Sprout/sprout/numeric/fft/fixed/bitrev_table.hpp
2015-01-10 19:13:57 +09:00

69 lines
2.4 KiB
C++

/*=============================================================================
Copyright (c) 2011-2015 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_NUMERIC_FFT_FIXED_BITREV_TABLE_HPP
#define SPROUT_NUMERIC_FFT_FIXED_BITREV_TABLE_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/index_tuple/metafunction.hpp>
#include <sprout/container/traits.hpp>
#include <sprout/container/functions.hpp>
#include <sprout/container/indexes.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/algorithm/fixed/results.hpp>
#include <sprout/bit/bit_reverse.hpp>
#include <sprout/bit/bit_length.hpp>
namespace sprout {
namespace fixed {
namespace detail {
template<typename Container, sprout::index_t... Indexes>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
bitrev_table_impl(
Container const& cont, sprout::index_tuple<Indexes...>,
std::size_t bit_length,
typename sprout::container_traits<Container>::difference_type offset,
typename sprout::container_traits<Container>::size_type size
)
{
return sprout::remake<Container>(
cont,
sprout::size(cont),
(Indexes >= offset && Indexes < offset + size
? sprout::bit_reverse_in(
static_cast<typename sprout::container_traits<Container>::value_type>(Indexes - offset),
bit_length
)
: *sprout::next(sprout::internal_begin(cont), Indexes)
)...
);
}
} // namespace detail
//
// bitrev_table
//
template<typename Container>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
bitrev_table(Container const& cont) {
return sprout::fixed::detail::bitrev_table_impl(
cont,
sprout::container_indexes<Container>::make(),
sprout::empty(cont) ? 0
: sprout::bit_length(sprout::size(cont) - 1)
,
sprout::internal_begin_offset(cont),
sprout::size(cont)
);
}
} // namespace fixed
using sprout::fixed::bitrev_table;
} // namespace sprout
#endif // #ifndef SPROUT_NUMERIC_FFT_FIXED_BITREV_TABLE_HPP