realm-js/index_set.hpp

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2015 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////

#ifndef REALM_INDEX_SET_HPP
#define REALM_INDEX_SET_HPP

#include <cstdlib>
#include <vector>

namespace realm {
class IndexSet {
public:
    using value_type = std::pair<size_t, size_t>;
    using iterator = std::vector<value_type>::iterator;
    using const_iterator = std::vector<value_type>::const_iterator;

    const_iterator begin() const { return m_ranges.begin(); }
    const_iterator end() const { return m_ranges.end(); }
    bool empty() const { return m_ranges.empty(); }
    size_t size() const { return m_ranges.size(); }

    // Add an index to the set, doing nothing if it's already present
    void add(size_t index);

    // Remove all indexes from the set and then add a single range starting from
    // zero with the given length
    void set(size_t len);

    // Insert an index at the given position, shifting existing indexes at or
    // after that point back by one
    void insert_at(size_t index);

    // Add an index which has had all of the ranges in the set before it removed
    void add_shifted(size_t index);

private:
    std::vector<value_type> m_ranges;

    // Find the range which contains the index, or the first one after it if
    // none do
    iterator find(size_t index);
    // Insert the index before the given position, combining existing ranges as
    // applicable
    void do_add(iterator pos, size_t index);
};
} // namespace realm

#endif // REALM_INDEX_SET_HPP