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// Copyright 2008, Google Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// 3. Neither the name of Google Inc. nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
// EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This example shows how KmlStream is used with a ParserObserver. Given that
// the ParserObserver inhibits adding Features to the DOM this program can be
// used to scan extremely large files such as those where DOM representation
// would exceed available memmory.
#include <fstream>
#include <iostream>
#include "kml/dom.h"
#include "kml/engine.h"
using kmldom::AsFeature;
using kmldom::ElementPtr;
using kmldom::FeaturePtr;
using kmldom::KmlFactory;
using kmldom::LatLonBoxPtr;
using kmldom::SerializePretty;
using kmlengine::Bbox;
using kmlengine::GetFeatureLatLon;
using kmlengine::KmlStream;
// This ParserObserver inhibits adding of any Feature to the DOM. A bounding
// box of all features is maintained.
class FeatureStreamer : public kmldom::ParserObserver {
public:
FeatureStreamer()
: feature_count_(0) {
}
// ParserObserver::EndElement()
virtual bool EndElement(const ElementPtr& parent, const ElementPtr& child) {
if (FeaturePtr feature = AsFeature(child)) {
// This is roughly 1hz in a 2 ghz MacBook.
if (++feature_count_ % 10000 == 0 ) {
std::cout << feature_count_ << " " << feature->get_name();
std::cout << std::endl;
}
GetFeatureBounds(feature, &bbox_);
// Do not add this feature to the DOM (note that this discards both
// <Documents> and <Folders>).
return false;
}
// Preserve all other parent-child relationships (such as those _within_
// a feature such as the Point child of Placemark and coordinates child
// of Point as expected in GetFeatureLatLon).
return true;
}
const Bbox& get_bbox() const {
return bbox_;
}
int get_feature_count() const {
return feature_count_;
}
private:
Bbox bbox_;
int feature_count_;
};
void StreamKml(std::istream* input) {
FeatureStreamer feature_streamer;
std::string errors;
boost::scoped_ptr<KmlStream> kml_stream(
KmlStream::ParseFromIstream(input, &errors, &feature_streamer));
if (!kml_stream.get()) {
std::cerr << "KmlStream error " << errors << std::endl;
return;
}
std::cout << "Streamed parse completed, ";
std::cout << feature_streamer.get_feature_count() << " features";
std::cout << std::endl;
// Emit the bounding box as KML.
KmlFactory* kml_factory = KmlFactory::GetFactory();
LatLonBoxPtr llab = kml_factory->CreateLatLonBox();
const Bbox& bbox = feature_streamer.get_bbox();
llab->set_north(bbox.get_north());
llab->set_south(bbox.get_south());
llab->set_east(bbox.get_east());
llab->set_west(bbox.get_west());
std::cout << SerializePretty(llab);
}
int main(int argc, char** argv) {
if (argc != 2) {
std::cerr << "usage: " << argv[0] << " huge.kml" << std::endl;
return 1;
}
const char* filename = argv[1];
std::ifstream input_file(filename, std::ios_base::in|std::ios_base::binary);
if (!input_file.is_open() || !input_file.good()) {
std::cerr << "open failed: " << filename << std::endl;
return 1;
}
StreamKml(&input_file);
}
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