ClickHouse/contrib/libpoco/Foundation/include/Poco/MetaProgramming.h

147 lines
2.0 KiB
C++

//
// MetaProgramming.h
//
// $Id: //poco/1.4/Foundation/include/Poco/MetaProgramming.h#1 $
//
// Library: Foundation
// Package: Core
// Module: MetaProgramming
//
// Common definitions useful for Meta Template Programming
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_MetaProgramming_INCLUDED
#define Foundation_MetaProgramming_INCLUDED
#include "Poco/Foundation.h"
namespace Poco {
template <typename T>
struct IsReference
/// Use this struct to determine if a template type is a reference.
{
enum
{
VALUE = 0
};
};
template <typename T>
struct IsReference<T&>
{
enum
{
VALUE = 1
};
};
template <typename T>
struct IsReference<const T&>
{
enum
{
VALUE = 1
};
};
template <typename T>
struct IsConst
/// Use this struct to determine if a template type is a const type.
{
enum
{
VALUE = 0
};
};
template <typename T>
struct IsConst<const T&>
{
enum
{
VALUE = 1
};
};
template <typename T>
struct IsConst<const T>
{
enum
{
VALUE = 1
};
};
template <typename T, int i>
struct IsConst<const T[i]>
/// Specialization for const char arrays
{
enum
{
VALUE = 1
};
};
template <typename T>
struct TypeWrapper
/// Use the type wrapper if you want to decouple constness and references from template types.
{
typedef T TYPE;
typedef const T CONSTTYPE;
typedef T& REFTYPE;
typedef const T& CONSTREFTYPE;
};
template <typename T>
struct TypeWrapper<const T>
{
typedef T TYPE;
typedef const T CONSTTYPE;
typedef T& REFTYPE;
typedef const T& CONSTREFTYPE;
};
template <typename T>
struct TypeWrapper<const T&>
{
typedef T TYPE;
typedef const T CONSTTYPE;
typedef T& REFTYPE;
typedef const T& CONSTREFTYPE;
};
template <typename T>
struct TypeWrapper<T&>
{
typedef T TYPE;
typedef const T CONSTTYPE;
typedef T& REFTYPE;
typedef const T& CONSTREFTYPE;
};
} // namespace Poco
#endif // Foundation_MetaProgramming_INCLUDED