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/** \file
 * \brief NFA graph state squashing analysis.
 */
#ifndef NG_SQUASH_H
#define NG_SQUASH_H

#include "ng_holder.h"
#include "som/som.h"
#include "ue2common.h"

#include <unordered_map>
#include <boost/dynamic_bitset.hpp>

namespace ue2 {

class NGHolder;
class ReportManager;

/**
 * Dynamically-sized bitset, as an NFA can have an arbitrary number of states.
 */
using NFAStateSet = boost::dynamic_bitset<>;

/**
 * Populates the squash mask for each vertex (i.e. the set of states to be left
 * on during squashing).
 *
 * The NFAStateSet in the output map is indexed by vertex_index.
 */
std::unordered_map<NFAVertex, NFAStateSet>
findSquashers(const NGHolder &g, som_type som = SOM_NONE);

/** Filters out squash states intended only for use in DFA construction. */
void filterSquashers(const NGHolder &g,
                     std::unordered_map<NFAVertex, NFAStateSet> &squash);

/** Populates squash masks for states that can be switched off by highlander
 * (single match) reporters. */
std::unordered_map<NFAVertex, NFAStateSet>
findHighlanderSquashers(const NGHolder &g, const ReportManager &rm);

} // namespace ue2

#endif // NG_SQUASH_H