atomtab.h

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// ============================================================================
// Project:     Deductive Database
// Filename:    atomtab.h
// Purpose:     Atom Table (stores set of atoms, similar to Enumeration Type)
// 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) 2010-2017 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 ATOMTAB_INCLUDED
#define ATOMTAB_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 ATOM_INCLUDED
#include "atom.h"
#endif


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

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

static const long ATOMTAB_MAGIC = 0x4154420AL;  // 'ATB\n'

//-----------------------------------------------------------------------------
// ATOMTAB_HASHSIZE: Size of hash table.
//-----------------------------------------------------------------------------

static const int ATOMTAB_HASHSIZE = 251; // Should be prime number

//=============================================================================
// Class for Atom Table (stores set of atoms, similar to Enumeration Type):
//=============================================================================

class atomtab_c {
        public:

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

        // Constructor:
        atomtab_c(str_t tab_name);

        // Destructor:
        ~atomtab_c();

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

        // put: Search current token in atom table, insert if not found.
        int put(str_t name_start, str_t name_end);

        // put: As above, but with '\0'-terminated string:
        int put(str_t atom_name) {
                CHECK_VALID("atomtab_c::put(str_t)");
                CHECK(atom_name != STR_NULL,
                                "atomtab_c::put(str_t): atom_name is null");
                return put(atom_name, atom_name + str_len(atom_name));
        }

        // get: Return atom name for given id:
        str_t get(int id);

        // name: Get name of this atom table (similar to enumeration type).
        str_t name() const {
                CHECK_VALID("atomtab_c::name");
                return Name;
        }

        // num_atoms: Get number of atoms in this table.
        int num_atoms() const {
                CHECK_VALID("atomtab_c::num_atoms");
                return NumAtoms;
        }

        // Return number of memory pages:
        int num_pages() const {
                return MemPool.num_alloc_pages();
        }

//-----------------------------------------------------------------------------
// 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 "ATOMTAB_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:

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

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

        private:

        // Memory Pool for Allocating Storage Pages:
        mpool_c MemPool;

        // Current Memory Page for Storing Atom Objects:
        page_t MemPage;

        // Pointer to next free place in current memory page:
        atom_t MemPtr;

        // Number of free places in current page:
        int MemFree;

        // Hash table:
        atom_t HashTab[ATOMTAB_HASHSIZE];

        // Name of this atom table (domain, enumeration type):
        str_t Name;

        // Current number of atoms (also Id of next atom):
        int NumAtoms;

        // Find atom by id, small (standard) version:
        atom_t AtomArr[ATOMTAB_HASHSIZE];

        // Find atom by id, large version:
        flexarr_c<atom_t> LargeAtomArr;

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

};

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

typedef atomtab_c *atomtab_t;

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

#define ATOMTAB_NULL (static_cast<atomtab_t>(0))

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

#endif