68482dc584
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@55333 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
97 lines
3.2 KiB
C++
97 lines
3.2 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: wx/meta/movable.h
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// Purpose: Test if a type is movable using memmove() etc.
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// Author: Vaclav Slavik
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// Created: 2008-01-21
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// RCS-ID: $Id$
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// Copyright: (c) 2008 Vaclav Slavik
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_META_MOVABLE_H_
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#define _WX_META_MOVABLE_H_
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#include "wx/defs.h"
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#include "wx/string.h" // for wxIsMovable<wxString> specialization
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// This macro declares something called "value" inside a class declaration.
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//
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// It has to be used because VC6 doesn't handle initialization of the static
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// variables in the class declaration itself while BCC5.82 doesn't understand
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// enums (it compiles the template fine but can't use it later)
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#if defined(__VISUALC__) && !wxCHECK_VISUALC_VERSION(7)
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#define wxDEFINE_TEMPLATE_BOOL_VALUE(val) enum { value = val }
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#else
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#define wxDEFINE_TEMPLATE_BOOL_VALUE(val) static const bool value = val
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#endif
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// Helper to decide if an object of type T is "movable", i.e. if it can be
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// copied to another memory location using memmove() or realloc() C functions.
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// C++ only gurantees that POD types (including primitive types) are
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// movable.
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template<typename T>
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struct wxIsMovable
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{
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wxDEFINE_TEMPLATE_BOOL_VALUE(false);
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};
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// Macro to add wxIsMovable<T> specialization for given type that marks it
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// as movable:
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#define WX_DECLARE_TYPE_MOVABLE(type) \
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template<> struct wxIsMovable<type> \
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{ \
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wxDEFINE_TEMPLATE_BOOL_VALUE(true); \
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};
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WX_DECLARE_TYPE_MOVABLE(bool)
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WX_DECLARE_TYPE_MOVABLE(unsigned char)
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WX_DECLARE_TYPE_MOVABLE(signed char)
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WX_DECLARE_TYPE_MOVABLE(unsigned int)
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WX_DECLARE_TYPE_MOVABLE(signed int)
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WX_DECLARE_TYPE_MOVABLE(unsigned short int)
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WX_DECLARE_TYPE_MOVABLE(signed short int)
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WX_DECLARE_TYPE_MOVABLE(signed long int)
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WX_DECLARE_TYPE_MOVABLE(unsigned long int)
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WX_DECLARE_TYPE_MOVABLE(float)
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WX_DECLARE_TYPE_MOVABLE(double)
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WX_DECLARE_TYPE_MOVABLE(long double)
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#if wxWCHAR_T_IS_REAL_TYPE
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WX_DECLARE_TYPE_MOVABLE(wchar_t)
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#endif
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#ifdef wxLongLong_t
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WX_DECLARE_TYPE_MOVABLE(wxLongLong_t)
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WX_DECLARE_TYPE_MOVABLE(wxULongLong_t)
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#endif
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// Visual C++ 6.0 can't compile partial template specializations and as this is
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// only an optimization, we can live with pointers not being recognized as
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// movable types under VC6
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#if !defined(__VISUALC__) || wxCHECK_VISUALC_VERSION(7)
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// pointers are movable:
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template<typename T>
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struct wxIsMovable<T*>
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{
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static const bool value = true;
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};
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template<typename T>
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struct wxIsMovable<const T*>
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{
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static const bool value = true;
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};
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#endif // !VC++ < 7
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// Our implementation of wxString is written in such way that it's safe to move
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// it around (unless position cache is used which unfortunately breaks this).
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// OTOH, we don't know anything about std::string.
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// (NB: we don't put this into string.h and choose to include wx/string.h from
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// here instead so that rarely-used wxIsMovable<T> code isn't included by
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// everything)
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#if !wxUSE_STL && !wxUSE_STRING_POS_CACHE
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WX_DECLARE_TYPE_MOVABLE(wxString)
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#endif
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#endif // _WX_META_MOVABLE_H_
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