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Sprout/sprout/detail/integer/integer_mask.hpp
2012-05-22 01:06:13 +09:00

65 lines
2.2 KiB
C++

#ifndef SPROUT_DETAIL_INTEGER_INTEGER_MASK_HPP
#define SPROUT_DETAIL_INTEGER_INTEGER_MASK_HPP
#include <cstddef>
#include <climits>
#include <limits>
#include <sprout/config.hpp>
#include <sprout/detail/integer.hpp>
namespace sprout {
namespace detail {
template<std::size_t Bits>
struct high_bit_mask_t {
public:
typedef typename sprout::detail::uint_t<(Bits + 1)>::least least;
typedef typename sprout::detail::uint_t<(Bits + 1)>::fast fast;
public:
SPROUT_STATIC_CONSTEXPR least high_bit = least(1u) << Bits;
SPROUT_STATIC_CONSTEXPR fast high_bit_fast = fast(1u) << Bits;
SPROUT_STATIC_CONSTEXPR std::size_t bit_position = Bits;
};
template<std::size_t Bits>
struct low_bits_mask_t {
public:
typedef typename sprout::detail::uint_t<Bits>::least least;
typedef typename sprout::detail::uint_t<Bits>::fast fast;
public:
SPROUT_STATIC_CONSTEXPR least sig_bits = ~(~(least(0u)) << Bits);
SPROUT_STATIC_CONSTEXPR fast sig_bits_fast = fast(sig_bits);
SPROUT_STATIC_CONSTEXPR std::size_t bit_count = Bits;
};
#define SPROUT_LOW_BITS_MASK_SPECIALIZE(Type) \
template<> \
struct low_bits_mask_t<std::numeric_limits<Type>::digits> { \
public: \
typedef std::numeric_limits<Type> limits_type; \
typedef typename sprout::detail::uint_t<limits_type::digits>::least least; \
typedef typename sprout::detail::uint_t<limits_type::digits>::fast fast; \
public: \
SPROUT_STATIC_CONSTEXPR least sig_bits = ~(least(0u)); \
SPROUT_STATIC_CONSTEXPR fast sig_bits_fast = fast(sig_bits); \
SPROUT_STATIC_CONSTEXPR std::size_t bit_count = limits_type::digits; \
}
SPROUT_LOW_BITS_MASK_SPECIALIZE(unsigned char);
#if USHRT_MAX > UCHAR_MAX
SPROUT_LOW_BITS_MASK_SPECIALIZE(unsigned short);
#endif
#if UINT_MAX > USHRT_MAX
SPROUT_LOW_BITS_MASK_SPECIALIZE(unsigned int);
#endif
#if ULONG_MAX > UINT_MAX
SPROUT_LOW_BITS_MASK_SPECIALIZE(unsigned long);
#endif
#if ULLONG_MAX > ULONG_MAX
SPROUT_LOW_BITS_MASK_SPECIALIZE(unsigned long long);
#endif
#undef SPROUT_LOW_BITS_MASK_SPECIALIZE
} // namespace detail
} // namespace sprout
#endif // #ifndef SPROUT_DETAIL_INTEGER_INTEGER_MASK_HPP