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geojson.input - geometry_type for disk-index

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This commit is contained in:
artemp 2015-10-16 17:31:36 +01:00
parent 097289ac3d
commit 4733c7ffc1
1 changed files with 42 additions and 0 deletions
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42
plugins/input/geojson/geojson_datasource.cpp
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@ -442,7 +442,49 @@ boost::optional<mapnik::datasource_geometry_t> geojson_datasource::get_geometry_
int multi_type = 0;
if (has_disk_index_)
{
using value_type = std::pair<std::size_t, std::size_t>;
std::ifstream index(filename_ + ".index", std::ios::binary);
if (!index) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + ".index'");
mapnik::filter_in_box filter(extent_);
std::vector<value_type> positions;
mapnik::util::spatial_index<value_type,
mapnik::filter_in_box,
std::ifstream>::query_first_n(filter, index, positions, 5);
mapnik::util::file file(filename_);
if (!file.open()) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
for (auto const& pos : positions)
{
std::fseek(file.get(), pos.first, SEEK_SET);
std::vector<char> record;
record.resize(pos.second);
std::fread(record.data(), pos.second, 1, file.get());
auto const* start = record.data();
auto const* end = start + record.size();
mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx,1));
using namespace boost::spirit;
standard::space_type space;
if (!boost::spirit::qi::phrase_parse(start, end,
(geojson_datasource_static_feature_grammar)(boost::phoenix::ref(*feature)), space)
|| start != end)
{
throw std::runtime_error("Failed to parse geojson feature");
}
result = mapnik::util::to_ds_type(feature->get_geometry());
if (result)
{
int type = static_cast<int>(*result);
if (multi_type > 0 && multi_type != type)
{
result.reset(mapnik::datasource_geometry_t::Collection);
return result;
}
multi_type = type;
}
}
}
else if (cache_features_)
{