InMemoryRegionsProvider.h

/*--------------------------------------------------------------------------------------------
Copyright (c) 2026, NDEVR LLC
tyler.parke@ndevr.org
 *-----------------------------------------------------------------------------------------**/
#pragma once
#include "DLLInfo.h"
#include <NDEVR/BaseValues.h>
#include <NDEVR/Dictionary.h>
 
// OpenMVG
#include <openMVG/sfm/pipelines/sfm_regions_provider.hpp>
#include <openMVG/features/regions.hpp>
#include <openMVG/matching/indMatch.hpp>
#include <openMVG/matching/indMatchDecoratorXY.hpp>
#include <openMVG/sfm/pipelines/sfm_matches_provider.hpp>
 
#include <memory>
 
namespace NDEVR
{
    // No DRONE_PHOTOGRAMMETRY_API: inherits from a non-DLL openMVG type (C4275).
    // This class is used only internally via shared_ptr and never exported directly.
    class InMemoryRegionsProvider
        : public openMVG::sfm::Regions_Provider
    {
    public:
        InMemoryRegionsProvider() = default;

        void add(openMVG::IndexT view_id,
            std::unique_ptr<openMVG::features::Regions> regions)
        {
            // Set the base-class region_type_ once so the non-virtual Type_id() / IsBinary()
            // / IsScalar() methods return the correct values.  Cascade_Hashing_Matcher_Regions
            // calls Type_id() to decide whether to dispatch to impl::Match<float> or
            // impl::Match<unsigned char>; leaving region_type_ null causes it to fall into the
            // "not implemented" branch and produce 0 matches.
            if (!region_type_)
                region_type_.reset(regions->EmptyClone());
            cache_[view_id] = std::shared_ptr<openMVG::features::Regions>(std::move(regions));
        }

        std::shared_ptr<openMVG::features::Regions>
            get(const openMVG::IndexT x) const override
        {
            auto it = cache_.find(x);
            return (it != cache_.end()) ? it->second : nullptr;
        }

        uint04 viewCount() const
        {
            return static_cast<uint04>(cache_.size());
        }
 
    private:
        // openMVG's Regions_Provider already declares the map; we shadow it here with a
        // direct std::unordered_map for O(1) lookup by view ID.
        std::unordered_map<openMVG::IndexT,
            std::shared_ptr<openMVG::features::Regions>> cache_;
    };

    // No DRONE_PHOTOGRAMMETRY_API: same reason as InMemoryRegionsProvider (C4275).
    class InMemoryMatchesProvider
        : public openMVG::sfm::Matches_Provider
    {
    public:
        InMemoryMatchesProvider() = default;

        void setMatches(openMVG::matching::PairWiseMatches matches)
        {
            pairWise_matches_ = std::move(matches);
        }

        bool load(const openMVG::sfm::SfM_Data&, const std::string&) override
        {
            return true; // already in memory, nothing to load
        }
    };
}