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1 | ///////////////////////////////////////////////////////////////////////////// | |
2 | // Name: wx/meta/movable.h | |
3 | // Purpose: Test if a type is movable using memmove() etc. | |
4 | // Author: Vaclav Slavik | |
5 | // Created: 2008-01-21 | |
6 | // Copyright: (c) 2008 Vaclav Slavik | |
7 | // Licence: wxWindows licence | |
8 | ///////////////////////////////////////////////////////////////////////////// | |
9 | ||
10 | #ifndef _WX_META_MOVABLE_H_ | |
11 | #define _WX_META_MOVABLE_H_ | |
12 | ||
13 | #include "wx/meta/pod.h" | |
14 | #include "wx/string.h" // for wxIsMovable<wxString> specialization | |
15 | ||
16 | // Helper to decide if an object of type T is "movable", i.e. if it can be | |
17 | // copied to another memory location using memmove() or realloc() C functions. | |
18 | // C++ only gurantees that POD types (including primitive types) are | |
19 | // movable. | |
20 | template<typename T> | |
21 | struct wxIsMovable | |
22 | { | |
23 | wxDEFINE_TEMPLATE_BOOL_VALUE(wxIsPod<T>::value); | |
24 | }; | |
25 | ||
26 | // Macro to add wxIsMovable<T> specialization for given type that marks it | |
27 | // as movable: | |
28 | #define WX_DECLARE_TYPE_MOVABLE(type) \ | |
29 | template<> struct wxIsMovable<type> \ | |
30 | { \ | |
31 | wxDEFINE_TEMPLATE_BOOL_VALUE(true); \ | |
32 | }; | |
33 | ||
34 | // Our implementation of wxString is written in such way that it's safe to move | |
35 | // it around (unless position cache is used which unfortunately breaks this). | |
36 | // OTOH, we don't know anything about std::string. | |
37 | // (NB: we don't put this into string.h and choose to include wx/string.h from | |
38 | // here instead so that rarely-used wxIsMovable<T> code isn't included by | |
39 | // everything) | |
40 | #if !wxUSE_STD_STRING && !wxUSE_STRING_POS_CACHE | |
41 | WX_DECLARE_TYPE_MOVABLE(wxString) | |
42 | #endif | |
43 | ||
44 | #endif // _WX_META_MOVABLE_H_ |