include/ds/BitArray.h


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/*
 * include/ds/BitArray.h
 *
 * Copyright (C) 2023 Dong Xie <dongx@psu.edu>
 *
 * All rights reserved. Published under the Modified BSD License.
 *
 */
#pragma once

#include <cstdlib>
#include <memory>
#include <cstring>

#include "util/base.h"

namespace de {

class BitArray {
public:
    BitArray(size_t bits): m_bits(bits), m_data(nullptr) {
        if (m_bits > 0) {
            size_t n_bytes = (m_bits >> 3) << 3;
            m_data = (char*) std::aligned_alloc(CACHELINE_SIZE, CACHELINEALIGN(n_bytes));
            memset(m_data, 0, n_bytes);
        }
    }

    ~BitArray() {
        if (m_data) free(m_data);
    }

    bool is_set(size_t bit) {
        if (bit >= m_bits) return false;
        return m_data[bit >> 3] & (1 << (bit & 7));
    }

    int set(size_t bit) {
        if (bit >= m_bits) return 0;
        m_data[bit >> 3] |= ((char) 1 << (bit & 7));
        return 1;
    }

    int unset(size_t bit) {
        if (bit >= m_bits) return 0;
        m_data[bit >> 3] &= ~((char) 1 << (bit & 7));
        return 1;
    }

    void clear() {
        memset(m_data, 0, (m_bits >> 3) << 3);
    }

    size_t mem_size() {
        return m_bits >> 3;
    }

    size_t size() {
        return m_bits;
    }
    
private:
    size_t m_bits;
    char* m_data;
};

}