www.pudn.com > SimpleMUD.rar > DatabasePointer.h

// MUD Programming 
// Ron Penton 
// (C)2003 
// DatabasePointer.h - A "smart" pointer class that looks up items in a database 
//  
//  
 
#ifndef SIMPLEMUDDATABASEPOINTER_H 
#define SIMPLEMUDDATABASEPOINTER_H 
 
#include  
#include "Entity.h" 
 
using std::ostream; 
using std::istream; 
 
 
// ====================================================== 
// This is the DATABASEPOINTER macro, which defines a  
// database pointer proxy class. Why macros? Because 
// I've learned that templates + circular dependencies 
// are a VERY BAD combination when dealing with simple 
// one pass compilers, like C++. 
// ====================================================== 
#define DATABASEPOINTER( pt, t )                        \ 
class t;                                                \ 
class pt                                                \ 
{                                                       \ 
public:                                                 \ 
    pt( entityid p_id = 0 )                             \ 
        : m_id( p_id ) {}                               \ 
                                                        \ 
    pt& operator=( entityid p_id )                      \ 
    {                                                   \ 
        m_id = p_id;                                    \ 
        return *this;                                   \ 
    }                                                   \ 
                                                        \ 
    operator entityid()                                 \ 
    {                                                   \ 
        return m_id;                                    \ 
    }                                                   \ 
                                                        \ 
    t& operator*();                                     \ 
    t* operator->();                                    \ 
    operator t*();                                      \ 
                                                        \ 
    entityid m_id;                                      \ 
};                                                      \ 
                                                        \ 
inline ostream& operator<<( ostream& s, const pt& p )   \ 
{                                                       \ 
    s << p.m_id;                                        \ 
    return s;                                           \ 
}                                                       \ 
                                                        \ 
inline istream& operator>>( istream& s, pt& p )         \ 
{                                                       \ 
    s >> p.m_id;                                        \ 
    return s;                                           \ 
} 
 
 
 
 
namespace SimpleMUD 
{ 
 
DATABASEPOINTER( player, Player ) 
DATABASEPOINTER( item, Item ) 
DATABASEPOINTER( room, Room ) 
DATABASEPOINTER( enemy, Enemy ) 
DATABASEPOINTER( enemytemplate, EnemyTemplate ) 
 
} // end namespace SimpleMUD 
 
#endif