IndexSet.hpp

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//
//  CeresEngine - A game development framework
//
//  Created by Rogiel Sulzbach.
//  Copyright (c) 2018-2022 Rogiel Sulzbach. All rights reserved.
//
 
// Based on https://github.com/TheLartians/IndexSet
 
#pragma once
 
#pragma once
 
#include "BitView.hpp"
 
#include "CeresEngine/DataTypes.hpp"
 
#include "CeresEngine/Foundation/Iterator.hpp"
#include "CeresEngine/Foundation/Container/Vector.hpp"
 
#include <ostream>
 
namespace CeresEngine {
 
    struct IndexSet {
    public:
        using Data = Vector<UInt32>;
        using Bits = BitView<Data>;
        using ConstBits = BitView<const Data>;
        using Index = std::size_t;
 
        struct IndexIterator : public InitializedIterable {
            Index current, max;
            ConstBits bits;
            IndexIterator(const IndexSet::Index c, const IndexSet::Index m, const IndexSet::ConstBits b) : current(c), max(m), bits(b) {}
 
            void fit() {
                while(current != max && !bits[current])
                    ++current;
            }
 
            [[nodiscard]] bool init() {
                fit();
                return current != max;
            }
 
            [[nodiscard]] bool advance() {
                ++current;
                fit();
                return current != max;
            }
 
            [[nodiscard]] IndexSet::Index value() const { return current; }
        };
 
    private:
        Data mData;
        void tighten();
 
    public:
        [[nodiscard]] Bits getBitView();
        [[nodiscard]] ConstBits getBitView() const;
 
        void ensureFits(Index idx);
 
        [[nodiscard]] bool hasIndex(Index idx) const;
        void addIndex(Index idx);
        void removeIndex(Index idx);
 
        void add(const IndexSet& other);
        void remove(const IndexSet& other);
        void intersect(const IndexSet& other);
        void clear();
 
        [[nodiscard]] size_t upperBound() const;
        [[nodiscard]] bool isEmpty() const;
        [[nodiscard]] size_t count() const;
 
        [[nodiscard]] bool operator==(const IndexSet&) const;
        [[nodiscard]] bool operator!=(const IndexSet&) const;
 
        [[nodiscard]] auto indices() const { return MakeIterable<IndexIterator>(0, upperBound(), getBitView()); }
    };
 
    [[nodiscard]] IndexSet createIndexSetFromIndex(IndexSet::Index idx);
    [[nodiscard]] IndexSet createIndexSetFromIndices(const Vector<IndexSet::Index>& input);
    std::ostream& operator<<(std::ostream&, const IndexSet&);
 
} // namespace CeresEngine