wxWidgets/include/wx/meta/movable.h
2010-06-14 15:12:37 +00:00

46 lines
1.7 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: wx/meta/movable.h
// Purpose: Test if a type is movable using memmove() etc.
// Author: Vaclav Slavik
// Created: 2008-01-21
// RCS-ID: $Id$
// Copyright: (c) 2008 Vaclav Slavik
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_META_MOVABLE_H_
#define _WX_META_MOVABLE_H_
#include "wx/meta/pod.h"
#include "wx/string.h" // for wxIsMovable<wxString> specialization
// Helper to decide if an object of type T is "movable", i.e. if it can be
// copied to another memory location using memmove() or realloc() C functions.
// C++ only gurantees that POD types (including primitive types) are
// movable.
template<typename T>
struct wxIsMovable
{
wxDEFINE_TEMPLATE_BOOL_VALUE(wxIsPod<T>::value);
};
// Macro to add wxIsMovable<T> specialization for given type that marks it
// as movable:
#define WX_DECLARE_TYPE_MOVABLE(type) \
template<> struct wxIsMovable<type> \
{ \
wxDEFINE_TEMPLATE_BOOL_VALUE(true); \
};
// Our implementation of wxString is written in such way that it's safe to move
// it around (unless position cache is used which unfortunately breaks this).
// OTOH, we don't know anything about std::string.
// (NB: we don't put this into string.h and choose to include wx/string.h from
// here instead so that rarely-used wxIsMovable<T> code isn't included by
// everything)
#if !wxUSE_STL && !wxUSE_STRING_POS_CACHE
WX_DECLARE_TYPE_MOVABLE(wxString)
#endif
#endif // _WX_META_MOVABLE_H_