/*

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 */

// -*- c++ -*-

#ifndef INDEX_BINARY_FLAT_H

#define INDEX_BINARY_FLAT_H

#include <vector>

#include <faiss/IndexBinary.h>

#include <faiss/impl/maybe_owned_vector.h>

#include <faiss/utils/approx_topk/mode.h>

namespace faiss {

/** Index that stores the full vectors and performs exhaustive search. */

struct IndexBinaryFlat : IndexBinary {

    /// database vectors, size ntotal * d / 8

    MaybeOwnedVector<uint8_t> xb;

    /** Select between using a heap or counting to select the k smallest values

     * when scanning inverted lists.

     */

    bool use_heap = true;

    size_t query_batch_size = 32;

    ApproxTopK_mode_t approx_topk_mode = ApproxTopK_mode_t::EXACT_TOPK;

    explicit IndexBinaryFlat(idx_t d);

    void add(idx_t n, const uint8_t* x) override;

    void reset() override;

    void search(

            idx_t n,

            const uint8_t* x,

            idx_t k,

            int32_t* distances,

            idx_t* labels,

            const SearchParameters* params = nullptr) const override;

    void range_search(

            idx_t n,

            const uint8_t* x,

            int radius,

            RangeSearchResult* result,

            const SearchParameters* params = nullptr) const override;

    void reconstruct(idx_t key, uint8_t* recons) const override;

    /** Remove some ids. Note that because of the indexing structure,

     * the semantics of this operation are different from the usual ones:

     * the new ids are shifted. */

    size_t remove_ids(const IDSelector& sel) override;

    IndexBinaryFlat() {}

};

} // namespace faiss

#endif // INDEX_BINARY_FLAT_H