77 lines
2.1 KiB
C++
77 lines
2.1 KiB
C++
/*****************************************************************************
|
|
*
|
|
* This file is part of Mapnik (c++ mapping toolkit)
|
|
*
|
|
* Copyright (C) 2015 Artem Pavlenko
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*
|
|
*****************************************************************************/
|
|
|
|
#ifndef MAPNIK_VALUE_HASH_HPP
|
|
#define MAPNIK_VALUE_HASH_HPP
|
|
|
|
// mapnik
|
|
#include <mapnik/util/variant.hpp>
|
|
#include <mapnik/value_types.hpp>
|
|
|
|
// stl
|
|
#include <functional>
|
|
|
|
// icu
|
|
#include <unicode/unistr.h>
|
|
|
|
namespace mapnik { namespace detail {
|
|
|
|
template <class T>
|
|
inline void hash_combine(std::size_t & seed, T const& v)
|
|
{
|
|
std::hash<T> hasher;
|
|
seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
|
|
}
|
|
|
|
struct value_hasher
|
|
{
|
|
std::size_t operator() (value_null val) const
|
|
{
|
|
return hash_value(val);
|
|
}
|
|
|
|
std::size_t operator() (value_unicode_string const& val) const
|
|
{
|
|
return static_cast<std::size_t>(val.hashCode());
|
|
}
|
|
|
|
template <class T>
|
|
std::size_t operator()(T const& val) const
|
|
{
|
|
std::hash<T> hasher;
|
|
return hasher(val);
|
|
}
|
|
};
|
|
|
|
} // namespace detail
|
|
|
|
template <typename T>
|
|
std::size_t mapnik_hash_value(T const& val)
|
|
{
|
|
std::size_t seed = util::apply_visitor(detail::value_hasher(), val);
|
|
detail::hash_combine(seed, val.get_type_index());
|
|
return seed;
|
|
}
|
|
|
|
} // namespace mapnik
|
|
|
|
#endif // MAPNIK_VALUE_HASH_HPP
|