mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
82 lines
3.2 KiB
C++
82 lines
3.2 KiB
C++
|
#ifndef SPROUT_INTEGER_BIT_REVERSE_HPP
|
||
|
|
#define SPROUT_INTEGER_BIT_REVERSE_HPP
|
||
|
|
|
||
|
|
#include <climits>
|
||
|
|
#include <cstddef>
|
||
|
|
#include <stdexcept>
|
||
|
|
#include <type_traits>
|
||
|
|
#include <sprout/config.hpp>
|
||
|
|
|
||
|
|
namespace sprout {
|
||
|
|
namespace detail {
|
||
|
|
SPROUT_STATIC_CONSTEXPR unsigned char bit_rev_8_table[std::size_t(UCHAR_MAX) + 1] = {
|
||
|
|
0, 128, 64, 192, 32, 160, 96, 224, 16, 144, 80, 208, 48, 176, 112, 240, 8, 136, 72, 200,
|
||
|
|
40, 168, 104, 232, 24, 152, 88, 216, 56, 184, 120, 248, 4, 132, 68, 196, 36, 164, 100, 228,
|
||
|
|
20, 148, 84, 212, 52, 180, 116, 244, 12, 140, 76, 204, 44, 172, 108, 236, 28, 156, 92, 220,
|
||
|
|
60, 188, 124, 252, 2, 130, 66, 194, 34, 162, 98, 226, 18, 146, 82, 210, 50, 178, 114, 242,
|
||
|
|
10, 138, 74, 202, 42, 170, 106, 234, 26, 154, 90, 218, 58, 186, 122, 250, 6, 134, 70, 198,
|
||
|
|
38, 166, 102, 230, 22, 150, 86, 214, 54, 182, 118, 246, 14, 142, 78, 206, 46, 174, 110, 238,
|
||
|
|
30, 158, 94, 222, 62, 190, 126, 254, 1, 129, 65, 193, 33, 161, 97, 225, 17, 145, 81, 209,
|
||
|
|
49, 177, 113, 241, 9, 137, 73, 201, 41, 169, 105, 233, 25, 153, 89, 217, 57, 185, 121, 249,
|
||
|
|
5, 133, 69, 197, 37, 165, 101, 229, 21, 149, 85, 213, 53, 181, 117, 245, 13, 141, 77, 205,
|
||
|
|
45, 173, 109, 237, 29, 157, 93, 221, 61, 189, 125, 253, 3, 131, 67, 195, 35, 163, 99, 227,
|
||
|
|
19, 147, 83, 211, 51, 179, 115, 243, 11, 139, 75, 203, 43, 171, 107, 235, 27, 155, 91, 219,
|
||
|
|
59, 187, 123, 251, 7, 135, 71, 199, 39, 167, 103, 231, 23, 151, 87, 215, 55, 183, 119, 247,
|
||
|
|
15, 143, 79, 207, 47, 175, 111, 239, 31, 159, 95, 223, 63, 191, 127, 255
|
||
|
|
};
|
||
|
|
template<std::size_t Size>
|
||
|
|
struct bit_rev {
|
||
|
|
private:
|
||
|
|
SPROUT_STATIC_CONSTEXPR std::size_t next_size = Size / 2;
|
||
|
|
SPROUT_STATIC_CONSTEXPR std::size_t shift_bits = next_size * CHAR_BIT;
|
||
|
|
public:
|
||
|
|
template <typename IntType>
|
||
|
|
SPROUT_CONSTEXPR IntType operator()(IntType x) const {
|
||
|
|
return (sprout::detail::bit_rev<next_size>().template operator()(x) << shift_bits)
|
||
|
|
| (sprout::detail::bit_rev<next_size>().template operator()(x >> shift_bits))
|
||
|
|
;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
template<>
|
||
|
|
struct bit_rev<1> {
|
||
|
|
public:
|
||
|
|
template<typename IntType>
|
||
|
|
SPROUT_CONSTEXPR IntType operator()(IntType x) const {
|
||
|
|
return sprout::detail::bit_rev_8_table[static_cast<unsigned char>(x & UCHAR_MAX)];
|
||
|
|
}
|
||
|
|
};
|
||
|
|
} // namespace detail
|
||
|
|
//
|
||
|
|
// bit_reverse
|
||
|
|
//
|
||
|
|
template<typename IntType>
|
||
|
|
SPROUT_CONSTEXPR typename std::enable_if<
|
||
|
|
std::is_integral<IntType>::value,
|
||
|
|
IntType
|
||
|
|
>::type bit_reverse(IntType x) {
|
||
|
|
typedef typename std::make_unsigned<IntType>::type unsigned_type;
|
||
|
|
return static_cast<IntType>(
|
||
|
|
sprout::detail::bit_rev<sizeof(IntType)>().template operator()<unsigned_type>(x)
|
||
|
|
);
|
||
|
|
}
|
||
|
|
//
|
||
|
|
// bit_reverse_in
|
||
|
|
//
|
||
|
|
template <typename IntType>
|
||
|
|
SPROUT_CONSTEXPR typename std::enable_if<
|
||
|
|
std::is_integral<IntType>::value,
|
||
|
|
IntType
|
||
|
|
>::type bit_reverse_in(IntType x, std::size_t length) {
|
||
|
|
typedef typename std::make_unsigned<IntType>::type unsigned_type;
|
||
|
|
return length <= sizeof(IntType) * CHAR_BIT
|
||
|
|
? static_cast<IntType>(
|
||
|
|
sprout::detail::bit_rev<sizeof(IntType)>().template operator()<unsigned_type>(x)
|
||
|
|
>> (sizeof(IntType) * CHAR_BIT - length)
|
||
|
|
)
|
||
|
|
: throw std::invalid_argument("invalid length")
|
||
|
|
;
|
||
|
|
}
|
||
|
|
} // namespace sprout
|
||
|
|
|
||
|
|
#endif // #ifndef SPROUT_INTEGER_BIT_REVERSE_HPP
|