263 lines
12 KiB
C++
263 lines
12 KiB
C++
// Copyright (C) 2022 Joaquin M Lopez Munoz.
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// Copyright (C) 2022 Christian Mazakas
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//
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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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#ifndef BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP
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#define BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP
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#include <boost/cstdint.hpp>
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#include <boost/preprocessor/seq/enum.hpp>
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#include <boost/preprocessor/seq/for_each.hpp>
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#include <boost/preprocessor/seq/size.hpp>
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#include <boost/config.hpp>
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#include <climits>
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#include <cstddef>
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#if defined(SIZE_MAX)
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#if ((((SIZE_MAX >> 16) >> 16) >> 16) >> 15) != 0
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#define BOOST_UNORDERED_FCA_HAS_64B_SIZE_T
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#endif
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#elif defined(UINTPTR_MAX) /* used as proxy for std::size_t */
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#if ((((UINTPTR_MAX >> 16) >> 16) >> 16) >> 15) != 0
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#define BOOST_UNORDERED_FCA_HAS_64B_SIZE_T
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#endif
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#endif
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#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) && defined(_MSC_VER)
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#include <intrin.h>
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#endif
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namespace boost {
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namespace unordered {
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namespace detail {
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template <class = void> struct prime_fmod_size
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{
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// Because we compile for C++03, we don't have access to any inline
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// initialization for array data members so the definitions must exist
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// out-of-line. To keep the library header-only, we introduce a dummy
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// template parameter which permits the definition to be included in
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// multiple TUs without conflict.
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//
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static std::size_t sizes[];
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static std::size_t const sizes_len;
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static std::size_t (*positions[])(std::size_t);
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#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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static boost::uint64_t inv_sizes32[];
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static std::size_t const inv_sizes32_len;
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#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
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static inline std::size_t size_index(std::size_t n)
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{
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std::size_t i = 0;
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for (; i < (sizes_len - 1); ++i) {
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if (sizes[i] >= n) {
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break;
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}
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}
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return i;
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}
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static inline std::size_t size(std::size_t size_index)
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{
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return sizes[size_index];
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}
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template <std::size_t Size> static std::size_t modulo(std::size_t hash)
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{
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return hash % Size;
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}
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#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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// We emulate the techniques taken from:
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// Faster Remainder by Direct Computation: Applications to Compilers and
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// Software Libraries
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// https://arxiv.org/abs/1902.01961
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//
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// In essence, use fancy math to directly calculate the remainder (aka
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// modulo) exploiting how compilers transform division
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//
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static inline boost::uint64_t get_remainder(
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boost::uint64_t fractional, boost::uint32_t d)
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{
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#if defined(_MSC_VER)
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// use MSVC intrinsics when available to avoid promotion to 128 bits
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return __umulh(fractional, d);
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#elif defined(BOOST_HAS_INT128)
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return static_cast<boost::uint64_t>(
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((boost::uint128_type)fractional * d) >> 64);
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#else
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// portable implementation in the absence of boost::uint128_type on 64
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// bits, which happens at least in GCC 4.5 and prior
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boost::uint64_t r1 = (fractional & UINT32_MAX) * d;
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boost::uint64_t r2 = (fractional >> 32) * d;
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r2 += r1 >> 32;
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return r2 >> 32;
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#endif /* defined(_MSC_VER) */
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}
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static inline boost::uint32_t fast_modulo(
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boost::uint32_t a, boost::uint64_t M, boost::uint32_t d)
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{
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boost::uint64_t fractional = M * a;
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return (boost::uint32_t)(get_remainder(fractional, d));
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}
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#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
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static inline std::size_t position(
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std::size_t hash, std::size_t size_index)
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{
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#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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std::size_t sizes_under_32bit = inv_sizes32_len;
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if (BOOST_LIKELY(size_index < sizes_under_32bit)) {
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return fast_modulo(
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boost::uint32_t(hash) + boost::uint32_t(hash >> 32),
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inv_sizes32[size_index], boost::uint32_t(sizes[size_index]));
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} else {
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return positions[size_index - sizes_under_32bit](hash);
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}
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#else
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return positions[size_index](hash);
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#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
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}
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}; // prime_fmod_size
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE \
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(13ul)(29ul)(53ul)(97ul)(193ul)(389ul)(769ul)(1543ul)(3079ul)(6151ul)( \
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12289ul)(24593ul)(49157ul)(98317ul)(196613ul)(393241ul)(786433ul)( \
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1572869ul)(3145739ul)(6291469ul)(12582917ul)(25165843ul)(50331653ul)( \
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100663319ul)(201326611ul)(402653189ul)(805306457ul)(1610612741ul)( \
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3221225473ul)
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#if !defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT \
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BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE(4294967291ul)
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
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#else
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT \
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BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE
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// The original sequence here is this:
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// (6442450939ul)
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// (12884901893ul)
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// (25769803751ul)
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// (51539607551ul)
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// (103079215111ul)
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// (206158430209ul)
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// (412316860441ul)
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// (824633720831ul)
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// (1649267441651ul)
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//
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// but this causes problems on versions of mingw where the `long` type is 32
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// bits, even for 64-bit targets. We work around this by replacing the literals
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// with compile-time arithmetic, using bitshifts to reconstruct the number.
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//
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// clang-format off
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT \
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((boost::ulong_long_type(1ul) << 32) + boost::ulong_long_type(2147483643ul)) \
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((boost::ulong_long_type(3ul) << 32) + boost::ulong_long_type(5ul)) \
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((boost::ulong_long_type(5ul) << 32) + boost::ulong_long_type(4294967271ul)) \
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((boost::ulong_long_type(11ul) << 32) + boost::ulong_long_type(4294967295ul)) \
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((boost::ulong_long_type(24ul) << 32) + boost::ulong_long_type(7ul)) \
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((boost::ulong_long_type(48ul) << 32) + boost::ulong_long_type(1ul)) \
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((boost::ulong_long_type(96ul) << 32) + boost::ulong_long_type(25ul)) \
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((boost::ulong_long_type(191ul) << 32) + boost::ulong_long_type(4294967295ul)) \
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((boost::ulong_long_type(383ul) << 32) + boost::ulong_long_type(4294967283ul))
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// clang-format on
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#endif /* BOOST_UNORDERED_FCA_HAS_64B_SIZE_T */
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#define BOOST_UNORDERED_PRIME_FMOD_SIZES \
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BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
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template <class T>
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std::size_t prime_fmod_size<T>::sizes[] = {
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BOOST_PP_SEQ_ENUM(BOOST_UNORDERED_PRIME_FMOD_SIZES)};
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template <class T>
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std::size_t const prime_fmod_size<T>::sizes_len = BOOST_PP_SEQ_SIZE(
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BOOST_UNORDERED_PRIME_FMOD_SIZES);
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// Similarly here, we have to re-express the integer initialization using
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// arithmetic such that each literal can fit in a 32-bit value.
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//
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#if defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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// clang-format off
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template <class T>
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boost::uint64_t prime_fmod_size<T>::inv_sizes32[] = {
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(boost::ulong_long_type(330382099ul) << 32) + boost::ulong_long_type(2973438898ul) /* = 1418980313362273202 */,
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(boost::ulong_long_type(148102320ul) << 32) + boost::ulong_long_type(2369637129ul) /* = 636094623231363849 */,
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(boost::ulong_long_type(81037118ul) << 32) + boost::ulong_long_type(3403558990ul) /* = 348051774975651918 */,
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(boost::ulong_long_type(44278013ul) << 32) + boost::ulong_long_type(1549730468ul) /* = 190172619316593316 */,
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(boost::ulong_long_type(22253716ul) << 32) + boost::ulong_long_type(2403401389ul) /* = 95578984837873325 */,
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(boost::ulong_long_type(11041047ul) << 32) + boost::ulong_long_type(143533612ul) /* = 47420935922132524 */,
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(boost::ulong_long_type(5585133ul) << 32) + boost::ulong_long_type(106117528ul) /* = 23987963684927896 */,
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(boost::ulong_long_type(2783517ul) << 32) + boost::ulong_long_type(1572687312ul) /* = 11955116055547344 */,
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(boost::ulong_long_type(1394922ul) << 32) + boost::ulong_long_type(3428720239ul) /* = 5991147799191151 */,
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(boost::ulong_long_type(698255ul) << 32) + boost::ulong_long_type(552319807ul) /* = 2998982941588287 */,
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(boost::ulong_long_type(349496ul) << 32) + boost::ulong_long_type(3827689953ul) /* = 1501077717772769 */,
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(boost::ulong_long_type(174641ul) << 32) + boost::ulong_long_type(3699438549ul) /* = 750081082979285 */,
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(boost::ulong_long_type(87372ul) << 32) + boost::ulong_long_type(1912757574ul) /* = 375261795343686 */,
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(boost::ulong_long_type(43684ul) << 32) + boost::ulong_long_type(3821029929ul) /* = 187625172388393 */,
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(boost::ulong_long_type(21844ul) << 32) + boost::ulong_long_type(3340590800ul) /* = 93822606204624 */,
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(boost::ulong_long_type(10921ul) << 32) + boost::ulong_long_type(4175852267ul) /* = 46909513691883 */,
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(boost::ulong_long_type(5461ul) << 32) + boost::ulong_long_type(1401829642ul) /* = 23456218233098 */,
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(boost::ulong_long_type(2730ul) << 32) + boost::ulong_long_type(2826028947ul) /* = 11728086747027 */,
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(boost::ulong_long_type(1365ul) << 32) + boost::ulong_long_type(1411150351ul) /* = 5864041509391 */,
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(boost::ulong_long_type(682ul) << 32) + boost::ulong_long_type(2857253105ul) /* = 2932024948977 */,
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(boost::ulong_long_type(341ul) << 32) + boost::ulong_long_type(1431073224ul) /* = 1466014921160 */,
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(boost::ulong_long_type(170ul) << 32) + boost::ulong_long_type(2862758116ul) /* = 733007198436 */,
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(boost::ulong_long_type(85ul) << 32) + boost::ulong_long_type(1431619357ul) /* = 366503839517 */,
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(boost::ulong_long_type(42ul) << 32) + boost::ulong_long_type(2863269661ul) /* = 183251896093 */,
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(boost::ulong_long_type(21ul) << 32) + boost::ulong_long_type(1431647119ul) /* = 91625960335 */,
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(boost::ulong_long_type(10ul) << 32) + boost::ulong_long_type(2863310962ul) /* = 45812983922 */,
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(boost::ulong_long_type(5ul) << 32) + boost::ulong_long_type(1431653234ul) /* = 22906489714 */,
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(boost::ulong_long_type(2ul) << 32) + boost::ulong_long_type(2863311496ul) /* = 11453246088 */,
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(boost::ulong_long_type(1ul) << 32) + boost::ulong_long_type(1431655764ul) /* = 5726623060 */,
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};
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// clang-format on
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template <class T>
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std::size_t const
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prime_fmod_size<T>::inv_sizes32_len = sizeof(inv_sizes32) /
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sizeof(inv_sizes32[0]);
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#endif /* defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T) */
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#define BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT(z, _, n) \
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prime_fmod_size<T>::template modulo<n>,
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template <class T>
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std::size_t (*prime_fmod_size<T>::positions[])(std::size_t) = {
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#if !defined(BOOST_UNORDERED_FCA_HAS_64B_SIZE_T)
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BOOST_PP_SEQ_FOR_EACH(BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT, ~,
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BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT)
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#else
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BOOST_PP_SEQ_FOR_EACH(BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT, ~,
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BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT)
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#endif
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};
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#undef BOOST_UNORDERED_PRIME_FMOD_POSITIONS_ELEMENT
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#undef BOOST_UNORDERED_PRIME_FMOD_SIZES
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#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_64BIT
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#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT
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#undef BOOST_UNORDERED_PRIME_FMOD_SIZES_32BIT_INCOMPLETE
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} // namespace detail
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} // namespace unordered
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} // namespace boost
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#endif // BOOST_UNORDERED_DETAIL_PRIME_FMOD_HPP
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