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Modified Jenkins hash to use frame_check_sequence classes.

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This commit is contained in:
jwellbelove 2016-11-16 13:04:04 +00:00
parent e5e3a6a4fc
commit 1171d7e555
1 changed files with 105 additions and 86 deletions
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191
src/jenkins.h
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@ -50,24 +50,96 @@ SOFTWARE.
namespace etl
{
//***************************************************************************
/// Calculates the jenkins hash.
///\ingroup jenkins
/// Jenkins32 policy.
/// Calculates 32 bit Jenkins hash.
//***************************************************************************
template <typename THash>
class jenkins
struct jenkins32_policy
{
typedef uint32_t value_type;
inline uint32_t initial() const
{
is_finalised = false;
return 0;
}
inline uint32_t add(uint8_t hash, uint8_t value) const
{
ETL_ASSERT(!is_finalised, ETL_ERROR(hash_finalised));
hash += value;
hash += (hash << 10);
hash ^= (hash >> 6);
return hash;
}
inline uint32_t final(uint8_t hash) const
{
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
is_finalised = true;
return hash;
}
bool is_finalised;
};
//***************************************************************************
/// Jenkins64 policy.
/// Calculates 32 bit Jenkins hash.
//***************************************************************************
struct jenkins64_policy
{
typedef uint64_t value_type;
inline uint64_t initial() const
{
is_finalised = false;
return 0;
}
inline uint64_t add(uint8_t hash, uint8_t value) const
{
ETL_ASSERT(!is_finalised, ETL_ERROR(hash_finalised));
hash += value;
hash += (hash << 10);
hash ^= (hash >> 6);
return hash;
}
inline uint64_t final(uint8_t hash) const
{
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
is_finalised = true;
return hash;
}
bool is_finalised;
};
//*************************************************************************
/// Jenkins32
//*************************************************************************
class jenkins32 : public etl::frame_check_sequence<etl::jenkins32_policy>
{
public:
STATIC_ASSERT((etl::is_same<THash, uint32_t>::value || etl::is_same<THash, uint64_t>::value), "Only 32 & 64 bit types supported");
typedef THash value_type;
//*************************************************************************
/// Default constructor.
//*************************************************************************
jenkins()
jenkins32()
{
reset();
this->reset();
}
//*************************************************************************
@ -76,92 +148,39 @@ namespace etl
/// \param end End of the range.
//*************************************************************************
template<typename TIterator>
jenkins(TIterator begin, const TIterator end)
jenkins32(TIterator begin, const TIterator end)
{
STATIC_ASSERT(sizeof(typename std::iterator_traits<TIterator>::value_type) == 1, "Incompatible type");
this->reset();
this->add(begin, end);
}
};
reset();
//*************************************************************************
/// Jenkins64
//*************************************************************************
class jenkins64 : public etl::frame_check_sequence<etl::jenkins64_policy>
{
public:
while (begin != end)
{
hash += *begin++;
hash += (hash << 10);
hash ^= (hash >> 6);
}
//*************************************************************************
/// Default constructor.
//*************************************************************************
jenkins64()
{
this->reset();
}
//*************************************************************************
/// Resets the CRC to the initial state.
//*************************************************************************
void reset()
{
hash = 0;
is_finalised = false;
}
//*************************************************************************
/// Adds a range.
/// \param begin
/// \param end
/// Constructor from range.
/// \param begin Start of the range.
/// \param end End of the range.
//*************************************************************************
template<typename TIterator>
void add(TIterator begin, const TIterator end)
jenkins64(TIterator begin, const TIterator end)
{
STATIC_ASSERT(sizeof(typename std::iterator_traits<TIterator>::value_type) == 1, "Incompatible type");
ETL_ASSERT(!is_finalised, ETL_ERROR(hash_finalised));
while (begin != end)
{
hash += *begin++;
hash += (hash << 10);
hash ^= (hash >> 6);
}
this->reset();
this->add(begin, end);
}
//*************************************************************************
/// \param value The char to add to the jenkins.
//*************************************************************************
void add(uint8_t value)
{
ETL_ASSERT(!is_finalised, ETL_ERROR(hash_finalised));
hash += value;
hash += (hash << 10);
hash ^= (hash >> 6);
}
//*************************************************************************
/// Gets the jenkins value.
//*************************************************************************
value_type value()
{
finalise();
return hash;
}
//*************************************************************************
/// Conversion operator to value_type.
//*************************************************************************
operator value_type ()
{
return value();
}
private:
void finalise()
{
if (!is_finalised)
{
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
is_finalised = true;
}
}
value_type hash;
bool is_finalised;
};
}