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#ifndef VTZERO_PROPERTY_MAPPER_HPP
#define VTZERO_PROPERTY_MAPPER_HPP
/*****************************************************************************
vtzero - Tiny and fast vector tile decoder and encoder in C++.
This file is from https://github.com/mapbox/vtzero where you can find more
documentation.
*****************************************************************************/
/**
* @file property_mapper.hpp
*
* @brief Contains the property_mapper class.
*/
#include "builder.hpp"
#include "layer.hpp"
#include <vector>
namespace vtzero {
/**
* Establishes a mapping between index values of properties of an existing
* layer and a new layer. Can be used when copying some features from an
* existing layer to a new layer.
*/
class property_mapper {
const layer& m_layer;
layer_builder& m_layer_builder;
std::vector<index_value> m_keys;
std::vector<index_value> m_values;
public:
/**
* Construct the mapping between the specified layers
*
* @param layer The existing layer from which (some) properties will
* be copied.
* @param layer_builder The new layer that is being created.
*/
property_mapper(const layer& layer, layer_builder& layer_builder) :
m_layer(layer),
m_layer_builder(layer_builder) {
m_keys.resize(layer.key_table().size());
m_values.resize(layer.value_table().size());
}
/**
* Map the value index of a key.
*
* @param index The value index of the key in the existing table.
* @returns The value index of the same key in the new table.
*/
index_value map_key(index_value index) {
auto& k = m_keys[index.value()];
if (!k.valid()) {
k = m_layer_builder.add_key_without_dup_check(m_layer.key(index));
}
return k;
}
/**
* Map the value index of a value.
*
* @param index The value index of the value in the existing table.
* @returns The value index of the same value in the new table.
*/
index_value map_value(index_value index) {
auto& v = m_values[index.value()];
if (!v.valid()) {
v = m_layer_builder.add_value_without_dup_check(m_layer.value(index));
}
return v;
}
/**
* Map the value indexes of a key/value pair.
*
* @param idxs The value indexes of the key/value pair in the existing
* table.
* @returns The value indexes of the same key/value pair in the new
* table.
*/
index_value_pair operator()(index_value_pair idxs) {
return {map_key(idxs.key()), map_value(idxs.value())};
}
}; // class property_mapper
} // namespace vtzero
#endif // VTZERO_PROPERTY_MAPPER_HPP
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