boost::multi_index_container, operations on std::set inside container

Question

I\'ve created a boost::multi_index_container (containerSet) over a container class and indexed the containerSet by std::string and

Answer 1

Andrew diagnosed the issue quite accutely.

To help you along, let me advertise a widely under-used library in Boost: Boost Interval Container.

I hope this demo can shed some light on how useful Boost ICL can be.

Live On Coliru

#include <boost/icl/separate_interval_set.hpp>
#include <boost/icl/interval_map.hpp>

#include <boost/multi_index_container.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/member.hpp>

#include <iostream>
#include <numeric>
#include <vector>

using Set = std::set<int>;

struct io_wrap { Set const& ref; };
static std::ostream& operator<<(std::ostream& os,const io_wrap& s) { os << "[ "; for (auto i : s.ref) os << i << " "; return os << ']'; }

namespace icl = boost::icl;
namespace bmi = boost::multi_index;

struct Record {
    std::string name;
    Set set;

    Record(std::string name = "noName", Set set = {}) : name{name}, set{set} {}

    friend std::ostream& operator<<(std::ostream& os,const Record& c) { return os << c.name << ", " << io_wrap{c.set}; }
};

using Map      = icl::interval_map<int, std::set<Record const*> >;
using Interval = Map::interval_type;
using Table    = bmi::multi_index_container<
         std::reference_wrapper<Record>,
         bmi::indexed_by<
             bmi::ordered_unique<
                bmi::tag<struct byName>,
                bmi::member<Record, std::string, &Record::name>
             >
         >
     >;

auto interval_set(Set const& is) { return std::accumulate(is.begin(), is.end(), icl::interval_set<int> { } ); }
auto envelope(Record const& r)   { return hull(interval_set(r.set)); }

void insert(Map& into, Set const& is, std::set<Record const*> const& rs = {}) {
    for (auto i : interval_set(is))
        into += Map::value_type { i, rs };
}

int main() {

    ////////////////////////////////
    // Prepare data
    std::vector<Record> backing_storage {
        {"c3", {2, 3, 9, 10, 65, 75, 91}},
        {"c1", {5, 6, 7, 18, 61, 77}},
        {"c2", {2, 4, 5, 21, 36, 88, 99}},
        // outliers
        {"c4", {0}},
        {"c5", {200}},
    };

    Table const byname(backing_storage.begin(), backing_storage.end());
    Map cs;
    for (auto& r : backing_storage) 
        insert(cs, r.set, { &r });

    ////////////////////////////////
    // Usage demos
    std::cout << "print by name (ordered)\n";
    for (auto const& e : byname) { std::cout << " - " << e << " - envelope: " << envelope(e) << "\n"; }
    std::cout << "\n";

    auto perform_match = [&cs](auto key) {
        Map::codomain_type matches;
        Map::codomain_combine combine;

        for (auto p : cs & key)
            combine(matches, p.second);

        std::cout << "matching " << key << ":\n";
        for (auto const* r : matches)
            std::cout << " - " << *r << "\n";
        std::cout << "\n";
    };

    for (auto key : { Set{2}, {99}, {2,99}, {2,99,5} }) {
        perform_match(interval_set(key));
    }

    perform_match(Interval::right_open(70, 81));
}

Prints:

print by name (ordered)
 - c1, [ 5 6 7 18 61 77 ] - envelope: [5,77]
 - c2, [ 2 4 5 21 36 88 99 ] - envelope: [2,99]
 - c3, [ 2 3 9 10 65 75 91 ] - envelope: [2,91]
 - c4, [ 0 ] - envelope: [0,0]
 - c5, [ 200 ] - envelope: [200,200]

matching {[2,2]}:
 - c3, [ 2 3 9 10 65 75 91 ]
 - c2, [ 2 4 5 21 36 88 99 ]

matching {[99,99]}:
 - c2, [ 2 4 5 21 36 88 99 ]

matching {[2,2][99,99]}:
 - c3, [ 2 3 9 10 65 75 91 ]
 - c2, [ 2 4 5 21 36 88 99 ]

matching {[2,2][5,5][99,99]}:
 - c3, [ 2 3 9 10 65 75 91 ]
 - c1, [ 5 6 7 18 61 77 ]
 - c2, [ 2 4 5 21 36 88 99 ]

matching [70,81):
 - c3, [ 2 3 9 10 65 75 91 ]
 - c1, [ 5 6 7 18 61 77 ]