"/> to reuse.</param>
/// <param name="sequence">Input sequence to look for in the automaton.</param>
/// <param name="start">Start index in the sequence array.</param>
/// <param name="length">Length of the byte sequence, must be at least 1.</param>
/// <param name="node">The node to start traversal from, typically the root node (<see cref="FSA.GetRootNode()"/>).</param>
/// <returns>The same object as <paramref name="reuse"/>, but with updated match <see cref="MatchResult.Kind"/>
/// and other relevant fields.</returns>
public MatchResult Match(MatchResult reuse, byte[] sequence, int start, int length, int node)
{
if (node == 0)
{
reuse.Reset(MatchResult.NoMatch, start, node);
return(reuse);
}
FSA fsa = this.fsa;
int end = start + length;
for (int i = start; i < end; i++)
{
int arc = fsa.GetArc(node, sequence[i]);
if (arc != 0)
{
if (i + 1 == end && fsa.IsArcFinal(arc))
{
/* The automaton has an exact match of the input sequence. */
reuse.Reset(MatchResult.ExactMatch, i, node);
return(reuse);
}
if (fsa.IsArcTerminal(arc))
{
/* The automaton contains a prefix of the input sequence. */
reuse.Reset(MatchResult.AutomatonHasPrefix, i + 1, node);
return(reuse);
}
// Make a transition along the arc.
node = fsa.GetEndNode(arc);
}
else
{
if (i > start)
{
reuse.Reset(MatchResult.AutomatonHasPrefix, i, node);
}
else
{
reuse.Reset(MatchResult.NoMatch, i, node);
}
return(reuse);
}
}
/* The sequence is a prefix of at least one sequence in the automaton. */
reuse.Reset(MatchResult.SequenceIsAPrefix, 0, node);
return(reuse);
}
/// <summary>
/// Traversals of the given FSA.
/// </summary>
/// <param name="fsa">The target automaton for traversals.</param>
public FSATraversal(FSA fsa)
{
this.fsa = fsa;
}
public ByteSequenceEnumerable(FSA fsa, int node)
{
this.fsa = fsa;
this.node = node;
}
/// <summary>
/// Create an instance of the enumerator iterating over all automaton sequences.
/// </summary>
/// <param name="fsa">The automaton to iterate over.</param>
public ByteSequenceEnumerator(FSA fsa)
: this(fsa, fsa.GetRootNode())
{
}