/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*                  This file is part of the class library                   */
/*       SoPlex --- the Sequential object-oriented simPlex.                  */
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/*  Copyright (c) 1996-2026 Zuse Institute Berlin (ZIB)                      */
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/**@file  spxid.h
 * @brief Row and columns Id's \ref soplex::SPxLP "SPxLP".
 */
#ifndef _SPXID_H_
#define _SPXID_H_

#include <ostream>

#include "soplex/datakey.h"

namespace soplex
{
class SPxId;

/**@brief   Ids for LP columns.
 * @ingroup Algo
 *
 *  Class SPxColId provides #DataKey%s for the
 *  column indices of an SPxLP.
 */
class SPxColId : public DataKey
{
public:
   /// default constructor.
   SPxColId()
   {}
   /// copy constructor from DataKey.
   explicit SPxColId(const DataKey& p_key);
   /// copy constructor from SPxId.
   explicit SPxColId(const SPxId& p_key);
};


/**@brief   Ids for LP rows.
 * @ingroup Algo
 *
 *  Class SPxRowId provides #DataKey%s for the row
 *  indices of an SPxLP.
 */
class SPxRowId : public DataKey
{
public:
   /// default constructor.
   SPxRowId()
   {}
   /// copy constructor from DataKey.
   explicit SPxRowId(const DataKey& p_key);
   /// copy constructor from SPxId.
   explicit SPxRowId(const SPxId& p_key);
};

/**@brief   Generic Ids for LP rows or columns.
 * @ingroup Algo
 *
 *  Both \ref soplex::SPxColId "SPxColIds" and \ref soplex::SPxRowId
 *  "SPxRowIds" may be treated uniformly as #SPxId%s:
 *
 *  Rows and columns are numbered from 0 to num()-1 and 0 to dim()-1
 *  respectively.  These numbers may be used to select individual rows or
 *  columns. However, these numbers may change if other rows or columns are
 *  added or removed.
 *
 *  Further, each row or column of the problem matrix is assigned a \ref
 *  soplex::SPxRowId "SPxRowId" or \ref soplex::SPxColId "SPxColId",
 *  respectively. They are be used to select individual rows or columns just
 *  like numbers. In contrast to row and column numbers, ids remain unchanged
 *  for the time a row or column belongs to a SPxLP, no matter what other
 *  rows or columns are added to it or removed from it.
 */
class SPxId : public DataKey
{
   friend std::ostream& operator<<(std::ostream& os, const SPxId& id);

public:

   //--------------------------------
   /**@name Types */
   ///@{
   /// type of the id.
   enum Type
   {
      ROW_ID  = -1,   ///< row identifier.
      INVALID = 0,    ///< invalid id.
      COL_ID  = 1     ///< column identifier.
   };
   ///@}

   //------------------------------------
   /**@name Construction / destruction */
   ///@{
   /// default constructor. Constructs an invalid id.
   SPxId()
      : DataKey(INVALID, -1)
   {}
   /// constructs an id out of a column identifier \p cid.
   explicit SPxId(const SPxColId& cid)
      : DataKey(COL_ID, cid.idx)
   {}
   /// constructs an id out of a row identifier \p rid.
   explicit SPxId(const SPxRowId& rid)
      : DataKey(ROW_ID, rid.idx)
   {}

   /// assignment operator
   SPxId& operator=(const SPxColId& cid)
   {
      DataKey::operator= (cid);
      info = COL_ID;
      return *this;
   }
   /// assignment operator
   SPxId& operator=(const SPxRowId& rid)
   {
      DataKey::operator= (rid);
      info = ROW_ID;
      return *this;
   }
   ///@}

   //--------------------------------
   /**@name Access / modification */
   ///@{
   /// returns the type of the id.
   inline Type type() const
   {
      return info ? (info < 0 ? ROW_ID : COL_ID) : INVALID;
   }
   /// returns TRUE iff the id is a valid column or row identifier.
   inline bool isValid() const
   {
      return info != 0;
   }
   /// makes the id invalid.
   inline void inValidate()
   {
      info = 0;
   }
   /// is id a row id?
   inline bool isSPxRowId() const
   {
      return info < 0;
   }
   /// is id a column id?
   inline bool isSPxColId() const
   {
      return info > 0;
   }
   ///@}

   //------------------------------------
   /**@name Comparison of Ids */
   ///@{
   /// equality operator.
   int operator==(const SPxId& id) const
   {
      return (this == &id);
   }
   /// inequality operator.
   int operator!=(const SPxId& id) const
   {
      return (this != &id);
   }
   /// less then operator
   bool operator<(const SPxId& id) const
   {
      return getIdx() < id.getIdx();
   }
   ///@}
};


} // namespace soplex
#endif // _SPXID_H_
