mapnik/include/mapnik/symbolizer_hash.hpp
artemp 18554ec0b1 remove static_visitor usage and rely on automatic result type deduction
(NOTE: expression_evaluator requires  ```using result_type = T1;``` )

Conflicts:
	src/image.cpp
2015-01-07 11:39:06 +01:00

97 lines
2.5 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2014 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_SYMBOLIZER_HASH_HPP
#define MAPNIK_SYMBOLIZER_HASH_HPP
// mapnik
#include <mapnik/symbolizer_base.hpp>
#include <mapnik/util/variant.hpp>
// stl
#include <typeinfo>
#include <typeindex>
#include <functional>
namespace mapnik {
struct property_value_hash_visitor
{
std::size_t operator() (color const& val) const
{
return val.rgba();
}
std::size_t operator() (font_feature_settings const&) const
{
return 0; //FIXME
}
std::size_t operator() (transform_type const&) const
{
return 0; //FIXME
}
std::size_t operator() (enumeration_wrapper const&) const
{
return 0; //FIXME
}
std::size_t operator() (dash_array const&) const
{
return 0; //FIXME
}
template <typename T>
std::size_t operator() (T const& val) const
{
return std::hash<T>()(val);
}
};
struct symbolizer_hash
{
template <typename T>
static std::size_t value(T const& sym)
{
std::size_t seed = std::hash<std::type_index>()(typeid(sym));
for (auto const& prop : sym.properties)
{
seed ^= std::hash<std::size_t>()(static_cast<std::size_t>(prop.first));
seed ^= util::apply_visitor(property_value_hash_visitor(), prop.second);
}
return seed;
}
};
struct symbolizer_hash_visitor
{
template <typename Symbolizer>
std::size_t operator() (Symbolizer const& sym) const
{
return symbolizer_hash::value(sym);
}
};
} // namespace mapnik
#endif // MAPNIK_SYMBOLIZER_HASH_HPP