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// Copyright (c) 2006-2018 Maxim Khizhinsky
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef CDSLIB_DETAILS_TYPE_PADDING_H
#define CDSLIB_DETAILS_TYPE_PADDING_H
namespace cds { namespace details {
//@cond none
template <typename T, int Align, int Modulo>
struct type_padding_helper: public T
{
enum {
value = Modulo
};
char _[Align - Modulo] ; // padding
using T::T;
};
template <typename T, int Align>
struct type_padding_helper<T, Align, 0>: public T
{
enum {
value = 0
};
using T::T;
};
//@endcond
/// Automatic alignment type \p T to \p AlignFactor
/**
The class adds appropriate bytes to type T that the following condition is true:
\code
sizeof( type_padding<T,AlignFactor>::type ) % AlignFactor == 0
\endcode
It is guaranteed that count of padding bytes no more than AlignFactor - 1.
\b Applicability: type \p T must not have constructors another that default ctor.
For example, \p T may be any POD type.
*/
template <typename T, int AlignFactor>
class type_padding {
public:
/// Align factor
enum {
align_factor = AlignFactor <= 0 ? 1 : AlignFactor
};
/// Result type
typedef type_padding_helper<T, align_factor, sizeof(T) % align_factor> type;
/// Padding constant
enum {
value = type::value
};
};
}} // namespace cds::details
#endif // #ifndef CDSLIB_DETAILS_TYPE_PADDING_H
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