// EdoIdContext.h

#ifndef hes_EdoIdContext_H
#define hes_EdoIdContext_H

// David Adams
// February 2002
//
// An EdoId context is used to assign compact indices to a
// collection of EdoId's. The context (the ID's and their
// indexing) can be converted into a HES IndexVector which
// can be written to a file and later read back to
// restore the ID's and indexing.
//
// Indices are assigned starting with 1.
// Zero is an invalid value.

#include <vector>
#include <iosfwd>
#include "Index.h"
#include "IndexVector.h"

namespace hes {

class EdoId;

class EdoIdContext {

public:  // static functions

  // Version.
  static Index version();

private:  // data

  // Largest allowed index.
  Index m_max_allowed_index;

  // Number of assigned indices.
  Index m_size;

  // Index table.
  vector<EdoId> m_ids;

public:  // functions

  // Default constructor.
  // The largest allowed index is set to 511 (8 bits).
  EdoIdContext();

  // Construct the context from an index vector.
  // The iterator is advanced past the description of the context.
  EdoIdContext(hes::IndexVector::const_iterator& iidv);

  // Return the largest allowed index.
  Index max_allowed_index() const;

  // Return the largest allowed index.
  // Set it to the the provided value if valid.
  // Valid means greater than zero and greater than or equal to the
  // largest assiged value.
  Index max_allowed_index(Index midx =0);

  // Return the largest assigned index.
  Index max_index() const;

  // Return the number of assigned indices.
  Index size() const;

  // Insert an ID with the specified index.
  // Fails if the ID or index are already assigned differently.
  // Returns the index if successful.
  // Returns zero for error.
  Index insert(EdoId id, Index idx);

  // Insert an ID at the first available index.
  // No action is taken if the ID is already present.
  // In either case the corresponding index is returned.
  // Zero is returned in case of error.
  Index insert(EdoId id);

  // Return the index for an EDO.
  Index index(EdoId id) const;

  // Return the EDO ID associated with a compact index.
  EdoId edo_id(Index idx) const;

  // Append a description of this table to an index vector.
  hes::IndexVector& write(hes::IndexVector& idv) const;

};

}  // end namespace 

// Output stream;
std::ostream& operator<<(std::ostream& lhs, const hes::EdoIdContext& rhs);

#endif