Re: [Boost-users] [hash] hash returning fixed width integer instead of size_t?

20 May 2011

      2011/5/20 Frédéric Bron :
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No sorry it isn't. If you're just hashing strings, you might want to
try the 32 bit version of murmurhash3:
No I am hashing strings and double so I have copied the boost code and
replaced size_t by boost::uint32_t. Works fine.
The hash type could be a template parameter, couldn't it?
Not really, since the hashing is done by 'hash_value' which can be user defined.

I'm not sure if this is a good idea, but I could use another parameter
to specify the hash type. Might have odd consequences for ADL.
Something like:

// Default to using the std::size_t version.
template < typename T, typename HashType>
HashType hash_value(T const& value, HashType*)
{
    return hash_value(value);
}

template <typename HashType>
HashType hash_value(double value, HashType* hash_type)
{
    return boost::hash_detail::float_hash_value(value, hash_type);
}

template <typename HashType>
HashType hash_value(long value, HashType*)
{
    return static_cast<HashType>(value);
}

// etc.

Re: [Boost-users] [hash] hash returning fixed width integer instead of size_t?

Daniel James