bloom/detail/block_base.hpp

0001 /* Copyright 2025 Joaquin M Lopez Munoz.
0002  * Distributed under the Boost Software License, Version 1.0.
0003  * (See accompanying file LICENSE_1_0.txt or copy at
0004  * http://www.boost.org/LICENSE_1_0.txt)
0005  *
0006  * See https://www.boost.org/libs/bloom for library home page.
0007  */
0008
0009 #ifndef BOOST_BLOOM_DETAIL_BLOCK_BASE_HPP
0010 #define BOOST_BLOOM_DETAIL_BLOCK_BASE_HPP
0011
0012 #include <boost/config.hpp>
0013 #include <boost/bloom/detail/constexpr_bit_width.hpp>
0014 #include <boost/bloom/detail/mulx64.hpp>
0015 #include <boost/bloom/detail/type_traits.hpp>
0016 #include <cstddef>
0017 #include <cstdint>
0018
0019 namespace boost{
0020 namespace bloom{
0021 namespace detail{
0022
0023 #if defined(BOOST_MSVC)
0024 #pragma warning(push)
0025 #pragma warning(disable:4714) /* marked as __forceinline not inlined */
0026 #endif
0027
0028 /* Validates type Block and provides common looping facilities for block
0029  * and multiblock.
0030  */
0031
0032 template<typename Block,std::size_t K>
0033 struct block_base
0034 {
0035   static_assert(
0036     is_unsigned_integral_or_extended_unsigned_integral<Block>::value||
0037     (
0038       is_array_of<
0039         Block,is_unsigned_integral_or_extended_unsigned_integral>::value&&
0040       is_power_of_two<array_size<Block>::value>::value
0041     ),
0042     "Block must be an (extended) unsigned integral type or an array T[N] "
0043     "with T an (extended) unsigned integral type and N a power of two");
0044   static constexpr std::size_t k=K;
0045   static constexpr std::size_t hash_width=sizeof(std::uint64_t)*CHAR_BIT;
0046   static constexpr std::size_t block_width=sizeof(Block)*CHAR_BIT;
0047   static constexpr std::size_t mask=block_width-1;
0048   static constexpr std::size_t shift=constexpr_bit_width(mask);
0049   static constexpr std::size_t rehash_k=(hash_width-shift)/shift;
0050
0051   template<typename F>
0052   static BOOST_FORCEINLINE void loop(std::uint64_t hash,F f)
0053   {
0054     for(std::size_t i=0;i<k/rehash_k;++i){
0055       auto h=hash;
0056       for(std::size_t j=0;j<rehash_k;++j){
0057         h>>=shift;
0058         f(h);
0059       }
0060       hash=detail::mulx64(hash);
0061     }
0062     auto h=hash;
0063     for(std::size_t i=0;i<k%rehash_k;++i){
0064       h>>=shift;
0065       f(h);
0066     }
0067   }
0068
0069   template<typename F>
0070   static BOOST_FORCEINLINE bool loop_while(std::uint64_t hash,F f)
0071   {
0072     for(std::size_t i=0;i<k/rehash_k;++i){
0073       auto h=hash;
0074       for(std::size_t j=0;j<rehash_k;++j){
0075         h>>=shift;
0076         if(!f(h))return false;
0077       }
0078       hash=detail::mulx64(hash);
0079     }
0080     auto h=hash;
0081     for(std::size_t i=0;i<k%rehash_k;++i){
0082       h>>=shift;
0083       if(!f(h))return false;
0084     }
0085     return true;
0086   }
0087 };
0088
0089 #if defined(BOOST_MSVC)
0090 #pragma warning(pop) /* C4714 */
0091 #endif
0092
0093 } /* namespace detail */
0094 } /* namespace bloom */
0095 } /* namespace boost */
0096 #endif