lotuswordpro/source/filter/clone.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 namespace detail
  11 {
  12
  13 template<typename T>
  14 struct has_clone
  15 {
  16     template<typename U, U x>
  17     struct test;
  18
  19     typedef char yes;
  20     typedef struct { char a[2]; } no;
  21
  22     template<typename U>
  23     static yes& check_sig(U*, test<U* (U::*)() const, &U::clone>* = 0);
  24     template<typename U>
  25     static no& check_sig(...);
  26
  27     enum
  28     {
  29         value = sizeof(check_sig<T>(0)) == sizeof(yes)
  30     };
  31 };
  32
  33 template<typename T, bool HasClone>
  34 struct cloner
  35 {
  36     static T* clone(T* const other)
  37     {
  38         return new T(*other);
  39     }
  40 };
  41
  42 template<typename T>
  43 struct cloner<T, true>
  44 {
  45     static T* clone(T* const other)
  46     {
  47         return other->clone();
  48     }
  49 };
  50
  51 }
  52
  53 /** Creates a new copy of the passed object.
  54     If other is 0, just returns 0. Otherwise, if other has function
  55     named clone with signature T* (T::*)() const, the function is called.
  56     Otherwise, copy constructor is used.
  57
  58     @returns 0 or newly allocated object
  59  */
  60 template<typename T>
  61 T* clone(T* const other)
  62 {
  63     return other ? ::detail::cloner<T, ::detail::has_clone<T>::value>::clone(other) : 0;
  64 }
  65
  66 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */