rel_n_n.h

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// ============================================================================
// Project:     Deductive Database
// Filename:    rel_n_n.h
// Purpose:     Relation with two non-negative integer columns, index over 1st.
// Last Change: 04.08.2017
// Language:    C++
// EMail:       brass@informatik.uni-halle.de
// WWW:         http://www.informatik.uni-halle.de/~brass/
// Address:     Feldschloesschen 15, D-06120 Halle (Saale), GERMANY
// Copyright:   (c) 2015-2017 by Stefan Brass
// License:     See file "LICENSE" for copying conditions.
// Note:        There is no warranty at all - this code may contain bugs.
// ============================================================================


//=============================================================================
// Include File Frame:
//=============================================================================

#ifndef REL_N_N_INCLUDED
#define REL_N_N_INCLUDED

//=============================================================================
// Used Types and Macros:
//=============================================================================

#ifndef VER_INCLUDED
#include "../base/ver.h"
#endif

#ifndef STR_INCLUDED
#include "../base/str.h"
#endif

#ifndef CHECK_INCLUDED
#include "../base/check.h"
#endif

#ifndef MPOOL_INCLUDED
#include "../mem/mpool.h"
#endif

#ifndef FLEXARR_INCLUDED
#include "../bds/flexarr.h"
#endif

#ifndef REL_INCLUDED
#include "../rel/rel.h"
#endif


//=============================================================================
// Private Constants:
//=============================================================================

//-----------------------------------------------------------------------------
// REL_N_N_MAGIC: Magic number (identifies objects of this class).
//-----------------------------------------------------------------------------

static const long REL_N_N_MAGIC = 0x524E4E0AL;  // 'RNN\n'

//=============================================================================
// Class for Relation with two non-negative integer columns:
//=============================================================================

// Non-negative integers are used as ID for strings and for atoms.
// This version has an index on the first column.
// It is assumed that the first column is dense, so we can basically use
// an array as index. However, it is also assumed that a fixed-size array
// is not sufficient, so the relation can be quite big or of an unknown size.

class rel_n_n_c : public rel_c {
        public:

//-----------------------------------------------------------------------------
// Constructor, Destructor:
//-----------------------------------------------------------------------------

        // Constructor:
        rel_n_n_c(str_t rel_name);

        // Destructor:
        ~rel_n_n_c();

//-----------------------------------------------------------------------------
// (Object) Methods:
//-----------------------------------------------------------------------------

        // insert: Insert tuple into relation.
        bool insert(int c1, int c2);

//-----------------------------------------------------------------------------
// Debugging Support:
//-----------------------------------------------------------------------------

#if     VER_DEBUG
        public:
        // Integrity check:
        str_t   check() const;

        private:
        // Magic number (identifies objects of this class for debugging).
        long    Magic;          // Must be "REL_N_N_MAGIC".
#endif

#if     VER_DUMP
        public:
        // Display data structure:
        void dump(str_t headline = STR_NULL) const;
#endif

//-----------------------------------------------------------------------------
// Copy-constructor and assignment operator are not supported for this class:
//-----------------------------------------------------------------------------

        private:

        rel_n_n_c(const rel_n_n_c& obj);                // Not implemented
        rel_n_n_c& operator=(const rel_n_n_c& obj);     // Not implemented

//-----------------------------------------------------------------------------
// This class works together with the corresponding cursor class:
//-----------------------------------------------------------------------------

        friend class cur_n_n_c;

//-----------------------------------------------------------------------------
// Private Object Members:
//-----------------------------------------------------------------------------

        private:

        // Array indexed by first column, contains second column or list index.
        flexarr_c<int> IndexArr;

        // List nodes to store value sets with >1 element for the 2nd column:
        flexarr_c<int> ValueArr;

//=============================================================================
// End of Class:
//=============================================================================

};

//-----------------------------------------------------------------------------
// Define pointer type:
//-----------------------------------------------------------------------------

typedef rel_n_n_c *rel_n_n_t;

//-----------------------------------------------------------------------------
// Define null pointer:
//-----------------------------------------------------------------------------

#define REL_N_N_NULL (static_cast<rel_n_n_t>(0))

//=============================================================================
// End of Include File:
//=============================================================================

#endif