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Update xxh3_128::result() to fix result extension

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This commit is contained in:
Peter Dimov
2025-04-29 19:05:11 +03:00
parent 5adcda338d
commit e8e817ea14
1 changed files with 23 additions and 14 deletions
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37
include/boost/hash2/xxh3.hpp
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@@ -622,6 +622,9 @@ public:
if( n_ == 0 )
{
r = xxh3_128_digest_empty();
// perturb state to enable result extension
seed_ += P64_5;
}
else if( n_ < 4 )
{
@@ -646,26 +649,32 @@ public:
else
{
r = xxh3_128_digest_long();
// perturb state to enable result extension
acc_[ 0 ] -= P64_1;
acc_[ 1 ] += P64_1;
acc_[ 2 ] -= P64_2;
acc_[ 3 ] += P64_2;
acc_[ 4 ] -= P64_3;
acc_[ 5 ] += P64_3;
acc_[ 6 ] -= P64_4;
acc_[ 7 ] += P64_4;
}
detail::memset( buffer_, 0, buffer_size );
// finalize buffer to clear plainext and enable result extension
// perturb state to enable result extension
{
std::uint64_t h1 = detail::read64le( r.data() + 0 );
std::uint64_t h2 = detail::read64le( r.data() + 8 );
// short string state
std::uint64_t v1 = detail::read64le( buffer_ + 0 );
detail::write64le( buffer_ + 0, v1 + h1 );
seed_ += P64_5;
std::uint64_t v2 = detail::read64le( buffer_ + 8 );
detail::write64le( buffer_ + 8, v2 + h2 );
// long string state
acc_[ 0 ] -= P64_1;
acc_[ 1 ] += P64_1;
acc_[ 2 ] -= P64_2;
acc_[ 3 ] += P64_2;
acc_[ 4 ] -= P64_3;
acc_[ 5 ] += P64_3;
acc_[ 6 ] -= P64_4;
acc_[ 7 ] += P64_4;
detail::memset( buffer_ + 16, 0, buffer_size - 16 );
}
return r;
}