www.pudn.com > Loki.rar > LokiTypeInfo.h

//////////////////////////////////////////////////////////////////////////////// 
// The Loki Library 
// Copyright (c) 2001 by Andrei Alexandrescu 
// This code accompanies the book: 
// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design  
//     Patterns Applied". Copyright (c) 2001. Addison-Wesley. 
// Permission to use, copy, modify, distribute and sell this software for any  
//     purpose is hereby granted without fee, provided that the above copyright  
//     notice appear in all copies and that both that copyright notice and this  
//     permission notice appear in supporting documentation. 
// The author or Addison-Welsey Longman make no representations about the  
//     suitability of this software for any purpose. It is provided "as is"  
//     without express or implied warranty. 
//////////////////////////////////////////////////////////////////////////////// 
 
// Last update: May 19, 2002 
 
#ifndef TYPEINFO_INC_ 
#define TYPEINFO_INC_ 
 
#include  
#include  
#include "Typelist.h" 
 
namespace Loki 
{ 
//////////////////////////////////////////////////////////////////////////////// 
// class TypeInfo 
// Purpose: offer a first-class, comparable wrapper over std::type_info 
//////////////////////////////////////////////////////////////////////////////// 
 
    class TypeInfo 
    { 
    public: 
        // Constructors 
        TypeInfo(); // needed for containers 
        TypeInfo(const std::type_info&); // non-explicit 
 
        // Access for the wrapped std::type_info 
        const std::type_info& Get() const; 
        // Compatibility functions 
        bool before(const TypeInfo& rhs) const; 
        const char* name() const; 
 
    private: 
        const std::type_info* pInfo_; 
    }; 
     
// Implementation 
     
    inline TypeInfo::TypeInfo() 
    { 
        class Nil {}; 
        pInfo_ = &typeid(Nil); 
        assert(pInfo_); 
    } 
     
    inline TypeInfo::TypeInfo(const std::type_info& ti) 
    : pInfo_(&ti) 
    { assert(pInfo_); } 
     
    inline bool TypeInfo::before(const TypeInfo& rhs) const 
    { 
        assert(pInfo_); 
        return pInfo_->before(*rhs.pInfo_) != 0; 
    } 
 
    inline const std::type_info& TypeInfo::Get() const 
    { 
        assert(pInfo_); 
        return *pInfo_; 
    } 
     
    inline const char* TypeInfo::name() const 
    { 
        assert(pInfo_); 
        return pInfo_->name(); 
    } 
 
// Comparison operators 
     
    inline bool operator==(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return (lhs.Get() == rhs.Get()) != 0; } 
 
    inline bool operator<(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return lhs.before(rhs); } 
 
    inline bool operator!=(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return !(lhs == rhs); }     
     
    inline bool operator>(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return rhs < lhs; } 
     
    inline bool operator<=(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return !(lhs > rhs); } 
      
    inline bool operator>=(const TypeInfo& lhs, const TypeInfo& rhs) 
    { return !(lhs < rhs); } 
} 
 
//////////////////////////////////////////////////////////////////////////////// 
// Change log: 
// June 20, 2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!! 
// May  10, 2002: ported by Rani Sharoni to VC7 (RTM - 9466) 
//////////////////////////////////////////////////////////////////////////////// 
 
#endif // TYPEINFO_INC_