static private int mapped_charset_size; // reduced charset size
static internal void simplify(Spec spec)
{
computeClasses(spec); // initialize fields.
/*
* now rewrite the NFA using our character class mapping.
*/
for (int i = 0; i < spec.nfa_states.Count; i++)
{
Nfa nfa = (Nfa)spec.nfa_states[i];
if (nfa.GetEdge() == Nfa.EMPTY || nfa.GetEdge() == Nfa.EPSILON)
{
continue; // no change.
}
if (nfa.GetEdge() == Nfa.CCL)
{
CharSet nset = new CharSet();
nset.map(nfa.GetCharSet(), ccls); // map it.
nfa.SetCharSet(nset);
}
else
{ // single character
nfa.SetEdge(ccls[nfa.GetEdge()]); // map it.
}
}
/*
* now update spec with the mapping.
*/
spec.ccls_map = ccls;
spec.dtrans_ncols = mapped_charset_size;
}
/*
* Compute minimum set of character classes needed to disambiguate
* edges. We optimistically assume that every character belongs to
* a single character class, and then incrementally split classes
* as we see edges that require discrimination between characters in
* the class.
*/
static private void computeClasses(Spec spec)
{
original_charset_size = spec.dtrans_ncols;
ccls = new int[original_charset_size]; // initially all zero.
int nextcls = 1;
BitSet clsA = new BitSet();
BitSet clsB = new BitSet();
Hashtable h = new Hashtable();
Console.WriteLine("Working on character classes.");
for (int index = 0; index < spec.nfa_states.Count; index++)
{
Nfa nfa = (Nfa)spec.nfa_states[index];
if (nfa.GetEdge() == Nfa.EMPTY || nfa.GetEdge() == Nfa.EPSILON)
{
continue; // no discriminatory information.
}
clsA.ClearAll();
clsB.ClearAll();
for (int i = 0; i < ccls.Length; i++)
{
if (nfa.GetEdge() == i || // edge labeled with a character
nfa.GetEdge() == Nfa.CCL &&
nfa.GetCharSet().contains(i)) // set of characters
{
clsA.Set(ccls[i], true);
}
else
{
clsB.Set(ccls[i], true);
}
}
/*
* now figure out which character classes we need to split.
*/
clsA.And(clsB); // split the classes which show up on both sides of edge
if (clsA.GetLength() == 0)
{
Console.Write(".");
continue;
}
Console.Write(":");
/*
* and split them.
*/
h.Clear(); // h will map old to new class name
for (int i = 0; i < ccls.Length; i++)
{
if (clsA.Get(ccls[i])) // a split class
{
if (nfa.GetEdge() == i ||
nfa.GetEdge() == Nfa.CCL &&
nfa.GetCharSet().contains(i))
{ // on A side
int split = ccls[i];
if (!h.ContainsKey(split))
{
h.Add(split, nextcls++); // make new class
#if DEBUG
Console.WriteLine("Adding char " + (nextcls - 1) + " split=" + split + " i=" + i);
#endif
}
ccls[i] = (int)h[split];
}
}
}
}
Console.WriteLine();
Console.WriteLine("NFA has " + nextcls + " distinct character classes.");
mapped_charset_size = nextcls;
}
/*
* Function: e_closure
* Description: Alters input set.
*/
public void e_closure()
{
Nfa state = null;
/*
* Debug checks
*/
#if DEBUG
Utility.assert(null != nfa_set);
Utility.assert(null != nfa_bit);
#endif
accept = null;
anchor = Spec.NONE;
accept_index = Utility.INT_MAX;
/*
* Create initial stack.
*/
Stack nfa_stack = new Stack();
int size = nfa_set.Count;
for (int i = 0; i < size; i++)
{
state = (Nfa)nfa_set[i];
#if DEBUG
Utility.assert(nfa_bit.Get(state.GetLabel()));
#endif
nfa_stack.Push(state);
}
/*
* Main loop.
*/
while (nfa_stack.Count > 0)
{
Object o = nfa_stack.Pop();
if (o == null)
{
break;
}
state = (Nfa)o;
#if OLD_DUMP_DEBUG
if (null != state.GetAccept())
{
Console.WriteLine("Looking at accepting state "
+ Int32.ToString(state.GetLabel())
+ " with <"
+ state.GetAccept().action
+ ">");
}
#endif
if (null != state.GetAccept() && state.GetLabel() < accept_index)
{
accept_index = state.GetLabel();
accept = state.GetAccept();
anchor = state.GetAnchor();
#if OLD_DUMP_DEBUG
Console.WriteLine("Found accepting state "
+ Int32.ToString(state.GetLabel())
+ " with <"
+ state.GetAccept().action
+ ">");
#endif
#if DEBUG
Utility.assert(null != accept);
Utility.assert(Spec.NONE == anchor ||
0 != (anchor & Spec.END) ||
0 != (anchor & Spec.START));
#endif
}
if (Nfa.EPSILON == state.GetEdge())
{
if (state.GetNext() != null)
{
if (false == nfa_set.Contains(state.GetNext()))
{
#if DEBUG
Utility.assert(false == nfa_bit.Get(state.GetNext().GetLabel()));
#endif
nfa_bit.Set(state.GetNext().GetLabel(), true);
nfa_set.Add(state.GetNext());
nfa_stack.Push(state.GetNext());
}
}
if (null != state.GetSib())
{
if (false == nfa_set.Contains(state.GetSib()))
{
#if DEBUG
Utility.assert(false == nfa_bit.Get(state.GetSib().GetLabel()));
#endif
nfa_bit.Set(state.GetSib().GetLabel(), true);
nfa_set.Add(state.GetSib());
nfa_stack.Push(state.GetSib());
}
}
}
}
if (null != nfa_set)
{
sort_states();
}
}