//---------------------------------------------------------------------------// // Copyright (c) 2013-2014 Kyle Lutz // // Distributed under the Boost Software License, Version 1.0 // See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt // // See http://boostorg.github.com/compute for more information. //---------------------------------------------------------------------------// #ifndef BOOST_COMPUTE_FUNCTIONAL_HASH_HPP #define BOOST_COMPUTE_FUNCTIONAL_HASH_HPP #include #include namespace boost { namespace compute { namespace detail { template std::string make_hash_function_name() { return std::string("boost_hash_") + type_name(); } template inline std::string make_hash_function_source() { std::stringstream source; source << "inline ulong " << make_hash_function_name() << "(const " << type_name() << " x)\n" << "{\n" // note we reinterpret the argument as a 32-bit uint and // then promote it to a 64-bit ulong for the result type << " ulong a = as_uint(x);\n" << " a = (a ^ 61) ^ (a >> 16);\n" << " a = a + (a << 3);\n" << " a = a ^ (a >> 4);\n" << " a = a * 0x27d4eb2d;\n" << " a = a ^ (a >> 15);\n" << " return a;\n" << "}\n"; return source.str(); } template struct hash_impl { typedef Key argument_type; typedef ulong_ result_type; hash_impl() : m_function("") { m_function = make_function_from_source( make_hash_function_name(), make_hash_function_source() ); } template invoked_function > operator()(const Arg &arg) const { return m_function(arg); } function m_function; }; } // end detail namespace /// The hash function returns a hash value for the input value. /// /// The return type is \c ulong_ (the OpenCL unsigned long type). template struct hash; /// \internal_ template<> struct hash : detail::hash_impl { }; /// \internal_ template<> struct hash : detail::hash_impl { }; /// \internal_ template<> struct hash : detail::hash_impl { }; } // end compute namespace } // end boost namespace #endif // BOOST_COMPUTE_FUNCTIONAL_HASH_HPP