Basic usage of boot multi index container

cpp_boost_multi_index_container_basic.cpp

#include <iostream>
#include <string>
#include <boost/filesystem.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/composite_key.hpp>
#include <boost/multi_index/ordered_index.hpp>

using namespace std;

int main()
{
    struct Video
	{
		uint64_t start_ts, end_ts;
		std::string path = "";

		Video(std::string &_path , uint64_t _start_ts) : path(_path), start_ts(_start_ts) {}
		Video(std::string _path, uint64_t _start_ts, uint64_t _end_ts) : path(_path), start_ts(_start_ts), end_ts(_end_ts) {}

		/* this operators can be used to order the default index 
		bool operator<(const employee& e)const { return id < e.id; } */

		/* returns the length of the name field - can be used to order indices
		std::size_t name_length()const { return name.size(); } */
	};

	using namespace boost::multi_index;
	
	// tags
	struct videoPath {};
	struct videoTS {};

	// define the multi index 
	typedef boost::multi_index_container< 
		Video,
		indexed_by<
		// sort by less<string> on path
		ordered_unique<tag<videoPath>, member<Video, std::string, &Video::path> >,

		// sort by less<int> on videoTS
		ordered_non_unique<tag<videoTS>, member<Video, uint64_t, &Video::start_ts> >
		>
	> VideoCache;

	// create the actual object
	VideoCache cache;

	// insert
	Video sample("c:/data/100.mp4", 100, 150);
	cache.insert(sample);
	Video sample1("c:/data/200.mp4", 200, 250);
	cache.insert(sample1);
	Video sample2("c:/data/300.mp4", 300, 350);
	cache.insert(sample2);

	// count
	VideoCache::index<videoTS>::type& videoTSIndex = cache.get<videoTS>();
	std::cout << "100 startTS count " << videoTSIndex.count(100)<< "\n";
	std::cout << "100.mp4 count " << cache.count("c:/data/100.mp4")<< "\n";
	std::cout << "300.mp4 count " << cache.count("c:/data/300.mp4")<< "\n";
	std::cout << "200.mp4 count " << cache.count("c:/data/200.mp4")<< "\n";

	// bound / range search operations
	int val = 100;
	// iterator to elem not less than val
	auto lb = videoTSIndex.lower_bound(val); 
	std::cout << "lower bound <" << lb->path << "," << lb->start_ts << "," << lb->end_ts << ">\n";
	std::cout << "prev elem: it is starting elem <" << bool(lb == videoTSIndex.begin()) << ">\n";

	/* upper bound - iter to elem greater than val - not required for our application
	auto ub = videoTSIndex.upper_bound(val); */

	val = 200;
	lb = videoTSIndex.lower_bound(val);
	std::cout << "lower bound <" << lb->path << "," << lb->start_ts << "," << lb->end_ts << ">\n";
	auto prev = --lb;
	std::cout << "prev elem <" << prev->path << "," << prev->start_ts << "," << prev->end_ts << ">\n";

	val = 250;
	lb = videoTSIndex.lower_bound(val);
	std::cout << "lower bound <" << lb->path << "," << lb->start_ts << "," << lb->end_ts << ">\n";
	prev = --lb;
	std::cout << "prev elem <" << prev->path << "," << prev->start_ts << "," << prev->end_ts << ">\n";

	// search
	std::cout << "Searching for 200 <" << bool(videoTSIndex.find(200) == videoTSIndex.end()) << ">\n";
	std::cout << "Searching for 250 <" << bool(videoTSIndex.find(250) == videoTSIndex.end()) << ">\n";

	// lower bound based on path
	std::string tempPath = "c:/data/250.mp4";
	auto lb2 = cache.lower_bound(tempPath);
	std::cout << "lower bound <" << lb2->path << "," << lb2->start_ts << "," << lb2->end_ts << ">\n";
	auto prev2 = --lb2;
	std::cout << "prev elem <" << prev2->path << "," << prev2->start_ts << "," << prev2->end_ts << ">\n";
}