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/////////////////////////////////////////////////////////////////////////////
// Name: wx/meta/implicitconversion.h
// Purpose: Determine resulting type from implicit conversion
// Author: Vaclav Slavik
// Created: 2010-10-22
// Copyright: (c) 2010 Vaclav Slavik
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_META_IMPLICITCONVERSION_H_
#define _WX_META_IMPLICITCONVERSION_H_
#include "wx/defs.h"
#include "wx/meta/if.h"
// C++ hierarchy of data types is:
//
// Long double (highest)
// Double
// Float
// Unsigned long int
// Long int
// Unsigned int
// Int (lowest)
//
// Types lower in the hierarchy are converted into ones higher up if both are
// involved e.g. in arithmetic expressions.
namespace wxPrivate
{
template<typename T>
struct TypeHierarchy
{
// consider unknown types (e.g. objects, pointers) to be of highest
// level, always convert to them if they occur
static const int level = 9999;
};
#define WX_TYPE_HIERARCHY_LEVEL(level_num, type) \
template<> struct TypeHierarchy<type> \
{ \
static const int level = level_num; \
}
WX_TYPE_HIERARCHY_LEVEL( 1, char);
WX_TYPE_HIERARCHY_LEVEL( 2, unsigned char);
WX_TYPE_HIERARCHY_LEVEL( 3, short);
WX_TYPE_HIERARCHY_LEVEL( 4, unsigned short);
WX_TYPE_HIERARCHY_LEVEL( 5, int);
WX_TYPE_HIERARCHY_LEVEL( 6, unsigned int);
WX_TYPE_HIERARCHY_LEVEL( 7, long);
WX_TYPE_HIERARCHY_LEVEL( 8, unsigned long);
#ifdef wxLongLong_t
WX_TYPE_HIERARCHY_LEVEL( 9, wxLongLong_t);
WX_TYPE_HIERARCHY_LEVEL(10, wxULongLong_t);
#endif
WX_TYPE_HIERARCHY_LEVEL(11, float);
WX_TYPE_HIERARCHY_LEVEL(12, double);
WX_TYPE_HIERARCHY_LEVEL(13, long double);
#if wxWCHAR_T_IS_REAL_TYPE
#if SIZEOF_WCHAR_T == SIZEOF_SHORT
template<> struct TypeHierarchy<wchar_t> : public TypeHierarchy<short> {};
#elif SIZEOF_WCHAR_T == SIZEOF_INT
template<> struct TypeHierarchy<wchar_t> : public TypeHierarchy<int> {};
#elif SIZEOF_WCHAR_T == SIZEOF_LONG
template<> struct TypeHierarchy<wchar_t> : public TypeHierarchy<long> {};
#else
#error "weird wchar_t size, please update this code"
#endif
#endif
#undef WX_TYPE_HIERARCHY_LEVEL
} // namespace wxPrivate
// Helper to determine resulting type of implicit conversion in
// an expression with two arithmetic types.
template<typename T1, typename T2>
struct wxImplicitConversionType
{
typedef typename wxIf
<
// if T2 is "higher" type, convert to it
(int)(wxPrivate::TypeHierarchy<T1>::level) < (int)(wxPrivate::TypeHierarchy<T2>::level),
T2,
// otherwise use T1
T1
>::value
value;
};
template<typename T1, typename T2, typename T3>
struct wxImplicitConversionType3 : public wxImplicitConversionType<
T1,
typename wxImplicitConversionType<T2,T3>::value>
{
};
#endif // _WX_META_IMPLICITCONVERSION_H_
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