cwprint.h

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// $Header$
//
// Copyright (C) 2000 - 2004, by
//
// Carlo Wood, Run on IRC <carlo@alinoe.com>
// RSA-1024 0x624ACAD5 1997-01-26                    Sign & Encrypt
// Fingerprint16 = 32 EC A7 B6 AC DB 65 A6  F6 F6 55 DD 1C DC FF 61
//
// This file may be distributed under the terms of the Q Public License
// version 1.0 as appearing in the file LICENSE.QPL included in the
// packaging of this file.
//
 
#ifndef LIBCWD_CWPRINT_H
#define LIBCWD_CWPRINT_H
 
namespace libcwd {
 
//===================================================================================================
// cwprint
//
 
template<class PRINTABLE_OBJECT>
  class cwprint_tct {
  private:
    PRINTABLE_OBJECT const& M_printable_object;
  public:
    cwprint_tct(PRINTABLE_OBJECT const& printable_object) : M_printable_object(printable_object) { }
 
    friend
    inline      // Must be defined inside the class declaration in order to avoid a compiler warning.
    std::ostream&
    operator<<(std::ostream& os, cwprint_tct<PRINTABLE_OBJECT> const& __cwprint)
    {
      __cwprint.M_printable_object.print_on(os);
      return os;
    }
  };
 
template<class T>
  inline
  cwprint_tct<T>
  cwprint(T const& printable_object)
  {
    return cwprint_tct<T>(printable_object);
  }
 
//===================================================================================================
// cwprint_using
//
 
template<class PRINTABLE_OBJECT>
  class cwprint_using_tct {
    typedef void (PRINTABLE_OBJECT::* print_on_method_t)(std::ostream&) const;
  private:
    PRINTABLE_OBJECT const& M_printable_object;
    print_on_method_t M_print_on_method;
  public:
    cwprint_using_tct(PRINTABLE_OBJECT const& printable_object, print_on_method_t print_on_method) :
        M_printable_object(printable_object), M_print_on_method(print_on_method) { }
 
    friend
    inline      // Must be defined inside the class declaration in order to avoid a compiler warning.
    std::ostream&
    operator<<(std::ostream& os, cwprint_using_tct<PRINTABLE_OBJECT> __cwprint_using)
    {
      (__cwprint_using.M_printable_object.*__cwprint_using.M_print_on_method)(os);
      return os;
    }
  };
 
// The use of T_OR_BASE_OF_T as extra parameter is a compiler bug around.
// Without it you'd run into bug
// http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=38
// when `print_on_method' is a method of the base class of T.
 
template<class T, class T_OR_BASE_OF_T>
  inline
  cwprint_using_tct<T_OR_BASE_OF_T>
  cwprint_using(T const& printable_object, void (T_OR_BASE_OF_T::*print_on_method)(std::ostream&) const)
  {
    T_OR_BASE_OF_T const& base(printable_object);
    return cwprint_using_tct<T_OR_BASE_OF_T>(base, print_on_method);
  }
 
} // namespace libcwd
 
#endif // LIBCWD_CWPRINT_H