mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
85 lines
3.4 KiB
C++
85 lines
3.4 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HPP
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#define SPROUT_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HPP
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#include <cstddef>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/functional/hash/hash_fwd.hpp>
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#include <sprout/math/fpclassify.hpp>
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#include <sprout/math/ldexp.hpp>
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#include <sprout/math/float2_sig_exp.hpp>
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#include <sprout/detail/integer/static_log2.hpp>
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namespace sprout {
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namespace detail {
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inline SPROUT_CONSTEXPR std::size_t
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hash_float_combine(std::size_t seed, std::size_t value) {
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return seed ^ (value + (seed << 6) + (seed >> 2));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_impl_4(T v, int exp, std::size_t seed, std::size_t length, std::size_t i = 0) {
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return i != length ? sprout::detail::float_hash_value_impl_4(
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sprout::ldexp(v - static_cast<T>(static_cast<std::size_t>(v)), sprout::numeric_limits<std::size_t>::digits),
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exp, sprout::detail::hash_float_combine(seed, static_cast<std::size_t>(v)),
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length, i + 1
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)
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: sprout::detail::hash_float_combine(seed, exp)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_impl_3(T v, int exp) {
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return sprout::detail::float_hash_value_impl_4(
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sprout::ldexp(v - static_cast<T>(static_cast<std::size_t>(v)), sprout::numeric_limits<std::size_t>::digits),
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exp, static_cast<std::size_t>(v),
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(sprout::numeric_limits<T>::digits * sprout::detail::static_log2<sprout::numeric_limits<T>::radix>::value + sprout::numeric_limits<std::size_t>::digits - 1)
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/ sprout::numeric_limits<std::size_t>::digits
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);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_impl_2(T v, int exp) {
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return sprout::detail::float_hash_value_impl_3(sprout::ldexp(v, sprout::numeric_limits<std::size_t>::digits), exp);
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}
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template<typename T, typename P>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_impl_1(P const& p) {
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return ((p.first) < 0) ? sprout::detail::float_hash_value_impl_2(
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-p.first, p.second + (sprout::numeric_limits<T>::max_exponent - sprout::numeric_limits<T>::min_exponent)
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)
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: sprout::detail::float_hash_value_impl_2(p.first, p.second)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_impl(T v) {
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return sprout::detail::float_hash_value_impl_1<T>(sprout::math::float2_sig_exp(v));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value_1(T v, int fp) {
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return fp == FP_ZERO ? 0
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: fp == FP_INFINITE ? std::size_t(v > 0 ? -1 : -2)
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: fp == FP_NAN ? std::size_t(-3)
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: sprout::detail::float_hash_value_impl(v)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR std::size_t
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float_hash_value(T v) {
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return sprout::detail::float_hash_value_1(v, sprout::fpclassify(v));
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}
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} // namespace detail
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} // namespace sprout
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#endif // #ifndef SPROUT_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HPP
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