EIC code displayed by LXR master/​include/​boost/​hash2/​xxhash.hpp	Source navigation Diff markup Identifier search General search
	Version: master test Revert   Change

File indexing completed on 2025-09-17 08:33:45

 #ifndef BOOST_HASH2_XXHASH_HPP_INCLUDED
 #define BOOST_HASH2_XXHASH_HPP_INCLUDED
 
 // Copyright 2017, 2018 Peter Dimov.
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 //
 // xxHash, https://cyan4973.github.io/xxHash/
 
 #include <boost/hash2/detail/read.hpp>
 #include <boost/hash2/detail/rot.hpp>
 #include <boost/hash2/detail/memset.hpp>
 #include <boost/hash2/detail/memcpy.hpp>
 #include <boost/assert.hpp>
 #include <boost/config.hpp>
 #include <cstdint>
 #include <cstring>
 #include <cstddef>
 
 #if defined(BOOST_MSVC) && BOOST_MSVC < 1920
 # pragma warning(push)
 # pragma warning(disable: 4307) // '+': integral constant overflow
 #endif
 
 namespace boost
 {
 namespace hash2
 {
 
 class xxhash_32
 {
 private:
 
     static constexpr std::uint32_t P1 = 2654435761U;
     static constexpr std::uint32_t P2 = 2246822519U;
     static constexpr std::uint32_t P3 = 3266489917U;
     static constexpr std::uint32_t P4 =  668265263U;
     static constexpr std::uint32_t P5 =  374761393U;
 
 private:
 
     std::uint32_t v1_ = P1 + P2;
     std::uint32_t v2_ = P2;
     std::uint32_t v3_ = 0;
     std::uint32_t v4_ = static_cast<std::uint32_t>( 0 ) - P1;
 
     unsigned char buffer_[ 16 ] = {};
     std::size_t m_ = 0; // == n_ % 16
 
     std::size_t n_ = 0;
 
 private:
 
     BOOST_CXX14_CONSTEXPR void init( std::uint32_t seed )
     {
         v1_ = seed + P1 + P2;
         v2_ = seed + P2;
         v3_ = seed;
         v4_ = seed - P1;
     }
 
     BOOST_CXX14_CONSTEXPR static std::uint32_t round( std::uint32_t seed, std::uint32_t input )
     {
         seed += input * P2;
         seed = detail::rotl( seed, 13 );
         seed *= P1;
         return seed;
     }
 
     BOOST_CXX14_CONSTEXPR void update_( unsigned char const * p, std::size_t k )
     {
         std::uint32_t v1 = v1_;
         std::uint32_t v2 = v2_;
         std::uint32_t v3 = v3_;
         std::uint32_t v4 = v4_;
 
         for( std::size_t i = 0; i < k; ++i, p += 16 )
         {
             v1 = round( v1, detail::read32le( p +  0 ) );
             v2 = round( v2, detail::read32le( p +  4 ) );
             v3 = round( v3, detail::read32le( p +  8 ) );
             v4 = round( v4, detail::read32le( p + 12 ) );
         }
 
         v1_ = v1; 
         v2_ = v2; 
         v3_ = v3; 
         v4_ = v4; 
     }
 
 public:
 
     using result_type = std::uint32_t;
 
     xxhash_32() = default;
 
     BOOST_CXX14_CONSTEXPR explicit xxhash_32( std::uint64_t seed )
     {
         std::uint32_t s0 = static_cast<std::uint32_t>( seed );
         std::uint32_t s1 = static_cast<std::uint32_t>( seed >> 32 );
 
         init( s0 );
 
         if( s1 != 0 )
         {
             v1_ = round( v1_, s1 );
             v2_ = round( v2_, s1 );
             v3_ = round( v3_, s1 );
             v4_ = round( v4_, s1 );
         }
     }
 
     BOOST_CXX14_CONSTEXPR xxhash_32( unsigned char const * p, std::size_t n )
     {
         if( n != 0 )
         {
             update( p, n );
             result();
         }
     }
 
     xxhash_32( void const * p, std::size_t n ): xxhash_32( static_cast<unsigned char const*>( p ), n )
     {
     }
 
     BOOST_CXX14_CONSTEXPR void update( unsigned char const* p, std::size_t n )
     {
         BOOST_ASSERT( m_ == n_ % 16 );
 
         if( n == 0 ) return;
 
         n_ += n;
 
         if( m_ > 0 )
         {
             std::size_t k = 16 - m_;
 
             if( n < k )
             {
                 k = n;
             }
 
             detail::memcpy( buffer_ + m_, p, k );
 
             p += k;
             n -= k;
             m_ += k;
 
             if( m_ < 16 ) return;
 
             BOOST_ASSERT( m_ == 16 );
 
             update_( buffer_, 1 );
             m_ = 0;
         }
 
         BOOST_ASSERT( m_ == 0 );
 
         {
             std::size_t k = n / 16;
 
             update_( p, k );
 
             p += 16 * k;
             n -= 16 * k;
         }
 
         BOOST_ASSERT( n < 16 );
 
         if( n > 0 )
         {
             detail::memcpy( buffer_, p, n );
             m_ = n;
         }
 
         BOOST_ASSERT( m_ == n_ % 16 );
     }
 
     void update( void const* pv, std::size_t n )
     {
         unsigned char const* p = static_cast<unsigned char const*>( pv );
         update( p, n );
     }
 
     BOOST_CXX14_CONSTEXPR std::uint32_t result()
     {
         BOOST_ASSERT( m_ == n_ % 16 );
 
         std::uint32_t h = 0;
 
         if( n_ >= 16 )
         {
             h = detail::rotl( v1_, 1 ) + detail::rotl( v2_, 7 ) + detail::rotl( v3_, 12 ) + detail::rotl( v4_, 18 );
         }
         else
         {
             h = v3_ + P5;
         }
 
         h += static_cast<std::uint32_t>( n_ );
 
         unsigned char const * p = buffer_;
 
         std::size_t m = m_;
 
         while( m >= 4 )
         {
             h += detail::read32le( p ) * P3;
             h = detail::rotl( h, 17 ) * P4;
 
             p += 4;
             m -= 4;
         }
 
         while( m > 0 )
         {
             h += p[0] * P5;
             h = detail::rotl( h, 11 ) * P1;
 
             ++p;
             --m;
         }
 
         n_ += 16 - m_;
         m_ = 0;
 
         // clear buffered plaintext
         detail::memset( buffer_, 0, 16 );
 
         // perturb state
         v1_ += h;
         v2_ += h;
         v3_ -= h;
         v4_ -= h;
 
         // apply final mix
         h ^= h >> 15;
         h *= P2;
         h ^= h >> 13;
         h *= P3;
         h ^= h >> 16;
 
         return h;
     }
 };
 
 class xxhash_64
 {
 private:
 
     static constexpr std::uint64_t P1 = 11400714785074694791ULL;
     static constexpr std::uint64_t P2 = 14029467366897019727ULL;
     static constexpr std::uint64_t P3 =  1609587929392839161ULL;
     static constexpr std::uint64_t P4 =  9650029242287828579ULL;
     static constexpr std::uint64_t P5 =  2870177450012600261ULL;
 
 private:
 
     std::uint64_t v1_ = P1 + P2;
     std::uint64_t v2_ = P2;
     std::uint64_t v3_ = 0;
     std::uint64_t v4_ = static_cast<std::uint64_t>( 0 ) - P1;
 
     unsigned char buffer_[ 32 ] = {};
     std::size_t m_ = 0; // == n_ % 32
 
     std::uint64_t n_ = 0;
 
 private:
 
     BOOST_CXX14_CONSTEXPR void init( std::uint64_t seed )
     {
         v1_ = seed + P1 + P2;
         v2_ = seed + P2;
         v3_ = seed;
         v4_ = seed - P1;
     }
 
     BOOST_CXX14_CONSTEXPR static std::uint64_t round( std::uint64_t seed, std::uint64_t input )
     {
         seed += input * P2;
         seed = detail::rotl( seed, 31 );
         seed *= P1;
         return seed;
     }
 
     BOOST_CXX14_CONSTEXPR static std::uint64_t merge_round( std::uint64_t acc, std::uint64_t val )
     {
         val = round( 0, val );
         acc ^= val;
         acc = acc * P1 + P4;
         return acc;
     }
 
     BOOST_CXX14_CONSTEXPR void update_( unsigned char const * p, std::size_t k )
     {
         std::uint64_t v1 = v1_;
         std::uint64_t v2 = v2_;
         std::uint64_t v3 = v3_;
         std::uint64_t v4 = v4_;
 
         for( std::size_t i = 0; i < k; ++i, p += 32 )
         {
             v1 = round( v1, detail::read64le( p +  0 ) );
             v2 = round( v2, detail::read64le( p +  8 ) );
             v3 = round( v3, detail::read64le( p + 16 ) );
             v4 = round( v4, detail::read64le( p + 24 ) );
         }
 
         v1_ = v1; 
         v2_ = v2; 
         v3_ = v3; 
         v4_ = v4; 
     }
 
 public:
 
     typedef std::uint64_t result_type;
 
     xxhash_64() = default;
 
     BOOST_CXX14_CONSTEXPR explicit xxhash_64( std::uint64_t seed )
     {
         init( seed );
     }
 
     BOOST_CXX14_CONSTEXPR xxhash_64( unsigned char const * p, std::size_t n )
     {
         if( n != 0 )
         {
             update( p, n );
             result();
         }
     }
 
     xxhash_64( void const * p, std::size_t n ): xxhash_64( static_cast<unsigned char const*>( p ), n )
     {
     }
 
     BOOST_CXX14_CONSTEXPR void update( unsigned char const* p, std::size_t n )
     {
         BOOST_ASSERT( m_ == n_ % 32 );
 
         if( n == 0 ) return;
 
         n_ += n;
 
         if( m_ > 0 )
         {
             std::size_t k = 32 - m_;
 
             if( n < k )
             {
                 k = n;
             }
 
             detail::memcpy( buffer_ + m_, p, k );
 
             p += k;
             n -= k;
             m_ += k;
 
             if( m_ < 32 ) return;
 
             BOOST_ASSERT( m_ == 32 );
 
             update_( buffer_, 1 );
             m_ = 0;
         }
 
         BOOST_ASSERT( m_ == 0 );
 
         {
             std::size_t k = n / 32;
 
             update_( p, k );
 
             p += 32 * k;
             n -= 32 * k;
         }
 
         BOOST_ASSERT( n < 32 );
 
         if( n > 0 )
         {
             detail::memcpy( buffer_, p, n );
             m_ = n;
         }
 
         BOOST_ASSERT( m_ == n_ % 32 );
     }
 
     void update( void const* pv, std::size_t n )
     {
         unsigned char const* p = static_cast<unsigned char const*>( pv );
         update( p, n );
     }
 
     BOOST_CXX14_CONSTEXPR std::uint64_t result()
     {
         BOOST_ASSERT( m_ == n_ % 32 );
 
         std::uint64_t h = 0;
 
         if( n_ >= 32 )
         {
             h = detail::rotl( v1_, 1 ) + detail::rotl( v2_, 7 ) + detail::rotl( v3_, 12 ) + detail::rotl( v4_, 18 );
 
             h = merge_round( h, v1_ );
             h = merge_round( h, v2_ );
             h = merge_round( h, v3_ );
             h = merge_round( h, v4_ );
         }
         else
         {
             h = v3_ + P5;
         }
 
         h += n_;
 
         unsigned char const * p = buffer_;
 
         std::size_t m = m_;
 
         while( m >= 8 )
         {
             std::uint64_t k1 = round( 0, detail::read64le( p ) );
 
             h ^= k1;
             h = detail::rotl( h, 27 ) * P1 + P4;
 
             p += 8;
             m -= 8;
         }
 
         while( m >= 4 )
         {
             h ^= static_cast<std::uint64_t>( detail::read32le( p ) ) * P1;
             h = detail::rotl( h, 23 ) * P2 + P3;
 
             p += 4;
             m -= 4;
         }
 
         while( m > 0 )
         {
             h ^= p[0] * P5;
             h = detail::rotl( h, 11 ) * P1;
 
             ++p;
             --m;
         }
 
         n_ += 32 - m_;
         m_ = 0;
 
         // clear buffered plaintext
         detail::memset( buffer_, 0, 32 );
 
         // perturb state
         v1_ += h;
         v2_ += h;
         v3_ -= h;
         v4_ -= h;
 
         // apply final mix
         h ^= h >> 33;
         h *= P2;
         h ^= h >> 29;
         h *= P3;
         h ^= h >> 32;
 
         return h;
     }
 };
 
 } // namespace hash2
 } // namespace boost
 
 #if defined(BOOST_MSVC) && BOOST_MSVC < 1920
 # pragma warning(pop)
 #endif
 
 #endif // #ifndef BOOST_HASH2_XXHASH_HPP_INCLUDED

This page was automatically generated by the 2.3.7 LXR engine. The LXR team