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 #ifndef INCLUDED_LOTUSWORDPRO_SOURCE_FILTER_CLONE_HXX
  11 #define INCLUDED_LOTUSWORDPRO_SOURCE_FILTER_CLONE_HXX
  12
  13 namespace detail
  14 {
  15
  16 template<typename T>
  17 struct has_clone
  18 {
  19     template<typename U, U x>
  20     struct test;
  21
  22     typedef char yes;
  23     typedef struct { char a[2]; } no;
  24
  25     template<typename U>
  26     static yes& check_sig(U*, test<U* (U::*)() const, &U::clone>* = nullptr);
  27     template<typename U>
  28     static no& check_sig(...);
  29
  30     enum
  31     {
  32         value = sizeof(check_sig<T>(0)) == sizeof(yes)
  33     };
  34 };
  35
  36 template<typename T, bool HasClone>
  37 struct cloner
  38 {
  39     static T* clone(T* const other)
  40     {
  41         return new T(*other);
  42     }
  43 };
  44
  45 template<typename T>
  46 struct cloner<T, true>
  47 {
  48     static T* clone(T* const other)
  49     {
  50         return other->clone();
  51     }
  52 };
  53
  54 }
  55
  56 /** Creates a new copy of the passed object.
  57     If other is 0, just returns 0. Otherwise, if other has function
  58     named clone with signature T* (T::*)() const, the function is called.
  59     Otherwise, copy constructor is used.
  60
  61     @returns 0 or newly allocated object
  62  */
  63 template<typename T>
  64 T* clone(T* const other)
  65 {
  66     return other ? ::detail::cloner<T, ::detail::has_clone<T>::value>::clone(other) : 0;
  67 }
  68
  69 #endif // INCLUDED_LOTUSWORDPRO_SOURCE_FILTER_CLONE_HXX
  70
  71 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */