multiple_variant_iterator.h

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#ifndef gamgee__multiple_variant_iterator__guard
#define gamgee__multiple_variant_iterator__guard

#include "htslib/vcf.h"

#include "variant.h"
#include "variant_iterator.h"

#include <memory>
#include <queue>

namespace gamgee {

using VariantIteratorIndexPair = std::pair<std::shared_ptr<VariantIterator>, uint32_t>;
using VariantIndexPair = std::pair<Variant, uint32_t>;

class MultipleVariantIterator {
 public:

  MultipleVariantIterator() = default;

  MultipleVariantIterator(const std::vector<std::shared_ptr<htsFile>>& variant_files, const std::vector<std::shared_ptr<bcf_hdr_t>>& variant_headers);

  MultipleVariantIterator(MultipleVariantIterator&&) = default;
  MultipleVariantIterator& operator=(MultipleVariantIterator&& other) = default;

  MultipleVariantIterator(const MultipleVariantIterator&) = delete;
  MultipleVariantIterator& operator=(const MultipleVariantIterator& other) = delete;

  bool operator!=(const MultipleVariantIterator& rhs);

  std::vector<VariantIndexPair>& operator*();

  std::vector<VariantIndexPair>& operator++();

 private:
  // fetches the next Variant vector
  void fetch_next_vector();

  // comparison class for genomic locations in the priority queue
  class Comparator {
   public:
    bool operator()(const VariantIteratorIndexPair& left, const VariantIteratorIndexPair& right);
  };

  // the individual file iterators
  std::priority_queue<VariantIteratorIndexPair, std::vector<VariantIteratorIndexPair>, Comparator> m_queue;

  // caches next Variant vector
  std::vector<VariantIndexPair> m_variant_vector;
};

}  // end namespace gamgee

#endif  // gamgee__multiple_variant_iterator__guard