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

// MUD Programming 
// Ron Penton 
// (C)2003 
// DatabasePointer.cpp - A "smart" pointer class that looks up items in a database 
//  
//  
 
#include "DatabasePointer.h" 
#include "ItemDatabase.h" 
#include "PlayerDatabase.h" 
#include "RoomDatabase.h" 
#include "EnemyDatabase.h" 
 
 
 
// ====================================================== 
// This is the DATABASEPOINTERIMPL 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 DATABASEPOINTERIMPL( pt, t, db )                \ 
t& pt::operator*()                                      \ 
{                                                       \ 
    return db::get( m_id );                             \ 
}                                                       \ 
                                                        \ 
t* pt::operator->()                                     \ 
{                                                       \ 
    return &( db::get( m_id ) );                        \ 
}                                                       \ 
                                                        \ 
pt::operator t*()                                       \ 
{                                                       \ 
    if( m_id == 0 )                                     \ 
        return 0;                                       \ 
    return &( db::get( m_id ) );                        \ 
} 
 
 
 
namespace SimpleMUD 
{ 
 
DATABASEPOINTERIMPL( player, Player, PlayerDatabase ) 
DATABASEPOINTERIMPL( item, Item, ItemDatabase ) 
DATABASEPOINTERIMPL( room, Room, RoomDatabase ) 
DATABASEPOINTERIMPL( enemy, Enemy, EnemyDatabase) 
DATABASEPOINTERIMPL( enemytemplate, EnemyTemplate, EnemyTemplateDatabase ) 
 
} // end namespace SimpleMUD